Nanostructured Thermoresponsive Surfaces Engineered via Stable Immobilization of Smart Nanogels with Assistance of Polydopamine.

Thermoresponsive surfaces featured with nanostructures have found wide potential applications in biological and chemical fields. Herein, we report nanostructured thermoresponsive surfaces engineered via stable immobilization of thermoresponsive nanogels with the assistance of polydopamine. The results show that the thin layer of polydopamine on the poly( N-isopropylacrylamide) (PNIPAM) nanogels nearly does not affect the thermoresponsive property of the nanogels. The stability of the thermoresponsive nanogels on the substrate surfaces immobilized under different pH conditions of dopamine solutions are quatitively studied by fluid shearing experiments inside capillaries, and the characterization results show that the strong interaction forces between the polydopamine layer on the substrate surfaces and the thermoresponsive nanogels are heavily dependent on the oxidation state of the dopamine molecules. With the proposed strategy, thermoresponsive nanostructured surfaces immobilized with PNIPAM nanogels on two-dimensional and three-dimensional substrate surfaces are generated to achieve smart cell culture plates and smart gating membranes, respectively, which demonstrate versatile applications of the nanostructured thermoresponsive surfaces.