In this study,a novel colorimetric detection method for tryptophan is developed using Au@MnO2NPs based on their redox reaction.Tryptophan etches the outer MnO2NPs shell and forms a stable protective layer outside the released AuNPs core in situ,accompanied by a noticeable color change from brown to pink.According to the absorbance ratio of 545 nm and 580 nm(A545/A580),a rapid(within 1 min),accurate,and specific detection method for tryptophan is constructed amidst other common amino acids.Coupling with a smartphone application,integrated Au@MnO2NPs-based portable test strips can be used for the point-of-care testing(POCT)of tryptophan.
Dual-signal electrochemical sensors have inherent self-correction function to overcome disturbances of experimental and environmental factors,but suffer from electrodes'modification or functional materials'preparation,resulting in cumbersome operation,weak stability and poor recognition efficiency.Herein,we propose a dual-signal electrochemical strategy for microRNA senstive detection based on target-driven T7 exonuclease(T7 Exo)-mediated signal amplification that eliminates the above-mentioned drawbacks.The recognition of methylene(MB)and ferrocene(Fc)co-tagged ssDNA(MB/Fc-ssDNA)by miRNA-155 resulted in the formation of double-stranded nucleic acids,which switched T7 Exo-assisted catalytic digestion on MB/Fc-ssDNA,achieving 1:N amplified generation of MB-mononucleotides(mNs)and Fc-mNs.Compared with MB/Fc-ssDNA,MB-mNs and Fc-mNs exhibited significantly declined electrostatic repulsion force toward working electrode,and then simultaneously generated two signals at distinct potentials,in which dual-signal analysis of miRNA-155 was achieved with limit of detection down to~fM level.This work renders a novel thinking concept to develop high-performance electrochemical sensors for early and reliable diagnosis of miRNA-related diseases,advancing the rapid development of intelligent medicines.
Volatile sulfur compounds(VSCs)are major contributors to odor pollution and acid rain formation,making accurate monitoring of atmospheric VSCs levels essential for controlling anthropogenic emissions.In this study,we developed a method for the enrichment and quantification of trace VSCs in actual gas using MIL-53(Al)as preconcentration adsorbent coupled with gas chromatography(GC).We investigated and optimized several factors affecting the efficiency of the method,including adsorbent amount,adsorption temperature,sampling volume,gas flow rate,and desorption temperature.Under optimal experimental conditions,the method demonstrated good linearity in the range of 0.10–26.67 nmol/mol(R2≥0.9968),with low detection limits ranging from 0.03 to 0.11 nmol/mol for ten VSCs.The established method was successfully applied to the enrichment and detection of trace VSCs in four complex actual gas samples,achieving satisfactory recoveries between 82.7%and 109.3%,and good precision with relative standard deviations(RSDs)≤7.12%.This study presents a simple and effective approach for the simultaneous detection of VSCs,offering great potential for VSCs monitoring.
In this study,a novel colorimetric detection method for tryptophan is developed using Au@MnO2NPs based on their redox reaction.Tryptophan etches the outer MnO2NPs shell and forms a stable protective layer outside the released AuNPs core in situ,accompanied by a noticeable color change from brown to pink.According to the absorbance ratio of 545 nm and 580 nm(A545/A580),a rapid(within 1 min),accurate,and specific detection method for tryptophan is constructed amidst other common amino acids.Coupling with a smartphone application,integrated Au@MnO2NPs-based portable test strips can be used for the point-of-care testing(POCT)of tryptophan.
Dual-signal electrochemical sensors have inherent self-correction function to overcome disturbances of experimental and environmental factors,but suffer from electrodes'modification or functional materials'preparation,resulting in cumbersome operation,weak stability and poor recognition efficiency.Herein,we propose a dual-signal electrochemical strategy for microRNA senstive detection based on target-driven T7 exonuclease(T7 Exo)-mediated signal amplification that eliminates the above-mentioned drawbacks.The recognition of methylene(MB)and ferrocene(Fc)co-tagged ssDNA(MB/Fc-ssDNA)by miRNA-155 resulted in the formation of double-stranded nucleic acids,which switched T7 Exo-assisted catalytic digestion on MB/Fc-ssDNA,achieving 1:N amplified generation of MB-mononucleotides(mNs)and Fc-mNs.Compared with MB/Fc-ssDNA,MB-mNs and Fc-mNs exhibited significantly declined electrostatic repulsion force toward working electrode,and then simultaneously generated two signals at distinct potentials,in which dual-signal analysis of miRNA-155 was achieved with limit of detection down to~fM level.This work renders a novel thinking concept to develop high-performance electrochemical sensors for early and reliable diagnosis of miRNA-related diseases,advancing the rapid development of intelligent medicines.
Volatile sulfur compounds(VSCs)are major contributors to odor pollution and acid rain formation,making accurate monitoring of atmospheric VSCs levels essential for controlling anthropogenic emissions.In this study,we developed a method for the enrichment and quantification of trace VSCs in actual gas using MIL-53(Al)as preconcentration adsorbent coupled with gas chromatography(GC).We investigated and optimized several factors affecting the efficiency of the method,including adsorbent amount,adsorption temperature,sampling volume,gas flow rate,and desorption temperature.Under optimal experimental conditions,the method demonstrated good linearity in the range of 0.10–26.67 nmol/mol(R2≥0.9968),with low detection limits ranging from 0.03 to 0.11 nmol/mol for ten VSCs.The established method was successfully applied to the enrichment and detection of trace VSCs in four complex actual gas samples,achieving satisfactory recoveries between 82.7%and 109.3%,and good precision with relative standard deviations(RSDs)≤7.12%.This study presents a simple and effective approach for the simultaneous detection of VSCs,offering great potential for VSCs monitoring.
In this study,a novel colorimetric detection method for tryptophan is developed using Au@MnO2NPs based on their redox reaction.Tryptophan etches the outer MnO2NPs shell and forms a stable protective layer outside the released AuNPs core in situ,accompanied by a noticeable color change from brown to pink.According to the absorbance ratio of 545 nm and 580 nm(A545/A580),a rapid(within 1 min),accurate,and specific detection method for tryptophan is constructed amidst other common amino acids.Coupling with a smartphone application,integrated Au@MnO2NPs-based portable test strips can be used for the point-of-care testing(POCT)of tryptophan.
Dual-signal electrochemical sensors have inherent self-correction function to overcome disturbances of experimental and environmental factors,but suffer from electrodes'modification or functional materials'preparation,resulting in cumbersome operation,weak stability and poor recognition efficiency.Herein,we propose a dual-signal electrochemical strategy for microRNA senstive detection based on target-driven T7 exonuclease(T7 Exo)-mediated signal amplification that eliminates the above-mentioned drawbacks.The recognition of methylene(MB)and ferrocene(Fc)co-tagged ssDNA(MB/Fc-ssDNA)by miRNA-155 resulted in the formation of double-stranded nucleic acids,which switched T7 Exo-assisted catalytic digestion on MB/Fc-ssDNA,achieving 1:N amplified generation of MB-mononucleotides(mNs)and Fc-mNs.Compared with MB/Fc-ssDNA,MB-mNs and Fc-mNs exhibited significantly declined electrostatic repulsion force toward working electrode,and then simultaneously generated two signals at distinct potentials,in which dual-signal analysis of miRNA-155 was achieved with limit of detection down to~fM level.This work renders a novel thinking concept to develop high-performance electrochemical sensors for early and reliable diagnosis of miRNA-related diseases,advancing the rapid development of intelligent medicines.
Volatile sulfur compounds(VSCs)are major contributors to odor pollution and acid rain formation,making accurate monitoring of atmospheric VSCs levels essential for controlling anthropogenic emissions.In this study,we developed a method for the enrichment and quantification of trace VSCs in actual gas using MIL-53(Al)as preconcentration adsorbent coupled with gas chromatography(GC).We investigated and optimized several factors affecting the efficiency of the method,including adsorbent amount,adsorption temperature,sampling volume,gas flow rate,and desorption temperature.Under optimal experimental conditions,the method demonstrated good linearity in the range of 0.10–26.67 nmol/mol(R2≥0.9968),with low detection limits ranging from 0.03 to 0.11 nmol/mol for ten VSCs.The established method was successfully applied to the enrichment and detection of trace VSCs in four complex actual gas samples,achieving satisfactory recoveries between 82.7%and 109.3%,and good precision with relative standard deviations(RSDs)≤7.12%.This study presents a simple and effective approach for the simultaneous detection of VSCs,offering great potential for VSCs monitoring.
