Fig. 2.

Design of an on-demand programmable dual-responsive release system in sdTEVGs. Dual-responsive hydrogels were successively modified on the adventitia of the sdTEVGs in vitro, which were than implanted into SD rats. Increasing ROS reacted with the external responsive hydrogel, which gradually released Netrin-1 to attract and guide nerve fibers to grow into the sdTEVGs. With the increased levels of the neurotransmitter ATP from the immigrated nerve fibers, single－stranded (ssDNA) of the ATP ligand in the internal responsive hydrogel was turned on. Then, the hydrogel released DENND1A, which was internalized by nerve fibers to promote the release of neural exosomes, which could inhibit the abnormal transformation of VSMCs into synthetic VSMCs in diabetic rats.