Abstract
In this study, electrochemical immunosensors were developed for the detection of prostate specific antigen (PSA) using ferrocene (Fc) and polyamidoamine dendrimer (PAMAM) constructs. The biosensor fabrication was designed by modifying the screen-printed gold electrode (Au) with ferrocene cored dendrimers (FcPAMAM) synthesized in three different generations. The self-assembled monolayer principle was followed, to obtain sensitive, selective and disposable electrodes. Therefore, the Au electrodes were modified with cysteamine (Cys) to obtain a functional surface for FcPAMAM dendrimers to bind. Dendrimer generations were attached to this surface using a cross-linker (glutaraldehyde) so that a suitable surface was obtained for binding of biological components. The Monoclonal PSA antibody (anti-PSA) was immobilized on the Au electrode surface which coated with dendrimer, and (Au/Cys/FcPAMAM/anti-PSA) biosensing electrode was obtained. The PSA detection performances of electrochemical impedance spectroscopy (EIS) and Amperometry based immunosensors exhibited very low detection limits; 0.001 ng mL(-1) and 0.1 pg mL(-1), respectively. In addition, EIS and Amperometry based biosensors using Au/Cys/FcPAMAM/anti-PSA sensing electrode were represented excellent linear ranges of 0.01 ng mL(-1) to 100 ng mL(-1) and 0.001 ng mL(-1) to 100 ng mL(-1). In order to determine the applicability recovery and selectivity tests were performed using three different proteins in human serum.