There is convincing evidence in vivo that the vascular homing of endothelial progenitor cells (EPCs) contributes to rapid endothelial regeneration, which could prevent thrombosis and restenosis of cardiovascular devices. To enhance the EPC homing on cardiovascular devices, immobilization of an EPC capture agent (e.g. an anti-CD34 antibody) on the surface of cardiovascular devices is critical. We describe a way of immobilizing anti-CD34 Ab on 316L Stainless Steel (316L SS). For this, surface modification of 316L SS was performed via self-polymerization of dopamine (DA) and covalent grafting of staphylococcal protein A (SPA). On this coating the anti-CD34 Abs were oriented immobilized through their Fc constant region with SPA. In this process, the results of quartz crystal microbalance, X-ray photoelectron spectroscopy and water contact angle studies indicate that DA, SPA and anti-CD34 Ab were successfully immobilized onto the surface step by step. In vitro blood-compatibility tests confirmed that the modified surface induced less pro-coagulant fibrinogen denaturation, less platelet adhesion and lower activation of the adherent platelets. The affinity of EPCs for the modified surface has been demonstrated under flow conditions. This study provides potential applications for cardiovascular implant materials.

Electrochromic devices (ECDs) have emerged as a unique class of optoelectronic devices for the development of smart windows. However, current ECDs typically suffer from low coloration efficiency (CE) and high energy consumption, which have thus hindered their practical applications, especially as components in solar-powered EC windows. Here, the high-performance ECDs with a fully crystalline viologen-immobilized 2D polymer (V2DP) thin film as the color-switching layer is demonstrated. The high density of vertically oriented pore channels (pore size ≈ 4.5 nm; pore density ≈ 5.8 × 1016 m-2) in the synthetic V2DP film enables high utilization of redox-active viologen moieties and benefits for Li+ ion diffusion/transport. As a result, the as-fabricated ECDs achieve a rapid switching speed (coloration, 2.8 s; bleaching, 1.2 s), and a high CE (989 cm2 C-1), and low energy consumption (21.1 µW cm-2). Moreover, it is managed to fabricate transmission-tunable, self-sustainable EC window prototypes by vertically integrating the V2DP ECDs with transparent solar cells. This work sheds light on designing electroactive 2D polymers with molecular precision for optoelectronics and paves a practical route toward developing self-powered EC windows to offset the electricity consumption of buildings.