Improved antibody loading on self-assembled graphene oxide films for using in surface plasmon resonance immunosensors

• Published in: Applied surface science Vol. 490; pp. 502 - 509
• Main Authors: Miyazaki, Celina Massumi, Camilo, Douglas Eleutério, Shimizu, Flavio Makoto, Ferreira, Marystela
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2019
• Subjects: Antibody loading; Graphene oxide; Prostate-specific antigen; Self-assembly; Surface functionalization; Surface plasmon resonance; Surface functionalization; EDC; Prostate-specific antigen; LS; AFM; 11-MUA; SA; BSA; SPR; NHS; Cys; PSA; LOD; PBS; GO; CVD; Self-assembly; LB; LbL; Antibody loading; PM-IRRAS; RMS; Graphene oxide; Surface plasmon resonance; SAM; ELISA
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.06.095

Immunoassays are important for the diagnosis of many diseases. Efficient methods for the immobilization of the biorecognition elements is a relevant subject because the antibody loading is directly related to the detection range and sensitivity. Here different self-assembled films were explored to take advantage of polar oxygenated groups from graphene oxide (GO) structure. Surface plasmon resonance (SPR) sensors were modified with different GO self-assembled films and compared to the well-established thiol-functionalization with 11-MUA (11- mercaptoundecanoic acid). Self-assembled cysteamine/GO functionalized sensor (Cys-GOSA) provided the highest protein loading (7.66 × 10−12 mol cm−2 against 1.29 × 10−11 mol cm−2 for the traditional thiol-functionalization). The Langmuir-Blodgett (LB) films of GO were composed of aggregates and empty spaces, which hindered the antibody anchoring (around 6.38 × 10−12 to 3.45 × 10−12 mol cm−2). The SPR response of the Cys-GOSA-modified sensor to the 4.0 ng mL−1 PSA was 125% higher than the thiol-functionalized sensor at the same concentration. This result indicates a simple and promising surface modification strategy for many important applications, not limited to SPR sensors, but for all immunoreaction-based assays as enzyme-linked immunosorbent assay (ELISA), electrochemical (e.g. amperometric and impedimetric) and quartz crystal microbalance (QCM) based sensors. [Display omitted] •Different self-assembled graphene oxide (GO) films were tested in SPR sensors.•Antibody loading was superior for the cysteamine-GO-modified surface.•125% higher sensitivity (than thiol-method) was achieved with Cys-GO modification.•Cys-GO self-assembled film is promising for immunosensing applications.