(316b) Protein Microarrays From Zwitterionic Carboxybetaine for Highly Sensitive Early Cancer Diagnostics Using SPR Imaging

Research has shown the extraordinary heterogeneity of cancer (numerous mutated and deregulated genes, abnormal expression of microRNAs, and genetic instability). This has lead to the use of high-throughput antibody-based biosensor platforms which can detect multiple disease biomarkers simultaneously in order to enhance the sensitivity and accuracy of diagnostic assays. The ability to sensitively detect these target analytes (at or below nanogram/milliliter quantities) from the complex environment of human blood serum or plasma has severely hindered the biomarker development and verification process using biosensors due to the presence of non-specific protein adsorption. In this work, antibody arrays were created using a simple yet robust zwitterionic poly(carboxybetaine methacrylate) (pCBMA) surface platform. The functionalization capabilities combined with the ultra-low protein fouling properties both before and after effective immobilization of biorecognition elements made pCBMA highly desirable. Using standard pin-spotting techniques on the pCBMA films, arrays containing antibodies to three cancer biomarkers were analyzed using a highly sensitive self-referencing surface plasmon resonance (SPR) imaging sensor with polarization contrast. The immobilization efficiency and reproducibility as well as subsequent biofouling, antibody activity, and stability in complex media were evaluated. Finally, the simultaneous detection of the three biomarkers directly from undiluted human serum was demonstrated.