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2017 Volume 45 Issue 12
2017, 45(12): 1757-1765
doi: 10.11895/j.issn.0253-3820.171337
Abstract:
Aptamers are single-stranded oligonucleotides (DNA or RNA) selected through a technology termed "Systematic evolution of ligands by exponential enrichment" (SELEX). In addition to high affinity and high specificity for their target molecules, aptamers have some advantages such as low molecular weight, easy synthesis, high chemical stability, low immunogenicity, and convenient modification. Based on the Cell-SELEX technique, a panel of aptamers which can specifically recognize target cell lines has been generated. By targeting specific membrane proteins in their native state, these aptamers can identify subtle molecular differences among different cell lines, thus have attracted a broad interest in biomedical research. In this review, we summarized the development of aptamers and their use in detection, profiling and imaging of tumor cells. Also, their perspectives were discussed.
Aptamers are single-stranded oligonucleotides (DNA or RNA) selected through a technology termed "Systematic evolution of ligands by exponential enrichment" (SELEX). In addition to high affinity and high specificity for their target molecules, aptamers have some advantages such as low molecular weight, easy synthesis, high chemical stability, low immunogenicity, and convenient modification. Based on the Cell-SELEX technique, a panel of aptamers which can specifically recognize target cell lines has been generated. By targeting specific membrane proteins in their native state, these aptamers can identify subtle molecular differences among different cell lines, thus have attracted a broad interest in biomedical research. In this review, we summarized the development of aptamers and their use in detection, profiling and imaging of tumor cells. Also, their perspectives were discussed.
2017, 45(12): 1766-1775
doi: 10.11895/j.issn.0253-3820.171201
Abstract:
Nanopore technique is a low-cost, ultrafast method for single-molecule level analysis without labels. Nanopore technique was first proposed more than 20 years ago and exhibited an excellent potential in DNA sequencing. So far, the commercial development of nanopore strand-sequencing as a portable device has been realized. Meanwhile, a remarkable number of studies have demonstrated that nanopore represents versatile single-molecule sensors for a wide range of molecule. Therefore, in this article we mainly review the use of nanopore technique based on the interface interactions between biological pore and the analytes such as protein/peptide to obtain kinetic and thermodynamic information at single-molecule level. And a large number of biological molecules and metal ions are quantitatively detected by nanopore analysis, allowing its development for the future biotechnologies and medicine applications. Besides, electrochemical detection system is crucial to nanopore technique. Therefore, we focus on advancements in relative software and ultralow current instrumentations with high-bandwidth.
Nanopore technique is a low-cost, ultrafast method for single-molecule level analysis without labels. Nanopore technique was first proposed more than 20 years ago and exhibited an excellent potential in DNA sequencing. So far, the commercial development of nanopore strand-sequencing as a portable device has been realized. Meanwhile, a remarkable number of studies have demonstrated that nanopore represents versatile single-molecule sensors for a wide range of molecule. Therefore, in this article we mainly review the use of nanopore technique based on the interface interactions between biological pore and the analytes such as protein/peptide to obtain kinetic and thermodynamic information at single-molecule level. And a large number of biological molecules and metal ions are quantitatively detected by nanopore analysis, allowing its development for the future biotechnologies and medicine applications. Besides, electrochemical detection system is crucial to nanopore technique. Therefore, we focus on advancements in relative software and ultralow current instrumentations with high-bandwidth.
2017, 45(12): 1776-1785
doi: 10.11895/j.issn.0253-3820.171292
Abstract:
In the past ten years, the development of electrochemiluminescent (ECL) analytical methods based on various types of nanostructures has become a research hotspot. Nanocluster, an intermediate between molecules and conventional nanoparticles, is renowned for its luminescent feature. The first report on ECL for nanoclusters can be traced back to 2009. Here we summarized the main research progresses since 2011. Firstly, the preparation of ECL-related nanoclusters was briefly introduced. Then, the mechanisms and applications of ECL by nanoclusters were described. To improve ECL performances, two main strategies, i.e., nanostructure-based ECL enhancement and biological signal amplification were proposed. Besides, the nanoclusters as the energy transfer receptors in ECL systems were also discussed. In prospect part, the future development of ECL by nanoclusters was considered. We believed that the synthesis of high quality nanoclusters, the reveal of ECL structure-activity relationships, the rationale design and application of near-infrared ECL, and the role of ECL in the interdisciplinary research were the main problems we faced in the future.
In the past ten years, the development of electrochemiluminescent (ECL) analytical methods based on various types of nanostructures has become a research hotspot. Nanocluster, an intermediate between molecules and conventional nanoparticles, is renowned for its luminescent feature. The first report on ECL for nanoclusters can be traced back to 2009. Here we summarized the main research progresses since 2011. Firstly, the preparation of ECL-related nanoclusters was briefly introduced. Then, the mechanisms and applications of ECL by nanoclusters were described. To improve ECL performances, two main strategies, i.e., nanostructure-based ECL enhancement and biological signal amplification were proposed. Besides, the nanoclusters as the energy transfer receptors in ECL systems were also discussed. In prospect part, the future development of ECL by nanoclusters was considered. We believed that the synthesis of high quality nanoclusters, the reveal of ECL structure-activity relationships, the rationale design and application of near-infrared ECL, and the role of ECL in the interdisciplinary research were the main problems we faced in the future.
2017, 45(12): 1786-1794
doi: 10.11895/j.issn.0253-3820.171324
Abstract:
Immunoassay is of great importance in the field of clinical detection. Our group proposes the inductively coupled plasma mass spectrometry (ICP-MS) based immunoassay. Multiplex immunoassay can be realized by stable isotope tagging strategy combined with ICP-MS detection. Since then, large amount of researches in this field have been made at home and abroad, and the method has been proved applicable to the analysis of biological small molecules, proteins, nucleic acids and cells. In this article, the history and development of immunoassay, the characters of ICP-MS based immunoassay, single component and multiplex immunoassay, and the magnetic immunoassay that is recently fast developed are reviewed. The prospect of the developing tendency is also anticipated, hoping to provide references for the research in this field.
Immunoassay is of great importance in the field of clinical detection. Our group proposes the inductively coupled plasma mass spectrometry (ICP-MS) based immunoassay. Multiplex immunoassay can be realized by stable isotope tagging strategy combined with ICP-MS detection. Since then, large amount of researches in this field have been made at home and abroad, and the method has been proved applicable to the analysis of biological small molecules, proteins, nucleic acids and cells. In this article, the history and development of immunoassay, the characters of ICP-MS based immunoassay, single component and multiplex immunoassay, and the magnetic immunoassay that is recently fast developed are reviewed. The prospect of the developing tendency is also anticipated, hoping to provide references for the research in this field.
2017, 45(12): 1795-1803
doi: 10.11895/j.issn.0253-3820.170272
Abstract:
Polypeptides play a vital role in physiological processes of life. The pharmacological and medical value of polypeptides has attracted the attention of researchers in recent years. Aptamers are short, single stranded DNA or RNA which developed by an in vitro process called systematic evolution of ligands by exponential enrichment (SELEX). Aptamers can bind targets with high affinity and specificity. Hence, aptamer is also called "chemical antibody" or "chemist's antibody". To date, there are two main application aspects for polypeptides-targeted aptamers. First, aptamer can be used as specific affinitive elements based on their ability of recognition, which would be applied to polypeptides detection or imaging. The other one is that aptamer can also be used as antagonists based on their ability of inhibiting, which can restrict the activity of polypeptides and block the downstream signaling pathways in vivo, thus can be used to treat the disease associated with polypeptides. In this review, we summarize the numbers of polypeptides-targeted aptamers and the related applications in vitro and in vivo. Current issues and development trends throughout the screening, characterizing and applying of polypeptides-targeted aptamers are also discussed.
Polypeptides play a vital role in physiological processes of life. The pharmacological and medical value of polypeptides has attracted the attention of researchers in recent years. Aptamers are short, single stranded DNA or RNA which developed by an in vitro process called systematic evolution of ligands by exponential enrichment (SELEX). Aptamers can bind targets with high affinity and specificity. Hence, aptamer is also called "chemical antibody" or "chemist's antibody". To date, there are two main application aspects for polypeptides-targeted aptamers. First, aptamer can be used as specific affinitive elements based on their ability of recognition, which would be applied to polypeptides detection or imaging. The other one is that aptamer can also be used as antagonists based on their ability of inhibiting, which can restrict the activity of polypeptides and block the downstream signaling pathways in vivo, thus can be used to treat the disease associated with polypeptides. In this review, we summarize the numbers of polypeptides-targeted aptamers and the related applications in vitro and in vivo. Current issues and development trends throughout the screening, characterizing and applying of polypeptides-targeted aptamers are also discussed.
2017, 45(12): 1804-1812
doi: 10.11895/j.issn.0253-3820.171338
Abstract:
Phosphopeptide enrichment is of great significance in phosphoproteomics related research. Pre-analysis enrichment helps concentrating phosphopeptides of low abundance, and other interferences of high abundance, such as non-phosphorylated peptides, will be eliminated at the same time. By this way, the enhanced sensitivity of mass-spectrometry analysis of phosphopeptides can be achieved, as well as better detection and identification performance. The key for phosphopeptide enrichment is enrichment materials with specific affinity towards phosphopeptides. Enrichment materials with different phosphopeptide adsorption mechanisms have been developed, while various improvements on material morphologies, enrichment operation, and enrichment specificity are also reported. In the review, we summarized recent progresses in phosphopeptide enrichment from perspectives of both enrichment materials with different enrichment mechanisms, and improvement on methodologies of phosphopeptide enrichment based on various enrichment materials.
Phosphopeptide enrichment is of great significance in phosphoproteomics related research. Pre-analysis enrichment helps concentrating phosphopeptides of low abundance, and other interferences of high abundance, such as non-phosphorylated peptides, will be eliminated at the same time. By this way, the enhanced sensitivity of mass-spectrometry analysis of phosphopeptides can be achieved, as well as better detection and identification performance. The key for phosphopeptide enrichment is enrichment materials with specific affinity towards phosphopeptides. Enrichment materials with different phosphopeptide adsorption mechanisms have been developed, while various improvements on material morphologies, enrichment operation, and enrichment specificity are also reported. In the review, we summarized recent progresses in phosphopeptide enrichment from perspectives of both enrichment materials with different enrichment mechanisms, and improvement on methodologies of phosphopeptide enrichment based on various enrichment materials.
2017, 45(12): 1813-1823
doi: 10.11895/j.issn.0253-3820.171313
Abstract:
Atomic force microscope (AFM) and fluorescence microscope (FM) have been emerging as two most commonly used tools for single-molecule study in living cells. Combining the advantages of two microscopes, the development of the integrated AFM-FM technique with high spatiotemporal resolution and multi-function has attracted increasing interest. In this review, the principles of AFM single-molecular force spectroscopy and single-molecule fluorescence imaging were briefly discussed, and the recent advances in the integrated AFM-FM instrumentation were summarized. Subsequently based on our own research in the investigation of ligand-receptors interactions with the integrated AFM-FM technique, its applications in live-cell single-molecule imaging and characterization were introduced.
Atomic force microscope (AFM) and fluorescence microscope (FM) have been emerging as two most commonly used tools for single-molecule study in living cells. Combining the advantages of two microscopes, the development of the integrated AFM-FM technique with high spatiotemporal resolution and multi-function has attracted increasing interest. In this review, the principles of AFM single-molecular force spectroscopy and single-molecule fluorescence imaging were briefly discussed, and the recent advances in the integrated AFM-FM instrumentation were summarized. Subsequently based on our own research in the investigation of ligand-receptors interactions with the integrated AFM-FM technique, its applications in live-cell single-molecule imaging and characterization were introduced.
2017, 45(12): 1824-1830
doi: 10.11895/j.issn.0253-3820.171303
Abstract:
Microbial fuel cell (MFC) is a type of energy device in which exoelectrogens are harnessed for directly converting the chemical energy of organic matter into electric energy. In addition to researches on the development of high-performance MFC, we have witnessed a rapid progress in the analytical application of MFCs. The MFC-based biosensors are simple and easy to operate, and they can also be used to monitor target online without external power sources, thus attracting more and more attention. Here, we summarize and discuss the progress on using MFCs for measuring biological oxygen demand (BOD), volatile fatty acids, pollutant and toxic compounds, microbial activities and other substances. Furthermore, the design principle of MFC-based biosensors is clarified. The outlook and future prospect of MFC-based biosensors are also discussed in the end.
Microbial fuel cell (MFC) is a type of energy device in which exoelectrogens are harnessed for directly converting the chemical energy of organic matter into electric energy. In addition to researches on the development of high-performance MFC, we have witnessed a rapid progress in the analytical application of MFCs. The MFC-based biosensors are simple and easy to operate, and they can also be used to monitor target online without external power sources, thus attracting more and more attention. Here, we summarize and discuss the progress on using MFCs for measuring biological oxygen demand (BOD), volatile fatty acids, pollutant and toxic compounds, microbial activities and other substances. Furthermore, the design principle of MFC-based biosensors is clarified. The outlook and future prospect of MFC-based biosensors are also discussed in the end.
2017, 45(12): 1831-1837
doi: 10.11895/j.issn.0253-3820.171236
Abstract:
In comparison with traditional organic dyes, semiconductor quantum dots (QDs) feature a series of superior luminescence properties, including narrow and symmetric emission, broad excitation and strong absorption, excellent photobleaching-resistance, and good water solubility. The addition of dopants can endows QDs with extra new properties, e.g., further increase the Stokes shift for avoiding self-quenching. Mn-doped ZnS QDs are a very representative example of doped QDs. No harmful elements such as Cd and Hg are involved in such type of bio-friendly QDs. Besides, the Mn2+ dopant further adds QDs with excellent room temperature phosphorescence. Phosphorescent detection can effectively eliminate the interference of biological background fluorescence, thus Mn-doped ZnS QDs can be widely used in phosphorescent bioanalysis. In this paper, the recent progress of room temperature phosphorescence analysis with Mn-doped ZnS QDs was reviewed. The emphasis was placed on the several stimulative sensing design strategies, including the luminescence mechanism, ion probes, detection of small molecules and biomacromolecules.
In comparison with traditional organic dyes, semiconductor quantum dots (QDs) feature a series of superior luminescence properties, including narrow and symmetric emission, broad excitation and strong absorption, excellent photobleaching-resistance, and good water solubility. The addition of dopants can endows QDs with extra new properties, e.g., further increase the Stokes shift for avoiding self-quenching. Mn-doped ZnS QDs are a very representative example of doped QDs. No harmful elements such as Cd and Hg are involved in such type of bio-friendly QDs. Besides, the Mn2+ dopant further adds QDs with excellent room temperature phosphorescence. Phosphorescent detection can effectively eliminate the interference of biological background fluorescence, thus Mn-doped ZnS QDs can be widely used in phosphorescent bioanalysis. In this paper, the recent progress of room temperature phosphorescence analysis with Mn-doped ZnS QDs was reviewed. The emphasis was placed on the several stimulative sensing design strategies, including the luminescence mechanism, ion probes, detection of small molecules and biomacromolecules.
2017, 45(12): 1838-1844
doi: 10.11895/j.issn.0253-3820.171334
Abstract:
Superoxide anion radical (O2·-) is the first generated reactive oxygen species (ROS) and plays essential function in life processes. Normal level of O2·- as important signaling molecular can regulate redox equilibrium, cellular proliferation and differentiation. However, abnormal level of O2·- is closely associated with diseases, such as cancer, neurodegenerative diseases and diabetes. Hence it is significant to uncover diseases mechanism by exploring dynamic regulation of O2·-. Considering the advantages of fluorescence imaging method, the key factor is to develop O2·- probes with highly selective and sensitive properties for revealing the molecular mechanism of diseases. Recently, with the development of fluorescence microscopy, many fluorescent probes have been constructed and applied for imaging analysis of O2·-. In this review, we mainly summarized the progress of O2·- fluorescent probes according to the different probe structure and prospected the development directions of O2·- probes.
Superoxide anion radical (O2·-) is the first generated reactive oxygen species (ROS) and plays essential function in life processes. Normal level of O2·- as important signaling molecular can regulate redox equilibrium, cellular proliferation and differentiation. However, abnormal level of O2·- is closely associated with diseases, such as cancer, neurodegenerative diseases and diabetes. Hence it is significant to uncover diseases mechanism by exploring dynamic regulation of O2·-. Considering the advantages of fluorescence imaging method, the key factor is to develop O2·- probes with highly selective and sensitive properties for revealing the molecular mechanism of diseases. Recently, with the development of fluorescence microscopy, many fluorescent probes have been constructed and applied for imaging analysis of O2·-. In this review, we mainly summarized the progress of O2·- fluorescent probes according to the different probe structure and prospected the development directions of O2·- probes.
2017, 45(12): 1845-1856
doi: 10.11895/j.issn.0253-3820.171296
Abstract:
Carbon dots have drawn a lot of attentions for their potential usage in bioimaging on the basis of their good biocompatibility and excellent anti-photobleaching ability. However, the relative low fluorescence quantum yield and lockage of near infrared fluorescence emission restrict their applications in the fluorescence imaging analysis. With the improvement of fluorescent properties through different elements doping, more and more carbon dots are used in biological imaging. In this paper, the synthesis of element-doped carbon dots, the influence by different elements doping and the development of element-doped carbon dots in imaging analysis are summarized, and the future prospect are anticipated.
Carbon dots have drawn a lot of attentions for their potential usage in bioimaging on the basis of their good biocompatibility and excellent anti-photobleaching ability. However, the relative low fluorescence quantum yield and lockage of near infrared fluorescence emission restrict their applications in the fluorescence imaging analysis. With the improvement of fluorescent properties through different elements doping, more and more carbon dots are used in biological imaging. In this paper, the synthesis of element-doped carbon dots, the influence by different elements doping and the development of element-doped carbon dots in imaging analysis are summarized, and the future prospect are anticipated.
2017, 45(12): 1857-1864
doi: 10.11895/j.issn.0253-3820.171297
Abstract:
Fluorous solid-phase extraction (FSPE) is a solid-phase extraction technique based on fluorous affinity between perfluorous compounds. It requires derivatization on analytes with fluorous tags and further specific separation accomplished by perfluorinated solid phase. This technique has extended to various research fields with broad application including organic synthesize, catalysis, chemical and biological analysis. Recently, owing to its good compatibility with mass spectrometry, new analytic techniques relying on FSPE coupled to biological mass spectrometry have received wide attention. This review briefly introduced the principle of FSPE and emphasized on its application for the analysis of biomolecules with mass spectrometry, as well as its outlook of future development.
Fluorous solid-phase extraction (FSPE) is a solid-phase extraction technique based on fluorous affinity between perfluorous compounds. It requires derivatization on analytes with fluorous tags and further specific separation accomplished by perfluorinated solid phase. This technique has extended to various research fields with broad application including organic synthesize, catalysis, chemical and biological analysis. Recently, owing to its good compatibility with mass spectrometry, new analytic techniques relying on FSPE coupled to biological mass spectrometry have received wide attention. This review briefly introduced the principle of FSPE and emphasized on its application for the analysis of biomolecules with mass spectrometry, as well as its outlook of future development.
2017, 45(12): 1865-1873, 1881
doi: 10.11895/j.issn.0253-3820.171311
Abstract:
In recent years, micro/nano-scaled separation technique has attracted increasing attention due to its inherent advantages. The porous layer open tubular (PLOT) capillary column is an important microcolumn form. Comparied to wide-bore PLOT capillary columns (inner diameter > 25 μm), the PLOT capillary columns with a narrow inner diameter yield higher separation efficiency and lower reagent consumption. In this paper, the preparation methods for porous layer open tubular capillary columns with narrow inner diameter, less than or equal to 25 μm, are reviewed. Detection techniques combined with mass spectrometry and their applications in liquid chromatography are also disussed.
In recent years, micro/nano-scaled separation technique has attracted increasing attention due to its inherent advantages. The porous layer open tubular (PLOT) capillary column is an important microcolumn form. Comparied to wide-bore PLOT capillary columns (inner diameter > 25 μm), the PLOT capillary columns with a narrow inner diameter yield higher separation efficiency and lower reagent consumption. In this paper, the preparation methods for porous layer open tubular capillary columns with narrow inner diameter, less than or equal to 25 μm, are reviewed. Detection techniques combined with mass spectrometry and their applications in liquid chromatography are also disussed.
2017, 45(12): 1874-1881
doi: 10.11895/j.issn.0253-3820.171298
Abstract:
A strategy based on immunomagnetic nanospheres (IMNs) for rapid, efficient and accurate detection of lymphnode metastasis carcinoma cells (LNMCCs) was developed in this study. First, IMNs processing magnetism and biological targeting were fabricated by the approach developed by our group previously. Then, LNMCCs in lymph node fine needle aspiration (LNFNA) specimens were separated and enriched by the immunomagnetic isolation using IMNs. At last, the captured cells were identified with Wright's staining and immunocytochemistry (ICC). The separation and enrichment of LNMCCs with immunomagnetic isolation could reduce the background interference of LNFNA specimens effectively; the identification with Wright's staining and ICC offered more reliable information for accurate diagnosis, so the sensitivity, specificity and overall diagnostic accuracy had an obvious improvement compared with the conventional cytologic diagnosis. Besides, the simple and rapid incubation of LNFNA specimens with IMNs needed just 5 min, so the cytomorphology of captured LNMCCs could be intactly retained, which enabled to provide important basis for classifying lymphnode metastasis carcinoma (LNMC) and the subsequent pathological study. Moreover, the specific capture of epithelial carcinoma cells in LNFNA specimens with IMNs could make a definite diagnosis of the captured cells as LNMCCs, thus realizing the differentiated diagnosis of LNMC and malignant lymphoma. Additionally, this strategy exhibited successful LNMCCs detection in LNFNA specimens from 110 patients and had higher sensitivity (98.0%), specificity (100.0%), and overall diagnostic accuracy (98.2%) than the conventional cytologic diagnosis. Therefore, it was a new attempt to use IMNs for detection of LNMCCs in LNFNA specimens from LNMC patients, and offered new ideas for LNMC diagnosis and study.
A strategy based on immunomagnetic nanospheres (IMNs) for rapid, efficient and accurate detection of lymphnode metastasis carcinoma cells (LNMCCs) was developed in this study. First, IMNs processing magnetism and biological targeting were fabricated by the approach developed by our group previously. Then, LNMCCs in lymph node fine needle aspiration (LNFNA) specimens were separated and enriched by the immunomagnetic isolation using IMNs. At last, the captured cells were identified with Wright's staining and immunocytochemistry (ICC). The separation and enrichment of LNMCCs with immunomagnetic isolation could reduce the background interference of LNFNA specimens effectively; the identification with Wright's staining and ICC offered more reliable information for accurate diagnosis, so the sensitivity, specificity and overall diagnostic accuracy had an obvious improvement compared with the conventional cytologic diagnosis. Besides, the simple and rapid incubation of LNFNA specimens with IMNs needed just 5 min, so the cytomorphology of captured LNMCCs could be intactly retained, which enabled to provide important basis for classifying lymphnode metastasis carcinoma (LNMC) and the subsequent pathological study. Moreover, the specific capture of epithelial carcinoma cells in LNFNA specimens with IMNs could make a definite diagnosis of the captured cells as LNMCCs, thus realizing the differentiated diagnosis of LNMC and malignant lymphoma. Additionally, this strategy exhibited successful LNMCCs detection in LNFNA specimens from 110 patients and had higher sensitivity (98.0%), specificity (100.0%), and overall diagnostic accuracy (98.2%) than the conventional cytologic diagnosis. Therefore, it was a new attempt to use IMNs for detection of LNMCCs in LNFNA specimens from LNMC patients, and offered new ideas for LNMC diagnosis and study.
2017, 45(12): 1882-1887
doi: 10.11895/j.issn.0253-3820.171378
Abstract:
Superoxide radical (O2·-), is one of reactive oxygen species (ROS) produced in TiO2 photocatalytic reactions, and plays an important role in the photodegradation of pollutants. In this work, we constructed two different procedures to study the generation of total O2·- and surface-adsorbed O2·- during TiO2 photocatalytic reaction using nitroblue tetrazolium (NBT) as capture probe. Furthermore, three different TiO2 (anatase, rutile and P25) were selected as model, and O2·- generation and its existence form were all studied. The results showed that the generation of total O2·- was followed by the order P25> anatase> rutile, but the surface-adsorbed O2·- was nearly the same. The study of surface-adsorbed ROS is very important due to their probably persistence for the pollutants photodegradation or antibacterial activity.
Superoxide radical (O2·-), is one of reactive oxygen species (ROS) produced in TiO2 photocatalytic reactions, and plays an important role in the photodegradation of pollutants. In this work, we constructed two different procedures to study the generation of total O2·- and surface-adsorbed O2·- during TiO2 photocatalytic reaction using nitroblue tetrazolium (NBT) as capture probe. Furthermore, three different TiO2 (anatase, rutile and P25) were selected as model, and O2·- generation and its existence form were all studied. The results showed that the generation of total O2·- was followed by the order P25> anatase> rutile, but the surface-adsorbed O2·- was nearly the same. The study of surface-adsorbed ROS is very important due to their probably persistence for the pollutants photodegradation or antibacterial activity.
2017, 45(12): 1888-1894
doi: 10.11895/j.issn.0253-3820.171218
Abstract:
Sampling truncation, i.e. sampling ends before signal decays to zero, introduces wiggle-like artifacts that impair the quality of nuclear magnetic resonance (NMR) spectra. In multidimensional (mD) NMR experiments, the first few hundred or less data points are commonly sampled in the indirect dimension, and the truncation is unavoidable. Apodization can suppress truncation artifacts with cost of line-broadening. Linear prediction is also beneficial to the reduction of truncation artifacts. The worst situation is in the constant time (CT) type experiments, where the signal doesn't decay at all in the CT evolution dimension. In this contribution we proposed that, although iterative soft thresholding (IST) was rarely used due to the difficult parameter tuning, it was particularly suitable to suppress the truncation artifacts in the CT type NMR experiments. The simulation and experiments were performed to show the performance of this method. And the processing result was compared with a method proposed recently.
Sampling truncation, i.e. sampling ends before signal decays to zero, introduces wiggle-like artifacts that impair the quality of nuclear magnetic resonance (NMR) spectra. In multidimensional (mD) NMR experiments, the first few hundred or less data points are commonly sampled in the indirect dimension, and the truncation is unavoidable. Apodization can suppress truncation artifacts with cost of line-broadening. Linear prediction is also beneficial to the reduction of truncation artifacts. The worst situation is in the constant time (CT) type experiments, where the signal doesn't decay at all in the CT evolution dimension. In this contribution we proposed that, although iterative soft thresholding (IST) was rarely used due to the difficult parameter tuning, it was particularly suitable to suppress the truncation artifacts in the CT type NMR experiments. The simulation and experiments were performed to show the performance of this method. And the processing result was compared with a method proposed recently.
2017, 45(12): 1895-1902
doi: 10.11895/j.issn.0253-3820.171290
Abstract:
A photochromic sensing platform composing of emeraldine salt of polyaniline (ES-PANI) and titanium dioxide nanoparticles (TiO2 NPs) for visual detection of trace copper was developed. Under ultraviolet light irradiation, the greenish ES-PANI could be oxidized to dark blue pernigraniline salt by the photogenerated hole of excited TiO2 NPs. In the presence of Cu2+, a light yellow leucoemeraldine salt was visually observed. The overall mechanism of color change was verified to be corresponding to the different redox states of PANI regulated by Cu species during the photochromic process. By integrating the advantages of both photoelectric property and visual detection, the redox reaction-based sensing mechanism led to a good sensitivity and high selectivity in the detection of Cu2+ with the detection limit of 0.4 μmol/L. Besides the naked eye, two color recognition methods including reading mean green intensities in Photoshop and recording ultraviolet absorbance in microplate reader were also studied. This method was successfully applied to Cu2+ detection in human hair with satisfactory recoveries. More significantly, this sensing platform was really simple, low-cost and able to detect an array of analytes within several minutes without requiring sophisticated equipment. This photoelectron-regulated colorimetric strategy provided a novel concept for the design of visual sensing platform, and could develop the portable test kits for rapid detection in clinical diagnosis.
A photochromic sensing platform composing of emeraldine salt of polyaniline (ES-PANI) and titanium dioxide nanoparticles (TiO2 NPs) for visual detection of trace copper was developed. Under ultraviolet light irradiation, the greenish ES-PANI could be oxidized to dark blue pernigraniline salt by the photogenerated hole of excited TiO2 NPs. In the presence of Cu2+, a light yellow leucoemeraldine salt was visually observed. The overall mechanism of color change was verified to be corresponding to the different redox states of PANI regulated by Cu species during the photochromic process. By integrating the advantages of both photoelectric property and visual detection, the redox reaction-based sensing mechanism led to a good sensitivity and high selectivity in the detection of Cu2+ with the detection limit of 0.4 μmol/L. Besides the naked eye, two color recognition methods including reading mean green intensities in Photoshop and recording ultraviolet absorbance in microplate reader were also studied. This method was successfully applied to Cu2+ detection in human hair with satisfactory recoveries. More significantly, this sensing platform was really simple, low-cost and able to detect an array of analytes within several minutes without requiring sophisticated equipment. This photoelectron-regulated colorimetric strategy provided a novel concept for the design of visual sensing platform, and could develop the portable test kits for rapid detection in clinical diagnosis.
2017, 45(12): 1903-1908
doi: 10.11895/j.issn.0253-3820.171340
Abstract:
A new electrochemical method for telomerase activity assay was developed on the basis of hybridization chain reaction (HCR)-assisted multiple signal amplification, aiming at improving the sensitivity and specificity of telomerase assay. The experiments utilized HeLa cells as original source of the telomerase in the electrochemical studies. The telomerase primer was firstly self-assembled on the surface of gold electrode. The telomerase catalyzed the elongation of the primer, producing the complementary sequences of hairpin probe H1. In this case, HCR was then initiated by interacting with two hairpin probes H1 and H2. Because both H1 and H2 were modified by biotin, horseradish peroxidase could be captured on the electrode surface through the high-affinity interaction between biotin and streptavidin, catalyzing the oxidation of o-phenylenediamine to produce 2, 3-diaminophenazine. Therefore, the telomerase assay was realized by tracing the electrochemical signals with differential pulse voltammetry. This electrochemical method was of high efficiency and feasibility for detecting telomerase activity, and could trace the telomerase activity down to 10 cells/mL HeLa cells with a wide linear range. Besides, it could also easily distinguish the target enzyme from the control proteins with high specificity.
A new electrochemical method for telomerase activity assay was developed on the basis of hybridization chain reaction (HCR)-assisted multiple signal amplification, aiming at improving the sensitivity and specificity of telomerase assay. The experiments utilized HeLa cells as original source of the telomerase in the electrochemical studies. The telomerase primer was firstly self-assembled on the surface of gold electrode. The telomerase catalyzed the elongation of the primer, producing the complementary sequences of hairpin probe H1. In this case, HCR was then initiated by interacting with two hairpin probes H1 and H2. Because both H1 and H2 were modified by biotin, horseradish peroxidase could be captured on the electrode surface through the high-affinity interaction between biotin and streptavidin, catalyzing the oxidation of o-phenylenediamine to produce 2, 3-diaminophenazine. Therefore, the telomerase assay was realized by tracing the electrochemical signals with differential pulse voltammetry. This electrochemical method was of high efficiency and feasibility for detecting telomerase activity, and could trace the telomerase activity down to 10 cells/mL HeLa cells with a wide linear range. Besides, it could also easily distinguish the target enzyme from the control proteins with high specificity.
2017, 45(12): 1909-1914
doi: 10.11895/j.issn.0253-3820.171216
Abstract:
The key to maximize the sensitivity of inner filter effect (IFE)-based assay is to enlarge the overlap between the absorption spectra of the absorber and the excitation or emission spectra of the fluorophore. In this work, Mn-doped ZnS quantum dots (QDs) were chosen for IFE-based detection of β-glucuronidase (GUS), since the excitation of QDs was perfectly overlapped with the absorption of the substrate of GUS, namely 4-nitrophenyl-β-D-glucuronide (PNPG). In addition, the phosphorescence emission from Mn-doped ZnS QDs could eliminate the fluorescence background from biological samples. Therefore, a simple turn-on phosphorescent GUS assay was developed, with the linear range of 10-300 U/L and limit of detection of 7 U/L (S/N=3).
The key to maximize the sensitivity of inner filter effect (IFE)-based assay is to enlarge the overlap between the absorption spectra of the absorber and the excitation or emission spectra of the fluorophore. In this work, Mn-doped ZnS quantum dots (QDs) were chosen for IFE-based detection of β-glucuronidase (GUS), since the excitation of QDs was perfectly overlapped with the absorption of the substrate of GUS, namely 4-nitrophenyl-β-D-glucuronide (PNPG). In addition, the phosphorescence emission from Mn-doped ZnS QDs could eliminate the fluorescence background from biological samples. Therefore, a simple turn-on phosphorescent GUS assay was developed, with the linear range of 10-300 U/L and limit of detection of 7 U/L (S/N=3).
2017, 45(12): 1915-1920
doi: 10.11895/j.issn.0253-3820.171293
Abstract:
A label-free method for sensitive and selective detection of thrombin (Tb) was constructed based on rare earth ion mediated fluorescence switch of graphene quantum dots (GQDs). Rare earth ion (Er3+) can assemble onto the surface of GQDs through the coordination interaction between Er3+ ions and the carboxylate groups located on the surface or edge of the GQDs, resulting in the aggregation of the GQDs and thereby decrease of the fluorescence of the GQDs. In the presence of Tb, the oxygen and nitrogen-donor atoms in Tb can coordinate with Er3+ ions and compete with the carboxylate groups on GQDs to coordinate Er3+ ions, thus the interaction between GQDs and Er3+ ions is reduced, which lead to the restoration of the GQDs fluorescence. In this study, the sensing mechanism was demonstrated by transmission electron microscopy, atomic force microscope, Fourier transform infrared spectroscopy, UV-Vis absorption and fluorescence spectroscopy. The limit of detection for Tb assay was as low as 0.049 nmol/L. Moreover, this assay was successfully applied to the selective determination of Tb in real samples.
A label-free method for sensitive and selective detection of thrombin (Tb) was constructed based on rare earth ion mediated fluorescence switch of graphene quantum dots (GQDs). Rare earth ion (Er3+) can assemble onto the surface of GQDs through the coordination interaction between Er3+ ions and the carboxylate groups located on the surface or edge of the GQDs, resulting in the aggregation of the GQDs and thereby decrease of the fluorescence of the GQDs. In the presence of Tb, the oxygen and nitrogen-donor atoms in Tb can coordinate with Er3+ ions and compete with the carboxylate groups on GQDs to coordinate Er3+ ions, thus the interaction between GQDs and Er3+ ions is reduced, which lead to the restoration of the GQDs fluorescence. In this study, the sensing mechanism was demonstrated by transmission electron microscopy, atomic force microscope, Fourier transform infrared spectroscopy, UV-Vis absorption and fluorescence spectroscopy. The limit of detection for Tb assay was as low as 0.049 nmol/L. Moreover, this assay was successfully applied to the selective determination of Tb in real samples.
2017, 45(12): 1921-1929
doi: 10.11895/j.issn.0253-3820.171286
Abstract:
Bladder cancer (BC) is a fatal malignancy with considerable mortality, and can cause a serious threat to human health. The successful treatment of bladder cancer relies mainly on early detection. Biomarkers are vital to early diagnosis of bladder cancer, and metabonomics play an important role in biomarkers finding. In this study, we used 69 polar metabolites to select the appropriate separation system and develop the zwitterionic hydrophilic chromatography/mass spectrometry (ZIC-HILIC/MS) method. In this method, 50 representative compounds had broad linear ranges between 2-6 orders of magnitude. Moreover the limit of detection of the method was below ng/mL levels. The analysis for six serum samples prepared in parallel showed that this method had good reproducibility, and the RSDs of more than 85% metabolites were less than 30%. Based on this method, it was found that 35 metabolites had significant differences in BC group and healthy control. After screening and validation, the combination of chenodeoxycholic acid, eicosenoic acid, GPC, dodecenoic acid and cystine was a potential biomarker to distinguish BC and normal group. These results indicated that the ZIC-HILIC/MS method could detect diverse metabolites for metabolomic analysis purpose with good reproducibility and stability.
Bladder cancer (BC) is a fatal malignancy with considerable mortality, and can cause a serious threat to human health. The successful treatment of bladder cancer relies mainly on early detection. Biomarkers are vital to early diagnosis of bladder cancer, and metabonomics play an important role in biomarkers finding. In this study, we used 69 polar metabolites to select the appropriate separation system and develop the zwitterionic hydrophilic chromatography/mass spectrometry (ZIC-HILIC/MS) method. In this method, 50 representative compounds had broad linear ranges between 2-6 orders of magnitude. Moreover the limit of detection of the method was below ng/mL levels. The analysis for six serum samples prepared in parallel showed that this method had good reproducibility, and the RSDs of more than 85% metabolites were less than 30%. Based on this method, it was found that 35 metabolites had significant differences in BC group and healthy control. After screening and validation, the combination of chenodeoxycholic acid, eicosenoic acid, GPC, dodecenoic acid and cystine was a potential biomarker to distinguish BC and normal group. These results indicated that the ZIC-HILIC/MS method could detect diverse metabolites for metabolomic analysis purpose with good reproducibility and stability.
A Ratiometric Fluorescence Sensing for Carboxylesterase Based on Semiconducting Polymer Quantum Dots
2017, 45(12): 1930-1936
doi: 10.11895/j.issn.0253-3820.171320
Abstract:
A carboxylesterase (CaE) ratiometric fluorescent probe based on semiconducting Poly(9, 9-dioctylfluorenyl-2, 7-diyl) (PFO) polymer quantum dots (Pdots) was prepared. The negatively charged PFO Pdots and the positively charged polyethyleneimine (PEI) formed a nanocomposite Pdots@PEI by electrostatic interaction, and emitted fluorescence at 440 nm and 467 nm. In the presence of CaE, the substrate fluorescein diacetate (FDA) was hydrolyed into negatively charged fluorescein molecule, and could get closer to the positively charged Pdots@PEI due to electrostatic interactions, which could induce resonance energy transfer, resulting in the energy donor Pdots@PEI fluorescence intensity gradually weakened and the fluorescence intensity of the FDA hydrolysis product increased. Based on the fluorescence intensity ratio of Pdots@PEI and the fluorescence enhancement of FDA hydrolysis products, a new method for selective detection of CaE was established. Under the optimal conditions, the linear range of the method on CaE testing was 0.75-50 U/L with detection limits of 0.75 U/L (S/N=3). This method was used for the detection of the content of CaE in rabbit blood with satisfactory results.
A carboxylesterase (CaE) ratiometric fluorescent probe based on semiconducting Poly(9, 9-dioctylfluorenyl-2, 7-diyl) (PFO) polymer quantum dots (Pdots) was prepared. The negatively charged PFO Pdots and the positively charged polyethyleneimine (PEI) formed a nanocomposite Pdots@PEI by electrostatic interaction, and emitted fluorescence at 440 nm and 467 nm. In the presence of CaE, the substrate fluorescein diacetate (FDA) was hydrolyed into negatively charged fluorescein molecule, and could get closer to the positively charged Pdots@PEI due to electrostatic interactions, which could induce resonance energy transfer, resulting in the energy donor Pdots@PEI fluorescence intensity gradually weakened and the fluorescence intensity of the FDA hydrolysis product increased. Based on the fluorescence intensity ratio of Pdots@PEI and the fluorescence enhancement of FDA hydrolysis products, a new method for selective detection of CaE was established. Under the optimal conditions, the linear range of the method on CaE testing was 0.75-50 U/L with detection limits of 0.75 U/L (S/N=3). This method was used for the detection of the content of CaE in rabbit blood with satisfactory results.
2017, 45(12): 1937-1943
doi: 10.11895/j.issn.0253-3820.171358
Abstract:
Rapid mass spectrometry analysis of protein in the solution sample was carried out by using a charged bubble extraction ionization device. In this work, experimental parameters including gases (N2 and CO2), bubble path length, voltage, and gas pressure on the charged bubble extraction ionization of lysozyme were investigated. Under the optimum experimental parameters including CO2 as extraction gas, bubble path length of 32 cm, solution voltage of 2 kV and gas pressure of 0.05 MPa, this method was successfully used for the protein detection with the limits of detection of 1×10-8 mol/L in water solution and 1×10-7 mol/L in diluted urine (200 times in ultrapure water). In addition, the limit of detection of 1×10-5 mol/L in undiluted urine was obtained with a urine volume of 6 mL at 2 kV voltage and 0.06 MPa gas pressure. By comparing the desalting effects in charged bubble extractive ionization mass spectrometry and ESI-MS, it was found that the bubble charged extraction ionization method could obtain a wider and lower charge state distribution of protein ions, and had higher tolerance ability when facing non-volatile inorganic salts. Off-line study of the collected catalase after charged bubble extraction showed that 53.9% enzyme activity was remained, which indicated that the proposed method was a soft ionization method. The method had merits including no sample pretreatment, no chemical reagent contamination and high speed, showing potential application to mass spectrometry analysis of protein components in solution. Therefore, this study provided a new method for mass spectrometry analysis of biological protein samples.
Rapid mass spectrometry analysis of protein in the solution sample was carried out by using a charged bubble extraction ionization device. In this work, experimental parameters including gases (N2 and CO2), bubble path length, voltage, and gas pressure on the charged bubble extraction ionization of lysozyme were investigated. Under the optimum experimental parameters including CO2 as extraction gas, bubble path length of 32 cm, solution voltage of 2 kV and gas pressure of 0.05 MPa, this method was successfully used for the protein detection with the limits of detection of 1×10-8 mol/L in water solution and 1×10-7 mol/L in diluted urine (200 times in ultrapure water). In addition, the limit of detection of 1×10-5 mol/L in undiluted urine was obtained with a urine volume of 6 mL at 2 kV voltage and 0.06 MPa gas pressure. By comparing the desalting effects in charged bubble extractive ionization mass spectrometry and ESI-MS, it was found that the bubble charged extraction ionization method could obtain a wider and lower charge state distribution of protein ions, and had higher tolerance ability when facing non-volatile inorganic salts. Off-line study of the collected catalase after charged bubble extraction showed that 53.9% enzyme activity was remained, which indicated that the proposed method was a soft ionization method. The method had merits including no sample pretreatment, no chemical reagent contamination and high speed, showing potential application to mass spectrometry analysis of protein components in solution. Therefore, this study provided a new method for mass spectrometry analysis of biological protein samples.
2017, 45(12): 1944-1950
doi: 10.11895/j.issn.0253-3820.171401
Abstract:
A device to produce low temperature plasma (LTP) was designed and constructed to serve as the ion source of a high resolution mass spectrometry, and was applied to qualitatively analyze the steroid samples. In comparison with conventional electrospray ionization mass spectrometry, low temperature plasma mass spectrometry (LTP-MS) had some advantages such as simple sample pretreatment and less interference. Mass spectrometry and tandem mass spectrometry were used to characterize the steroid samples in this research, and it was found that the structural stability of each steroid sample was presented in its mass spectrum, while in the tandem mass spectra there were more fragments of H2O lost. And then the fragmentation process of typical steroid samples in collision induced dissociation (CID) was discussed based on theoretical calculation. In addition, by comparing tandem mass spectrometry and the fragmentation process, a pair of isomers of testosterone and dehydroepiandrosterone could be distinguished successfully.
A device to produce low temperature plasma (LTP) was designed and constructed to serve as the ion source of a high resolution mass spectrometry, and was applied to qualitatively analyze the steroid samples. In comparison with conventional electrospray ionization mass spectrometry, low temperature plasma mass spectrometry (LTP-MS) had some advantages such as simple sample pretreatment and less interference. Mass spectrometry and tandem mass spectrometry were used to characterize the steroid samples in this research, and it was found that the structural stability of each steroid sample was presented in its mass spectrum, while in the tandem mass spectra there were more fragments of H2O lost. And then the fragmentation process of typical steroid samples in collision induced dissociation (CID) was discussed based on theoretical calculation. In addition, by comparing tandem mass spectrometry and the fragmentation process, a pair of isomers of testosterone and dehydroepiandrosterone could be distinguished successfully.
2017, 45(12): 1951-1955
doi: 10.11895/j.issn.0253-3820.171284
Abstract:
In this work, a simple and fast approach for dipeptide detection was developed. AuNPs were decorated onto the surface of indium tin oxide (ITO) glass to serve as the working electrode to trigger the electrochemiluminescence (ECL) of luminol. The property of this electrode was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), electrochemistry and spectroscopic method. Under the optimum conditions, the dipeptide His-Ala could be detected within a linear range from 2.44×10-11 mol/L to 1.22×10-7 mol/L, with a detection limit of 2.42×10-12 mol/L (S/N=3). In human body, the glucagon-like peptide 1(GLP-1) might lose activity during degradation under the enzymatic action of dipeptidyl peptidase Ⅳ (PDD-Ⅳ), meanwhile release same concentrated His-Ala dipeptide. Thus, the detection of His-Ala dipeptide was of great significance for investigation of diabetes not only for understanding the relation between GLP-1, PDD-Ⅳ and its inhibitor, but also the drug discovering because of its potential availability as the target to control the blood GLP-1 level of type Ⅱ diabetics.
In this work, a simple and fast approach for dipeptide detection was developed. AuNPs were decorated onto the surface of indium tin oxide (ITO) glass to serve as the working electrode to trigger the electrochemiluminescence (ECL) of luminol. The property of this electrode was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), electrochemistry and spectroscopic method. Under the optimum conditions, the dipeptide His-Ala could be detected within a linear range from 2.44×10-11 mol/L to 1.22×10-7 mol/L, with a detection limit of 2.42×10-12 mol/L (S/N=3). In human body, the glucagon-like peptide 1(GLP-1) might lose activity during degradation under the enzymatic action of dipeptidyl peptidase Ⅳ (PDD-Ⅳ), meanwhile release same concentrated His-Ala dipeptide. Thus, the detection of His-Ala dipeptide was of great significance for investigation of diabetes not only for understanding the relation between GLP-1, PDD-Ⅳ and its inhibitor, but also the drug discovering because of its potential availability as the target to control the blood GLP-1 level of type Ⅱ diabetics.
2017, 45(12): 1956-1962
doi: 10.11895/j.issn.0253-3820.171125
Abstract:
Folate receptor (FR)-targeted fluorescent nanoprobes (RSiNPs-Folate) were constructed by modifying Rubpy-doped silica nanoparticles (RSiNPs) with folic acid (FA) based on click chemistry coupling method, which was successfully used for cancer cell imaging. Firstly, RSiNPs were prepared by Stöber method and modified with azide groups through the hydrolysis of silane coupling agents (Az-PTES), then propargyl folate were conjugated onto the nanoparticle surfaces via click reaction. It was demonstrated that the FA-functionalized nanoprobes were successfully prepared by monitoring the characteristic peak of the azide group at 2105 cm-1 before and after coupling. In the condition of physiological pH, the nanoprobes exhibited strong red emission at 601 nm when excited at the 458 nm excitation wavelength. The cell imaging results showed that RSiNPs-Folate could effectively target FR-positive HeLa cells, while no obvious fluorescence was observed for FR-negative A549 cells. The receptor-mediated imaging mechanism was confirmed by free FA competition experiments. More importantly, HeLa cells could be selectively recognized and imaged in the mixing cell system. Compared with the carbodiimide conjugation protocols, the click-functionalized nanoprobes had many advantages such as simple synthesis procedures, mild reaction conditions and high yields, which could be potentially used for fluorescent labeling and imaging of different cancer cells.
Folate receptor (FR)-targeted fluorescent nanoprobes (RSiNPs-Folate) were constructed by modifying Rubpy-doped silica nanoparticles (RSiNPs) with folic acid (FA) based on click chemistry coupling method, which was successfully used for cancer cell imaging. Firstly, RSiNPs were prepared by Stöber method and modified with azide groups through the hydrolysis of silane coupling agents (Az-PTES), then propargyl folate were conjugated onto the nanoparticle surfaces via click reaction. It was demonstrated that the FA-functionalized nanoprobes were successfully prepared by monitoring the characteristic peak of the azide group at 2105 cm-1 before and after coupling. In the condition of physiological pH, the nanoprobes exhibited strong red emission at 601 nm when excited at the 458 nm excitation wavelength. The cell imaging results showed that RSiNPs-Folate could effectively target FR-positive HeLa cells, while no obvious fluorescence was observed for FR-negative A549 cells. The receptor-mediated imaging mechanism was confirmed by free FA competition experiments. More importantly, HeLa cells could be selectively recognized and imaged in the mixing cell system. Compared with the carbodiimide conjugation protocols, the click-functionalized nanoprobes had many advantages such as simple synthesis procedures, mild reaction conditions and high yields, which could be potentially used for fluorescent labeling and imaging of different cancer cells.
2017, 45(12): 1963-1970
doi: 10.11895/j.issn.0253-3820.171312
Abstract:
The reversible covalent interaction between boronic acids and cis-diol-containing compounds provides unique affinity for recognition and separation of cis-diol-containing biomolecules such as glycoproteins and sugars. Herein, by using β-blockers and β-agonists as representative hydroxyethylamines, the interaction between phenylboronic acid and hydroxyethylamines was investigated through nuclear magnetic resonance (NMR) and high performance liquid chromatography (HPLC). The results showed that strong interaction between hydroxyethylamines and phenylboronic acid occurred at high pH value, while the interaction became much weaker and even disappeared at low pH value. This interaction was similar to boronate affinity interaction between boronic acids and cis-diol-containing compounds. However, unlike boronate affinity, the presence of an aprotic solvent disrupted the interaction. The above findings not only provided new insights for in-depth understanding boronate affinity interaction, but also paved the basis for the application of the interaction between boronic acid and hydroxyethylamines.
The reversible covalent interaction between boronic acids and cis-diol-containing compounds provides unique affinity for recognition and separation of cis-diol-containing biomolecules such as glycoproteins and sugars. Herein, by using β-blockers and β-agonists as representative hydroxyethylamines, the interaction between phenylboronic acid and hydroxyethylamines was investigated through nuclear magnetic resonance (NMR) and high performance liquid chromatography (HPLC). The results showed that strong interaction between hydroxyethylamines and phenylboronic acid occurred at high pH value, while the interaction became much weaker and even disappeared at low pH value. This interaction was similar to boronate affinity interaction between boronic acids and cis-diol-containing compounds. However, unlike boronate affinity, the presence of an aprotic solvent disrupted the interaction. The above findings not only provided new insights for in-depth understanding boronate affinity interaction, but also paved the basis for the application of the interaction between boronic acid and hydroxyethylamines.
2017, 45(12): 1971-1979
doi: 10.11895/j.issn.0253-3820.171319
Abstract:
Screening aptamers using nano-materials (such as graphene oxide, gold nanoparticle, carbon nano-tube, etc.) that can quench fluorescence and absorb single stranded DNA using hydrogen bond, π-π bond, charge transfer, and other non-covalent ways to combine with ssDNA, but without other conformational DNA, can excellently separate specific aptamers from non-specific ones. In this case, we can shorten the cycle numbers, enhance the success rate, and reduce the labour intensity of systematic evolution of ligands by exponential enrichment (SELEX). Especially for small molecular target, due to its difficulty in immobilization and small size, it is difficult to use traditional methods such as SPR-SELEX or affinity-SELEX for screening. In this experiment, polydopamine nanospheres (MNPs@PDAs) were used to screen the Lomefloxacin. Also, we used magnetic separation technique to screen small molecular target rapidly. The interaction between aptamer candidates and the target could be monitored by recovery ratio of ssDNA and the whole MNPs@PDAs-SELEX process was performed through seven-round selection. As a result, we successfully obtained the aptamer named AF-3 which could recognize the lomefloxacin with high affinity (KD=(17.57±0.5) nmol/L). This screening method based on MNPs@PDAs makes it a promising reagent in the efficient aptamers selection of other targets.
Screening aptamers using nano-materials (such as graphene oxide, gold nanoparticle, carbon nano-tube, etc.) that can quench fluorescence and absorb single stranded DNA using hydrogen bond, π-π bond, charge transfer, and other non-covalent ways to combine with ssDNA, but without other conformational DNA, can excellently separate specific aptamers from non-specific ones. In this case, we can shorten the cycle numbers, enhance the success rate, and reduce the labour intensity of systematic evolution of ligands by exponential enrichment (SELEX). Especially for small molecular target, due to its difficulty in immobilization and small size, it is difficult to use traditional methods such as SPR-SELEX or affinity-SELEX for screening. In this experiment, polydopamine nanospheres (MNPs@PDAs) were used to screen the Lomefloxacin. Also, we used magnetic separation technique to screen small molecular target rapidly. The interaction between aptamer candidates and the target could be monitored by recovery ratio of ssDNA and the whole MNPs@PDAs-SELEX process was performed through seven-round selection. As a result, we successfully obtained the aptamer named AF-3 which could recognize the lomefloxacin with high affinity (KD=(17.57±0.5) nmol/L). This screening method based on MNPs@PDAs makes it a promising reagent in the efficient aptamers selection of other targets.
2017, 45(12): 1980-1987
doi: 10.11895/j.issn.0253-3820.171309
Abstract:
The diffusion coefficient ((4.11±0.78)×10-11 m2/s) and hydrated radius ((6.12±1.21) nm) of FITC-DSA (fluorescein isothiocyanate conjugate dog albumin) were investigated and measured by combining Taylor dispersion analysis with laser induced fluorescence in microchip. The influence of size of gold nanoparticles (15, 30 and 50 nm) on the interactions between FITC-DSA and gold nanoparticles was studied. The preliminary result demonstrated that the binding of protein and gold nanoparticle displayed a size-dependent relationship. It was interesting that the 50-nm gold nanoparticles could enhance the FITC-DSA fluorescence in microchannel driven with pressure. This method was simple, fast, low sample consumption and high throughput and could be used to study the interaction of nanoparticles and proteins. Systematical study using this method would enable us to have a deep understanding of the toxicity of nanomaterials, and promote the development of safe nanomedicine.
The diffusion coefficient ((4.11±0.78)×10-11 m2/s) and hydrated radius ((6.12±1.21) nm) of FITC-DSA (fluorescein isothiocyanate conjugate dog albumin) were investigated and measured by combining Taylor dispersion analysis with laser induced fluorescence in microchip. The influence of size of gold nanoparticles (15, 30 and 50 nm) on the interactions between FITC-DSA and gold nanoparticles was studied. The preliminary result demonstrated that the binding of protein and gold nanoparticle displayed a size-dependent relationship. It was interesting that the 50-nm gold nanoparticles could enhance the FITC-DSA fluorescence in microchannel driven with pressure. This method was simple, fast, low sample consumption and high throughput and could be used to study the interaction of nanoparticles and proteins. Systematical study using this method would enable us to have a deep understanding of the toxicity of nanomaterials, and promote the development of safe nanomedicine.
2017, 45(12): 1988-1995
doi: 10.11895/j.issn.0253-3820.170350
Abstract:
A method of identification of C＝C location and relative quantitation of unsaturated phosphatidylcholine (PC) isomers in breast cells by online photochemical reaction-pulsed directed current electrospray-tandem mass spectrometry (PB-pulsed-dc-ESI-MS/MS) was established with benzophenone (BP) as a photochemical reactant. The three-phase extraction method was used to extract the lipids in the cells, and then the C＝C in the unsaturated PC and the carbonyl in BP were specifically cycled under the irradiation of 254 nm ultraviolet light (Paternò-Büchi, PB reaction). The PB products were ionized and mass-isolated for low-energy collision dissociation through the non-contact pulsed-dc-ESI ionization method. The double bond position and the relative content of the location isomers were obtained from the resulting ions in the MS/MS spectrum. The C＝C location of 8 kinds of unsaturated PCs in MCF-7 and MCF-10A was detected, and the relative contents of 4 kinds of C＝C location isoforms were analyzed. It was found that the relative abundance of Δ9 isomer in PC 16:0_18:1 was not significantly different between the two cells. The relative abundance of Δ9 isomers in PC 18:0_18:1 and PC 18:1_18:1 was slightly different. However, there is a big difference of Δ9 in LPC 18:1 between the cancer cell and normal cell (56.0% ±1.3% vs. 71.7% ±6.8%). The establishment of such a rapid and easy mass spectrometry method can analyze the C＝C location and the relative content of location isomers, and it is expected to be a powerful tool to identify different cell states and different disease states.
A method of identification of C＝C location and relative quantitation of unsaturated phosphatidylcholine (PC) isomers in breast cells by online photochemical reaction-pulsed directed current electrospray-tandem mass spectrometry (PB-pulsed-dc-ESI-MS/MS) was established with benzophenone (BP) as a photochemical reactant. The three-phase extraction method was used to extract the lipids in the cells, and then the C＝C in the unsaturated PC and the carbonyl in BP were specifically cycled under the irradiation of 254 nm ultraviolet light (Paternò-Büchi, PB reaction). The PB products were ionized and mass-isolated for low-energy collision dissociation through the non-contact pulsed-dc-ESI ionization method. The double bond position and the relative content of the location isomers were obtained from the resulting ions in the MS/MS spectrum. The C＝C location of 8 kinds of unsaturated PCs in MCF-7 and MCF-10A was detected, and the relative contents of 4 kinds of C＝C location isoforms were analyzed. It was found that the relative abundance of Δ9 isomer in PC 16:0_18:1 was not significantly different between the two cells. The relative abundance of Δ9 isomers in PC 18:0_18:1 and PC 18:1_18:1 was slightly different. However, there is a big difference of Δ9 in LPC 18:1 between the cancer cell and normal cell (56.0% ±1.3% vs. 71.7% ±6.8%). The establishment of such a rapid and easy mass spectrometry method can analyze the C＝C location and the relative content of location isomers, and it is expected to be a powerful tool to identify different cell states and different disease states.
2017, 45(12): 1996-2003
doi: 10.11895/j.issn.0253-3820.171270
Abstract:
Heteroatom doping is an effective way to elevate the fluorescent performance of carbon dots. In this study, a microwave one-pot approach for the synthesis of SiBCDs was proposed by using citric acid (C6H8O7), boric acid (H3BO3) and (3-aminopropyl) triethoxy sliane (APTES) as source materials. PAAS-SiBCDs were prepared with the assistance of microwave when sodium polyacrylate (PAAS) was added in the precursor of SiBCDs. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra, respectively, confirming that the product was amorphous CDs, with small amount of Si and B. The synthesized SiBCDs had good monodispersity with size of 4-8 nm, the average size of PAAS-SiBCDs was 5.2 nm, and the excitation/emission maximum was 350 nm/445 nm. The quantum yield of SiBCDs was 20.1%, and that of PAAS-SiBCDs was 34.6%. Based on the quenching effect of hemoglobin (Hb) on the fluorescence PAAS-SiBCDs, a sensitive Hb detection method was developed. A linear range of 0.21-5.22 μmol/L was obtained together with a detection limit of 0.06 μmol/L. The method was applied in the determination of Hb in human blood samples.
Heteroatom doping is an effective way to elevate the fluorescent performance of carbon dots. In this study, a microwave one-pot approach for the synthesis of SiBCDs was proposed by using citric acid (C6H8O7), boric acid (H3BO3) and (3-aminopropyl) triethoxy sliane (APTES) as source materials. PAAS-SiBCDs were prepared with the assistance of microwave when sodium polyacrylate (PAAS) was added in the precursor of SiBCDs. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra, respectively, confirming that the product was amorphous CDs, with small amount of Si and B. The synthesized SiBCDs had good monodispersity with size of 4-8 nm, the average size of PAAS-SiBCDs was 5.2 nm, and the excitation/emission maximum was 350 nm/445 nm. The quantum yield of SiBCDs was 20.1%, and that of PAAS-SiBCDs was 34.6%. Based on the quenching effect of hemoglobin (Hb) on the fluorescence PAAS-SiBCDs, a sensitive Hb detection method was developed. A linear range of 0.21-5.22 μmol/L was obtained together with a detection limit of 0.06 μmol/L. The method was applied in the determination of Hb in human blood samples.
2017, 45(12): 2004-2010
doi: 10.11895/j.issn.0253-3820.171306
Abstract:
The Poly(3, 4-ethylenedioxythiophene) graphene (PEDOT-rGO) composite film was prepared by one step pulse potentiostatic method, based on the π-π* interaction and the polymerization reaction of hydrogen bond between the graphene (rGO) and the aromatic ring of 3, 4-ethylenedioxythiophene (EDOT) monomer. Then the nickel nanoparticles (NiNPs) were electrodeposited on composite film to obtain a composite film-modified glassy carbon electrode (NiNPs/PEDOT-rGO/GCE). The catalytic performance of NiNPs/PEDOT-rGO/GCE towards the oxidation of glucose was studied by electrochemical method. The experimental results showed that the NiNPs/PEDOT-rGO/GCE could be used as a nonenzyematic sensor for detection of glucose. This method had high stability, good selectivity, wide linear range (2 μmol/L-58 mmol/L) and low detection limit (0.7 μmol/L), realizing the rapid and sensitive detection of glucose.
The Poly(3, 4-ethylenedioxythiophene) graphene (PEDOT-rGO) composite film was prepared by one step pulse potentiostatic method, based on the π-π* interaction and the polymerization reaction of hydrogen bond between the graphene (rGO) and the aromatic ring of 3, 4-ethylenedioxythiophene (EDOT) monomer. Then the nickel nanoparticles (NiNPs) were electrodeposited on composite film to obtain a composite film-modified glassy carbon electrode (NiNPs/PEDOT-rGO/GCE). The catalytic performance of NiNPs/PEDOT-rGO/GCE towards the oxidation of glucose was studied by electrochemical method. The experimental results showed that the NiNPs/PEDOT-rGO/GCE could be used as a nonenzyematic sensor for detection of glucose. This method had high stability, good selectivity, wide linear range (2 μmol/L-58 mmol/L) and low detection limit (0.7 μmol/L), realizing the rapid and sensitive detection of glucose.
2017, 45(12): 2011-2017
doi: 10.11895/j.issn.0253-3820.171215
Abstract:
Graphene and silver nanoparticles showed good application potentials in electrochemistry due to their unique folded layered structure and good catalytic performance. In this work, reduced graphene oxide-Ag nanoparticles (rGO/AgNPs) composite material was prepared in situ by using hydrothermal reduction synthesis method with sodium citrate as reducing agent. The material was then used as modified electrodes to study the electrochemical behaviors of bisphenol A (BPA). The results of cyclic voltammetry and square wave voltammetry showed that the fast oxidation-reduction reaction of BPA could occur on the rGO/AgNPs modified glassy carbon electrode and lead to the sensitive determination of BPA. Under the optimal conditions, the oxidation current of BPA was linear to its concentration in the range of 0.1-40.0 μmol/L and the detection limit was 50.7 nmol/L (S/N=3). The presented method was also used for the determination of BPA in plastic samples with satisfactory results.
Graphene and silver nanoparticles showed good application potentials in electrochemistry due to their unique folded layered structure and good catalytic performance. In this work, reduced graphene oxide-Ag nanoparticles (rGO/AgNPs) composite material was prepared in situ by using hydrothermal reduction synthesis method with sodium citrate as reducing agent. The material was then used as modified electrodes to study the electrochemical behaviors of bisphenol A (BPA). The results of cyclic voltammetry and square wave voltammetry showed that the fast oxidation-reduction reaction of BPA could occur on the rGO/AgNPs modified glassy carbon electrode and lead to the sensitive determination of BPA. Under the optimal conditions, the oxidation current of BPA was linear to its concentration in the range of 0.1-40.0 μmol/L and the detection limit was 50.7 nmol/L (S/N=3). The presented method was also used for the determination of BPA in plastic samples with satisfactory results.
2017, 45(12): 2018-2025
doi: 10.11895/j.issn.0253-3820.171317
Abstract:
There is high demand for a sensitive method for miRNA detection in clinical diagnosis. In this work, we developed a method for miRNA detection based on the surface plasmon-enhanced energy transfer (SPEET) between gold nanoparticles (AuNPs) and silver nanoclusters (AgNCs), coupled with DNA polymerase and nicking enzyme-assisted isothermal amplification for target recycling. Two DNA probes (Probe a and Probe b) were assembled onto the surface of AuNPs to form Probe b-Probe a-AuNP conjugates. Probe a consisted three domains: the complementary sequence of miRNA, the specific site of the nicking enzyme, and the self-assembly sequence for AgNCs. The 3' end of Probe a was modified with thiol as a binding site for AuNPs. The SPEET of AgNCs and AuNPs was inhibited when miRNA was added to produce the dumbbell shaped template by polymerase. The template could promote synthesis of AgNCs, resulting in replacement and subsequently recycling of the target molecule for signal amplification. In comparison with the traditional method of miRNA detection with commercial RT-PCR kits, this method avoided the process of reverse transcription and was easy to perform. In addition, this method with a detection limit of 2.5×10-11 mol/L was cost-effective, label-free, and highly selective for detecting miRNA, and could be applied to the analysis of miRNA in biological samples.
There is high demand for a sensitive method for miRNA detection in clinical diagnosis. In this work, we developed a method for miRNA detection based on the surface plasmon-enhanced energy transfer (SPEET) between gold nanoparticles (AuNPs) and silver nanoclusters (AgNCs), coupled with DNA polymerase and nicking enzyme-assisted isothermal amplification for target recycling. Two DNA probes (Probe a and Probe b) were assembled onto the surface of AuNPs to form Probe b-Probe a-AuNP conjugates. Probe a consisted three domains: the complementary sequence of miRNA, the specific site of the nicking enzyme, and the self-assembly sequence for AgNCs. The 3' end of Probe a was modified with thiol as a binding site for AuNPs. The SPEET of AgNCs and AuNPs was inhibited when miRNA was added to produce the dumbbell shaped template by polymerase. The template could promote synthesis of AgNCs, resulting in replacement and subsequently recycling of the target molecule for signal amplification. In comparison with the traditional method of miRNA detection with commercial RT-PCR kits, this method avoided the process of reverse transcription and was easy to perform. In addition, this method with a detection limit of 2.5×10-11 mol/L was cost-effective, label-free, and highly selective for detecting miRNA, and could be applied to the analysis of miRNA in biological samples.
2017, 45(12): 2026-2031
doi: 10.11895/j.issn.0253-3820.171314
Abstract:
A simple and efficient method for fabricating a novel surface-enhanced Raman scattering (SERS) substrate with good reproducibility and high SERS activity was reported. Cu2O was prepared by mixing CuCl2·2H2O with ascorbic acid, which was then used as the templates for depositing of gold nanoparticles (AuNPs) on their surfaces, forming Cu2O@Au with heterostructures. Transmission electron microscopy, scanning electron microscopy and X-ray diffraction observation revealed that Cu2O had polyhedral structure and smooth surface, and AuNPs were closely deposited on the surface of Cu2O. It was used as SERS substrate for detection of Rhodamine B with linear detection range of 1×10-2-5×10-6 mol/L, and detection limit of 3×10-7 mol/L. Cu2O@Au showed good chemical stability, remained stable in acid, PBS and river samples, and could be used in the SERS detection of target in water sample.
A simple and efficient method for fabricating a novel surface-enhanced Raman scattering (SERS) substrate with good reproducibility and high SERS activity was reported. Cu2O was prepared by mixing CuCl2·2H2O with ascorbic acid, which was then used as the templates for depositing of gold nanoparticles (AuNPs) on their surfaces, forming Cu2O@Au with heterostructures. Transmission electron microscopy, scanning electron microscopy and X-ray diffraction observation revealed that Cu2O had polyhedral structure and smooth surface, and AuNPs were closely deposited on the surface of Cu2O. It was used as SERS substrate for detection of Rhodamine B with linear detection range of 1×10-2-5×10-6 mol/L, and detection limit of 3×10-7 mol/L. Cu2O@Au showed good chemical stability, remained stable in acid, PBS and river samples, and could be used in the SERS detection of target in water sample.
