Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most prominent cause of dementia.In 2019,over 57.4million people were living with AD and other dementia subtypes,a number which is ex...Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most prominent cause of dementia.In 2019,over 57.4million people were living with AD and other dementia subtypes,a number which is expected to increase to over 152.8 million in the next 25years.This ever-increasing burden has resulted in AD and other neurodegenerative diseases rising to one of the top 10 causes of death globally (O'Connell et al.,2024).展开更多
A microelectrode array（MEA） is presented, which is composed of 60 independent electrodes with 59 working ones and one reference one, and they are divided into 30 pairs. Except for the reference electrode, each pair ...A microelectrode array（MEA） is presented, which is composed of 60 independent electrodes with 59 working ones and one reference one, and they are divided into 30 pairs. Except for the reference electrode, each pair consists of one stimulating electrode and one recording electrode. Supported by the peripheral circuits, four electrode states to study the bioelectrical signal of biological tissue or slice cultured in-vitro on the surface of the electrodes can be realized through each pair of electrodes. The four electrode states are stimulation, recording, stimulation and recording simultaneously, and isolation. The state of each pair of working electrodes can be arbitrarily controlled according to actual needs. The MEAs are fabricated in printed circuit board （PCB） technology. The total area of the PCB-based MEA is 49 mm × 49 mm. The impedance measurement of MEA is carried out in 0.9% sodium chloride solution at room temperature by means of 2-point measurements with an Agilent LCR meter, and the test signal for the impedance measurement is sinusoidal （AC voltage 50 mV, sweeping frequency 20 Hz to 10 kHz）. The electrode impedance is between 200 and 3 kΩ while the frequency is between 500 and 1 000 Hz. The electrode impedance magnitude is inversely proportional to the frequency. Experiments of toad sciatic nerve in-vitro stimulation and recording and signal regeneration between isolated toad sciatic nerves are carried out on the PCB-based MEA. The results show that the MEA can be used for bioelectrical signal stimulation, recording, stimulation and recording simultaneously, and isolation of biological tissues or slices in-vitro.展开更多
Presented in this paper is a biosensor constructed for the determination of neurotransmitters. It is an eggplant-banana-tissue-based carbon paste microelectrode. As oxidative enzymes in banana tissue can bio-catalytic...Presented in this paper is a biosensor constructed for the determination of neurotransmitters. It is an eggplant-banana-tissue-based carbon paste microelectrode. As oxidative enzymes in banana tissue can bio-catalytically oxidize dopamine (DA), norepinephrine(NE), L-dopa, etc, the biosensor's sensitivity is improved. Because of the ability of eggplant tissue to eliminate the oxidation of ascorbic acid (AA), the signal of AA is a steady-state response. and thereby the selectivity of the biosensor is enhanced. The effect of experimental conditions such as pH, temperature, ratio of two plant tissues, response time, and linear range were evaluated in order to optimize the analytical performance. The detection limit for DA is 3. 2 × 10-7 mol/L.Our results showed that the idea of multienzyme system is applicable to the plant tissue-based carbon paste microelectrodes.展开更多
The relationship between the parameters of Transcorneal Electrical Stimulation (TES) and its neuro-protective effect of TES on axotomised Retinal Ganglion Cells (RGCs) is still unclear. This work discusses the design ...The relationship between the parameters of Transcorneal Electrical Stimulation (TES) and its neuro-protective effect of TES on axotomised Retinal Ganglion Cells (RGCs) is still unclear. This work discusses the design strategy of a new non conventional TES stimulator, the micro fabrication processes and characterization of an array of MEMS microelectrodes over a flexible polymer layer substrate to stimulate the human cornea. The micro-array of electrodes, over a flexible smooth biocompatible polyimide substrate, fine tunes the curvature of the cornea. This tool can help researchers to define the optimal electric stimulation parameters required in TES.展开更多
Neuronal connections can be detected by neuronal network discharges in hippocampal neurons cultured on multi-electrodes.However,the multi-electrode-array（MEA）has not been widely used in hippocampal slice culture stu...Neuronal connections can be detected by neuronal network discharges in hippocampal neurons cultured on multi-electrodes.However,the multi-electrode-array（MEA）has not been widely used in hippocampal slice culture studies focused on epilepsy.The present study induced spontaneous synchronous epileptiform activity using low Mg2＋artificial cerebrospinal fluid on acute hippocampal slices to record hippocampal discharges with MEA.Results showed that burst duration and average number of spikes in a burst were significantly greater in the CA3 compared with dentate gyrus and CA1 areas.In Schaffer cut-off group,CA1 area discharges disappeared,but synchronous discharges remained in the CA3 area.Moreover,synchronous discharge frequency in the Schaffer cut-off group was similar to control.However,burst duration and average number of spikes in a burst were significantly decreased compared with control（P 〈 0.05）.Results demonstrated that highest neuronal excitability occurred in the CA3 area,and synchronous discharges induced by low Mg2＋originated from the CA3 region.展开更多
Conventional implantable electrical stimulation microelectrodes have small surface area,high electrode-tissue interface impedance and low charge storage capacity(CSC),which will increase power consumption and hinder s...Conventional implantable electrical stimulation microelectrodes have small surface area,high electrode-tissue interface impedance and low charge storage capacity(CSC),which will increase power consumption and hinder stimulation effect.In this paper,a method was presented to increase the effective surface area(ESA)of microelectrode by coating Pt-black on the electrode sites.The method combines with electroplating Pt-black by pulse current under ultrasonic bath,which can significantly increase the ESA,decrease the interface impedance,and increase the CSC and charge-injection capacity.Moreover,the geometrical properties of Pt-black coated microelectrodes were demonstrated by using a scanning elec-tron microscope(SEM)and the electrical properties were measured by an electrochemical analyzer com-pared with conventional microelectrodes without coatings.The mechanical stability of Pt-black coating was also tested.Experimental results show that approximately 16 times lower interface impedance and 13 times higher CSC were achieved by this nanostructured microelectrode.Cathodal charge storage capacity(CSCc)decreased only by 20%after an ultrasonic bath at room temperature for 5 min.展开更多
The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were stud...The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were studied at pH 6.6. Also the adsorption of heavy metals such as Cd 2＋ , Zn 2＋ and Ni 2＋ on humic acid-polyaniline systems （HA-PEB） was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy （SEM）, infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities （q max ） of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q max of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB followed the order： THA-PEB YHA-PEB PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.展开更多
Conducting polymers have been studied extensively. An interesting property of the conducting polymer is that the conductivity of some polymers, such as polypyrrolc, polyaniline, poly(3-methylthiophene) etc. , is affec...Conducting polymers have been studied extensively. An interesting property of the conducting polymer is that the conductivity of some polymers, such as polypyrrolc, polyaniline, poly(3-methylthiophene) etc. , is affected by the voltage applied to them. For polypyrrole, the oxidized state is an electronic conductor and the reduced state is essentially insulating. Using this property, one can fabricate the polymer-based electronic devices. Experimental results of Pickun展开更多
Silicon-based microelectrodes have been confirmed to be helpful in neural prostheses. The fabricated 7-channel silicon-based microelectrode was feasible to be implanted into the brain cortex. The manufacturing process...Silicon-based microelectrodes have been confirmed to be helpful in neural prostheses. The fabricated 7-channel silicon-based microelectrode was feasible to be implanted into the brain cortex. The manufacturing process by micro-electromechanical system （MEMS） technology was detailed with four photolithographic masks. The microscopic photographs and SEM images indicated that the probe shank was 3 mm long, 100μm wide and 20 μm thick with the recording sites spaced 120μm apart for good signal isolation. To facilitate the insertion and minimize the trauma, the microelectrode is narrowed down gradually near the tip with the tip taper angle of 6 degrees. Curve of the single recording site impedance versus frequency was shown by test in vitro and the impedance declined from 150.5 kΩ to 6.0 kΩ with frequency changing from 10 k to 10 MHz.展开更多
Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a n...Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.展开更多
The behaviors ot PbSO4/Pb and PbO4/PbSO4 electrode prepared from PbCO3 have been examined using powder microelectrode(PME) technique and cyclic voltammetry(CV). Firstly, PMEs parked with Pb- CO3 transformed into PtSO4...The behaviors ot PbSO4/Pb and PbO4/PbSO4 electrode prepared from PbCO3 have been examined using powder microelectrode(PME) technique and cyclic voltammetry(CV). Firstly, PMEs parked with Pb- CO3 transformed into PtSO4 PME in 1. 0 mol/L H2SO4 solution at 30 C, and then the PbSO4 in the PMEs were formed to Pb or PbO2 using an unsymmetrical signal(Qa/Qe for PbSO4/Pb electrode and Qe/Qa for PsO2/ PbSO4 electrode being 0. 1-0. 3) in 2. S mol/L H2SO4 solution. The results show that the CV characteristic of either PbSO4/Pb or PsO2/PbSO4 PME prepared from PhCO3 are as good as that of both electrodes made from lead oxide powder produced by ball mill.展开更多
The present paper describes experiments aimed at delineating significant chemical characteristics of electrochemical reactions in polymeric solutions, including how rigid solvent environments affect mass transport rat...The present paper describes experiments aimed at delineating significant chemical characteristics of electrochemical reactions in polymeric solutions, including how rigid solvent environments affect mass transport rates, and also discusses the possibility that the microelectrode coated with poly(ethylene oxide)(PEO) film can be used as gas sensor.展开更多
Developing excellent pseudocapacitive electrodes with long cycle,high areal capacity and large rate has been challenged.3 D printing is an additive manufacture technique that has been explored to construct microelectr...Developing excellent pseudocapacitive electrodes with long cycle,high areal capacity and large rate has been challenged.3 D printing is an additive manufacture technique that has been explored to construct microelectrodes of arbitrary geometries for high-energy–density supercapacitors.In comparison with conventional electrodes with uncontrollable geometries and architectures,3 D-printed electrodes possess unique advantage in geometrical shape,mechanical properties,surface area,especially in ion transport and charge transfer.Thus,a desirable 3 D electrode with ordered porous structures can be elaborately designed by 3 D printing technology for improving electrochemical capacitance and rate capability.In this work,a designed,monolithic and ordered multi-porous 3 D Cu conductive skeleton was manufactured through 3 D direct ink writing technique and coated with Cu O nanosheet arrays by an in situ electro-oxidation treatment.Benefiting from the highly ordered multiporous nature,the 3 D-structured skeleton can eff ectively enlarge the surface area,enhance the penetration of electrolyte and facilitate fast electron and ion transport.As a result,the 3 D-printed Cu deposited with electro-oxidation-generated CuO(3 DP Cu@Cu O)electrodes demonstrates an ultrahigh areal capacitance of 1.690 F cm^(-2)(38.79 F cm^(-3))at a large current density of 30 m A cm^(-2)(688.59 m A cm^(-3)),excellent lifespan of 88.20%capacitance retention after 10,000 cycles at 30 m A cm^(-2) and superior rate capability(94.31%retention,2-30 m A cm^(-2)).This design concept of 3 D printing multi-porous current collector with hierarchical active materials provides a novel way to build high-performance 3 D microelectrodes.展开更多
In-situ monitoring of neurochemicals is of vital importance for the understanding of brain functions.Microelectrode-based photoelectrochemical(PEC) sensing has emerged as a promising tool for in vivo analysis since it...In-situ monitoring of neurochemicals is of vital importance for the understanding of brain functions.Microelectrode-based photoelectrochemical(PEC) sensing has emerged as a promising tool for in vivo analysis since it inherits the merits of both optical and electrochemical methods. However, the in-situ excitation of photoactive materials on the photoelectrode in living body is still a challenge because of limited tissue penetration depth of light. To circumvent this problem, we herein developed an implantable optical fiber(OF)-based microelectrode for in vivo PEC analysis. The working electrode was constructed by coating Au film as conducting layer and CdS@ZnO as photoactive material on a micron-sized OF,which was free of the limitation of light penetration in biological tissues. Further decoration of an antibiofouling layer on the surface made the sensor robust in biosamples. It was successfully applied for monitoring Cu^(2+) level in three different brain regions in the rat model of cerebral ischemia/reperfusion.展开更多
A microfabricated electrical impedance spectroscopy (EIS) chip with microelectrodes was developed.The substrate and the electrodes of the chip were made of glass and gold,respectively.The experimental results demonstr...A microfabricated electrical impedance spectroscopy (EIS) chip with microelectrodes was developed.The substrate and the electrodes of the chip were made of glass and gold,respectively.The experimental results demonstrated that the EIS-chip could distinguish different solutions (physiological saline,culture medium,living cell suspension etc.) by scanning from 10Hz to 45kHz.A 6-element circuit model was used for fitting the real part and the imaginary part admittance curves of the living cell suspension.An actual circuit was also built and tested to verify the 6-element circuit model proposed.The micro-EIS chip has several advantages including the use of small sample volumes,high resolution and ease of operation.It shows good application prospects in the areas of cellular electrophysioiogy,drug screening and bio-sensors etc.展开更多
For microelectronic devices,the on-chip microsupercapacitors with facile construction and high performance,are attracting researchers'prior consideration due to their high compatibility with modern microsystems.He...For microelectronic devices,the on-chip microsupercapacitors with facile construction and high performance,are attracting researchers'prior consideration due to their high compatibility with modern microsystems.Herein,we proposed interchanging interdigital Au-/MnO_(2)/polyethylene dioxythiophene stacked microsupercapacitor based on a microfabrication process followed by successive electrochemical deposition.The stacked configuration of two pseudocapacitive active microelectrodes meritoriously leads to an enhanced contact area between MnO_(2)and the conductive and electroactive layer of polyethylene dioxythiophene,hence providing excellent electron transport and diffusion pathways of electrolyte ions,resulting in increased pseudocapacitance of MnO_(2)and polyethylene dioxythiophene.The stacked quasi-solid-state microsupercapacitors delivered the maximum specific capacitance of 43 mF cm^(-2)(211.9 F cm^(-3)),an energy density of 3.8μWh cm^(-2)(at a voltage window of 0.8 V)and 5.1μWh cm^(-2)(at a voltage window of 1.0 V)with excellent rate capability(96.6%at 2 mA cm^(-2))and cycling performance of 85.3%retention of initial capacitance after 10000 consecutive cycles at a current density of 5 mA cm^(-2),higher than those of ever reported polyethylene dioxythiophene and MnO_(2)-based planar microsupercapacitors.Benefiting from the favorable morphology,bilayer microsupercapacitor is utilized as a flexible humidity sensor with a response/relaxation time superior to those of some commercially available integrated microsensors.This strategy will be of significance in developing high-performance on-chip integrated microsupercapacitors/microsensors at low cost and environment-friendly routes.展开更多
The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep location.Multichannel micr...The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep location.Multichannel microelectrode arrays(MEAs)can rapidly and precisely locate the STN,which is important for precise stimulation.In this paper,16-channel MEAs modified with multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(MWCNT/PEDOT:PSS)nanocomposites were designed and fabricated,and the accurate and rapid identification of the STN in PD rats was performed using detection sites distributed at different brain depths.These results showed that nuclei in 6-hydroxydopamine hydrobromide(6-OHDA)-lesioned brains discharged more intensely than those in unlesioned brains.In addition,the MEA simultaneously acquired neural signals from both the STN and the upper or lower boundary nuclei of the STN.Moreover,higher values of spike firing rate,spike amplitude,local field potential(LFP)power,and beta oscillations were detected in the STN of the 6-OHDA-lesioned brain,and may therefore be biomarkers of STN localization.Compared with the STNs of unlesioned brains,the power spectral density of spikes and LFPs synchronously decreased in the delta band and increased in the beta band of 6-OHDA-lesioned brains.This may be a cause of sleep and motor disorders associated with PD.Overall,this work describes a new cellular-level localization and detection method and provides a tool for future studies of deep brain nuclei.展开更多
The reduction of nitrite at Au or carbon electrode in-H_2SO_4 was found to follow achemical-electrochemical (CE) mechanism with a very thin (4×10(-8)cm) preceding reaction zone.It was proposed and experimentally ...The reduction of nitrite at Au or carbon electrode in-H_2SO_4 was found to follow achemical-electrochemical (CE) mechanism with a very thin (4×10(-8)cm) preceding reaction zone.It was proposed and experimentally verified that for such kind of electrode processes the totalreaction the could be effectively enhanced by using electrodes with increased true surface area.such as porous electrodes. As a combination of porous electrode and microelectrode, the powdermicroclectrode shows excellent performance for nitrite detection.展开更多
Qualitative and quantitative analysis of trace heavy metals in aqueous environment are rapidly assuming significance along with the rapid development of industry.In this paper,gold microelectrode array(MEA)plated with...Qualitative and quantitative analysis of trace heavy metals in aqueous environment are rapidly assuming significance along with the rapid development of industry.In this paper,gold microelectrode array(MEA)plated with mercury film was used for simultaneous voltammetric detection of zinc,cadmium,lead and copper ions in water.The electrochemical behavior and the actual surface area of the MEA were investigated by cyclic voltammetry in K_(3)[Fe(CN)_(6)].Electrochemical impedance spectrum(EIS)was utilized to examine the deposition of mercury on the electrode surface.Based on anodic stripping voltammetry,mercury filmAu MEA was applied to the detection of heavy metals in artificial analyte,where good calibrate linearity was obtained for cadmium,lead and copper ions,but with zinc exhibiting poor linearity.展开更多
文摘Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most prominent cause of dementia.In 2019,over 57.4million people were living with AD and other dementia subtypes,a number which is expected to increase to over 152.8 million in the next 25years.This ever-increasing burden has resulted in AD and other neurodegenerative diseases rising to one of the top 10 causes of death globally (O'Connell et al.,2024).
基金The National Natural Science Foundation of China(No. 61076118, 90307013, 90707005)the Natural Science Foundation of Jiangsu Province (No. BK2008032)Special Foundation and Open Foundation of the State Key Laboratory of Bioelectronics of Southeast University
文摘A microelectrode array（MEA） is presented, which is composed of 60 independent electrodes with 59 working ones and one reference one, and they are divided into 30 pairs. Except for the reference electrode, each pair consists of one stimulating electrode and one recording electrode. Supported by the peripheral circuits, four electrode states to study the bioelectrical signal of biological tissue or slice cultured in-vitro on the surface of the electrodes can be realized through each pair of electrodes. The four electrode states are stimulation, recording, stimulation and recording simultaneously, and isolation. The state of each pair of working electrodes can be arbitrarily controlled according to actual needs. The MEAs are fabricated in printed circuit board （PCB） technology. The total area of the PCB-based MEA is 49 mm × 49 mm. The impedance measurement of MEA is carried out in 0.9% sodium chloride solution at room temperature by means of 2-point measurements with an Agilent LCR meter, and the test signal for the impedance measurement is sinusoidal （AC voltage 50 mV, sweeping frequency 20 Hz to 10 kHz）. The electrode impedance is between 200 and 3 kΩ while the frequency is between 500 and 1 000 Hz. The electrode impedance magnitude is inversely proportional to the frequency. Experiments of toad sciatic nerve in-vitro stimulation and recording and signal regeneration between isolated toad sciatic nerves are carried out on the PCB-based MEA. The results show that the MEA can be used for bioelectrical signal stimulation, recording, stimulation and recording simultaneously, and isolation of biological tissues or slices in-vitro.
文摘Presented in this paper is a biosensor constructed for the determination of neurotransmitters. It is an eggplant-banana-tissue-based carbon paste microelectrode. As oxidative enzymes in banana tissue can bio-catalytically oxidize dopamine (DA), norepinephrine(NE), L-dopa, etc, the biosensor's sensitivity is improved. Because of the ability of eggplant tissue to eliminate the oxidation of ascorbic acid (AA), the signal of AA is a steady-state response. and thereby the selectivity of the biosensor is enhanced. The effect of experimental conditions such as pH, temperature, ratio of two plant tissues, response time, and linear range were evaluated in order to optimize the analytical performance. The detection limit for DA is 3. 2 × 10-7 mol/L.Our results showed that the idea of multienzyme system is applicable to the plant tissue-based carbon paste microelectrodes.
基金the support of the National Science Council and Technology of México,CONACyT,Hospital Dr.Luis Sánchez Bulnes.
文摘The relationship between the parameters of Transcorneal Electrical Stimulation (TES) and its neuro-protective effect of TES on axotomised Retinal Ganglion Cells (RGCs) is still unclear. This work discusses the design strategy of a new non conventional TES stimulator, the micro fabrication processes and characterization of an array of MEMS microelectrodes over a flexible polymer layer substrate to stimulate the human cornea. The micro-array of electrodes, over a flexible smooth biocompatible polyimide substrate, fine tunes the curvature of the cornea. This tool can help researchers to define the optimal electric stimulation parameters required in TES.
文摘Neuronal connections can be detected by neuronal network discharges in hippocampal neurons cultured on multi-electrodes.However,the multi-electrode-array（MEA）has not been widely used in hippocampal slice culture studies focused on epilepsy.The present study induced spontaneous synchronous epileptiform activity using low Mg2＋artificial cerebrospinal fluid on acute hippocampal slices to record hippocampal discharges with MEA.Results showed that burst duration and average number of spikes in a burst were significantly greater in the CA3 compared with dentate gyrus and CA1 areas.In Schaffer cut-off group,CA1 area discharges disappeared,but synchronous discharges remained in the CA3 area.Moreover,synchronous discharge frequency in the Schaffer cut-off group was similar to control.However,burst duration and average number of spikes in a burst were significantly decreased compared with control（P 〈 0.05）.Results demonstrated that highest neuronal excitability occurred in the CA3 area,and synchronous discharges induced by low Mg2＋originated from the CA3 region.
基金supported by the National Natural Science Foundation of China(60876082)the Science and Technology De-partment of Shanghai(0852nm06600)+2 种基金the Program for New Cen-tury Excellent Talents in University(2009)the"Shu Guang"project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(08SG13)Aviation Science Foundation(2008ZE57019)
文摘Conventional implantable electrical stimulation microelectrodes have small surface area,high electrode-tissue interface impedance and low charge storage capacity(CSC),which will increase power consumption and hinder stimulation effect.In this paper,a method was presented to increase the effective surface area(ESA)of microelectrode by coating Pt-black on the electrode sites.The method combines with electroplating Pt-black by pulse current under ultrasonic bath,which can significantly increase the ESA,decrease the interface impedance,and increase the CSC and charge-injection capacity.Moreover,the geometrical properties of Pt-black coated microelectrodes were demonstrated by using a scanning elec-tron microscope(SEM)and the electrical properties were measured by an electrochemical analyzer com-pared with conventional microelectrodes without coatings.The mechanical stability of Pt-black coating was also tested.Experimental results show that approximately 16 times lower interface impedance and 13 times higher CSC were achieved by this nanostructured microelectrode.Cathodal charge storage capacity(CSCc)decreased only by 20%after an ultrasonic bath at room temperature for 5 min.
文摘The adsorption capacities of new humic acids isolated from Yakouren forest （YHA） and Sahara （Tamenrasset： THA） soils （Algeria） and commercial humic acid （PFHA） on polyaniline emeraldine base （PEB） were studied at pH 6.6. Also the adsorption of heavy metals such as Cd 2＋ , Zn 2＋ and Ni 2＋ on humic acid-polyaniline systems （HA-PEB） was investigated at the same conditions. HA-PEB compounds were characterized by scanning electron microscopy （SEM）, infrared spectrometry and cavity microelectrode. In addition, batch adsorption and cavity microelectrode were used in the adsorption study of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB. To develop biocaptors of polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity were investigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of a granular morphology. The maximum adsorption capacities （q max ） of PFHA, THA and YHA determined by adsorption isotherms were 91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that q max of Cd 2＋ , Zn 2＋ and Ni 2＋ on HA-PEB followed the order： THA-PEB YHA-PEB PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showed the appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms were characterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may be exploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.
基金Supported by the National Natural Science Foundation of China
文摘Conducting polymers have been studied extensively. An interesting property of the conducting polymer is that the conductivity of some polymers, such as polypyrrolc, polyaniline, poly(3-methylthiophene) etc. , is affected by the voltage applied to them. For polypyrrole, the oxidized state is an electronic conductor and the reduced state is essentially insulating. Using this property, one can fabricate the polymer-based electronic devices. Experimental results of Pickun
基金Project supported by the National High Technology Research and Development Program of China （Grant No 2005AA311030） and the National Natural Science Foundation of China （Grant No 60536030）. Acknowledgments The authors are grateful to Professor Gao Shang-Kai and her group at Tsinghua University for their kind help in the work. They also would like to ac-knowledge Professor Yang Xiao-Hong and Zhou Fan for their technical support.
文摘Silicon-based microelectrodes have been confirmed to be helpful in neural prostheses. The fabricated 7-channel silicon-based microelectrode was feasible to be implanted into the brain cortex. The manufacturing process by micro-electromechanical system （MEMS） technology was detailed with four photolithographic masks. The microscopic photographs and SEM images indicated that the probe shank was 3 mm long, 100μm wide and 20 μm thick with the recording sites spaced 120μm apart for good signal isolation. To facilitate the insertion and minimize the trauma, the microelectrode is narrowed down gradually near the tip with the tip taper angle of 6 degrees. Curve of the single recording site impedance versus frequency was shown by test in vitro and the impedance declined from 150.5 kΩ to 6.0 kΩ with frequency changing from 10 k to 10 MHz.
基金supported by the National Natural Science Foundation of China(30270790).
文摘Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.
基金Supported by the National Natural Science of China (29677013) Chenguang Foundation of Wuhan Municipal Science and Technology
文摘The behaviors ot PbSO4/Pb and PbO4/PbSO4 electrode prepared from PbCO3 have been examined using powder microelectrode(PME) technique and cyclic voltammetry(CV). Firstly, PMEs parked with Pb- CO3 transformed into PtSO4 PME in 1. 0 mol/L H2SO4 solution at 30 C, and then the PbSO4 in the PMEs were formed to Pb or PbO2 using an unsymmetrical signal(Qa/Qe for PbSO4/Pb electrode and Qe/Qa for PsO2/ PbSO4 electrode being 0. 1-0. 3) in 2. S mol/L H2SO4 solution. The results show that the CV characteristic of either PbSO4/Pb or PsO2/PbSO4 PME prepared from PhCO3 are as good as that of both electrodes made from lead oxide powder produced by ball mill.
文摘The present paper describes experiments aimed at delineating significant chemical characteristics of electrochemical reactions in polymeric solutions, including how rigid solvent environments affect mass transport rates, and also discusses the possibility that the microelectrode coated with poly(ethylene oxide)(PEO) film can be used as gas sensor.
基金financially supported by the National Natural Science Foundation of China(Nos.51771236,51901249 and U1904216)the Science Fund for Distinguished Young Scholars of Hunan Province(No.2018JJ1038)。
文摘Developing excellent pseudocapacitive electrodes with long cycle,high areal capacity and large rate has been challenged.3 D printing is an additive manufacture technique that has been explored to construct microelectrodes of arbitrary geometries for high-energy–density supercapacitors.In comparison with conventional electrodes with uncontrollable geometries and architectures,3 D-printed electrodes possess unique advantage in geometrical shape,mechanical properties,surface area,especially in ion transport and charge transfer.Thus,a desirable 3 D electrode with ordered porous structures can be elaborately designed by 3 D printing technology for improving electrochemical capacitance and rate capability.In this work,a designed,monolithic and ordered multi-porous 3 D Cu conductive skeleton was manufactured through 3 D direct ink writing technique and coated with Cu O nanosheet arrays by an in situ electro-oxidation treatment.Benefiting from the highly ordered multiporous nature,the 3 D-structured skeleton can eff ectively enlarge the surface area,enhance the penetration of electrolyte and facilitate fast electron and ion transport.As a result,the 3 D-printed Cu deposited with electro-oxidation-generated CuO(3 DP Cu@Cu O)electrodes demonstrates an ultrahigh areal capacitance of 1.690 F cm^(-2)(38.79 F cm^(-3))at a large current density of 30 m A cm^(-2)(688.59 m A cm^(-3)),excellent lifespan of 88.20%capacitance retention after 10,000 cycles at 30 m A cm^(-2) and superior rate capability(94.31%retention,2-30 m A cm^(-2)).This design concept of 3 D printing multi-porous current collector with hierarchical active materials provides a novel way to build high-performance 3 D microelectrodes.
基金financially supported by the National Natural Science Foundation of China(Nos.21625503 and 21906047)Natural Science Fund for Creative Research Groups of Hubei Province of China(No.2020CFA035)。
文摘In-situ monitoring of neurochemicals is of vital importance for the understanding of brain functions.Microelectrode-based photoelectrochemical(PEC) sensing has emerged as a promising tool for in vivo analysis since it inherits the merits of both optical and electrochemical methods. However, the in-situ excitation of photoactive materials on the photoelectrode in living body is still a challenge because of limited tissue penetration depth of light. To circumvent this problem, we herein developed an implantable optical fiber(OF)-based microelectrode for in vivo PEC analysis. The working electrode was constructed by coating Au film as conducting layer and CdS@ZnO as photoactive material on a micron-sized OF,which was free of the limitation of light penetration in biological tissues. Further decoration of an antibiofouling layer on the surface made the sensor robust in biosamples. It was successfully applied for monitoring Cu^(2+) level in three different brain regions in the rat model of cerebral ischemia/reperfusion.
文摘A microfabricated electrical impedance spectroscopy (EIS) chip with microelectrodes was developed.The substrate and the electrodes of the chip were made of glass and gold,respectively.The experimental results demonstrated that the EIS-chip could distinguish different solutions (physiological saline,culture medium,living cell suspension etc.) by scanning from 10Hz to 45kHz.A 6-element circuit model was used for fitting the real part and the imaginary part admittance curves of the living cell suspension.An actual circuit was also built and tested to verify the 6-element circuit model proposed.The micro-EIS chip has several advantages including the use of small sample volumes,high resolution and ease of operation.It shows good application prospects in the areas of cellular electrophysioiogy,drug screening and bio-sensors etc.
基金the financial support of the National Key R&D Program of China(Grant Nos.2021YFB3200701 and 2018YFA0208501)the National Natural Science Foundation of China(Grant Nos.21875260,21671193,91963212,51773206,21731001,and 52272098)Beijing Natural Science Foundation(No.2202069)
文摘For microelectronic devices,the on-chip microsupercapacitors with facile construction and high performance,are attracting researchers'prior consideration due to their high compatibility with modern microsystems.Herein,we proposed interchanging interdigital Au-/MnO_(2)/polyethylene dioxythiophene stacked microsupercapacitor based on a microfabrication process followed by successive electrochemical deposition.The stacked configuration of two pseudocapacitive active microelectrodes meritoriously leads to an enhanced contact area between MnO_(2)and the conductive and electroactive layer of polyethylene dioxythiophene,hence providing excellent electron transport and diffusion pathways of electrolyte ions,resulting in increased pseudocapacitance of MnO_(2)and polyethylene dioxythiophene.The stacked quasi-solid-state microsupercapacitors delivered the maximum specific capacitance of 43 mF cm^(-2)(211.9 F cm^(-3)),an energy density of 3.8μWh cm^(-2)(at a voltage window of 0.8 V)and 5.1μWh cm^(-2)(at a voltage window of 1.0 V)with excellent rate capability(96.6%at 2 mA cm^(-2))and cycling performance of 85.3%retention of initial capacitance after 10000 consecutive cycles at a current density of 5 mA cm^(-2),higher than those of ever reported polyethylene dioxythiophene and MnO_(2)-based planar microsupercapacitors.Benefiting from the favorable morphology,bilayer microsupercapacitor is utilized as a flexible humidity sensor with a response/relaxation time superior to those of some commercially available integrated microsensors.This strategy will be of significance in developing high-performance on-chip integrated microsupercapacitors/microsensors at low cost and environment-friendly routes.
基金funded by the National Natural Science Foundation of China(Nos.L2224042,T2293731,62121003,61960206012,61973292,62171434,61975206,and 61971400)the Frontier Interdisciplinary Project of the Chinese Academy of Sciences(No.XK2022XXC003)+2 种基金the National Key Research and Development Program of China(Nos.2022YFC2402501 and 2022YFB3205602)the Major Program of Scientific and Technical Innovation 2030(No.2021ZD02016030)the Scientific Instrument Developing Project of he Chinese Academy of Sciences(No.GJJSTD20210004).
文摘The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep location.Multichannel microelectrode arrays(MEAs)can rapidly and precisely locate the STN,which is important for precise stimulation.In this paper,16-channel MEAs modified with multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(MWCNT/PEDOT:PSS)nanocomposites were designed and fabricated,and the accurate and rapid identification of the STN in PD rats was performed using detection sites distributed at different brain depths.These results showed that nuclei in 6-hydroxydopamine hydrobromide(6-OHDA)-lesioned brains discharged more intensely than those in unlesioned brains.In addition,the MEA simultaneously acquired neural signals from both the STN and the upper or lower boundary nuclei of the STN.Moreover,higher values of spike firing rate,spike amplitude,local field potential(LFP)power,and beta oscillations were detected in the STN of the 6-OHDA-lesioned brain,and may therefore be biomarkers of STN localization.Compared with the STNs of unlesioned brains,the power spectral density of spikes and LFPs synchronously decreased in the delta band and increased in the beta band of 6-OHDA-lesioned brains.This may be a cause of sleep and motor disorders associated with PD.Overall,this work describes a new cellular-level localization and detection method and provides a tool for future studies of deep brain nuclei.
文摘The reduction of nitrite at Au or carbon electrode in-H_2SO_4 was found to follow achemical-electrochemical (CE) mechanism with a very thin (4×10(-8)cm) preceding reaction zone.It was proposed and experimentally verified that for such kind of electrode processes the totalreaction the could be effectively enhanced by using electrodes with increased true surface area.such as porous electrodes. As a combination of porous electrode and microelectrode, the powdermicroclectrode shows excellent performance for nitrite detection.
基金This work has been supported by grants from the National Basic Research Program of China(973 program),Grant No.2009CB320303.
文摘Qualitative and quantitative analysis of trace heavy metals in aqueous environment are rapidly assuming significance along with the rapid development of industry.In this paper,gold microelectrode array(MEA)plated with mercury film was used for simultaneous voltammetric detection of zinc,cadmium,lead and copper ions in water.The electrochemical behavior and the actual surface area of the MEA were investigated by cyclic voltammetry in K_(3)[Fe(CN)_(6)].Electrochemical impedance spectrum(EIS)was utilized to examine the deposition of mercury on the electrode surface.Based on anodic stripping voltammetry,mercury filmAu MEA was applied to the detection of heavy metals in artificial analyte,where good calibrate linearity was obtained for cadmium,lead and copper ions,but with zinc exhibiting poor linearity.
