Highly sensitive carboxyl-graphene oxide-based surface plasmon resonance immunosensor for the detection of lung cancer for cytokeratin 19 biomarker in human plasma

Functionalized graphene oxide is a novel type of highly efficient biosensing material. In this study, we present a carboxyl-functionalized graphene oxide (GO-COOH)-based surface plasmon resonance (SPR) chip for the rapid and quantitative detection of non-small cell lung carcinoma (NSCLC) via the cytolerayin 19 (CK19) protein biomarker in spiked human plasma. We demonstrated the binding specificity of kinetic analysis of interactions between GO-COOH and anti-CK19 and CK19 protein. We also calculated the relationship between the SPR angle and refractive index of GO-COOH, and demonstrated that-COOH modified GO sheets on Au film can enhance the field energy propagation intensity of an SPR sensor, resulting in a higher sensitivity for the detection of CK19 protein compared to a conventional Au-based SPR chip. The immunosensor was constructed and engineered by immobilizing a low concentration (10 mu g/mL) of CK19 antibody on an SPR chip. The lowest detectable concentration was as low as 1 mu g/mL. A spiked 10% human plasma CK19 detection limit of 0.05 pg/mL was achieved, well below the normal physiological level of serum protein (3.3 ng/mL). Therefore, a carboxyl-GO based SPR biosensor appears to have high sensitivity and specificity for the detection of clinical whole plasma biomarkers and possible application in diagnosing diseases. (C) 2018 Elsevier B.V. All rights reserved.