An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH2 labeled,single strand DNA（NH2-ssDNA） onto a self-assembled diazo-thiourea and gold nanoparticles modified ...An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH2 labeled,single strand DNA（NH2-ssDNA） onto a self-assembled diazo-thiourea and gold nanoparticles modified Au electrode（diazo-thiourea/GNM/Au）.Gold nano-particles expand the electrode surface area and increase the amount of immobilized thiourea and single stranded DNA（ssDNA） onto the electrode surface.Diazo-thiourea film provides a surface with high conductibility for electron transfer and a bed for the covalent coupling of NH2-ssDNA onto the electrode surface.The immobilization and hybridization of the probe DNA on the modified electrode is studied by differential pulse voltammetry（DPV） using methylene blue（MB） as a well-known electrochemical hybridization indicator.The linear range for the determination of complementary target ssDNA is from 9.5（±0.1） × 10^-13 mol/L to1.2（±0.2） x 10^-9 mol/L with a detection limit of 1.2（±0.1） 〉 10^-13 mol/L.展开更多
A DNA biosensor with [Ru（DA-bpy）3]Cl2（DA-bpy：4,4＇-diamino-2,2＇-bipyridine） （RuL） as the electrochemical probe was prepared on pyrolytic graphite electrode （PGE） through the supramolecular interaction betwee...A DNA biosensor with [Ru（DA-bpy）3]Cl2（DA-bpy：4,4＇-diamino-2,2＇-bipyridine） （RuL） as the electrochemical probe was prepared on pyrolytic graphite electrode （PGE） through the supramolecular interaction between RuL complex and DNA template. Cyclic voltammetry of RuL-DNA film showed a pair of stable and reversible peaks corresponding to the Ru（Ⅲ）/Ru（Ⅲ） redox potential of-0.165 V versus AglAgCl in pa 7.4 0.1 mol·L^-1Tris-HCl. The electron transfer was expected across the double-strand DNA by an ＂electron tunneling＂ mechanism. When the DNA biosensor was immerged in gold （Ⅲ） buffer solution, the current peak signal （I） of the RuL-DNA supramolecular depressed and △I was linear in the concentration range of Au ion from 1×10^-7 to 2×10^-5 mol·L^-1 with a regression coefficient of 0.9879. The detection limit was 5×10^-8 mol·L^-1. The developed procedures were applied to the analysis of synthetic samples of real materials with good sensitivity and selectivity.展开更多
Titanium dioxide (TiO2) thin film was deposited on the surface of the light addressable potentiometric sensor (LAPS) to modify the sensor surface for the non-labeled detection of DNA molecules. To evaluate the effect ...Titanium dioxide (TiO2) thin film was deposited on the surface of the light addressable potentiometric sensor (LAPS) to modify the sensor surface for the non-labeled detection of DNA molecules. To evaluate the effect of ultraviolet (UV) treatment on the silanization level of TiO2 thin film by 3-aminopropyltriethoxysilane (APTS),fluorescein isothiocyanate (FITC) was used to label the amine group on the end of APTS immobilized onto the TiO2 thin film. We found that,with UV irradiation,the silanization level of the irradiated area of the TiO2 film was improved compared with the non-irradiated area under well-controlled conditions. This result indicates that TiO2 can act as a coating material on the biosensor surface to improve the effect and efficiency of the covalent immobilization of biomolecules on the sensor surface. The artificially synthesized probe DNA molecules were covalently linked onto the surface of TiO2 film. The hybridization of probe DNA and target DNA was monitored by the recording of I-V curves that shift along the voltage axis during the process of reaction. A significant LAPS signal can be detected at 10 μmol/L of target DNA sample.展开更多
Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is bas...Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00;as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 μM with a detection limit of 3.32 μM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.展开更多
Objective: To establish a DNA detection platform based on a tapered optical fiber to detect Leptospira DNA by targeting the leptospiral secY gene.Methods: The biosensor works on the principle of light propagating in t...Objective: To establish a DNA detection platform based on a tapered optical fiber to detect Leptospira DNA by targeting the leptospiral secY gene.Methods: The biosensor works on the principle of light propagating in the special geometry of the optical fiber tapered from a waist diameter of 125 to 12 μm. The fiber surface was functionalized through a cascade of chemical treatments and the immobilization of a DNA capture probe targeting the secY gene. The presence of the target DNA was determined from the wavelength shift in the optical transmission spectrum.Results: The biosensor demonstrated good sensitivity, detecting Leptospira DNA at 0.001 ng/μL, and was selective for Leptospira DNA without cross-reactivity with non-leptospiral microorganisms. The biosensor specifically detected DNA that was specifically amplified through the loop-mediated isothermal amplification approach.Conclusions: These findings warrant the potential of this platform to be developed as a novel alternative approach to diagnose leptospirosis.展开更多
A localized surface plasmon resonance(LSPR) biosensor was prepared with gold nanospheres(Au NSs) coated on the tip face of the optical silica fiber. Au NSs with the sizes of 20 nm and 80 nm were used. The sensitivitie...A localized surface plasmon resonance(LSPR) biosensor was prepared with gold nanospheres(Au NSs) coated on the tip face of the optical silica fiber. Au NSs with the sizes of 20 nm and 80 nm were used. The sensitivities of Au NS_(20 nm) and Au NS_(80 nm) modified sensors to bulk refractive index(RI) variation are 82.86 nm/RIU and 218.98 nm/RIU, respectively. The Au NS_(80 nm) modified sensor was used for the detection of 40 bases DNA hybridization and the limit of detection is 50 nmol/L, where the 40-bases DNA probe was covalently linked with Au NS_(80 nm). The complementary DNA sequence in tris-acetate-EDTA(TAE) buffer solution was detected as the target DNA. This fiber sensor has the advantages of small sample consumption, easy fabrication and high sensitivity.展开更多
Fiber-optic DNA biosensors are a kind of ana-lytic setups, which convert the Waston-Crick base pairs matching duplex or Hoogsteen’s tri-plex (T/A-T, C/G-C) formation into a readable analytical signals when functional...Fiber-optic DNA biosensors are a kind of ana-lytic setups, which convert the Waston-Crick base pairs matching duplex or Hoogsteen’s tri-plex (T/A-T, C/G-C) formation into a readable analytical signals when functionalized single- strands DNA (ssDNA) or double-strands DNA (dsDNA) of interest are immobilized on the sur-face of fiber-optic hybrids with target DNA or interacts with ligands. This review will provide the information about the fiber-optic DNA bio-sensors classified into two categories depend-ing on the end fiber and side fiber with or with-out the labels—label-free fiber-optic DNA bio-sensors and labeled fiber-optic DNA biosensor in recent years. Both are dissertated, and em-phasis is on the label-free fiber-optic DNA bio-sensors. Fiber-optic DNA biosensors had got great progresses because fiber-optic has more advantages over the other transducers and are easily processed by nanotechnology. So fiber- optic DNA biosensors have increasingly at-tracted more attention to research and develop the new fiber-optic DNA biosensors that inte-grated with the “nano-bio-info” technology for in vivo test, single molecular detection and on-line medical diagnosis. Finally, future pros-pects to the fiber-optic DNA biosensors are predicted.展开更多
The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission ele...The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission electron microscopy and energy-dispersive X-ray spectroscopy.Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of-NH2 modified on 5’-end of probe DNA and Au@Bi2S3.Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect.The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L.The limit of detection was estimated to be 2 fmol/L(S/N=3).The biosensor also presents remarkable selectivity to distinguish fully complementa ry sequences from basemismatched and non-complementary ones,showing great promising in practical application.展开更多
In the present study, a disposable electrochemical DNA nano-biosensor is proposed for the rapid detection of genotoxic compounds and bio-analysis of water pollution. The DNA nano-biosensor is prepared by immobilizing ...In the present study, a disposable electrochemical DNA nano-biosensor is proposed for the rapid detection of genotoxic compounds and bio-analysis of water pollution. The DNA nano-biosensor is prepared by immobilizing DNA on Au nanoparticles and a self-assembled monolayer of cysteamine modified Au electrode. The assembly processes of cysteamine, Au nanoparticles and DNA were characterized by cyclic voltammetry （CV）. The Au nanoparticles enhanced DNA immobilization resulting in an increased guanine signal. The interaction of the analyte with the immobilized DNA was measured through the variation of the electrochemical signal of guanine by square wave voltammetry （SWV）. The biosensor was able to detect the known genotoxic compounds： 2-anthramine, acridine orange and 2- naphthylamine with detection limits of 2, 3 and 50 nmol/L, respectively. The biosensor was also used to test actual water samples to evaluate the contamination level. Additionally, the comparison of results from the classical genotoxiciw bioassay has confirmed the applicability of the method for real samoles.展开更多
A new method of preparing fiber-optic DNA biosensor and its arrayfor the simultaneous detection of multiple genes is described. The optical fibers were first treated with poly-l-lysine, and then were made into fiber-o...A new method of preparing fiber-optic DNA biosensor and its arrayfor the simultaneous detection of multiple genes is described. The optical fibers were first treated with poly-l-lysine, and then were made into fiber-optic DNA biosensors by adsorbing and immobilizing the oligonucleotide probe on its end. By assembling the fiber-optic DNA biosensors in a bundle in which each fiber carried a different DNA probe, the fiber-optic DNA biosensor array was well prepared. Hybridization of fluorescent- labeled cDNA of p53 gene, N-ras gene and Rb1 gene to the DNA array was monitored by CCD camera. A good result was achieved.展开更多
MicroRNAs(miRNAs),as the small,non-coding,evolutionary conserved,and post-transcriptional gene regulators of the genome,have been highly associated with various diseases such as cancers,viral infections,and cardiovasc...MicroRNAs(miRNAs),as the small,non-coding,evolutionary conserved,and post-transcriptional gene regulators of the genome,have been highly associated with various diseases such as cancers,viral infections,and cardiovascular diseases.Several techniques have been established to detect miRNAs,including northern blotting,real-time polymerase chain reaction(RT-PCR),and fluorescent microarray platform.However,it remains a significant challenge to develop sensitive,accurate,rapid,and cost-effective methods to detect miRNAs due to their short size,high similarity,and low abundance.The electro-chemical biosensors exhibit tremendous potential in miRNA detection because they satisfy feature integration,portability,mass production,short response time,and minimal sample consumption.This article reviewed the working principles and signal amplification strategies of electrochemical DNA biosensors summarized the recent improvements.With the develop-ment of DNA nanotechnology,nanomaterials and biotechnology,electrochemical DNA biosensors of high sensitivity and specificity for microRNA detection will shortly be commercially accessible.展开更多
Celestine blue(CB)was introduced as a new electroactive indicator in DNA biosensors.The interaction of CB with DNA was investigated by electrochemical and spectroscopic methods.The effect of buffer kind and p H on the...Celestine blue(CB)was introduced as a new electroactive indicator in DNA biosensors.The interaction of CB with DNA was investigated by electrochemical and spectroscopic methods.The effect of buffer kind and p H on the electrochemical behavior of CB was studied.The peak currents of CB were linearly related to DNA concentration in the range of 5.0×10^(-9) to 1.0×10^(-7)mol/L.The detection limit of this approach was 4.76×10^(-10) mol/L.Based on spectrometry data a hypochromic effect was observed in UV-Vis spectra of CB with increasing DNA concentration.The results illustrate the possible interaction mode between CB and DNA is electrostatic binding.展开更多
An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation...An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.展开更多
DNA methylation plays a significant role in various biological events, and its precise determination is vital for the prognosis and treatment of cancer. Here, we proposed an ultrasensitive electrochemical biosensor fo...DNA methylation plays a significant role in various biological events, and its precise determination is vital for the prognosis and treatment of cancer. Here, we proposed an ultrasensitive electrochemical biosensor for the quantitative analysis of multiple methylation-locus in DNA sequence via DNA anchoring the gold nanoparticles (DNA-AuNPs) and bienzyme dual signal amplifications. After the target DNA captured by the DNA-AuNPs of the biosensor, the methyl-CpG binding protein MeCP2 could specifically conjugate to the methylation-loci in the double-stranded DNA. Successively, the glucose oxidase (GOD) and horseradish (HRP) co-labeled antibody captured the His tagged MeCP2, which leads to a cascade enzymatic catalysis of the substrates to yield a detectable electrochemical signal. Both the two strategies, including the high content of DNA-AuNPs and the associated catalysis of bienzyme, dramatically enhanced the sensitivity of the biosensor. The response current elevated with the increasing numbers of methylation-locus, thus the multiple methylated DNA was identified by detecting the corresponding current signals. This method could detect the methylated target as low as 0.1 fM, and showed a wide linear range from 10 - 15 M to 10 - 7 M. Besides, the long-term stability and repeatability of the biosensor were also validated. The prepared electrochemical immunosensor exhibits ultrasensitivity through the bienzyme labeling process, which can be applied for the detection of DNA methylation with low concentration.展开更多
文摘An effective procedure for constructing a DNA biosensor is developed based on covalent immobilization of NH2 labeled,single strand DNA（NH2-ssDNA） onto a self-assembled diazo-thiourea and gold nanoparticles modified Au electrode（diazo-thiourea/GNM/Au）.Gold nano-particles expand the electrode surface area and increase the amount of immobilized thiourea and single stranded DNA（ssDNA） onto the electrode surface.Diazo-thiourea film provides a surface with high conductibility for electron transfer and a bed for the covalent coupling of NH2-ssDNA onto the electrode surface.The immobilization and hybridization of the probe DNA on the modified electrode is studied by differential pulse voltammetry（DPV） using methylene blue（MB） as a well-known electrochemical hybridization indicator.The linear range for the determination of complementary target ssDNA is from 9.5（±0.1） × 10^-13 mol/L to1.2（±0.2） x 10^-9 mol/L with a detection limit of 1.2（±0.1） 〉 10^-13 mol/L.
基金This study is financially supported by the National Natural Science Foundation of China (No. 60508012)the Natural Sci-ence Foundation of Zhejiang Province (No. Y106725)+1 种基金the Natural Science Foundation of Ningbo (No. 2006A610048)the Scientific and Technological Project Funding of Zhejiang Province (No. 2006C31040).
文摘A DNA biosensor with [Ru（DA-bpy）3]Cl2（DA-bpy：4,4＇-diamino-2,2＇-bipyridine） （RuL） as the electrochemical probe was prepared on pyrolytic graphite electrode （PGE） through the supramolecular interaction between RuL complex and DNA template. Cyclic voltammetry of RuL-DNA film showed a pair of stable and reversible peaks corresponding to the Ru（Ⅲ）/Ru（Ⅲ） redox potential of-0.165 V versus AglAgCl in pa 7.4 0.1 mol·L^-1Tris-HCl. The electron transfer was expected across the double-strand DNA by an ＂electron tunneling＂ mechanism. When the DNA biosensor was immerged in gold （Ⅲ） buffer solution, the current peak signal （I） of the RuL-DNA supramolecular depressed and △I was linear in the concentration range of Au ion from 1×10^-7 to 2×10^-5 mol·L^-1 with a regression coefficient of 0.9879. The detection limit was 5×10^-8 mol·L^-1. The developed procedures were applied to the analysis of synthetic samples of real materials with good sensitivity and selectivity.
基金Project supported by the National Natural Science Foundation of China (Nos. 30627002 and 60725102)the Interdisciplinary Research Foundation of Zhejiang University (No. 2009-15), China
文摘Titanium dioxide (TiO2) thin film was deposited on the surface of the light addressable potentiometric sensor (LAPS) to modify the sensor surface for the non-labeled detection of DNA molecules. To evaluate the effect of ultraviolet (UV) treatment on the silanization level of TiO2 thin film by 3-aminopropyltriethoxysilane (APTS),fluorescein isothiocyanate (FITC) was used to label the amine group on the end of APTS immobilized onto the TiO2 thin film. We found that,with UV irradiation,the silanization level of the irradiated area of the TiO2 film was improved compared with the non-irradiated area under well-controlled conditions. This result indicates that TiO2 can act as a coating material on the biosensor surface to improve the effect and efficiency of the covalent immobilization of biomolecules on the sensor surface. The artificially synthesized probe DNA molecules were covalently linked onto the surface of TiO2 film. The hybridization of probe DNA and target DNA was monitored by the recording of I-V curves that shift along the voltage axis during the process of reaction. A significant LAPS signal can be detected at 10 μmol/L of target DNA sample.
基金the Ministry of Higher Education Malaysia for the ERGS grant(600/RMI/st/ERGS/5/3/fst12/2011)Universiti Teknologi MARA for financial support via postgraduate teaching assistant scheme(UPTA)to Nur Azimah Mansor for conducting this research.
文摘Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00;as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 μM with a detection limit of 3.32 μM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.
基金funded by Universiti Putra Malaysia through the Geran Inisiatif Putra Siswazah (GP-IPS/2019/9678200)。
文摘Objective: To establish a DNA detection platform based on a tapered optical fiber to detect Leptospira DNA by targeting the leptospiral secY gene.Methods: The biosensor works on the principle of light propagating in the special geometry of the optical fiber tapered from a waist diameter of 125 to 12 μm. The fiber surface was functionalized through a cascade of chemical treatments and the immobilization of a DNA capture probe targeting the secY gene. The presence of the target DNA was determined from the wavelength shift in the optical transmission spectrum.Results: The biosensor demonstrated good sensitivity, detecting Leptospira DNA at 0.001 ng/μL, and was selective for Leptospira DNA without cross-reactivity with non-leptospiral microorganisms. The biosensor specifically detected DNA that was specifically amplified through the loop-mediated isothermal amplification approach.Conclusions: These findings warrant the potential of this platform to be developed as a novel alternative approach to diagnose leptospirosis.
基金supported by the National Basic Research Program of China(No.2014M561055)the National High Technology Research and Development Program(No.2012AA101608)the National Natural Science Foundation of China(No.61401433)
文摘A localized surface plasmon resonance(LSPR) biosensor was prepared with gold nanospheres(Au NSs) coated on the tip face of the optical silica fiber. Au NSs with the sizes of 20 nm and 80 nm were used. The sensitivities of Au NS_(20 nm) and Au NS_(80 nm) modified sensors to bulk refractive index(RI) variation are 82.86 nm/RIU and 218.98 nm/RIU, respectively. The Au NS_(80 nm) modified sensor was used for the detection of 40 bases DNA hybridization and the limit of detection is 50 nmol/L, where the 40-bases DNA probe was covalently linked with Au NS_(80 nm). The complementary DNA sequence in tris-acetate-EDTA(TAE) buffer solution was detected as the target DNA. This fiber sensor has the advantages of small sample consumption, easy fabrication and high sensitivity.
文摘Fiber-optic DNA biosensors are a kind of ana-lytic setups, which convert the Waston-Crick base pairs matching duplex or Hoogsteen’s tri-plex (T/A-T, C/G-C) formation into a readable analytical signals when functionalized single- strands DNA (ssDNA) or double-strands DNA (dsDNA) of interest are immobilized on the sur-face of fiber-optic hybrids with target DNA or interacts with ligands. This review will provide the information about the fiber-optic DNA bio-sensors classified into two categories depend-ing on the end fiber and side fiber with or with-out the labels—label-free fiber-optic DNA bio-sensors and labeled fiber-optic DNA biosensor in recent years. Both are dissertated, and em-phasis is on the label-free fiber-optic DNA bio-sensors. Fiber-optic DNA biosensors had got great progresses because fiber-optic has more advantages over the other transducers and are easily processed by nanotechnology. So fiber- optic DNA biosensors have increasingly at-tracted more attention to research and develop the new fiber-optic DNA biosensors that inte-grated with the “nano-bio-info” technology for in vivo test, single molecular detection and on-line medical diagnosis. Finally, future pros-pects to the fiber-optic DNA biosensors are predicted.
基金supported by the National Natural Science Foundation of China (Nos.21802064,21275127)Natural Science Foundation of Fujian Province,China (Nos.2018J01435,2017J01419)Foundation of Key Laboratory of Sensor Analysis of Tumor Marker,Ministry of Education,Qingdao University of Science and Technology
文摘The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission electron microscopy and energy-dispersive X-ray spectroscopy.Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of-NH2 modified on 5’-end of probe DNA and Au@Bi2S3.Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect.The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L.The limit of detection was estimated to be 2 fmol/L(S/N=3).The biosensor also presents remarkable selectivity to distinguish fully complementa ry sequences from basemismatched and non-complementary ones,showing great promising in practical application.
基金funded by the National Natural Science Foundation of China(Nos.21103059,51136002 and 51076079)the China Key Technologies R&D Program(No.2012BAJ02B03)
文摘In the present study, a disposable electrochemical DNA nano-biosensor is proposed for the rapid detection of genotoxic compounds and bio-analysis of water pollution. The DNA nano-biosensor is prepared by immobilizing DNA on Au nanoparticles and a self-assembled monolayer of cysteamine modified Au electrode. The assembly processes of cysteamine, Au nanoparticles and DNA were characterized by cyclic voltammetry （CV）. The Au nanoparticles enhanced DNA immobilization resulting in an increased guanine signal. The interaction of the analyte with the immobilized DNA was measured through the variation of the electrochemical signal of guanine by square wave voltammetry （SWV）. The biosensor was able to detect the known genotoxic compounds： 2-anthramine, acridine orange and 2- naphthylamine with detection limits of 2, 3 and 50 nmol/L, respectively. The biosensor was also used to test actual water samples to evaluate the contamination level. Additionally, the comparison of results from the classical genotoxiciw bioassay has confirmed the applicability of the method for real samoles.
文摘A new method of preparing fiber-optic DNA biosensor and its arrayfor the simultaneous detection of multiple genes is described. The optical fibers were first treated with poly-l-lysine, and then were made into fiber-optic DNA biosensors by adsorbing and immobilizing the oligonucleotide probe on its end. By assembling the fiber-optic DNA biosensors in a bundle in which each fiber carried a different DNA probe, the fiber-optic DNA biosensor array was well prepared. Hybridization of fluorescent- labeled cDNA of p53 gene, N-ras gene and Rb1 gene to the DNA array was monitored by CCD camera. A good result was achieved.
基金We gratefully thank the financial support from Shanghai Municipal Science and Technology Project(18430760500 and 2017SHZDZX01)Shanghai Municipal Education Commission Project(ZXWF082101)+1 种基金Shanghai Jiao Tong University Projects(YG2021ZD19,Agri-X20200101,SL2020MS026,19X190020154,ZH2018ZDA01,YG2016QN24,YG2016MS60,2020 SJTU-HUJI,2019 SJTU-Usyd,SD0820016)Shanghai Municipal Health Commission Project(2019CXJQ03),Shanghai Clinical Medical Research Center Project(19MC1910800).
文摘MicroRNAs(miRNAs),as the small,non-coding,evolutionary conserved,and post-transcriptional gene regulators of the genome,have been highly associated with various diseases such as cancers,viral infections,and cardiovascular diseases.Several techniques have been established to detect miRNAs,including northern blotting,real-time polymerase chain reaction(RT-PCR),and fluorescent microarray platform.However,it remains a significant challenge to develop sensitive,accurate,rapid,and cost-effective methods to detect miRNAs due to their short size,high similarity,and low abundance.The electro-chemical biosensors exhibit tremendous potential in miRNA detection because they satisfy feature integration,portability,mass production,short response time,and minimal sample consumption.This article reviewed the working principles and signal amplification strategies of electrochemical DNA biosensors summarized the recent improvements.With the develop-ment of DNA nanotechnology,nanomaterials and biotechnology,electrochemical DNA biosensors of high sensitivity and specificity for microRNA detection will shortly be commercially accessible.
文摘Celestine blue(CB)was introduced as a new electroactive indicator in DNA biosensors.The interaction of CB with DNA was investigated by electrochemical and spectroscopic methods.The effect of buffer kind and p H on the electrochemical behavior of CB was studied.The peak currents of CB were linearly related to DNA concentration in the range of 5.0×10^(-9) to 1.0×10^(-7)mol/L.The detection limit of this approach was 4.76×10^(-10) mol/L.Based on spectrometry data a hypochromic effect was observed in UV-Vis spectra of CB with increasing DNA concentration.The results illustrate the possible interaction mode between CB and DNA is electrostatic binding.
基金supported by the National Natural Science Foundation of China (No. 20707034, 20877091,20890112, 20921063)the National Basic Research Program (973) of China (No. 09CB421605,2010CB933500, 2011CB936001)
文摘An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.
文摘DNA methylation plays a significant role in various biological events, and its precise determination is vital for the prognosis and treatment of cancer. Here, we proposed an ultrasensitive electrochemical biosensor for the quantitative analysis of multiple methylation-locus in DNA sequence via DNA anchoring the gold nanoparticles (DNA-AuNPs) and bienzyme dual signal amplifications. After the target DNA captured by the DNA-AuNPs of the biosensor, the methyl-CpG binding protein MeCP2 could specifically conjugate to the methylation-loci in the double-stranded DNA. Successively, the glucose oxidase (GOD) and horseradish (HRP) co-labeled antibody captured the His tagged MeCP2, which leads to a cascade enzymatic catalysis of the substrates to yield a detectable electrochemical signal. Both the two strategies, including the high content of DNA-AuNPs and the associated catalysis of bienzyme, dramatically enhanced the sensitivity of the biosensor. The response current elevated with the increasing numbers of methylation-locus, thus the multiple methylated DNA was identified by detecting the corresponding current signals. This method could detect the methylated target as low as 0.1 fM, and showed a wide linear range from 10 - 15 M to 10 - 7 M. Besides, the long-term stability and repeatability of the biosensor were also validated. The prepared electrochemical immunosensor exhibits ultrasensitivity through the bienzyme labeling process, which can be applied for the detection of DNA methylation with low concentration.
