The extracellular vesicles show great potential as a noninvasive biomarker for the early detection of cancer.Hence,there is an urgent requirement to create biosensors that are time-saving,simple,and easily scalable in...The extracellular vesicles show great potential as a noninvasive biomarker for the early detection of cancer.Hence,there is an urgent requirement to create biosensors that are time-saving,simple,and easily scalable in order to accomplish rapid,sensitive,and quantitative detection of extracellular vesicles.In this study,we present a self-propelled DNA walker powered by endonuclease Nt.Bbv CI,which enables the development of a“signal on”sensing platform for the rapid and highly sensitive detection of extracellular vesicles.The DNA motor employed tracks made of streptavidin magnetic beads,which consisted of substrate strands labeled with fluorescein and motor strands locked by aptamers.The aptamer recognition of the target protein on extracellular vesicles unlocked the motor strand,initiating the DNA motor process.After replacing the optimal buffer solution containing the endonuclease Nt.BbvC I,the motor strands autonomously moved along the streptavidin magnetic beads track,continuously releasing fluorescent molecules and producing detectable fluorescence signals.Under optimal conditions,the detection range was from 2×10~4particles/mL to 2×10~9particles/mL,with a detection limit of 2.9×10~3particles/mL,demonstrating excellent selectivity.This method has demonstrated good selectivity in different tumorderived extracellular vesicles and performs well in complex biological samples.The ability to effectively analyze surface proteins of extracellular vesicles in a short period of time gives our DNA walker a tremendous potential for developing simple and cost-effective clinical diagnostic devices.展开更多
An improved ssDNA library immobilized systematic evolution of ligands by enrichment(SELEX)was applied to select aptamers against carbaryl.After nine selection rounds,a highly enriched ssDNA pool was obtained.The Apta3...An improved ssDNA library immobilized systematic evolution of ligands by enrichment(SELEX)was applied to select aptamers against carbaryl.After nine selection rounds,a highly enriched ssDNA pool was obtained.The Apta3 was demonstrated as the optimal aptame r.In order to facilitate the modification of aptamer,the Apta3 was further truncated with the dissociation constant(K_(d))of 0.364±0.055μmol/L and a fluorescent aptasensor was developed.The linear range for carbaryl was from 100 nmol/L to1500 nmol/L,with the limit of detection was as low as 15.23 nmol/L.Besides,the biosensor was validated for the carbaryl spiked real samples,and the recoveries were between 97.7%and 107.3%.展开更多
A new α-fetoprotein-MIP(AFP-MIP) immunosensor based on glass carbon electrode(GCE) modified with polythionine(PTh) and gold nanoparticles(AuNPs) was successfully fabricated for sensitive detection ofα-fetoprotein(AF...A new α-fetoprotein-MIP(AFP-MIP) immunosensor based on glass carbon electrode(GCE) modified with polythionine(PTh) and gold nanoparticles(AuNPs) was successfully fabricated for sensitive detection ofα-fetoprotein(AFP). Through controlling electropolymerization, A "polydopamine(PDA)-AFP" complex was achieved applying AFP as template and dopamine(DA) as imprinted monomers. After elution, the specific cavities can adsorb the target molecules. Using differential pulse voltammetry(DPV) detection,the peak current decreased with the increase in concentration of AFP, and the linear response range of the AFP-MIP immunosensor was from 0.001 ng/mL to 800 ng/mL with the detection limit as low as0.8138 pg/mL. The MIP immunosensor could become a new promising method for the detection of AFP.Furthermore, this MIP sensor was demonstrated in testing AFP in human serum samples with satisfactory results.展开更多
In this work, a simple gold nanoparticles(Au NPs) based colorimetric biosensor was developed for chlorpyrifos(Chl) detection using an aptamer as the capture probe. The Chl-aptamer with low dissociation constant(Kd) of...In this work, a simple gold nanoparticles(Au NPs) based colorimetric biosensor was developed for chlorpyrifos(Chl) detection using an aptamer as the capture probe. The Chl-aptamer with low dissociation constant(Kd) of 58.59 ± 6.08 nmol/L was selected by ss DNA library immobilized systematic evolution of ligands by enrichment(SELEX). In the absence of Chl, the Chl-aptamer acted as the stabilizer for Au NPs in salt solution. In the presence of Chl, the highly specific Chl-aptamer bound with Chl targets immediately,thus a self-aggregation of Au NPs induced by salt was displayed. The fabricated colorimetric aptasensor exhibited an excellent sensitivity for Chl detection with the LOD as low as 14.46 nmol/L. In addition, the aptasensor was applied to test Chl in tap water, cucumber and cabbage samples, the excellent recoveries with acceptable RSD values below 5% demonstrated that the method can be considered as a promising tool for simple, rapid Chl detection.展开更多
Diarrhea,as a global public health problem,causes a large number of infections and deaths every year.Although Escherichia coli(E.coli)is one of the normal flo ra microorganisms in the human intestinal tract,it has fiv...Diarrhea,as a global public health problem,causes a large number of infections and deaths every year.Although Escherichia coli(E.coli)is one of the normal flo ra microorganisms in the human intestinal tract,it has five pathogenic bacteria types that can cause human diarrhea,known as diarrheagenic E.coli.When people are infected,rapid and accurate diagnosis,along with timely treatment,are especially important.Here,we introduce a new method to identify and analyze a large number of pathogenic strains in E.coli by multiplex PCR and barcoded magnetic bead hybridization.Results show that the detection sensitivities of enterohemorrhagic E.coli,enterotoxigenic E.coli,enteropathogenic E.coli,enteroinvasive E.coli and enteroaggregative E.coli were 1.3×10^3 CFU/mL,2×10^4 CFU/mL,4×10^4 CFU/mL,7.2×10^4 CFU/mL and 1.7 CFU/mL respectively.This method has strong specificity and high sensitivity and detects multiple target sequences in one experiment.Compared with other methods,BMB array has great application potential.展开更多
A novel gold-label silver-stain electrochemical immunosensor was developed based on polythioninegold nanoparticles（PTh-Au） modified glassy carbon electrode（GCE） as a platform and secondary antibody labeled Au NPs...A novel gold-label silver-stain electrochemical immunosensor was developed based on polythioninegold nanoparticles（PTh-Au） modified glassy carbon electrode（GCE） as a platform and secondary antibody labeled Au NPs（Ab;-Au） as immumoprobe for carcinoembryonic antigen（CEA） detection. The sandwich-type biosensor adopted anodic stripping voltammetry to detect silver stripping signal when the Ab;-Au of the formed immunocomplexes were stained with silver. The optimized detection conditions were investigated. The effect of different electrochemical responses at various concentrations of CEA was checked by anodic stripping voltammetry. This immunosensor showed a low detection limit of 0.055 ng/mL and a wide linear calibration of 0.1-120 ng/mL（R;=0.99856）. Moreover, this immunoassay also existed the advantages of good reproducibility, stability and selectivity. Thus, this immunosensing protocol may provide a potential application for effective clinical detection of CEA.展开更多
基金supported financially by the National Natural Science Foundation of China(NSFC,Nos.62071119 and 62075098)the National Key Research and Development Program of China(Nos.2017YFA0205301 and 2018YFC1602905)。
文摘The extracellular vesicles show great potential as a noninvasive biomarker for the early detection of cancer.Hence,there is an urgent requirement to create biosensors that are time-saving,simple,and easily scalable in order to accomplish rapid,sensitive,and quantitative detection of extracellular vesicles.In this study,we present a self-propelled DNA walker powered by endonuclease Nt.Bbv CI,which enables the development of a“signal on”sensing platform for the rapid and highly sensitive detection of extracellular vesicles.The DNA motor employed tracks made of streptavidin magnetic beads,which consisted of substrate strands labeled with fluorescein and motor strands locked by aptamers.The aptamer recognition of the target protein on extracellular vesicles unlocked the motor strand,initiating the DNA motor process.After replacing the optimal buffer solution containing the endonuclease Nt.BbvC I,the motor strands autonomously moved along the streptavidin magnetic beads track,continuously releasing fluorescent molecules and producing detectable fluorescence signals.Under optimal conditions,the detection range was from 2×10~4particles/mL to 2×10~9particles/mL,with a detection limit of 2.9×10~3particles/mL,demonstrating excellent selectivity.This method has demonstrated good selectivity in different tumorderived extracellular vesicles and performs well in complex biological samples.The ability to effectively analyze surface proteins of extracellular vesicles in a short period of time gives our DNA walker a tremendous potential for developing simple and cost-effective clinical diagnostic devices.
基金financially supported by the National Key Research and Development Program of China(No.2018YFC1602905)the National Natural Science Foundation of China(Nos.61527806 and 61871180)。
文摘An improved ssDNA library immobilized systematic evolution of ligands by enrichment(SELEX)was applied to select aptamers against carbaryl.After nine selection rounds,a highly enriched ssDNA pool was obtained.The Apta3 was demonstrated as the optimal aptame r.In order to facilitate the modification of aptamer,the Apta3 was further truncated with the dissociation constant(K_(d))of 0.364±0.055μmol/L and a fluorescent aptasensor was developed.The linear range for carbaryl was from 100 nmol/L to1500 nmol/L,with the limit of detection was as low as 15.23 nmol/L.Besides,the biosensor was validated for the carbaryl spiked real samples,and the recoveries were between 97.7%and 107.3%.
基金the National Natural Science Foundation of China (Nos. 61471168, 61571187)China Postdoctoral Science Foundation (No. 2016T90403)+2 种基金Postdoctoral Science Foundation of Jiangsu Province (No. 1601021A)the Natural Science Foundation of Hunan Province (No. 2017JJ209) Hunan Key Research Project (No. 2017SK2174) for the financial supports
文摘A new α-fetoprotein-MIP(AFP-MIP) immunosensor based on glass carbon electrode(GCE) modified with polythionine(PTh) and gold nanoparticles(AuNPs) was successfully fabricated for sensitive detection ofα-fetoprotein(AFP). Through controlling electropolymerization, A "polydopamine(PDA)-AFP" complex was achieved applying AFP as template and dopamine(DA) as imprinted monomers. After elution, the specific cavities can adsorb the target molecules. Using differential pulse voltammetry(DPV) detection,the peak current decreased with the increase in concentration of AFP, and the linear response range of the AFP-MIP immunosensor was from 0.001 ng/mL to 800 ng/mL with the detection limit as low as0.8138 pg/mL. The MIP immunosensor could become a new promising method for the detection of AFP.Furthermore, this MIP sensor was demonstrated in testing AFP in human serum samples with satisfactory results.
基金financially supported by the National Key Research and Development Program of China (No. 2018YFC1602905)the National Natural Science Foundation of China (Nos.61871180 and 61527806) for the financial supports。
文摘In this work, a simple gold nanoparticles(Au NPs) based colorimetric biosensor was developed for chlorpyrifos(Chl) detection using an aptamer as the capture probe. The Chl-aptamer with low dissociation constant(Kd) of 58.59 ± 6.08 nmol/L was selected by ss DNA library immobilized systematic evolution of ligands by enrichment(SELEX). In the absence of Chl, the Chl-aptamer acted as the stabilizer for Au NPs in salt solution. In the presence of Chl, the highly specific Chl-aptamer bound with Chl targets immediately,thus a self-aggregation of Au NPs induced by salt was displayed. The fabricated colorimetric aptasensor exhibited an excellent sensitivity for Chl detection with the LOD as low as 14.46 nmol/L. In addition, the aptasensor was applied to test Chl in tap water, cucumber and cabbage samples, the excellent recoveries with acceptable RSD values below 5% demonstrated that the method can be considered as a promising tool for simple, rapid Chl detection.
基金the National Natural Science Foundation of China(Nos.61971187,61571187,61871180)Education Department Outstanding Young Project of Hunan Province(No.18B299)。
文摘Diarrhea,as a global public health problem,causes a large number of infections and deaths every year.Although Escherichia coli(E.coli)is one of the normal flo ra microorganisms in the human intestinal tract,it has five pathogenic bacteria types that can cause human diarrhea,known as diarrheagenic E.coli.When people are infected,rapid and accurate diagnosis,along with timely treatment,are especially important.Here,we introduce a new method to identify and analyze a large number of pathogenic strains in E.coli by multiplex PCR and barcoded magnetic bead hybridization.Results show that the detection sensitivities of enterohemorrhagic E.coli,enterotoxigenic E.coli,enteropathogenic E.coli,enteroinvasive E.coli and enteroaggregative E.coli were 1.3×10^3 CFU/mL,2×10^4 CFU/mL,4×10^4 CFU/mL,7.2×10^4 CFU/mL and 1.7 CFU/mL respectively.This method has strong specificity and high sensitivity and detects multiple target sequences in one experiment.Compared with other methods,BMB array has great application potential.
基金financial supports of the National Natural Science Foundation of China(Nos.61471168,61571187)China Postdoctoral Science Foundation(No.2016T90403)+2 种基金Postdoctoral Science Foundation of Jiangsu Province(No.1601021A)the Natural Science Foundation of Hunan Province(No.2017JJ209)Hunan Key Research Project(No.2017SK2174)
文摘A novel gold-label silver-stain electrochemical immunosensor was developed based on polythioninegold nanoparticles（PTh-Au） modified glassy carbon electrode（GCE） as a platform and secondary antibody labeled Au NPs（Ab;-Au） as immumoprobe for carcinoembryonic antigen（CEA） detection. The sandwich-type biosensor adopted anodic stripping voltammetry to detect silver stripping signal when the Ab;-Au of the formed immunocomplexes were stained with silver. The optimized detection conditions were investigated. The effect of different electrochemical responses at various concentrations of CEA was checked by anodic stripping voltammetry. This immunosensor showed a low detection limit of 0.055 ng/mL and a wide linear calibration of 0.1-120 ng/mL（R;=0.99856）. Moreover, this immunoassay also existed the advantages of good reproducibility, stability and selectivity. Thus, this immunosensing protocol may provide a potential application for effective clinical detection of CEA.
