Supramolecular Hydrogels via Light-Responsive Homoternary Cross-Links.

Supramolecular Hydrogels via Light-Responsive Homoternary Cross-Links.
Biomacromolecules. 2020 Aug 17;:
Authors: Zou L, Addonizio CJ, Su B, Sis MJ, Braegelman AS, Liu D, Webber MJ
Abstract
Host-guest physical cross-linking has been used to prepare supramolecular hydrogels for various biomedical applications. More recent efforts to endow these materials with stimuli-responsivity offers an opportunity to precisely tune their function for a target use. In the context of light-responsive materials, azobenzenes are one prevailing motif. Here, an asymmetric azobenzene was explored for its ability to form homoternary complexes with the cucurbit[8]uril macrocycle, exhibiting an affinity (Keq) of 6.21 × 1010 M-2 for sequential binding, though having negative cooperativity. Copolymers were first prepared from different and tunable ratios of NIPAM and DMAEA, and DMAEA groups were then postsynthetically modified with this asymmetric azobenzene. Upon macrocycle addition, these polymers formed supramolecular hydrogels; relaxation dynamics increased with temperature due to temperature-dependent affinity reduction for the ternary complex. Application of UV light disrupted the supramolecular motif through azobenzene photoisomerization, prompting a gel-to-sol transition in the hydrogel. Excitingly, within several minutes at room temperature, thermal relaxation of azobenzene to its trans state afforded rapid hydrogel recovery. By revealing this supram...

Source: Biomacromolecules - August 16, 2020 Category: Biochemistry Authors: Zou L, Addonizio CJ, Su B, Sis MJ, Braegelman AS, Liu D, Webber MJ Tags: Biomacromolecules Source Type: research