The target population for coronary artery bypass grafting is patients with significant coronary artery disease (CAD). Our goal is to implement late-outgrowth endothelial progenitor cells (EPCs) from the peripheral blood of CAD patients (CAD-EPCs) as an autologous source for the endothelialization of small diameter synthetic vascular grafts and tissue engineered blood vessels. While CAD EPCs can be acquired readily and noninvasively, their extreme rarity in peripheral blood imposes a 4-6 week post-harvest lead time needed to expand the cells ex vivo before grafts can be endothelialized. We propose to reduce this duration to around two weeks through the design of an aptamer-based affinity capture device that can efficiently and specifically capture large numbers of CAD-EPCs directly from the bloodstream. The aims of this R21 project are to (1) generate and (2) test the CAD-EPC capturing ability of both DNA- and RNA-based biorecognition aptamers, which will serve as the cell-capturing agents.