A novel bioassay for the monitoring of hydrogen peroxide in human plasma samples based on binding of horseradish peroxidase-conjugated prostate specific antigen to poly (toluidine blue) as imprinted polymer receptor.

A low cost, sensitive and selective electrochemical imprinted biosensor for horseradish peroxidase-conjugated prostate-specific antigen (PSA) was designed and prepared based on the combination of Toluidine blue (TB) and self-assembly surface molecular imprinting technique. Poly toluidine blue [P(TB)] provided high surface area for dense loading of HRP-PSA antibody on GCE surface. P(TB), as supporting material, could effectively enhance imprinting efficiency and the electrode conductivity and facilitate electron transfer. The imprinted biosensor was characterized through Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDX) and electrochemical methods. The proposed biosensor indicates very highly electrocatalytical activity for the reduction of hydrogen peroxide (H2O2). Also, engineered biosensor was used for determination of H2O2 by different electrochemical techniques including differential pulse voltammetry, square wave voltammetry and chronoamperometry. Under the optimized conditions, the proposed bio-imprinted polymer exhibit excellent electrocatalytical activity toward the reduction of H2O2 with wide linear range of 0.001 to 40 mM and a low limit of quantification (LLOQ) of 1 μM.