Direct Electrochemistry and Application in Electrocatalysis of Hemoglobin in a Polyacrylic Resin-Gold Colloid Nanocomposite Film

A novel nanocomposite integrating the good biocompatibility of polyacrylic resin nanoparticles (PAR) and the good conductivity of colloidal gold nanoparticles was proposed to construct the matrix for the immobilization of hemoglobin (Hb) on the surface of a glassy carbon electrode (GCE). UV-vis spectra demonstrated that Hb preserved its native structure after being entrapped into the composite film. The direct electrochemistry of hemoglobin (lib) in this nanocomposite films showed a pair of well-defined and quasi-reversible cyclic voltammetric peaks with a formal potential of -0.307 mV and a constant electron transfer rate of 2.51 +/- 0.2 s(-1). The resultant amperometric biosensor showed fast responses to the analytes with excellent detection limits of 0.2 mu M for H(2)O(2) and 0.89 mu M for TCA (S/N=3), and high sensitivity of 1108.6 for H(2)O(2) and 77.14 mA cm(-2) M(-1) for TCA, respectively. The linear current response was found in the range from 0.59 to 7.3 mu M (R(2)=0.9996) for H(2)O(2) and from 5 to 85 mu M (R(2)=0.9996) for TCA, while the superior apparent Michaelis-Menten constant was 0.012 mM for H(2)O(2) and 0.536 mM for TCA, respectively. Therefore, the PAR-Au-Hb nanocomposite as a novel matrix opens up a possibility for further study on the direct electrochemistry of other proteins.