Photo and Thermo Dual-Responsive Copolymer Surfaces for Efficient Cell Capture and Release.

To overcome the low efficiency of single-responsive smart surfaces, we have constructed a dual-responsive smart surface - poly(spiropyran-co-N-isopropylacrylamide) (poly(SP-co-NiPAAm))-grafted silicon nanowire arrays - by combining photo-responsive SP and thermo-responsive NiPAAm units for enhancing the efficiencies of cancer-cell capture and release. These enhanced efficiencies probably originate from the binary cooperative effect of two responsive building units: NiPAAm units can decrease the steric hindrance between SP units during the isomerization while SP units can facilitate phase transition of NiPAAm units. This study provides a new strategy for designing smart materials and surfaces with efficient responsiveness for biomedical applications.