Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed f...Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed for rapid and sensitive detection of S.typhimurium.First,the bacterial sample,the magnetic nanoparticles(MNPs)modified with capture antibodies,and the enzymatic probes modified with detection antibodies and glucose oxidase(GOx)were simultaneously injected into the microfluidic chip,followed by mixing and incubation to form MNP-bacteria-probe sandwich complexes.Then,glucose with high impedance was injected into the chip and catalyzed by the GOx on the complexes into hydrogen peroxide with high impedance and gluconic acid with low impedance,which was finally measured using the low-cost interdigitated microelectrode and the electrochemical impedance analyzer to determine the target bacteria.Under the optimal conditions,this biosensor could quantitatively detect S.typhimurium at the concentrations from 1.6×10^(2) CFU/m L to 1.6×10^(6) CFU/m L in 1 h with the low detection limit of 73 CFU/m L.Besides,this biosensor was demonstrated with good feasibility for practical applications by detecting the S.typhimurium spiked chicken meat samples.展开更多
Although metal nanoclusters(NCs)are ideal building units,significant challenges remain in manipulating their gathering and tuning the as-obtained aggregate properties.Herein,we introduce an electro-driven strategy and...Although metal nanoclusters(NCs)are ideal building units,significant challenges remain in manipulating their gathering and tuning the as-obtained aggregate properties.Herein,we introduce an electro-driven strategy and reveal the voltage-dependent assembly on interdigitated microelectrodes based on Au_(25)NCs:crystallizing at 0.5 V,NC-based filming at 1.3 V,and nanocrystal-based filming at 2.6 V.More interestingly,the film formed at 2.6 V can be varied from an insulator to a conductor,and even such a large conductivity tunability(from∞to∼0.3Ω)can be extended to the films formed from some other metal NCs such as Au_(25),Pt_(23),and Pd_(8).The as-obtained films show novel,promising properties not found in molecular NCs,as illustrated by the electrothermy and current-limiting properties.Thus,this work not only provides a novel strategy for metal NCs’gathering but also pioneers metal NC-based electro-manufacturing for novel findings and potential applications.展开更多
文摘Rapid screening of foodborne pathogens is of great significance to ensure food safety.A microfluidic biosensor based on immunomagnetic separation,enzyme catalysis and electrochemical impedance analysis was developed for rapid and sensitive detection of S.typhimurium.First,the bacterial sample,the magnetic nanoparticles(MNPs)modified with capture antibodies,and the enzymatic probes modified with detection antibodies and glucose oxidase(GOx)were simultaneously injected into the microfluidic chip,followed by mixing and incubation to form MNP-bacteria-probe sandwich complexes.Then,glucose with high impedance was injected into the chip and catalyzed by the GOx on the complexes into hydrogen peroxide with high impedance and gluconic acid with low impedance,which was finally measured using the low-cost interdigitated microelectrode and the electrochemical impedance analyzer to determine the target bacteria.Under the optimal conditions,this biosensor could quantitatively detect S.typhimurium at the concentrations from 1.6×10^(2) CFU/m L to 1.6×10^(6) CFU/m L in 1 h with the low detection limit of 73 CFU/m L.Besides,this biosensor was demonstrated with good feasibility for practical applications by detecting the S.typhimurium spiked chicken meat samples.
基金National Natural Science Foundation of China(Nos.22471275,92475105,22403096,21925303,U24A20480,21829501,22075291,21771186,21528303,21222301,and 21171170)Hefei Institute of Physical Science,Chinese Academy of Sciences(BR-E44BGGBR12B)+4 种基金CASHIPS Director’s Fund(BJPY2019A02 and YZJJ-GGZX-2022-01)Key Program of 13th five-year plan,CASHIPS(KP-2017-16)Collaborative Innovation Program of Hefei Center for Physical Science and Technology(2020HSC-CIP005 and 2022HSC-CIP018)the Anhui Provincial Natural Science Foundation(2408085QB040)the China Postdoctoral Science Foundation(2024M763306).
文摘Although metal nanoclusters(NCs)are ideal building units,significant challenges remain in manipulating their gathering and tuning the as-obtained aggregate properties.Herein,we introduce an electro-driven strategy and reveal the voltage-dependent assembly on interdigitated microelectrodes based on Au_(25)NCs:crystallizing at 0.5 V,NC-based filming at 1.3 V,and nanocrystal-based filming at 2.6 V.More interestingly,the film formed at 2.6 V can be varied from an insulator to a conductor,and even such a large conductivity tunability(from∞to∼0.3Ω)can be extended to the films formed from some other metal NCs such as Au_(25),Pt_(23),and Pd_(8).The as-obtained films show novel,promising properties not found in molecular NCs,as illustrated by the electrothermy and current-limiting properties.Thus,this work not only provides a novel strategy for metal NCs’gathering but also pioneers metal NC-based electro-manufacturing for novel findings and potential applications.
