Design And Applications Of NO Sensors In The Vivo Measurement

Nitric oxide(NO) was proved as endothelium-derived relaxing factor(EDRF) since 1986, a lot of study results showed that NO played an important role in various physiological process. The possibility of exactly measuring free NO is of great advantage in medicine be advantage in medicine because No or compounds that release No in-vivo or which inhibit its formation are currently put to therapeutic use. Measuring amounts of No in biological systems is difficult because of its short half-life and its low concentrations.Different methods for NO detection have been reviewed such as detecting the spectrual changes, electrochemical detection of NO, Ultraviolet-visible spectra etal. A number of chemical modifications of electrodes have been proposed for NO sensoring. In general, the materials used for these modifications are metal complexes with different ligands such as macrocycles, electropolymerized nickel porphyrin film (poly-NiTMHPP), Metal-phthalocyanines (M-PCs).We design two diffirent sensors of measuring NO with different chemically modified electrode. Through the constrast of measuring results of different methods with NO kits, we get to know that tow sensors of measuring No may be used to measure in-vivo NO.Design of two NO Sensors and the contrast of two NO sensors in the qualities NO Sensor was made of the pure platinum wire. The chitin membranes with positively charge under physiological PH conditions were wired at the sensor's surface. After modified by the NiSO4 solution, then decorates the Nafion membranes. To carry on the scanning by using cyclic voltammetry in pH7.4 phosphate buffer solution,In the scanning voltage within 600 mV to -1000mV observation of nitric oxide's voltammetric characteristics in the modified electrode. The sensor has the linear response range of 6.25×10-7～1.0×10-4mol·L-1 with the square of the correlation coefficient 0.9944. The selectivity, potential stability and reproducibility of the sensor is good, satisfied to the requirements of Physiological analysis.NO Sensor was made of the pure platinum wire The platinum electrode was modified with Sulfophthalocyanine Tetrabutylammonium Perchlorate(CoTSPc) by electrodeposi- tion,then the electrode was dipped in the Nafion solution to be coated with a Nafion layer. In pH7.4 phosphate buffer solutions,the electrochemical behavior of NO at the nitric oxide Biosensor modified electrode was studied.The best condition in which the electrode was modified is: the electrode was kept in the solution consisted in 0.05mol/L TBAP and 2.5×10-3mol/L CoTSPC and scan-round 60 cycles by cyclic voltammetry, then dipped in 0.5% Nafion for 15 s and dried twice. The sensor has the linear response range of 1.0×10-7～1.0×10-4mol·L-1 with the square of the correlation coefficient 0.9979. The selectivity, potential stability and reproducibility of the sensor is good, satisfied to the requirements of Physiological analysis.The two NO sensors both have the capacity of catalysis and oxidation, and are both copulated with NO in the direction of axis. This cominational compound is more easilier oxidated than the NO because it has more lowwer energy of activation.To contrast their qualities with each other and analyse their characteristic.The contrast of NO sensors and NO kits in the applicationThe rat 4-vessel occluding brain ischemic model was used.To test the feasibility of two NO sensors by obersving changes of NOS activity content following a transient celebral ischemia with NO kits.To achieve in the request of the real vivo measurement.At last, the NO sensors provide a convincing data for the cerebral ischemic model and Meridian Theory by the application of the two sensors in the experiments of rats.