Sequence-defined and degradable polymers can mimic biopolymers, such as peptides and DNA, to undertake life-supporting functions in a chemical way. The design and development of well-structured oligomers/polymers is the most concern for the public, even to further uncover their degradation process illustrating the degraded products and their properties. However, seldom investigation has been reported on the aforementioned aspects. In this work, the alternating photo-reversible addition-fragmentation chain-transfer (photo-RAFT) single unit monomer insertion (SUMI) of different N-substituted maleimides and thermal radical ring-opening SUMI of a cyclic ketene acetal monomer (i.e., 5,6-benzo-2-methylene-1,3-dioxepane (BMDO)) is adopted, to produce two degradable pentamers owing to the conversion of the exo-methylene group of BMDO into ester bonds along the main chains of the prepared products. Moreover, the possible degraded approach of pentamers is studied by combining high-resolution mass spectrometry (HRMS) and liquid chromatography-mass spectrometry (LC-MS) for the first time. This work also sheds light on the precise structures and cytotoxicity of SUMI products and their degraded compounds, proposing a detailed and credible outlook for biomedical applications.

中文翻译：

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具有显式片段化途径的序列控制、可降解和细胞相容性低聚物的开发

序列确定和可降解的聚合物可以模仿生物聚合物，如肽和 DNA，以化学方式承担维持生命的功能。结构良好的低聚物/聚合物的设计和开发是公众最关心的问题，甚至进一步揭示其降解过程，说明降解产物及其性能。然而，很少有关于上述方面的调查报道。在这项工作中，不同N的交替光可逆加成断裂链转移 (photo-RAFT) 单单元单体插入 (SUMI)-取代的马来酰亚胺和环烯酮缩醛单体（即5,6-苯并-2-亚甲基-1,3-二氧杂环己烷（BMDO））的热自由基开环SUMI被采用，由于转化产生了两种可降解的五聚体BMDO 的外亚甲基沿制备产物的主链转变为酯键。此外，首次通过结合高分辨率质谱（HRMS）和液相色谱-质谱（LC-MS）研究了五聚体可能的降解途径。这项工作还阐明了 SUMI 产品及其降解化合物的精确结构和细胞毒性，为生物医学应用提出了详细而可靠的前景。