ABSTRACT
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.
ABSTRACT
A wireless electrochemical recording device was designed for in_vivo neurotransmitters real_time detection. Low_power microcontroller MSP430 was chosen as main control unit in hardware system. Other modules were current detection module, waveform generator module and data transceiver module. This device had the merits of small size (2. 3 cm×1. 8 cm×0. 6 cm) and low power consumption. Firmware program design was based on uC/OS operating system. Combined with the PC software, the device could achieve online display and analysis of the recording data. For neurotransmitter detecting needs, the device implemented fast_scan cyclic voltammetry ( FSCV) and fixed_potential amperometry. By using fast_scan cyclic voltammetry method, a linear relationship ( R=0. 99 ) between the concentration of dopamine and response current was acquired in the range of 5. 0×10-7-7. 0×10-5 mol/L. In the in_vivo experiments, the electrically evoked dopamine was recorded in the caudate_putamen area of brain in rats. Experimental results showed that the system had high detection accuracy, which could realize qualitative and quantitative analysis of the brain neurotransmitter. This work would have a broad application prospect in the field of neuroscience research.
ABSTRACT
A highly sensitive magnetic enzymE-linked chemiluminescent immunoassay method was developed for the detection of human chorionic gonadotropin(HCG). The monoclonal antibody was covalently coupled on the surface of carboxylated magnetic beads to generate magnetic-biotargeting; Alkaline phosphatase(ALP) was utilized as a labeled reagent of another monoclonal antibody, whereas 3-(2-spimadamantane) 4-methoxy-4-(3-phosphoryloxy)phenyl-1,2-dioxetane(AMPPD) was utilized as the chemiluminescent substrate. Based on this concept, a highly sensitive chemiluminescent immunoassay method was established to test HCG. Then, several modifications were made to optimize the method, and the detection sensitivity and procedure were improved accordingly. The detection of the assay could be fulfilled within 60 min and the test result of HCG concentration was linear over the range of 0.15 150 IU/L with good relativity(r=0.960). The relative standard deviation(RSD) were below 5% and the sensitivity of this method was 0.15 IU/L. The proposed method with wide linear range, simple operation and fast detection showed good prospect in practical application on-site.
ABSTRACT
The magnetic nanoparticle probe was prepared by specifically connecting the streptavidin-conjugated magnetic nanoparticles and the antibody of analyte via the strong streptavidin-biotin interaction. Based on the magnetic nanoparticle probes, the concentration of human chorionicgonadotropin (HCG) was detected and a new CL method for of hormone was further established. The performances of the magnetic nanoparticle probes were characterized by UV-Vis spectrometry, transmission electron microscopy and dynamic light scattering. The experimental conditions that affected the chemiluminescence were optimized. The optimal concentrations of luminal and H_2O_2 were 2×10~(-4) mol/L and 8×10~(-4) mol/L, respectively, and optimal pH was 13. Under the optimized experiment conditions, a linear response of chemiluminescence intensity to HCG concentration was obtained with a correlation coefficients of 0.9924. The linear range was from 0.5 to 250 μg/L and wider than the conventional ELISA method (5-200 μg/L). The relative standard deviation was 3.8%. Correlation analysis showed that there was significant correlation between the method of magnetic nanoparticle probes and ELISA in 34 clinical samples. The proposed method with characters of sensitive, effective, fast response and wide detection range provided good application prospect in analysis of other ultra-micro protein.