Bifunctional Surfaces With Immobilized Antibodies and Bioactive Peptides Mediate Selective Capture and Proliferation...

Endothelial colony-forming cells (ECFCs) are of significant interest in vascular biomaterials engineering and cell-based therapies for cardiovascular diseases. Efficient isolation and expansion of ECFCs on polymeric surfaces either in vitro or in situ in the case of implants could significantly advance ECFC-based therapies. We present a novel bifunctional surface modification strategy combining oriented antibodies and extracellular matrix-derived peptides to selectively capture ECFCs on surfaces and then mediate firm adhesion, spreading and proliferation. Studies were conducted with anti-CD309 antibodies and custom RGD peptides, previously shown to respectively enable ECFC capture and clonal expansion. To aid in oriented antibody immobilization on surfaces while modulating antibody-RGD surface concentrations, Fc-binding peptides and RGD peptides were co-immobilized on aminated surfaces using click chemistry, followed by affinity-mediated antibody immobilization. Bifunctional anti-CD309 + RGD surfaces selectively captured ECFCs from a mixture with peripheral blood mononuclear cells in dynamic conditions. The presence of RGD peptides significantly enhanced cell spreading and proliferation, leading to additive effects on surface coverage under flow. Proof-of-concept studies demonstrated successful adaptation to 3D polystyrene microcarriers, showcasing potential scalability for clinical-grade cell production. The surface modification scheme provides a versatile and clinically translatable platform for advancing ECFC-based regenerative therapies.