Research progress on electrode technology for dental plaque pH detection / 口腔疾病防治

@#Plaque pH detection technology can detect the risk of caries and assist in the prevention of caries, with a mature theory and a relatively simple operation. With the increasing demand for clinical caries risk detection technology and the rapid development of microelectrode techniques, there is an increasing variety of types of microelectrodes that can detect the pH of dental plaque, including glass microelectrodes, metal oxide microelectrodes and ion-sensitive field effect transistors. The glass microelectrode was the first microelectrode to be applied in this field, but its structure is weak. Among the various options, the iridium oxide microelectrode has become the most promising caries risk detection electrode in recent years because of its high strength and excellent response. Metal oxide microelectrodes can also effectively compensate for the insufficient strength of glass microelectrodes. With advances in electrode technology, miniaturized, sensitive ion-sensitive field effect transistors have attracted the attention of researchers. Scientists have also recently developed a way to detect the pH of dental plaque with an optical no-contact technique. Optical contactless detection technology will not damage the dental plaque structure, so it has great research and clinical prospects. Future research will further improve the strength and performance of these electrodes on the premise of ensuring miniaturization and achieving noncontact detection.

Design and verification of microelectrode twisting machine / 生物医学工程学杂志

As an interface between external electronic devices and internal neural nuclei, microelectrodes play an important role in many fields, such as animal robots, deep brain stimulation and neural prostheses. Aiming at the problem of high price and complicated fabrication process of microelectrode, a microelectrode twisting machine based on open source electronic prototyping platform (Arduino) and three-dimensional printing technology was proposed, and its microelectrode fabrication performance and neural stimulation performance were verified. The results show that during the fabrication of microelectrodes, the number of positive twisting turns of the electrode wire should generally be set to about 1.8 times of its length, and the number of reverse twisting rings is independent of the length, generally about 5. Moreover, compared with the traditional instrument, the device is not only inexpensive and simple to manufacture, but also has good expandability. It has a positive significance for both the personalization and popularization of microelectrode fabrication and the reduction of experimental cost.

pathological model of Alzheimer's disease based on neuronal network chip and its real-time dynamic analysis / 生物医学工程学杂志

Alzheimer's disease (AD) is a chronic central neurodegenerative disease. The pathological features of AD are the extracellular deposition of senile plaques formed by amyloid-β oligomers (AβOs) and the intracellular accumulation of neurofibrillary tangles formed by hyperphosphorylated tau protein. In this paper, an in vitro pathological model of AD based on neuronal network chip and its real-time dynamic analysis were presented. The hippocampal neuronal network was cultured on the microelectrode array (MEA) chip and induced by AβOs as an AD model to simultaneously record two firing patterns from the interneurons and pyramidal neurons. The spatial firing patterns mapping and cross-correlation between channels were performed to validate the degeneration of neuronal network connectivity. This biosensor enabled the detection of the AβOs toxicity responses, and the identification of connectivity and interactions between neuronal networks, which can be a novel technique in the research of AD pathological model .

In vitro pathological model of Alzheimer's disease based on neuronal network chip and its real-time dynamic analysis / 生物医学工程学杂志

Alzheimer's disease (AD) is a chronic central neurodegenerative disease. The pathological features of AD are the extracellular deposition of senile plaques formed by amyloid-β oligomers (AβOs) and the intracellular accumulation of neurofibrillary tangles formed by hyperphosphorylated tau protein. In this paper, an in vitro pathological model of AD based on neuronal network chip and its real-time dynamic analysis were presented. The hippocampal neuronal network was cultured on the microelectrode array (MEA) chip and induced by AβOs as an AD model in vitro to simultaneously record two firing patterns from the interneurons and pyramidal neurons. The spatial firing patterns mapping and cross-correlation between channels were performed to validate the degeneration of neuronal network connectivity. This biosensor enabled the detection of the AβOs toxicity responses, and the identification of connectivity and interactions between neuronal networks, which can be a novel technique in the research of AD pathological model in vitro.

GABA Receptor Activity Suppresses the Transition from Inter-ictal to Ictal Epileptiform Discharges in Juvenile Mouse Hippocampus / 神经科学通报·英文版

Exploring the transition from inter-ictal to ictal epileptiform discharges (IDs) and how GABA receptor-mediated action affects the onset of IDs will enrich our understanding of epileptogenesis and epilepsy treatment. We used Mg-free artificial cerebrospinal fluid (ACSF) to induce epileptiform discharges in juvenile mouse hippocampal slices and used a micro-electrode array to record the discharges. After the slices were exposed to Mg-free ACSF for 10 min-20 min, synchronous recurrent seizure-like events were recorded across the slices, and each event evolved from inter-ictal epileptiform discharges (IIDs) to pre-ictal epileptiform discharges (PIDs), and then to IDs. During the transition from IIDs to PIDs, the duration of discharges increased and the inter-discharge interval decreased. After adding 3 μmol/L of the GABA receptor agonist muscimol, PIDs and IDs disappeared, and IIDs remained. Further, the application of 10 μmol/L muscimol abolished all the epileptiform discharges. When the GABA receptor antagonist bicuculline was applied at 10 μmol/L, IIDs and PIDs disappeared, and IDs remained at decreased intervals. These results indicated that there are dynamic changes in the hippocampal network preceding the onset of IDs, and GABA receptor activity suppresses the transition from IIDs to IDs in juvenile mouse hippocampus.

Effects of Two Drugs on the Respiration of Zebrafish / 中国药师

Objective:To investigate the effects of two drugs on the asphyxia oxygen concentration and the oxygen consumption rate of zebrafish,and explore the possibility of zebrafish as a drug model and the feasibility of oxygen microelectrode used for drug screening. Methods:The zebrafish were treated with the drugs for 5 days,and transferred into the asphyxia chambers. The solute oxy-gen concentration was assessed continuously until the asphyxia condition. The asphyxia oxygen concentration,asphyxia time and mass specific oxygen consumption rate were determined. Results:The results showed that the asphyxia time,asphyxia concentration and ox-ygen consumption rate of the zebrafish were not significantly changed by deproteinized calfblood extractives injection(P>0.05),sug-gesting no reduction in hypoxia tolerance ability. The asphyxia time and oxygen consumption rate of the zebrafish were not significantly changed,either (P>0.05),however,the asphyxia concentration was increased significantly by cervus and cucumis polypeptide injec-tion (P<0.05),suggesting the reduction in hypoxia tolerance ability. Conclusion:It is suggested that the hypoxia tolerance ability of zebrafish can be significantly decreased by the solution of cervus and cucumis polypeptide. The results also suggest that zebrafish can be used as an experimental animal in medicine studies,and the oxygen microelectrode method can be used in drug screening.

Effect of Electroacupuncture at "Shenmen" (HT 7)- "Tongli" (HT 5) of Heart Meridian on Neuronal Activities in Paraventricular Nucleus of Hypothalamus in Myocardial Ischemia Rats / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) stimulation of "Shenmen" (HT 7) - "Tongli" (HT 5) segment of the Heart Meridian on neuronal electrical activities of hypothalamic paraventricular nucleus (PVN) in rats with myocardial ischemia (MI), so as to investigate its possible mechanism underlying improvement of MI. METHODS: Thirty-two SD rats were randomly divided into sham control, model, HT 7-HT 5 and "Taiyuan" (LU 9)- "Lieque" (LU 7) groups (n=8 in each group). EA preconditioning (2 Hz, 1 V, 20 min) was applied to bilateral HT 7-HT 5 and bilateral LU 9-LU 7, respectively, once everyday for 7 days. The electrical activities of the right PVN region were recorded by the implanted microelectrode array(2×4)and Plexon multi-channel acquisition system. Cluster analysis of neuronal signals was carried out by Offline Sorter software. The discharge waveforms, autocorrelation and cross-correlation of neuronal activities were analyzed by using Neuro Explorer software. RESULTS: Cluster analysis of neuronal signals showed that 2, 2, 1 and 1 interneuron in the sham, model, HT 7-HT 5, and LU 9-LU 7 groups, and 3 pyramidal neurons in the HT 7-HT 5 were acquired. Cross correlation analysis showed that the SPK 02 a and SPK 02 b neurons of the HT 7-HT 5 group had an inhibitory relationship. The total discharge frequency was significantly increased in the model group relevant to the sham group (P<0.01), and was markedly lower in the HT 7-HT 5 group than in the model group and LU 9-LU 7 group (P<0.01). Real-time spectrum analysis showed that the local field potential spectrum energy of the HT 7-HT 5 group was significantly lower than that of the model group and the LU 9-LU 7 group. CONCLUSION: EA of HT 7-HT 5 segment of the Heart Meridian can inhibit the electrical activity of interneuron and activate the electrical activity of pyramidal neuron in PVN region, and an inhibitory relationship exists between the interneuron and pyramidal neuron in MI rats, which may be a mechanism of EA in regulating activities of the ischemic heart.

Immunosensor construction of label free detection of CD4+T lymphocytes / 国际检验医学杂志

Objective To construct an immunosensor for detecting CD4+ T lymphocytes without labeling .Methods The staphy-lococcus protein A(SPA) method was adopted to conduct the oriented immobilization of CD4 monoclonal antibodies on the gold in-terdigitated microelectrode surface for capturing CD4+ T lymphocytes .Then cyclic voltammetry(CV) method was used to conduct the representation of modification situation on the gold interdigitated microelectrode surface .Finally the electrochemical impedance spectroscopy(EIS) was used to detect the impedance of CD4+ T lymphocytes captured by the immunosensor .The standard curve was drawn by the impedance values change obtained by the equivalent electric circuit fitting .Results The linear range of this im-munosensor for detecting CD4+ T lymphocytes was (5 × 103 -5 .0 × 106 )/mL ,with lower detection limit of 5 .0 × 102/mL .Conclu-sion The constructed immunosensor has accurate and reliable detection results uhidn is simple to operate accurate ,convenient and cheap ,which might be expected to be used in the real-time detection system ,and offers help for realizing rapid ,accurate and inex-pensive CD4+ T lymphocyte count .

Intervention of acupuncture on abnormal spatiotemporal pattern of visual cortex area 17 neuron in monocular deprivation amblyopia rats / 中国针灸

<p><b>OBJECTIVE</b>To preliminarily explore the electrophysiological mechanism of acupuncture on plasticity variability of visual cortex.</p><p><b>METHODS</b>Fifty 14-day-old Wistar rats were randomly divided into a blank group, a model group, an early-stage acupuncture group, a middle-stage acupuncture group and a late-stage acupuncture group, 10 rats in each one. Except the blank group, the rats in the remaining groups were treated with eyelid suture to establish the model of monocular deprivation amblyopia. After model establishment, the rats in the blank group and model group were grasped without any intervention everyday. The rats in the acupuncture groups were treated with acupuncture at bilateral "Jingming" (BL 1), "Cuanzhu" (BL 2), "Fengchi" (GB 20) and "Guangming" (GB 37) on the 3rd, 12th and 21st days into model establishment. The needles were retained for 10 min, once a day for totally 9 days. After treatment, the M-NEMEA technology was applied to measure the discharge amplitude and power spectral density of visual cortex area 17 neuron of each group.</p><p><b>RESULTS</b>Compared with the blank group, the number of discharged neuron of visual cortex area 17 was reduced, and the amplitude was significantly reduced in the model group (both<0.05). Compared with the model group, the numbers of discharged neuron were increased, and the amplitudes were significantly increased in the early-stage acupuncture group and middle-stage acupuncture group (all<0.05). The neuron discharge amplitude in the early-stage acupuncture group was higher than those in the middle-stage acupuncture group and late-stage acupuncture group (both<0.05); the neuron discharge amplitude in the middle-stage acupuncture group was higher than that in the late-stage acupuncture group (<0.05). In the 120-second time domain of acquisition, the distribution of power spectral density in the blank group was mainly between -105 dB and -100 dB; compared with the blank group, the power spectral density in the model group was increased and distributed between -132 dB and -124 dB; compared with the model group, the power spectral densities in the acupuncture groups was reduced and distributed between -115 dB and -110 dB in the early-stage acupuncture group, -120 dB and -115 dB in the middle-stage acupuncture group and -129 dB and -122 dB in the late-stage acupuncture group.</p><p><b>CONCLUSIONS</b>There are abnormal changes of spatiotemporal pattern in visual cortex area 17 of monocular deprivation rats, but acupuncture can regulate abnormal spatiotemporal pattern of neuron. Therefore, there is developmental plasticity of visual cortex neuron in the sensitive period, and early treatment is key to superior efficacy.</p>

Adaptive common average reference for in vivo multichannel local field potentials

For in vivo neural recording, local field potential (LFP) is often corrupted by spatially correlated artifacts, especially in awake/behaving subjects. A method named adaptive common average reference (ACAR) based on the concept of adaptive noise canceling (ANC) that utilizes the correlative features of common noise sources and implements with common average referencing (CAR), was proposed for removing the spatially correlated artifacts. Moreover, a correlation analysis was devised to automatically select appropriate channels before generating the CAR reference. The performance was evaluated in both synthesized data and real data from the hippocampus of pigeons, and the results were compared with the standard CAR and several previously proposed artifacts removal methods. Comparative testing results suggest that the ACAR performs better than the available algorithms, especially in a low SNR. In addition, feasibility of this method was provided theoretically. The proposed method would be an important pre-processing step for in vivo LFP processing.

Preparation of Electrochemical Microfluidic Device Based onPulse Driving and Controlling of Microfluids Technique / 分析化学

The fabrication system for the electrochemical microfluidic device was set up based on the pulse driving and controlling of microfluids technology.The nano silver ink and glycerol solution were jetted on the glass substrates to form the microelectrode pattern and the liquid mold pattern for the microchannel.Then the microelectrode and microchannel were obtained through a sintering process and a molding process, respectively.The electrochemical mircrofluidic device was Finally prepared through a bonding process with the microelectrode and the microchannel.The influences of the system parameters on the formation of the droplet were studied, as well as the influences of the droplets diameter and the overlap on the formation of the liquid lines.The minimal width, the thickness and the resistance of the prepared microelectrode were 45 μm, 2.2 μm and 5.2 μΩ cm, respectively.The minimal width of the microelectrode was 35 μm and the surface was smooth.The electrochemical flow detection of glucose concentration was carried out with the device, and the results showed that the glucose concentration had a high linear correlation with the response current, which could be used in the quantitative detection of glucose concentration.The fabrication of the electrochemical microfluidic device based on the pulse driving and controlling of micro fluids technology has many advantages such as simple system structure, lower cost and higher accuracy of the micro droplet and can be used in the preparation of the devices in the biochemical analysis and biosensor areas.

Amplitude Modulation-based Electrical Stimulation for Encoding Multipixel Spatiotemporal Visual Information in Retinal Neural Activities

Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed ‘stimulation strategy’ for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.

Synchronous Detection of Rat Neural Spike Firing and Neurochemical Signals Based on Dual-mode Recording Instrument / 分析化学

A dual-mode recording system used for synchronous detection of neuroeletrical and neurochemical signals was developed, and a dual-mode synchronous detection experiment was carried out using the instrument. The device comprised 64-channel neuroelectricity recording module with voltage resolution of 0. 3 μV and 4-channel neurochemistry recording module with current resolution of 1 pA. The software had many basic features, including Spike separation and sort, chronoamperometry, cyclic voltammetry, etc. In particular, the software could observe and analyze the dual-mode neural signals synchronously. The performance of the system was demonstrated in the single mode detection experiments. In neuroeletrical experiments, 64-channel simulate neural signals were detected and the signal to noise ratio ( S/N) of Spike recorded from cortex of Sprague-Dawley ( SD ) rat was 6. In the K3 [ Fe ( CN )6 ] and ascorbic acid measurement experiments, the current response of K3 [ Fe ( CN)6 ] in the range of 0. 1-10 mmol/L was obtained by cyclic voltammetry, with a correlation coefficient of 0. 9889, and the current response of ascorbic acid ( concentration:10-800 μmol/L) by chronoamperometry increased linearly with a correlation coefficient of 0. 9841. Based on the rat model of global cerebral ischemia, a dual-mode detection experiment was carried out. In the experiment, the neuroelectrical and neurochemical signals were synchronously recorded in the SD rat primary visual cortex. According to the experimental results, we got the conclusion that the concentration of ascorbic acid negatively related to the Spike firing in the SD rat primary visual cortex.

Multiple Microelectrode Guided Precise Positioning of Sensory-motor Area of the Subthalamic Nucleus / 中国医科大学学报

Objective To explore the significance of multiple microelectrode guided technique in determining the sensory?motor area of the sub?thalamic nucleus(STN)in deep brain stimulation(DBS)surgeries. Methods A total of 22 electrophysiological recording data of STNs recorded by multiple microelectrode was retrospectively analyzed ,while another 20 electrophysiological recording data of STNs recorded by a single micro?electrode was recruited as the control group. Results A total of 64 microelectrodes were used in 22 STNs guided by multiple electrophysiological recording electrodes. Sensory or motor activated potentials were recorded in 21 sides(95.5%),while regular discharge was recorded in one side. The average length of typical STN activity on the optimal channel of multiple electrophysiological recording electrodes was 5.58±0.53 mm,and the average length of sensory or motor activated potentials was 3.27±1.54 mm. In contrast,the average length of typical STN activity recorded by single microelectrode was 5.02±1.01 mm. However,sensory or motor activated potentials were recorded in 13 sides(65.0%)with the average length of 1.36±0.98 mm. Among the 22 STNs guided by multiple electrophysiological recording electrodes,the final implanted target was consistent with the initially selected anatomic target in 13 sides(coincidence rate,59.1%). In 9 sides,the electrophysiological target was inconsistent with the initially selected anatomic target. Conclusion STN DBS performed with multiple electrophysiological recording electrodes resulted in better outcomes of recording of the average length of typical STN activity or the average length of sensory or motor activated potentials of STN ,final confirmation of STN sensory motor area and determination of the optimal channel of implantation. Application of multiple electrophysiological recording electrodes provides a premise for the precise electrode placement in STN DBS surgeries.

Clinical analysis of microelectrode guided stereotactic functional nucleus lesioning operation in treatment of Parkinson′s disease / 重庆医学

Objective To study the application of microelectrode stereotactic functional nucleus lesioning operation in the treatment of Parkinson′s disease(PD) ,and to explore its clinical value .Methods The clinical data in 84 cases of PD treated with‐out using the microelectrode stereotactic functional nucleus lesioning operation(observation group) and 74 cases of PD treated by u‐sing microelectrode guided stereotactic functional nucleus lesioning in our hospital were retrospectively analyzed .At the same time the Unified Parkinson′s Disease Rating Scale (UPDRS) scores before the nucleus lesioning and at postoperative different medication states were obtained in the observation and the control group .Furthermore the difference of the UPDRS motor scores before and af‐ter operation were compared between the two groups .Results The UPDRS motor scores at postoperative 3 ,6 months and 1 year in the observation group were significantly improved compared with before operation(P0 .05) .Conclusion Stereotactic nucleus lesioning in treating PD has satisfactory effect and can significantly improve the UPRDS motor scores .Accurate positioning is the key to the operation success ,whether microelectrode recording can significantly improving the operation accuracy needs further discussion .

A Microfluidic Chip with Integrated Microelectrode for Real-time Dopamine Detection / 分析化学

A microfluidic chip with integrated microelectrode for real-time dopamine detection was designed and fabricated. The chip consisted of a polydimethylsiloxane ( PDMS) channel plate and a glass electrode plate. One central channel as the culture chamber of neural stem cells and two lateral channels for transport of the culture medium were integrated on the PDMS channel plate. Microelectrodes for real-time dopamine detection were integrated on the glass electrode plate. To solve the problem in demoulding the PDMS channel plate from the silicon mould, a novel demoulding method was developed. An Au-Au-Au three-electrode system was constructed, and it performed well in electrochemical detection. The performance of the microfluidic chip was primarily studied by detecting dopamine dissolved in the medium for the culture of neural stem cells. The limit of detection was 3. 92 μmol/L, the linear detection range was from 10 μmol/L to 500 μmol/L, and the detection reproducibility from different chips was less than 4%.

Study of Microelectrode Array Probe for Simultaneous Detection of Glutamate and Local Field Potential during Brain Death / 分析化学

High extracellular potassium can induce spreading depression-like depolarizations, elevations of extracellular glutamate and even neuronal death in normal brain. To investigate the contribution of high potassium in vivo, a microelectrode arrays ( MEAs ) probe integrated with recording sites for glutamate concentration (50í150 μm) and local field potential ( LFP) ( diameter=15 μm) was fabricated by Micro-electro-mechanical-systems ( MEMS) technologies. We implanted the MEA probe acutely in the rat brain and exposed the brain to a high potassium solution. During these multi-modal recordings, it was observed that high potassium elevated extracellular glutamate while suppressing the LFP irreversibly. This is one of the first studies in which a dual mode MEA probes is applied in vivo for neuronal death, and it is concluded that our MEA probes are capable of examining specific spatiotemporal relationships between electrical and chemical signaling in the brain.

Effects of Zhigancao Decoction medicated serum combined with myocardial tissue/silicon substrate micro-electrode technique on cardiac electrophysiology / 医学研究生学报

[Abstract ] Objective Modern pharmacological studies confirmed Zhigancao Decoction total extract, single active ingredients and their combinations could obviously inhibit arrhythmia.This study was to investigate the effects of Zhigancao Decoction medicated serum combined with myocardial tissue/silicon substrate microelectrode arrays (MEA) on rapid atrial pacing(RAP). Methods New Zealand white rabbits were randomly divided into normal control group, normal serum control group, Zhigancao Decoction medica-ted serum group and water decoction group, 8 in each group.After the establishment of an atrial fibrillation rabbit model, the field ac-tion potential duration ( fAPD) of the right atrial appendage ( RAA ) tissue was measured and the effections of Zhigancao Decoction medicated serum and water decoction on the fAPD of RAA were observed. Results The successful modeling of rapid atrial pacing induced atrial fibrillation in rabbits contributed to the significant shortening of fAPD 12 h after pacing compared to that before pacing ([174.30 ±1.36]ms vs[162.48 ±0.88]ms, P<0.05).After giving 10%~25% Zhigancao Decoction medicated serum and water decoction, the fAPDs of RAA tissue in rabbits with atrial fibrillation were prolonged, which represented positive dose-response relation-ship.The fAPDs of the rabbits given serum containing 10%, 15%, 20%and 25%Zhigancao Decoction were respectively (170.81 ± 0.61)ms, (171.00 ±0.46)ms, (179.08 ±0.67)ms, (179.76 ±2.26)ms, which were longer than those of water decoction group ([163.82 ±0.780]ms, [163.66 ±0.95]ms, [174.06 ±1.32]ms, [176.84 ±1.19]ms), and the difference was statistically sig-nificant (P<0.05). Conclusion The fAPD can be taken as one index of cardiac electrophysiological change, and 10%~25%Zh-igancao Decoction medicated serum can lead to fAPD extension in rabbit model of atrial fibrillation, which might be the electrophysio-logical mechanism of anti-atrial fibrillation.

Evaluation of Anti-atrial Fibrillation Drug With Multi Ion Channel Targets by Micro-electrode Chip Technology in Experimental Rabbit Model / 中国循环杂志

Objective:To evaluate and screen the anti-atrial ifbrillation drug with multiion channel targets by micro-electrode chip technology in a rapid atrial pacing (RAP) rabbit model. Methods:A total of 32 rabbits were randomly divided into 4 groups, n=8 in each group. Potassium channel blocker (TEA) group, Potassium channel blocker (BaCl2) group, Potassium channel blocker (CdCl2) group and Amiodarone group. The electrode was inserted into right atrium via internal jugular vein with rapid right atrial pacing (600 beat/min) and the effect of each anti-atrial ifbrillation drug on ifeld action potential (fAPD) were measured in different groups. Results:With 24 hour RAP, the fAPD was prolonged from (176.67 ± 8.66) ms to (196.11 ± 10.76) ms, P=0.012 in TEA group;from (182.22 ± 12.87) ms to (191.11 ± 13.09) ms, P=0.039 in BaCl2 group;from (178.33±7.85) ms to (206.67 ± 9.70) ms, P=0.0015 in CdCl2 group;from (167.38 ± 13.67) ms to (185 ± 15.14) ms, P=0.002 in Amiodarone group. Conclusion: RAP induced atrial fibrillation in experimental rabbit model is a simple and feasible method for screening the anti-atrial fibrillation drugs, combining with micro-electrode chip technology, it might be used for developing the new product.

Application of Planar Microelectrode Array Modified by Nano-structure Titanium Nitride on Dual Mode Neural Information Recording / 分析化学

The nano-structure TiN was modified on the laboratory self-made planar microelectrode array pMEA by magnetron sputtering method. The performance of modified pMEA was investigated. Research on neuroelectrical and neurochemical recording was studied in vitro. The impedance of the modified pMEA was decreased almost one order of magnitude, and the background noise level was reduced to ±6 μV. In the same testing environment, the signal-to-noise ratio (SNR) of modified electrodes was 1. 7 times of bare electrodes. The SNR of neuroelectrical recording on the brain slice of SD rats reached 10:1 , and the weak signal such as ±12 μV was separated easily. For neuroelectrical recordings, the detection limit of dopamine ( DA) solution reached 50 nmol/L with the 2:1 (S/N). During the concentration range of 0. 05-100 μmol/L, the linearly correlation coefficient of the DA oxidation currents was 0 . 998 . The modification of nano-structure TiN on pMEA reduced pMEA impedance and background noise level, meanwhile the SNR was increased. The weak signals of neuroelectrical and neurochemical recording were successfully recorded.