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Polyhistidine-Based Metal Coordination Hydrogels with Physiologically Relevant pH Responsiveness and Enhanced
Quan Tang1, Dinglei Zhao1, Qiang Zhou1
1CAS Key Laboratory of Soft Matter Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026, P. R. China.
Abstract:
Utilizing the abnormal physiological conditions of disease tissues can result in a site-specific functionality with high control and efficiency of stimuli-responsive hydrogels. Here, a physiologically relevant pH-responsive and self-healing hydrogel is reported based on coordination between Ni2+ and four-arm poly(ethylene glycol)-b-polyhistidine (4PEG-PHis) that is synthesized by a novel and facile PHis preparation method using amino-terminalized four-arm PEG as the macroinitiator. Reversible PHisNi coordination bonds endow the hydrogel with multistimuli-triggered sol-gel transition (physiologically relevant pH, EDTA) and self-healing properties. It is also demonstrated that 4PEG-PHis could be used as an injectable hydrogel in phosphate buffer (pH 7.4), and excellent stability in neutral buffer via multivalent coordination is shown, thus indicating its potential applications in controlled drug release systems.
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