标题：Label-free electrochemical immunosensor based on graphene/methylene blue nanocomposite
作者：Mao, K.;Wu, D.;Li, Y.;Ma, H.;Ni, Z.;Yu, H.;Luo, C.;Wei, Q.;Du, B.
作者机构：Key Laboratory of Chemical Sensing and Analysis, School of Chemistry and Chemical Engineering, Universities of Shandong (Univers
通讯作者地址：[Wei, Q]Univ Jinan, Key Lab Chem Sensing & Anal, Shandong Univ, Sch Chem & Chem Engn, Jinan 250022, Peoples R China.
来源：Analytical Biochemistry: An International Journal of Analytical and Preparative Methods
关键词：Graphene sheets;Immunosensor;Methylene blue;Prostate specific antigen
摘要：For the specificity of prostate cancer markers, protsate specific antigen (PSA) has been widely used in prostate cancer screening, diagnosis, and treatment after monitoring. In normal male serum, PSA can only be detected in traces of 0-4 ng mL ~(-1). In this paper, we constructed an electrochemical immunosensor for PSA detection using a nanocomposite film of graphene sheets-methylene blue-chitosan (GS-MB-CS) as electrode material. The nanocomposite film showed high binding affinity to the electrode and was used to immobilize the antibody of PSA. The modification procedure was monitored by cyclic voltammetry (CV). An amperometric biosensor was easily developed based on the response of peak current to the capture of PSA induced by specific antigen-antibody reactions. Under optimum conditions, the amperometric signal decreased linearly with PSA concentration (0.05-5.00 ng mL ~(-1)). A low limit of detection (13 pg mL ~(-1)) and a high selectivity are obtained. Moreover, the prepared immunosensor was applied for the analysis of PSA in serum samples with satisfactory results. The proposed method may have a promising future in biochemical assays for high selectivity, good reproducibility, and stability.