title: Label-free electrochemical immunosensor based on graphene/methylene blue nanocomposite.
abstract: For the specificity of prostate cancer markers, prostate 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.
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong (University of Jinan), School of Chemistry and Chemical Engineering, University of Jinan, Jinan, People's Republic of China.
authors.forename: Kexia
authors.initials: K
authors.lastname: Mao
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Hongmin
authors.initials: H
authors.lastname: Ma
authors.forename: Zizhen
authors.initials: Z
authors.lastname: Ni
authors.forename: Haiqin
authors.initials: H
authors.lastname: Yu
authors.forename: Chuannan
authors.initials: C
authors.lastname: Luo
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
authors.forename: Bin
authors.initials: B
authors.lastname: Du
mesh_terms: D000937:Antigen-Antibody Reactions; D014408:Biomarkers, Tumor / Q000097:blood / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D048271:Chitosan / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D008297:Male; D008751:Methylene Blue / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000097:blood* / Q000737:chemistry; D015203:Reproducibility of Results; D013194:Staining and Labeling
chemical_list: D014408:Biomarkers, Tumor; D006108:Graphite; D048271:Chitosan; D017430:Prostate-Specific Antigen; D008751:Methylene Blue