The incorporation of molecular switches into polymer networks has been a powerful approach for the development of functional polymer materials that display macroscopic actuation and function enabled directly by molecu...The incorporation of molecular switches into polymer networks has been a powerful approach for the development of functional polymer materials that display macroscopic actuation and function enabled directly by molecular changes.However,such materials sometimes require harsh conditions to perform their functions,and the design of new molecular photoswitches that can function under physiological conditions is highly needed.Here,we report the design and synthesis of a spiropyridine-based photoswitchable hydrogel that exhibits light-driven actuation at physiological pH.Owing to its high p Ka,spiropyridine maintains its ring-open protonated form at neutral pH,and the resulting hydrogel remains in a swollen state.Upon irradiation with visible light,the ring closure of spiropyridine leads to a decrease in the charge and a reduction in the volume of the hydrogel.The contracted gel could spontaneously recover to its expanding state in the dark,and this process is highly dynamic and reversible when the light is switched on and off.Furthermore,the hydrogel shows switchable fluorescence in response to visible light.Bending deformation is observed in the hydrogel thin films upon irradiation from one side.Importantly,the independence of this spiropyridine hydrogel from the acidic environment makes it biotolerant and shows excellent biocompatibility.This biocompatible spiropyridine hydrogel might have important biorelated applications in the future.展开更多
基金supported by the National Natural Science Foundation of China(No.52373121)the National Key R&D Program of China(No.2022YFA1305100)the Natural Science Foundation of Anhui Province(No.2208085MB27)。
文摘The incorporation of molecular switches into polymer networks has been a powerful approach for the development of functional polymer materials that display macroscopic actuation and function enabled directly by molecular changes.However,such materials sometimes require harsh conditions to perform their functions,and the design of new molecular photoswitches that can function under physiological conditions is highly needed.Here,we report the design and synthesis of a spiropyridine-based photoswitchable hydrogel that exhibits light-driven actuation at physiological pH.Owing to its high p Ka,spiropyridine maintains its ring-open protonated form at neutral pH,and the resulting hydrogel remains in a swollen state.Upon irradiation with visible light,the ring closure of spiropyridine leads to a decrease in the charge and a reduction in the volume of the hydrogel.The contracted gel could spontaneously recover to its expanding state in the dark,and this process is highly dynamic and reversible when the light is switched on and off.Furthermore,the hydrogel shows switchable fluorescence in response to visible light.Bending deformation is observed in the hydrogel thin films upon irradiation from one side.Importantly,the independence of this spiropyridine hydrogel from the acidic environment makes it biotolerant and shows excellent biocompatibility.This biocompatible spiropyridine hydrogel might have important biorelated applications in the future.
基金This work was mainly supported by National Basic Research Program of China (No.2014CB931802),the Major Project of International Cooperation of the Ministry of Science and Technology (No.2013DFB50340),National Natural Science Foundations of China (Nos.51272012,21471013,51532001,51333001,51173003,51402006 and 51303007),the Major Program of Chinese Ministry of Education (No.313002),the Beijing Natural Science Foundation (No.2163052) and China Postdoctoral Science Foundation Funded Project (No.2015M570916).
