| Nano material is one of the novel materials to which scientists are paying more and more attention, due to its high surface active, special size effect, catalytic effect and wide application potential. When the unit of material decreases to nano size, the material special surface volume electrical character, magnetic characters and chemical characters may change greatly. Therefore, nano particles are useful in the field of catalyst, electrical material, micro device material and sensor material. According to all these factors, nano technology are important to the future industry and to the development of traditional industry. This part reviews the nano materials preparation, characteristic, and their applications to bioactive molecules analysis.The main work of this paper is focus on one of the most active field where nano technique combines with electroanalytical chemistry, developing and fabrication ovel modified electrodes based on nano materials (electrochemical sensors). The emphasis of this paper is to find out and study the advantages of nano material modified electrodes comparing with the conventional and traditional modified electrodes. Besides, the other emphasis of the paper is to apply these novel nano material modified electrodes to realizing the detection and analysis of some biological molecules, which may provide many important analytical methods for the life science and relative fields. What we have done is to try our best to combine the nano technique, life science with electroanalytical chemistry firmly. The details are listed below:First, hemoglobin (Hb) was successfully immobilized on nanometer-sized SiO2. A novel amperometric sensor of hydrogen peroxide was constructed in the presence of an electron mediator hydroquinone. The electrochemical response of the biosensor with respect to the effects of mediator concentration, pH of measuring solution was investigated for optimum analytical performance by an amperometric method. The biosensor had a fast response of less than 10 s and linear calibration rang of 6.25×10-7 to 1.63×10-4mol/L, with a detection limit of 1.8×10-7mol/L based on S/N = 3. The apparent Michaelis-Menten constant (KappM) was found to be 7.5×10-4mol/L. The low KappM value demonstrated that Hb immobilized on the SiO2/Chitosan composite film exhibited a high affinity to H2O2. The protein electrode exhibited excellent stability, long-term life and good reproducibility.Secondly, a novel renewable reagentless hydrogen peroxide (H2O2) sensor based on the direct electron transfer of hemoglobin was proposed. The direct electrochemistry of Hb immobilized on Fe/C nanocomposite modified glassy carbon electrode was studied using electrochemical methods. The modified electrode displayed a pair of stable and quasireversible cyclic voltammertric peaks for the Hb Fe(III)/Hb Fe( II) redox couple in a pH 7.0 phosphate buffer solution. The biosensor showed a surface-controlled electrode process with the scan rate range from 40 to 250 mV/s. The biosensor exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide without the aid of an electron mediator. The electrocatalytic response displayed a linear dependence on the H2O2 concentration ranging from 3.1×10-6mol/L to 4.0×10-3mol/L with a detection limit of 1.2×10-6mol/L (S/N=3).Last, an amperometric third-generation hydrogen peroxide biosensor was designed by immobilizing on a glassy carbon electrode modified with natural polymer magnetic microspheres. Magnetic microspheres were prepared by the carboxymethylation of chitosan and the followed binding on the surface of Fe/C nanocomposite via carbodiimide activation. The fabricated procedures and electrochemical behaviors of protein were characterized with electrochemical impedance spectroscopy and cyclic voltammetry. It was found that the electrode transfer between the Hb and the underlying electrode was greatly enhanced in the advantageous microenvironment with the natural polymer magnetic microspheres. The modified electrode exhibited excellent electrocatalytic activity and rapid response for H2O2. In a pH 7.0 phosphate buffer solution, the electrocatalytic response showed a linear dependence on the H2O2 concentration ranging from 5.2×10-5-2.3×10-3mol/L with a detection limit of 8.7×10-6 mol/L. In addition, the biosensor had good repeatability and long-term stability.
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