Surface modification of poly(styrene) 96-well plates using aptamers via a dendrimer-templated strategy to enhance ELISA performances.

Poly(styrene) (PS) 96-well plates were surface modified to improve the detection performances of an otherwise traditional enzyme-linked immunosorbent assay (ELISA). Poly(amidoamine) generation 7 (G7) dendrimers were covalently immobilized on the surface of PS plates and subsequently conjugated with aptamers specific for a model analyte, i.e., human platelet-derived growth factor BB (PDGF-BB). This surface functionalization was followed by Fourier-transform infrared spectroscopy, water contact angle, atomic force microscopy, and X-ray photoelectron spectroscopy (XPS) to confirm the success of the modifications. Moreover, the assay performances of the G7-aptamer modified PS plates were compared to those of traditional ELISA performed on regular PS 96-well plates. The G7-aptamer assay demonstrated a 2.3-time broader linear detection range and a 13-time improved detection limit than the traditional ELISA. More importantly, the new G7-aptamer modified PS plates also showed excellent analytical specificities, detection recoveries, and precisions when the targets were assayed in a cell culture medium. This combined dendrimer templates and aptamers surface modification approach significantly reduces background noises and increases detection signals, and can be readily incorporated into existing ELISA workflows and many other PS microplate based high throughput and automated bioassays.