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2019 Volume 30 Issue 9
2019, 30(9): 1545-1546
doi: 10.1016/j.cclet.2019.07.045
Abstract:
2019, 30(9): 1547-1556
doi: 10.1016/j.cclet.2019.06.016
Abstract:
Persistent luminescence nanoparticles (PLNPs) are a series of emerging luminescent nanomaterials which can emit persistently after ceasing the external excitation. Due to the long decay time of persistent luminescence, the background autofluorescence in complex sample and tissues can be effectively eliminated, thus significantly improving the sensitivity of bioanalysis. Besides, such a long decay time of luminescence also makes PLNPs valuable for long-term bioimaging. Benefiting from these merits, PLNPs have been widely used for biomedical applications, especially biosensing and bioimaging. In this review, we conclude the progress in the application of PLNPs at biosensing and bioimaging in recent years, and also provide our understanding of the prospects.
Persistent luminescence nanoparticles (PLNPs) are a series of emerging luminescent nanomaterials which can emit persistently after ceasing the external excitation. Due to the long decay time of persistent luminescence, the background autofluorescence in complex sample and tissues can be effectively eliminated, thus significantly improving the sensitivity of bioanalysis. Besides, such a long decay time of luminescence also makes PLNPs valuable for long-term bioimaging. Benefiting from these merits, PLNPs have been widely used for biomedical applications, especially biosensing and bioimaging. In this review, we conclude the progress in the application of PLNPs at biosensing and bioimaging in recent years, and also provide our understanding of the prospects.
2019, 30(9): 1557-1564
doi: 10.1016/j.cclet.2019.06.025
Abstract:
The complexity of biological samples determines that the detection of a single biomolecule is unable to satisfy actual needs. Moreover, the "false positives" results caused by a single biomolecule detections easily leads to erroneous clinical diagnosis and treatment. Thus, it is important for the homogenous quantification of multiple biomolecules in not only basic research but also practical application. As a consequent, a large number of literatures have been exploited to monitor multiple biomolecules in homogenous solution, enabling facilitating the development of the disease diagnosis, treatment as well as drug discovery. One-dimensional nanomaterials and two-dimensional nanomaterials have special physical and chemical properties, such as good electrochemical properties, stable structure, large specific surface area, and biocompatibility, which are widely used in electrochemical and fluorescent detection of biomolecules. This tutorial review highlights the recent development for the detection of multiple biomolecules by using nanomaterials including one-dimensional materials (1DMs) as well as twodimensional materials (2DMs).
The complexity of biological samples determines that the detection of a single biomolecule is unable to satisfy actual needs. Moreover, the "false positives" results caused by a single biomolecule detections easily leads to erroneous clinical diagnosis and treatment. Thus, it is important for the homogenous quantification of multiple biomolecules in not only basic research but also practical application. As a consequent, a large number of literatures have been exploited to monitor multiple biomolecules in homogenous solution, enabling facilitating the development of the disease diagnosis, treatment as well as drug discovery. One-dimensional nanomaterials and two-dimensional nanomaterials have special physical and chemical properties, such as good electrochemical properties, stable structure, large specific surface area, and biocompatibility, which are widely used in electrochemical and fluorescent detection of biomolecules. This tutorial review highlights the recent development for the detection of multiple biomolecules by using nanomaterials including one-dimensional materials (1DMs) as well as twodimensional materials (2DMs).
2019, 30(9): 1565-1574
doi: 10.1016/j.cclet.2019.05.036
Abstract:
With growing interests paid to the enantioselective analysis of chiral molecules, roles played by noble metal and semiconductor nanomaterials surface gradually. Given the unique physicochemical properties of noble metal and semiconductor nanomaterials, the enantioselective analyses are classified into three categories:fluorescence-based, colorimetry-based, and circular dichroism-based ones. In this paper, we review the existing progresses on enantioselective analysis, thanks to noble metal and semiconductor nanomaterials. Finally, the prospect of enantioselective analysis based on noble metal and semiconductor are discussed.
With growing interests paid to the enantioselective analysis of chiral molecules, roles played by noble metal and semiconductor nanomaterials surface gradually. Given the unique physicochemical properties of noble metal and semiconductor nanomaterials, the enantioselective analyses are classified into three categories:fluorescence-based, colorimetry-based, and circular dichroism-based ones. In this paper, we review the existing progresses on enantioselective analysis, thanks to noble metal and semiconductor nanomaterials. Finally, the prospect of enantioselective analysis based on noble metal and semiconductor are discussed.
2019, 30(9): 1575-1580
doi: 10.1016/j.cclet.2019.06.005
Abstract:
As a promising signaling transduction approach, fluorescence polarization (FP)/fluorescence anisotropy (FA), provides a powerful quantitative tool for the rotational motion of fluorescently labeled molecules in chemical or biological homogeneous systems. Unlike fluorescence intensity, FP/FA is almost independent the concentration or quantum of fluorophores, but they are highly dependent on the size or molecular weight of the molecules or materials attached to fluorophores. Recently, significant progress in FP/FA was made, due to the introduction of some nanomaterials as FP/FA enhancers. The detection sensitivity is thus greatly improved by using nanomaterials as FP/FA enhancers, and nanomaterial-based FP/FA is currently used successfully in immunoassay, and analysis of protein, nucleic acid, small molecule and metal ion. Nanomaterial-based FP/FA provides a new kind of strategy to design fluorescent sensors and establishes innovative analytical methods. In this review, we summarize the scientific publications in the field of FP/FA sensor in recent five years, and first introduce the recent progress of FP/FA sensor based on nanomaterial. Subsequently, the various analytical applications of FP/FA based on nanomaterial are discussed. Finally, we provide perspectives on the current challenges and future prospects in this promising field.
As a promising signaling transduction approach, fluorescence polarization (FP)/fluorescence anisotropy (FA), provides a powerful quantitative tool for the rotational motion of fluorescently labeled molecules in chemical or biological homogeneous systems. Unlike fluorescence intensity, FP/FA is almost independent the concentration or quantum of fluorophores, but they are highly dependent on the size or molecular weight of the molecules or materials attached to fluorophores. Recently, significant progress in FP/FA was made, due to the introduction of some nanomaterials as FP/FA enhancers. The detection sensitivity is thus greatly improved by using nanomaterials as FP/FA enhancers, and nanomaterial-based FP/FA is currently used successfully in immunoassay, and analysis of protein, nucleic acid, small molecule and metal ion. Nanomaterial-based FP/FA provides a new kind of strategy to design fluorescent sensors and establishes innovative analytical methods. In this review, we summarize the scientific publications in the field of FP/FA sensor in recent five years, and first introduce the recent progress of FP/FA sensor based on nanomaterial. Subsequently, the various analytical applications of FP/FA based on nanomaterial are discussed. Finally, we provide perspectives on the current challenges and future prospects in this promising field.
2019, 30(9): 1593-1599
doi: 10.1016/j.cclet.2019.05.038
Abstract:
Electrochemiluminescence (ECL) is a kind of luminescent phenomenon caused by electrochemical reactions. Based on the advantages of ECL including low background, high sensitivity, strong spatiotemporal controllability and simple operation, ECL imaging is able to visualize the ECL process, which can additionally achieve high throughput, fast and visual analysis. With the development of optical imaging technique, ECL imaging at micro-or nanoscale has been successfully applied in immunoassay, cell imaging, biochemical analysis, single-nanoparticle detection and study of mechanisms and kinetics of reactions, which has attracted extensive attention. In this review, the basic principles and apparatus of ECL imaging were briefly introduced at first. Then several latest and representative applications of ECL imaging based on nanomaterials and micro-/nanostructures were overviewed. Finally, the superiorities and challenges in ECL imaging for further development were discussed.
Electrochemiluminescence (ECL) is a kind of luminescent phenomenon caused by electrochemical reactions. Based on the advantages of ECL including low background, high sensitivity, strong spatiotemporal controllability and simple operation, ECL imaging is able to visualize the ECL process, which can additionally achieve high throughput, fast and visual analysis. With the development of optical imaging technique, ECL imaging at micro-or nanoscale has been successfully applied in immunoassay, cell imaging, biochemical analysis, single-nanoparticle detection and study of mechanisms and kinetics of reactions, which has attracted extensive attention. In this review, the basic principles and apparatus of ECL imaging were briefly introduced at first. Then several latest and representative applications of ECL imaging based on nanomaterials and micro-/nanostructures were overviewed. Finally, the superiorities and challenges in ECL imaging for further development were discussed.
2019, 30(9): 1600-1606
doi: 10.1016/j.cclet.2019.04.066
Abstract:
Electrogenerated chemiluminescence, also known as electrochemiluminescence, abbreviated ECL, is a new technology combining electrochemistry and chemiluminescence. It is generated by high-energy electrons generated on the surface of the electrode in the emission process of excited state photons formed in the transfer process, and is a perfect combination of electrochemistry and spectroscopy. It not only has the advantages of good environment, high luminosity and wide dynamic range, but also has the characteristics of simple, stable and practical electrochemical methods, and nearly zero background signals. With the rapid development of nanomaterials, due to their unique electrical properties, large specific surface area, good biocompatibility and other characteristics, various nanomaterials have been widely used in the field of biosensors and sensitive detection. This review presented a general description of the research status of four different types of biosensors from the last decade years, summarized the application forms of nanomaterials in ECL biosensor, and outlines the building patterns and application example of the four main types of biosensors.
Electrogenerated chemiluminescence, also known as electrochemiluminescence, abbreviated ECL, is a new technology combining electrochemistry and chemiluminescence. It is generated by high-energy electrons generated on the surface of the electrode in the emission process of excited state photons formed in the transfer process, and is a perfect combination of electrochemistry and spectroscopy. It not only has the advantages of good environment, high luminosity and wide dynamic range, but also has the characteristics of simple, stable and practical electrochemical methods, and nearly zero background signals. With the rapid development of nanomaterials, due to their unique electrical properties, large specific surface area, good biocompatibility and other characteristics, various nanomaterials have been widely used in the field of biosensors and sensitive detection. This review presented a general description of the research status of four different types of biosensors from the last decade years, summarized the application forms of nanomaterials in ECL biosensor, and outlines the building patterns and application example of the four main types of biosensors.
2019, 30(9): 1607-1617
doi: 10.1016/j.cclet.2019.06.011
Abstract:
Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores, ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.
Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores, ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.
2019, 30(9): 1618-1626
doi: 10.1016/j.cclet.2019.02.005
Abstract:
In addition to the canonical nucleobases, a variety of chemical modifications have been identified presence in nucleic acids. These modifications have been demonstrated to involve in regulating the spatiotemporal expression of genes. Up to date, over 150 types of chemical modifications have been found existence in nucleic acids. Understanding the functional roles of modifications relies on deciphering the location information of modifications in nucleic acids. Analytical methods for studying nucleic acid modifications have greatly advanced in the last decade. To locate the modifications in nucleic acids, various mass spectrometry (MS)-based analytical strategies have been established. Recent progress in next-generation sequencing (NGS) in conjugation with immunoprecipitation, chemical reaction, enzyme-mediated mutation, or nanomaterials offer genome-wide or transcriptome-wide mapping of modifications, which greatly revolutionize the field of epigenetic modifications. Herein, we reviewed and summarized the established methods and the breakthrough of the techniques for locating modifications in nucleic acids. In addition, we discussed the principles, applications, advantages and drawbacks of these methods. We believe that with the rapid advancement of techniques and methods, the functions of nucleic acid modifications will be fully understood in the future.
In addition to the canonical nucleobases, a variety of chemical modifications have been identified presence in nucleic acids. These modifications have been demonstrated to involve in regulating the spatiotemporal expression of genes. Up to date, over 150 types of chemical modifications have been found existence in nucleic acids. Understanding the functional roles of modifications relies on deciphering the location information of modifications in nucleic acids. Analytical methods for studying nucleic acid modifications have greatly advanced in the last decade. To locate the modifications in nucleic acids, various mass spectrometry (MS)-based analytical strategies have been established. Recent progress in next-generation sequencing (NGS) in conjugation with immunoprecipitation, chemical reaction, enzyme-mediated mutation, or nanomaterials offer genome-wide or transcriptome-wide mapping of modifications, which greatly revolutionize the field of epigenetic modifications. Herein, we reviewed and summarized the established methods and the breakthrough of the techniques for locating modifications in nucleic acids. In addition, we discussed the principles, applications, advantages and drawbacks of these methods. We believe that with the rapid advancement of techniques and methods, the functions of nucleic acid modifications will be fully understood in the future.
2019, 30(9): 1581-1592
doi: 10.1016/j.cclet.2019.05.049
Abstract:
The novel graphitic nanomaterial of metal graphitic nanocapsules (MGNs) with superior stability, unique optical properties and biocompatibility possess great potential in biomedical and bioanalytical applications. The graphitic shell can quench the background fluorescence interference from external environments via a fluorescence resonance energy transfer (FRET) process and even avoid unnecessary reactions catalyzed by inner metal core. The graphitic shell with several characteristic Raman bands itself can act as Raman signal probe or internal standard (IS), especially the 2D-band within the cellular Raman-silent region helps to reduce the interference signals from external conditions. The present context attempts to give a comprehensive overview about the preparation and unique properties of MGNs as well as their applications in SERS biodetection and bioimaging.
The novel graphitic nanomaterial of metal graphitic nanocapsules (MGNs) with superior stability, unique optical properties and biocompatibility possess great potential in biomedical and bioanalytical applications. The graphitic shell can quench the background fluorescence interference from external environments via a fluorescence resonance energy transfer (FRET) process and even avoid unnecessary reactions catalyzed by inner metal core. The graphitic shell with several characteristic Raman bands itself can act as Raman signal probe or internal standard (IS), especially the 2D-band within the cellular Raman-silent region helps to reduce the interference signals from external conditions. The present context attempts to give a comprehensive overview about the preparation and unique properties of MGNs as well as their applications in SERS biodetection and bioimaging.
2019, 30(9): 1627-1630
doi: 10.1016/j.cclet.2019.05.019
Abstract:
With D-proline as the reducing and capping agent, fluorescent gold nanoclusters were rapidly prepared (D-Pro@AuNCs) within 10 min at 100 ℃. In the present of gold nanoparticles, the fluorescence of D-Pro@AuNCs was remarkably quenched. Interestingly, based on the electrostatic interaction between anticancer drug Raltitrexed and gold nanoparticles induced fluorescence "turn-on" principle, a high selective assay for detection of Raltitrexed was established with the probe associating the fluorescence emission at 435 nm. The fluorescence intensity of D-Pro@AuNCs linearly correlated with the concentration of Raltitrexed in the range from 5.0 μmol/L to 40.0 μmol/L (R2=0.999) and the limit of detection was 1.9 μmol/L. Further, after Raltitrexed was abdominal injected in rats, a metabolic approach was constructed with the prepared fluorescent probe. It showed great potential of AuNCs-based sensing probes for application in analysis of serum anticancer drugs.
With D-proline as the reducing and capping agent, fluorescent gold nanoclusters were rapidly prepared (D-Pro@AuNCs) within 10 min at 100 ℃. In the present of gold nanoparticles, the fluorescence of D-Pro@AuNCs was remarkably quenched. Interestingly, based on the electrostatic interaction between anticancer drug Raltitrexed and gold nanoparticles induced fluorescence "turn-on" principle, a high selective assay for detection of Raltitrexed was established with the probe associating the fluorescence emission at 435 nm. The fluorescence intensity of D-Pro@AuNCs linearly correlated with the concentration of Raltitrexed in the range from 5.0 μmol/L to 40.0 μmol/L (R2=0.999) and the limit of detection was 1.9 μmol/L. Further, after Raltitrexed was abdominal injected in rats, a metabolic approach was constructed with the prepared fluorescent probe. It showed great potential of AuNCs-based sensing probes for application in analysis of serum anticancer drugs.
2019, 30(9): 1631-1634
doi: 10.1016/j.cclet.2019.03.045
Abstract:
A nanoparticle-based potentiometric immunoassay was designed for the sensitive detection of squamous cell carcinoma antigen (SCCA; cervical carcinoma marker) on a portable pH meter coupling enzyme-labeled hybridization chain reaction (HCR) with two alternating hairpin DNA probes for the signal amplification. Initially, a sandwich-type immunoreaction was carried out between anti-SCCA capture antibody-conjugated magnetic bead and detection antibody/initiator strand-coated gold nanoparticle (AuNP). Then, the HCR reaction was readily executed between two glucose oxidase (GOx)-labeled hairpins through the initiator strand to form numerous GOx concatamers on the AuNP via the long nicked double-helix. The concatenated GOx oxidized glucose into gluconic acid and hydrogen peroxide, thus resulting in the pH change of the detection solution on a handheld pH meter. Several labeling protocols including GOx-antibody, GOx-AuNP-antibody and GOx-HCR-AuNP-antibody were investigated for detection of target SCCA, and improved analytical features were obtained with the immune-HCR assay. Under optimum conditions, the immune-HCR assay exhibited good pH responses for the determination of SCCA at a concentration as low as 5.7 pg/mL. Additionally, the immune-HCR assay had good precision and reproducibility, high specificity, and acceptable accuracy for analyzing human serum specimens.
A nanoparticle-based potentiometric immunoassay was designed for the sensitive detection of squamous cell carcinoma antigen (SCCA; cervical carcinoma marker) on a portable pH meter coupling enzyme-labeled hybridization chain reaction (HCR) with two alternating hairpin DNA probes for the signal amplification. Initially, a sandwich-type immunoreaction was carried out between anti-SCCA capture antibody-conjugated magnetic bead and detection antibody/initiator strand-coated gold nanoparticle (AuNP). Then, the HCR reaction was readily executed between two glucose oxidase (GOx)-labeled hairpins through the initiator strand to form numerous GOx concatamers on the AuNP via the long nicked double-helix. The concatenated GOx oxidized glucose into gluconic acid and hydrogen peroxide, thus resulting in the pH change of the detection solution on a handheld pH meter. Several labeling protocols including GOx-antibody, GOx-AuNP-antibody and GOx-HCR-AuNP-antibody were investigated for detection of target SCCA, and improved analytical features were obtained with the immune-HCR assay. Under optimum conditions, the immune-HCR assay exhibited good pH responses for the determination of SCCA at a concentration as low as 5.7 pg/mL. Additionally, the immune-HCR assay had good precision and reproducibility, high specificity, and acceptable accuracy for analyzing human serum specimens.
2019, 30(9): 1635-1638
doi: 10.1016/j.cclet.2019.06.029
Abstract:
Development of sensitive biosensors for biocatalytic transformations monitoring is in high demand but remains a great challenge. It is ascribed to the current strategies that focused on the single metabolite detection, which may bring about the relatively low sensitivity and false diagnosis result. Herein, we report the design and fabrication of novel carbon dots (CDs) with strong orange light emission, pH and H2O2 dual-responsive characteristics. The fluorescence quenching of CDs by H+ and H2O2 enables the highly sensitive detection of H+/H2O2-generating biocatalytic transformations. This is exemplified by the glucose oxidase-mediated catalytic oxidation reaction on glucose, in which H+ and H2O2 would be formed. As compared to the case in which glucose is present, significant fluorescence reduction is detected, and the fluorescence intensity is negatively proportional to glucose concentration. Thus, highly sensitive detection of glucose was readily achieved with a detection limit down to 10.18 nmol/L. The prepared CDs not only realize the highly sensitive detection of glucose, but also allows the probing other substances by changing the enzymes, thus providing a versatile platform, and demonstrating good potential to be used for biocatalytic transformations effective monitoring.
Development of sensitive biosensors for biocatalytic transformations monitoring is in high demand but remains a great challenge. It is ascribed to the current strategies that focused on the single metabolite detection, which may bring about the relatively low sensitivity and false diagnosis result. Herein, we report the design and fabrication of novel carbon dots (CDs) with strong orange light emission, pH and H2O2 dual-responsive characteristics. The fluorescence quenching of CDs by H+ and H2O2 enables the highly sensitive detection of H+/H2O2-generating biocatalytic transformations. This is exemplified by the glucose oxidase-mediated catalytic oxidation reaction on glucose, in which H+ and H2O2 would be formed. As compared to the case in which glucose is present, significant fluorescence reduction is detected, and the fluorescence intensity is negatively proportional to glucose concentration. Thus, highly sensitive detection of glucose was readily achieved with a detection limit down to 10.18 nmol/L. The prepared CDs not only realize the highly sensitive detection of glucose, but also allows the probing other substances by changing the enzymes, thus providing a versatile platform, and demonstrating good potential to be used for biocatalytic transformations effective monitoring.
2019, 30(9): 1639-1642
doi: 10.1016/j.cclet.2019.05.058
Abstract:
The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on recrystallization and ultrasonic exfoliation. Size-controllable graphitic carbon nitride (g-C3N4) QDs can be obtained from the precursor of recrystallized dicyandiamide, only 90 min is needed and the size of QDs is adjusted from 5 nm to 200 nm by controlling the ultrasonic time. Moreover, better fluorescent efficiency is also obtained comparing to traditional g-C3N4 QDs. The obtained g-C3N4 QDs responds to Cu(Ⅱ) in the 0.5 nmol/L to 30 μmol/L concentration range, with a 0.3 nmol/L detection limit. The method was applied to the determination of Cu(Ⅱ) in different environmental water samples.
The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on recrystallization and ultrasonic exfoliation. Size-controllable graphitic carbon nitride (g-C3N4) QDs can be obtained from the precursor of recrystallized dicyandiamide, only 90 min is needed and the size of QDs is adjusted from 5 nm to 200 nm by controlling the ultrasonic time. Moreover, better fluorescent efficiency is also obtained comparing to traditional g-C3N4 QDs. The obtained g-C3N4 QDs responds to Cu(Ⅱ) in the 0.5 nmol/L to 30 μmol/L concentration range, with a 0.3 nmol/L detection limit. The method was applied to the determination of Cu(Ⅱ) in different environmental water samples.
2019, 30(9): 1643-1646
doi: 10.1016/j.cclet.2019.05.042
Abstract:
A highly selective and sensitive electrochemical method was developed for the detection of serotonin (5-hydroxytryptamine, 5-HT) at gold nanoflowers (Au NFs) and overoxidized polypyrrole (OPPy) modified carbon fiber microelectrode (CFME). Carbon fiber was firstly modified with gold nanoflowers using electroless deposition method, and then modified with overoxidized polypyrrole using electrochemical polymerization and overoxidization to obtain OPPy/Au NFs/CFME. The obtained OPPy/Au NFs/CFME was characterized by field emission scanning electron microscopy and electrochemical techniques. It was found that the OPPy/Au NFs/CFME showed good sensitivity for the detection of 5-HT in the range of 10 nmol/L-7.0 μmol/L with detection limit of 2.3 nmol/L, and negligible interferences from ascorbic acid, 5-hydroxyindole acetic acid and uric acid. The OPPy/Au NFs/CFME was successfully applied to the detection of 5-HT in human serum samples with good recovery. The work demonstrates that the electrochemical method, incorporating signal amplification of Au NFs with higher cation selection of OPPy, provides a promising tool for the detection of 5-HT in biological systems
A highly selective and sensitive electrochemical method was developed for the detection of serotonin (5-hydroxytryptamine, 5-HT) at gold nanoflowers (Au NFs) and overoxidized polypyrrole (OPPy) modified carbon fiber microelectrode (CFME). Carbon fiber was firstly modified with gold nanoflowers using electroless deposition method, and then modified with overoxidized polypyrrole using electrochemical polymerization and overoxidization to obtain OPPy/Au NFs/CFME. The obtained OPPy/Au NFs/CFME was characterized by field emission scanning electron microscopy and electrochemical techniques. It was found that the OPPy/Au NFs/CFME showed good sensitivity for the detection of 5-HT in the range of 10 nmol/L-7.0 μmol/L with detection limit of 2.3 nmol/L, and negligible interferences from ascorbic acid, 5-hydroxyindole acetic acid and uric acid. The OPPy/Au NFs/CFME was successfully applied to the detection of 5-HT in human serum samples with good recovery. The work demonstrates that the electrochemical method, incorporating signal amplification of Au NFs with higher cation selection of OPPy, provides a promising tool for the detection of 5-HT in biological systems
2019, 30(9): 1647-1651
doi: 10.1016/j.cclet.2019.06.012
Abstract:
Intracellular pH plays a significant role in various biological processes, including cell proliferation, apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation of pH responsive carbon dots (CDs-pH) for ratiometric intracellular imaging was reported. By using SciFinder database, fluorescent CDs-pH with the required pKa value of 6.84 were rationally designed, which is vital important for precise sensing of intracellular pH. As a result, the synthesized CDspH demonstrated robust ability to test pH fluctuations within the physiological range of 5.4-7.4. The CDspH was further utilized for fluorescent ratiometric imaging of pH in living HeLa cells, effectively avoided the influence of autofluorescence from native cellular species. Moreover, real-time monitoring of intracellular pH fluctuation under heat shock was successfully realized. This SciFinder-guided design strategy is simple and flexible, which has a great potential to be used for the development of other types of CDs for various applications.
Intracellular pH plays a significant role in various biological processes, including cell proliferation, apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation of pH responsive carbon dots (CDs-pH) for ratiometric intracellular imaging was reported. By using SciFinder database, fluorescent CDs-pH with the required pKa value of 6.84 were rationally designed, which is vital important for precise sensing of intracellular pH. As a result, the synthesized CDspH demonstrated robust ability to test pH fluctuations within the physiological range of 5.4-7.4. The CDspH was further utilized for fluorescent ratiometric imaging of pH in living HeLa cells, effectively avoided the influence of autofluorescence from native cellular species. Moreover, real-time monitoring of intracellular pH fluctuation under heat shock was successfully realized. This SciFinder-guided design strategy is simple and flexible, which has a great potential to be used for the development of other types of CDs for various applications.
2019, 30(9): 1652-1654
doi: 10.1016/j.cclet.2019.05.037
Abstract:
Fast and sensitive antigen detection is important in biomedical research and development. Despite, being invented 48 years ago, the enzyme-linked immunosorbent assay (ELISA) remains one of the most successful and widely employed bioanalytical techniques in research and clinical diagnostics due to its reliability and simplistic design. Recently, nanotechnology has offered efficient signal reporting. In spite of some improvements in these systems, there are typically increased material costs involved and the need for expensive equipment or complicated chemical processes, thus negating any possible benefits over ELISA. Herein, we communicate a simple Cu-DNAzyme system for signal transduction of a CuO nanoparticle-labeled immunoassay. The reported immunoassay amplifies signal generation similar to traditional ELISA and is fast, simple, cost-effective, and sensitive, holding promise for biomedical applications and point-of-care testing.
Fast and sensitive antigen detection is important in biomedical research and development. Despite, being invented 48 years ago, the enzyme-linked immunosorbent assay (ELISA) remains one of the most successful and widely employed bioanalytical techniques in research and clinical diagnostics due to its reliability and simplistic design. Recently, nanotechnology has offered efficient signal reporting. In spite of some improvements in these systems, there are typically increased material costs involved and the need for expensive equipment or complicated chemical processes, thus negating any possible benefits over ELISA. Herein, we communicate a simple Cu-DNAzyme system for signal transduction of a CuO nanoparticle-labeled immunoassay. The reported immunoassay amplifies signal generation similar to traditional ELISA and is fast, simple, cost-effective, and sensitive, holding promise for biomedical applications and point-of-care testing.
2019, 30(9): 1655-1658
doi: 10.1016/j.cclet.2019.05.062
Abstract:
Nanozyme catalysis has been mainly focused on a few chromogenic and fluorogenic substrates, while environmentally and biologically important compounds need to be tested to advance the field. In this work, we studied oxidation of estradiol (E2) in the presence of various nanomaterials including gold nanoparticles (AuNPs), nanoceria (CeO2), Fe3O4, Fe2O3, MnO2 and Mn2O3, and found that AuNPs had a dehydrogenase-mimicking activity to convert E2 to estrone (E1). This conversion was monitored using HPLC. The reaction was faster at higher pH and reached saturation at pH 8. Smaller AuNPs had a higher catalytic efficiency and 5 nm AuNPs were 4.8-fold faster than 13 nm at the same total surface area. Finally, we tried 17α-ethinylestradiol (EE2) as a substrate and found that 5 nm AuNPs can catalyze EE2 oxidation in the presence of H2O2. This work indicated that some nanomaterials can affect environmentally important hormones via oxidation reactions, and this study has expanded the scope of substrate of nanozymes.
Nanozyme catalysis has been mainly focused on a few chromogenic and fluorogenic substrates, while environmentally and biologically important compounds need to be tested to advance the field. In this work, we studied oxidation of estradiol (E2) in the presence of various nanomaterials including gold nanoparticles (AuNPs), nanoceria (CeO2), Fe3O4, Fe2O3, MnO2 and Mn2O3, and found that AuNPs had a dehydrogenase-mimicking activity to convert E2 to estrone (E1). This conversion was monitored using HPLC. The reaction was faster at higher pH and reached saturation at pH 8. Smaller AuNPs had a higher catalytic efficiency and 5 nm AuNPs were 4.8-fold faster than 13 nm at the same total surface area. Finally, we tried 17α-ethinylestradiol (EE2) as a substrate and found that 5 nm AuNPs can catalyze EE2 oxidation in the presence of H2O2. This work indicated that some nanomaterials can affect environmentally important hormones via oxidation reactions, and this study has expanded the scope of substrate of nanozymes.
2019, 30(9): 1659-1662
doi: 10.1016/j.cclet.2019.05.032
Abstract:
The development of efficient methods for the detection of hazardous and toxic elements is extremely important for environmental security and public health. In this work, we developed a facile colorimetric assaying system for Ag+ detection in aqueous solution. Chitosan-stabilized platinum nanoparticles (ChPtNPs) were synthesized and severed as an artificial oxidase to catalyze the oxidation of the substrate 3, 30, 5, 50-tetramethylbenzidine (TMB) and generate color signal. In the presence of Ag+, due to the strong metallophilic interactions between Ag+ and Pt2+ on the surface of Ch-PtNPs, Ag+ can weaken the affinity to the substrates and inactivate the catalytic activity of Ch-PtNPs, leading to decreased absorbance signal to varying degrees depending on Ag+ amount. Combing the specific binding between Ch-PtNPs and Ag+ with signal amplification procedure based on the Ch-PtNPs-catalyzed TMB oxidation, a sensitive, selective, simple, cost-effective, and rapid detection method for Ag+ can be realized. Ag+ ions in tap and lake waters have been successfully detected. We ensured that the proposed method can be a potential alternative for Ag+ determination in environmental samples.
The development of efficient methods for the detection of hazardous and toxic elements is extremely important for environmental security and public health. In this work, we developed a facile colorimetric assaying system for Ag+ detection in aqueous solution. Chitosan-stabilized platinum nanoparticles (ChPtNPs) were synthesized and severed as an artificial oxidase to catalyze the oxidation of the substrate 3, 30, 5, 50-tetramethylbenzidine (TMB) and generate color signal. In the presence of Ag+, due to the strong metallophilic interactions between Ag+ and Pt2+ on the surface of Ch-PtNPs, Ag+ can weaken the affinity to the substrates and inactivate the catalytic activity of Ch-PtNPs, leading to decreased absorbance signal to varying degrees depending on Ag+ amount. Combing the specific binding between Ch-PtNPs and Ag+ with signal amplification procedure based on the Ch-PtNPs-catalyzed TMB oxidation, a sensitive, selective, simple, cost-effective, and rapid detection method for Ag+ can be realized. Ag+ ions in tap and lake waters have been successfully detected. We ensured that the proposed method can be a potential alternative for Ag+ determination in environmental samples.
2019, 30(9): 1663-1666
doi: 10.1016/j.cclet.2019.06.038
Abstract:
Gold nanorods (GNRs) have been well employed for sensing/bio-sensing based on analytes modulated morphology or self-assembly states. Herein, we employed H2O2 based etching system (H2O2 molecules themselves and H2O2-Fe2+ Fenton reagents) as an example to study the diameters of GNRs on the analytical performances, for the colorimetric platforms using GNRs as reporters. We have found that the thinner GNRs possess a higher sensitivity; while the thicker ones bring more abound color presentation during the etching processes, which is especially for naked eye detection. In addition, a red shift of the plasmonic bands is observed for three kinds of thinner GNRs at the initial stage of the etching reaction, and the mechanism is also discussed.
Gold nanorods (GNRs) have been well employed for sensing/bio-sensing based on analytes modulated morphology or self-assembly states. Herein, we employed H2O2 based etching system (H2O2 molecules themselves and H2O2-Fe2+ Fenton reagents) as an example to study the diameters of GNRs on the analytical performances, for the colorimetric platforms using GNRs as reporters. We have found that the thinner GNRs possess a higher sensitivity; while the thicker ones bring more abound color presentation during the etching processes, which is especially for naked eye detection. In addition, a red shift of the plasmonic bands is observed for three kinds of thinner GNRs at the initial stage of the etching reaction, and the mechanism is also discussed.
