The synthesis of a contraction-type glucose-sensitive microgel working at physiological temperature guided by a new glucose-sensing mechanism
The synthesis of a contraction-type glucose-sensitive microgel working at physiological temperature guided by a new glucose-sensing mechanism
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DOI：
10.1039/c8py00072g
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发表时间：
2018-02
影响因子：
4.6
通讯作者：
Zhuo Tang;Ying Guan;Yongjun Zhang
中科院分区：
文献类型：
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作者：
Zhuo Tang;Ying Guan;Yongjun Zhang
收缩型葡萄糖敏感性微凝胶在加入葡萄糖后会收缩，在自我调节胰岛素释放和葡萄糖传感方面具有潜在的应用前景。聚（N-异丙基丙烯酰胺-co-2-丙烯酰胺基苯基硼酸）（P（NIPAM-2-AAPBA））微凝胶随葡萄糖浓度的增加而单调收缩，但在生理温度下不起作用。在这里，我们重新研究了它的葡萄糖传感机制，发现通常用于解释其他收缩型凝胶行为的交联机制不能解释P（NIPAM-2-AAPBA）微凝胶的行为。为了解释P（NIPAM-2-AAPBA）微凝胶的行为，提出了一种新的葡萄糖传感机理。与其他PBA官能化凝胶不同，其中葡萄糖通过改变电离度或交联度来改变其溶胀度，在P（NIPAM-2-AAPBA）微凝胶的情况下，葡萄糖作为添加剂通过降低微凝胶的VPTT（体积相变温度）来改变凝胶溶胀度。葡萄糖的加入相当于提高微凝胶分散体的温度，因此导致微凝胶的收缩。葡萄糖与PBA基团的结合缩短了葡萄糖和PNIPAM链之间的距离，因此显著增强了葡萄糖降低微凝胶的VPTT的能力。这一新的机理可以很好地解释微凝胶随葡萄糖浓度增加而单调收缩的现象，微凝胶对葡萄糖以外的其他物质的响应，以及微凝胶对葡萄糖响应的最佳温度的存在。新的机制还表明，葡萄糖传感的最佳温度可以通过调节微凝胶的VPTT来调节。在此新机理指导下，成功合成了一种在生理温度下工作的新型收缩型葡萄糖敏感微凝胶。
Contraction-type glucose-sensitive microgels, which shrink upon the addition of glucose, have potential for applications in self-regulated insulin release and glucose sensing. Poly(N-isopropylacrylamide-co-2-acrylamidophenylboronic acid) (P(NIPAM-2-AAPBA)) microgel shrinks monotonously with increasing glucose concentrations, but does not work at physiological temperature. Here we re-examined its glucose-sensing mechanism and found that the crosslinking mechanism, which is commonly used to explain the behaviors of other contraction-type gels, cannot explain the behavior of the P(NIPAM-2-AAPBA) microgel. To explain the behavior of the P(NIPAM-2-AAPBA) microgel, a new glucose-sensing mechanism was proposed. Unlike other PBA-functionalized gels, in which glucose changes their swelling degree via changing the ionization degree or crosslink degree, in the case of the P(NIPAM-2-AAPBA) microgel, glucose changes the gel swelling degree via lowering the VPTT (volume phase transition temperature) of the microgel as an additive. The addition of glucose is equivalent to raising the temperature of the microgel dispersion, and therefore leads to shrinkage of the microgel. Binding of glucose with PBA groups shortens the distance between glucose and PNIPAM chains, and hence significantly enhances the ability of glucose to lower the VPTT of the microgel. This new mechanism can explain well the monotonous shrinking of the microgel with increasing glucose concentration, the response of the microgel to other saccharides besides glucose, and the existence of an optimal temperature for the microgel to respond to glucose. The new mechanism also suggests that the optimal temperature for glucose sensing can be modulated by tuning the VPTT of the microgel. Guided by the new mechanism, a new contraction-type glucose-sensitive microgel working at physiological temperature was successfully synthesized.