Abstract OEGylated homopolypeptide (i.e., P(Azo-S-OEG7)) bearing azobenzene, thioether spacers, and oligo(ethylene glycol) OEG tails were prepared via a copper-mediated 1,3-dipolar cycloaddition. P(Azo-S-OEG7) showed an upper critical solution temperature (UCST)-type thermo-, light-, and oxidation-responsive in ethanol/water solvent mixtures. The UCST-type cloud point temperature (Tcp) decreased after UV irradiation and it increased after visible light irradiation due to the trans-cis isomerization of azobenzene moieties. P(Azo-S-OEG7) can be readily oxidized in the presence of H2O2, yielding P(Azo-SOX-OEG7) with sulfone or sulfoxide spacers. P(Azo-SOX-OEG7) showed an increase of UCST-type Tcp after UV irradiation and the Tcp decreased after visible light irradiation, which is an opposite trend to the UCST-type phase behavior of P(Azo-S-OEG7) as well as previous report. P(Azo-S-OEG7) showed poor water-solubility, yet it underwent H2O2 induced solution phase transition yielding P(Azo-SOX-OEG7) with lower critical solution temperature (LCST)-type phase behavior in water. The P(Azo-SOX-OEG7) aqueous solutions showed a decrease of LCST-type Tcp after UV irradiation and consequently Tcp decreased after visible light irradiation.

中文翻译：

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具有偶氮苯和硫醚间隔物的 OEGylated 同源多肽的异常光可调热响应行为

摘要 通过铜介导的 1,3-偶极环加成反应制备了带有偶氮苯、硫醚间隔基和低聚（乙二醇）OEG 尾部的 OEG 化同源多肽（即 P(Azo-S-OEG7)）。P(Azo-S-OEG7) 在乙醇/水溶剂混合物中显示出上临界溶解温度 (UCST) 型热响应、光响应和氧化响应。由于偶氮苯部分的反式异构化，UCST 型浊点温度 (Tcp) 在紫外线照射后降低，在可见光照射后升高。P(Azo-S-OEG7) 在 H2O2 存在下很容易被氧化，产生带有砜或亚砜间隔物的 P(Azo-SOX-OEG7)。P(Azo-SOX-OEG7) 在紫外线照射后显示出 UCST 型 Tcp 增加，而在可见光照射后 Tcp 下降，这与 P(Azo-S-OEG7) 的 UCST 型相行为以及之前的报告相反。P(Azo-S-OEG7) 表现出较差的水溶性，但它经历了 H2O2 诱导的溶液相变，产生了在水中具有较低临界溶解温度 (LCST) 型相行为的 P(Azo-SOX-OEG7)。P(Azo-SOX-OEG7)水溶液在紫外线照射后显示出LCST型Tcp降低，因此在可见光照射后Tcp降低。