A Reusable Substrate for Capture and Red Light‐Responsive Release of Circulating Rare Cells with High Cytoactivity

Abstract Efficient and reusable biomedical interfaces are necessary for the isolation and nondestructive release of circulating rare cells in blood. However, photo‐responsive release strategy, particularly that using red light, relies on photothermal effect, which could potentially affect cell activity through local overheating. To overcome this issue, we develop reusable functional substrates (RuSub‐S‐SA‐Ab) based on ruthenium (Ru) complexes with photo‐responsive ligand substitution to capture cells by using replaceable antibodies with high sensitivity and specificity. Our RuSub‐S‐SA‐Ab achieved capture efficiencies >85% for four different cell lines and release efficiencies of 90% under safe doses of red light (660 nm, 100 mW·cm −2 , 60 s), thus offering a new platform for the development of responsive biomedical interfaces with high biosafety.