Main observation and conclusion An enzyme-free amperometric sensor based on a heptadecapeptide possessing an electroactive ferrocene(Fc)linker as ferrocene-Gly-Gly-Gly-Gly-Phe-Gly-His-Ile-His-Glu-Gly-Tyr-Gly-Gly-Gly-G...Main observation and conclusion An enzyme-free amperometric sensor based on a heptadecapeptide possessing an electroactive ferrocene(Fc)linker as ferrocene-Gly-Gly-Gly-Gly-Phe-Gly-His-Ile-His-Glu-Gly-Tyr-Gly-Gly-Gly-Gly-Lys-(CH_(2))_(4)-dithiocyclopentane self-assembled on gold substrate was designed and fabricated for specific determination of L-arginine(L-Arg).The detection mechanism is based on conformational change of surface-immobilized peptide induced by the target L-Arg,which was confirmed via SEM,TEM,AFM,XPS,and SPR studies.The binding affinity and the recognition feasibility of immobilized specific and non-specific peptides were also assessed using electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV),and differential pulse voltammetry(DPV).The proposed method can serve as“signal-on”sensor for detection of L-Arg down to 31 pmol/L with broad linear range(0.0001 to 10μmol/L).Furthermore,the Fc-conjugated specific peptide sensor was successfully applied to the determination of L-Arg in pig serums with a recovery rate of 97.5%—106.9%,and its test results are in good agreement with that of chromatographic instrument,evidencing that the oligopeptide-based sensor can be served as a simple and enzyme-free biosensing platform towards L-Arg for future application.展开更多
A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide...A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10^-7 to 6.8×10^-5 mol·L^-1, and the detection limit was 7.2×10^-8 mol·L^-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.展开更多
This paper presents a low noise complimentary metal-oxide-semiconductor（CMOS） detection chip for amperometric electrochemical sensors.In order to effectively remove the input offset of the cascaded integrators and t...This paper presents a low noise complimentary metal-oxide-semiconductor（CMOS） detection chip for amperometric electrochemical sensors.In order to effectively remove the input offset of the cascaded integrators and the low frequency noise in the modulator,a novel offset cancellation chopping scheme was proposed in the Incremental AS analog to digital converter（IADC）.A novel low power potentiostat was employed in this chip to provide the biasing voltage for the sensor while mirroring the sensor current out for detection.The chip communicates with FPGA through standard built in I2 C interface and SPI bus.Fabricated in 0.18-μm CMOS process,this chip detects current signal with high accuracy and high linearity.A prototype microsystem was produced to verify the detection chip performance with current input as well as micro-sensors.展开更多
A new type of solid polymer electrolyte based on polyacrylonitrile (PAN )-dimethylsulfoxide (DMSO)-tetrabutylammonium perchlorate (TBAP) system has been prepared. The ionic conductivities of such solid-electrolytes re...A new type of solid polymer electrolyte based on polyacrylonitrile (PAN )-dimethylsulfoxide (DMSO)-tetrabutylammonium perchlorate (TBAP) system has been prepared. The ionic conductivities of such solid-electrolytes reach values as high as 10-4 S. cm-1 at room temperature. At proper content of each component in the solid-electrolyte the polymeric film has a porous network microstructure of three dimen-sions,and exhibits a good level of mechanical properties and dimensional stability. The full-solid-state elec-trochemical cell contains two coplanar electrodes coated by a thin layer of PAN-DMSO-TBAP solid-elec-trolyte: a Au microdisk as working electrode and a Ag ring counter/reference electrode. This study has shown that the integrated two-electrode assembly can be directly used for the amperometric solid-state car-bon dioxide gas sensor devices,and it shows good response characteristics for direct amperometric determi-nation of the CO2 concentration in the gas phase. Also, such full-solid-state amperometric sensor devices possess their own original advantages.展开更多
Here,we report a comprehensive study on the characterization of cotton biomass residue,its conversion into carbon-based materials via pyrolysis,and its application as an electrochemical sensor for ascorbic acid(AA).Th...Here,we report a comprehensive study on the characterization of cotton biomass residue,its conversion into carbon-based materials via pyrolysis,and its application as an electrochemical sensor for ascorbic acid(AA).The compositions,morphologies,and structures of the resulting materials were investigated using XRD,FTIR,TGA,SEM,and EDS.Pyrolysis was carried out in an air atmosphere at different temperatures(300℃ and 400℃)and durations(1,60,and 240min),leading to the transformation of lignocellulosic cotton residue into carbon-basedmaterials embedded with inorganic nanoparticles,including carbonates,sulfates,chlorates,and phosphates of potassium,calcium,and magnesium.These inorganic nanoparticles exhibited irregular shapes with sizes ranging from 50 to 150 nm.The pyrolysis conditions significantly influenced both the mass ratio and the crystallinity of the inorganic phases,with treatment at 400℃ for 60 min resulting in enhanced crystallinity and an inorganic content of 54.4%.The cotton biomass-based nanomaterials were used in the construction of carbon paste electrodes(CPEs)and evaluated in PBS for AA oxidation.The electrocatalytic performance increased with the inorganic nanoparticle content.Among all,the sample pyrolyzed at 400℃ for 60 min demonstrated the highest sensitivity(3.31±0.16μA(mmol⋅L^(−1)),along with low limits of detection(2.90±1.87μmol⋅L^(−1))and quantification(9.66±6.23μmol⋅L^(−1)).These promising sensor characteristics highlight the potential of cotton biomass residue as a renewable source of electroactive nanomaterials,considering the simplicity of the carbon material preparation process and the ease of electrode fabrication.展开更多
Au nanoparticles(AuNPs)were prepared by reducing HAuCl4 with NaBH4,and then adsorbed uniformly on the surface of carboxylated nanocrystalline cellulose(CNCC).The obtained AuNPs/CNCC particles were doped into a conduct...Au nanoparticles(AuNPs)were prepared by reducing HAuCl4 with NaBH4,and then adsorbed uniformly on the surface of carboxylated nanocrystalline cellulose(CNCC).The obtained AuNPs/CNCC particles were doped into a conductive polymer of poly(3,4-ethylenedioxythiophene)(PEDOT)to yield a highly conductive nanocomposite,which was deposited onto a glassy carbon electrode(GCE)by an electrochemical method.The PEDOT/AuNPs/CNCC nanocomposite showed low electrochemical impedance and good electrocatalytic activity toward ascorbic acid.Based on this novel nanocomposite material,an amperometric sensor was developed for the detection of ascorbic acid with a detection limit as low as 0.29μM.When operated at-0.15 V,the sensor detected ascorbic acid in the range of 0.88μM to 15000μM.展开更多
This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further deliver...This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further delivering a 10-bit digital output.A fast stabilization-enhanced potentiostat has been proposed in the design, which is used to maintain a constant bias potential for amperometric biochemical sensors.A technique based on source voltage shifting that reduces the leakage current of the MOS transistor to the reverse diode leakage level at room temperature was employed in the circuit.The chip was fabricated in the 0.35 μm chartered CMOS process, with a single 3.3 V power supply.The interface circuit maintains a dynamic range of more than 100 dB.Currents from 1 pA to 300 nA can be detected with a maximum nonlinearity of 0.3% over the full scale.展开更多
基金supported by the projects of the National Natural Science Foundation of China(Nos.31527803,21545010,21275022 and 21645009)the Natural Science Foundation of Hunan Province,China(Nos.2020JJ4599,2019JJ50651).
文摘Main observation and conclusion An enzyme-free amperometric sensor based on a heptadecapeptide possessing an electroactive ferrocene(Fc)linker as ferrocene-Gly-Gly-Gly-Gly-Phe-Gly-His-Ile-His-Glu-Gly-Tyr-Gly-Gly-Gly-Gly-Lys-(CH_(2))_(4)-dithiocyclopentane self-assembled on gold substrate was designed and fabricated for specific determination of L-arginine(L-Arg).The detection mechanism is based on conformational change of surface-immobilized peptide induced by the target L-Arg,which was confirmed via SEM,TEM,AFM,XPS,and SPR studies.The binding affinity and the recognition feasibility of immobilized specific and non-specific peptides were also assessed using electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV),and differential pulse voltammetry(DPV).The proposed method can serve as“signal-on”sensor for detection of L-Arg down to 31 pmol/L with broad linear range(0.0001 to 10μmol/L).Furthermore,the Fc-conjugated specific peptide sensor was successfully applied to the determination of L-Arg in pig serums with a recovery rate of 97.5%—106.9%,and its test results are in good agreement with that of chromatographic instrument,evidencing that the oligopeptide-based sensor can be served as a simple and enzyme-free biosensing platform towards L-Arg for future application.
基金This research was supported by the National Natural Science Foundation of China. （Nos. 60571042 and 30370397）
文摘A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10^-7 to 6.8×10^-5 mol·L^-1, and the detection limit was 7.2×10^-8 mol·L^-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.
基金supported by the State Key Development Program for Basic Research of China(No.2015CB352100)
文摘This paper presents a low noise complimentary metal-oxide-semiconductor（CMOS） detection chip for amperometric electrochemical sensors.In order to effectively remove the input offset of the cascaded integrators and the low frequency noise in the modulator,a novel offset cancellation chopping scheme was proposed in the Incremental AS analog to digital converter（IADC）.A novel low power potentiostat was employed in this chip to provide the biasing voltage for the sensor while mirroring the sensor current out for detection.The chip communicates with FPGA through standard built in I2 C interface and SPI bus.Fabricated in 0.18-μm CMOS process,this chip detects current signal with high accuracy and high linearity.A prototype microsystem was produced to verify the detection chip performance with current input as well as micro-sensors.
文摘A new type of solid polymer electrolyte based on polyacrylonitrile (PAN )-dimethylsulfoxide (DMSO)-tetrabutylammonium perchlorate (TBAP) system has been prepared. The ionic conductivities of such solid-electrolytes reach values as high as 10-4 S. cm-1 at room temperature. At proper content of each component in the solid-electrolyte the polymeric film has a porous network microstructure of three dimen-sions,and exhibits a good level of mechanical properties and dimensional stability. The full-solid-state elec-trochemical cell contains two coplanar electrodes coated by a thin layer of PAN-DMSO-TBAP solid-elec-trolyte: a Au microdisk as working electrode and a Ag ring counter/reference electrode. This study has shown that the integrated two-electrode assembly can be directly used for the amperometric solid-state car-bon dioxide gas sensor devices,and it shows good response characteristics for direct amperometric determi-nation of the CO2 concentration in the gas phase. Also, such full-solid-state amperometric sensor devices possess their own original advantages.
基金financial support of Brazilian agencies FAPESC/ACAFE,CAPES,CNPq and Nationals Institutes of Science and Technology of Carbon Nanomaterials(INCT-Nanocarbon,421701/2017-0)Nanomaterials for Life(INCT Nano Life,406079/2022-6)+2 种基金J.P.M.C.A.acknowledges his scientific initiation(PIBIT)grant from CNPq,D.O.S.thanks CAPES for his post-doctoral grant(PNPD/CAPES 2017-2019)J.A.is grateful for his grant from CNPq(CNPq 303633/2023-9)the financial support from FAPESC through various projects(contracts:2018TR1546,2023TR001521 and 2024TR002662).
文摘Here,we report a comprehensive study on the characterization of cotton biomass residue,its conversion into carbon-based materials via pyrolysis,and its application as an electrochemical sensor for ascorbic acid(AA).The compositions,morphologies,and structures of the resulting materials were investigated using XRD,FTIR,TGA,SEM,and EDS.Pyrolysis was carried out in an air atmosphere at different temperatures(300℃ and 400℃)and durations(1,60,and 240min),leading to the transformation of lignocellulosic cotton residue into carbon-basedmaterials embedded with inorganic nanoparticles,including carbonates,sulfates,chlorates,and phosphates of potassium,calcium,and magnesium.These inorganic nanoparticles exhibited irregular shapes with sizes ranging from 50 to 150 nm.The pyrolysis conditions significantly influenced both the mass ratio and the crystallinity of the inorganic phases,with treatment at 400℃ for 60 min resulting in enhanced crystallinity and an inorganic content of 54.4%.The cotton biomass-based nanomaterials were used in the construction of carbon paste electrodes(CPEs)and evaluated in PBS for AA oxidation.The electrocatalytic performance increased with the inorganic nanoparticle content.Among all,the sample pyrolyzed at 400℃ for 60 min demonstrated the highest sensitivity(3.31±0.16μA(mmol⋅L^(−1)),along with low limits of detection(2.90±1.87μmol⋅L^(−1))and quantification(9.66±6.23μmol⋅L^(−1)).These promising sensor characteristics highlight the potential of cotton biomass residue as a renewable source of electroactive nanomaterials,considering the simplicity of the carbon material preparation process and the ease of electrode fabrication.
基金supported by the National Natural Science Foundation of China(21422504 and 21275087)the Natural Science Foundation of Shandong Province of China(JQ201406).
文摘Au nanoparticles(AuNPs)were prepared by reducing HAuCl4 with NaBH4,and then adsorbed uniformly on the surface of carboxylated nanocrystalline cellulose(CNCC).The obtained AuNPs/CNCC particles were doped into a conductive polymer of poly(3,4-ethylenedioxythiophene)(PEDOT)to yield a highly conductive nanocomposite,which was deposited onto a glassy carbon electrode(GCE)by an electrochemical method.The PEDOT/AuNPs/CNCC nanocomposite showed low electrochemical impedance and good electrocatalytic activity toward ascorbic acid.Based on this novel nanocomposite material,an amperometric sensor was developed for the detection of ascorbic acid with a detection limit as low as 0.29μM.When operated at-0.15 V,the sensor detected ascorbic acid in the range of 0.88μM to 15000μM.
基金supported by the National High-Tech Research and Development Program of China(No.2007AA04Z349)
文摘This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further delivering a 10-bit digital output.A fast stabilization-enhanced potentiostat has been proposed in the design, which is used to maintain a constant bias potential for amperometric biochemical sensors.A technique based on source voltage shifting that reduces the leakage current of the MOS transistor to the reverse diode leakage level at room temperature was employed in the circuit.The chip was fabricated in the 0.35 μm chartered CMOS process, with a single 3.3 V power supply.The interface circuit maintains a dynamic range of more than 100 dB.Currents from 1 pA to 300 nA can be detected with a maximum nonlinearity of 0.3% over the full scale.
