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 incorpo-rated into existing ELISA workflows and many other PS microplate based high throughput and automated bioassays.