Stimuli-responsive polymers have received considerable attention due to their ability to change properties in response to environmental changes. Polypeptoids are biocompatible and candidates for biomedical applications such as in controlled drug release and tissue engineering. In this work, we synthesized UV-sensitive diblock polypeptoids poly(sarcosine-r-butylglycine)-b-PNB (P(Sar-r-NBG)-b-PNB) and triblock polypeptoids polysarcosine-b-polybutylglycine-b-PNB (PSar-b-PNBG-b-PNB). Exposure to 254 nm UV light triggers the cleavage of nitrobenzyl groups leading to an increase in hydrophilicity, which is confirmed by UV/vis, ¹H NMR, and dynamic light scattering (DLS) analysis. Consequently, micelles formed by these block polypeptoids can undergo UV-trigged release of encapsulated cargo, herein exemplified using Nile red or pyrene as model payload. Furthermore, the diblock polypeptoids containing random P(Sar-r-NBG) segment exhibit thermoresponsive behavior, which is investigated by optical transmittance and DLS, and their cloud point temperatures (T_cps) can be adjusted by the feed molar ratio of Sar-NTA and NBG-NTA monomers. Furthermore, the block polypeptoids are able to self-assemble in water and show morphological changes from spherical nanoparticles to linear aggregates of several millimeters in length when the concentration increases. CCK-8 cell viability assays prove that the block polypeptoids’ micellar aqueous solution is noncytotoxic before and after UV irradiation. Such novel biocompatible block polypeptoids with dual-responsive properties and varying morphology are of interest for applications in the field of biomedicine.

中文翻译：

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嵌段多肽：合成，表征，以及对紫外线和温度辐射的响应。

刺激响应性聚合物由于其响应环境变化而改变性质的能力而受到了相当大的关注。多肽类具有生物相容性，是生物医学应用的候选药物，例如可控药物释放和组织工程。在这项工作中，我们合成了UV敏感的二嵌段polypeptoids聚（sarcosine- ř -butylglycine） - b -PNB（P（Sar- ř -NBG） - b -PNB）和三嵌段polypeptoids polysarcosine- b -polybutylglycine- b -PNB（ PSar- b -PNBG- b -PNB）。暴露于254 nm的紫外线会触发硝基苄基的裂解，从而导致亲水性增加，这可以通过UV / vis进行确认，¹ H NMR和动态光散射（DLS）分析。因此，由这些嵌段多聚肽形成的胶束可以经历紫外线触发的封装货物的释放，在此以尼罗红或pyr作为模型有效载荷来举例说明。此外，含有P（Sar - r -NBG）随机链段的二嵌段多肽表现出热响应性，这是通过光透射率和DLS及其浊点温度（T _cps）可以通过Sar-NTA和NBG-NTA单体的进料摩尔比来调节。此外，当浓度增加时，嵌段多肽能够在水中自组装，并显示出从球形纳米颗粒到长度为几毫米的线性聚集体的形态变化。CCK-8细胞活力分析证明，封闭的类肽胶束水溶液在紫外线照射之前和之后均无细胞毒性。这种具有双重响应特性和变化形态的新型生物相容性嵌段多肽对于生物医学领域的应用是令人感兴趣的。