OEGylated polypeptide bearing triethylene glycol monomethylether (OEG3) and poly(ethylene glycol) methyl ether 350 (OEG7) were first prepared by copper-mediated 1,3-dipolar cycloaddition. 1H NMR, FTIR, and GPC results indicated the successful conjugation of oligo(ethylene glycol) (OEG) pendants with high grafting efficiency (≥ 98%). Variable temperature UV–vis spectroscopy revealed a reversible lower critical solution temperature (LCST)-type phase transition of the resulting polypeptides. The LCST-type cloud point temperature (Tcp) in the range of 20–60 °C can be readily tuned by changing the OEG3 and OEG7 composition. Thermo- and pH-responsive polypeptide was prepared by first conjugating of OEG and 6-aldehyde hexyl pendants, then crosslinking in the presence of 1,6-hexanediamine, yielding OEGylated polypeptide bearing pH-labile imine bonds. The resulting polypeptide showed pH-responsive property and less pronounced thermoresponsive property at high pH values (i.e., ≥ 6.15) and noticeable thermo- and pH- dual responsive properties at low pH values (i.e., ≤ 5.80). Graphical abstract We developed a new type of pH- and thermo-responsive OEGylated polypeptides containing imine bonds. The polypeptides are able to show pH-responsive property and less pronounced thermoresponsive property at high pH values and noticeable thermo- and pH- dual responsive properties at low pH values. We developed a new type of pH- and thermo-responsive OEGylated polypeptides containing imine bonds. The polypeptides are able to show pH-responsive property and less pronounced thermoresponsive property at high pH values and noticeable thermo- and pH- dual responsive properties at low pH values.

中文翻译：

---

带有OEG和醛挂件的热和pH响应多肽的制备及性质

带有三甘醇单甲醚 (OEG3) 和聚 (乙二醇) 甲醚 350 (OEG7) 的 OEG 化多肽首先通过铜介导的 1,3-偶极环加成反应制备。1H NMR、FTIR 和 GPC 结果表明低聚（乙二醇）（OEG）悬垂物成功结合，接枝效率高（≥ 98%）。变温紫外-可见光谱揭示了所得多肽的可逆低临界溶解温度 (LCST) 型相变。通过改变 OEG3 和 OEG7 的成分，可以很容易地调整 20-60 °C 范围内的 LCST 型浊点温度 (Tcp)。通过首先将 OEG 和 6-醛己基侧链缀合，然后在 1,6-己二胺存在下交联，产生带有 pH 不稳定亚胺键的 OEG 化多肽，制备热和 pH 响应多肽。所得多肽在高 pH 值（即≥ 6.15）下表现出 pH 响应特性和不太明显的热响应特性，在低 pH 值（即≤ 5.80）下显示出明显的热和 pH 双重响应特性。图形摘要 我们开发了一种新型的含有亚胺键的 pH 和热响应 OEGylated 多肽。多肽能够在高pH值下显示出pH响应特性和不太明显的热响应特性，并且在低pH值下显示出显着的热和pH双重响应特性。我们开发了一种新型的含有亚胺键的 pH 和热响应 OEGylated 多肽。多肽能够在高pH值下显示出pH响应特性和不太明显的热响应特性，并且在低pH值下显示出显着的热和pH双重响应特性。