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 PHisNi 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.

中文翻译：

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通过新型合成法，具有与生理相关的pH响应性和增强的稳定性的基于多组氨酸的金属配位水凝胶

利用疾病组织的异常生理状况可以产生特定部位的功能，从而高度控制和刺激刺激性水凝胶。这里，生理学相关pH响应性和自我修复水凝胶基于Ni之间的协调报道²⁺ -和四臂聚（乙二醇）b，其由新的和容易制备PHIS合成-polyhistidine（4PEG-PHIS）用氨基末端四臂PEG作为大分子引发剂的方法。可逆PHIS Ni配位键使水凝胶具有多刺激触发的溶胶-凝胶转变（生理学相关的pH值，EDTA）和自愈特性。还证明了4PEG-PHis可用作磷酸盐缓冲液（pH 7.4）中的可注射水凝胶，并且通过多价配位显示出在中性缓冲液中的优异稳定性，从而表明其在控制药物释放系统中的潜在应用。