A tissue biosensor based on sol-gel immobilization technique

A new technique on the preparation of biosensor was reported. SiO2 sol-gel and plant juice were mixed by a certain proportion to make the enzyme from natural plant immobilized in the SiO2 sol-gel film. The dopamine (DA) biosensor was prepared from a platinum electrode coated with a nafion film and then the modified SiO2 sol-gel layer. Cyclic voltammetry and linear scan voltammetry were used to investigate the electrochemical characteristics of the sensor. The catalysis effect of different plant species and parts was compared. The effect of dosage of ethanol, water, tetraethyl orthosilicate (TEOS) and plant juice was studied. The linearity of DA in the range of 2 x 10(-6) similar to 1 x 10(-4) mol/L with detection limit of 8.0 x 10(-7) mol/L and the correlation coefficient of 0.999 were obtained in the detrmination by differential pulse voltammetry. No interference was found from ascorbic acid, nitrite, uric acid, epinephrine and noradrenalin in the determination of DA. Satisfactory determination results of DA in samples were obtained by this method.