Precision Synthesis of Polysarcosine via Controlled Ring-Opening Polymerization of N-Carboxyanhydride: Fast Kinetics, Ultrahigh Molecular Weight, and Mechanistic Insights.

The rapid and controlled synthesis of high-molecular-weight (HMW) polysarcosine (pSar), a potential polyethylene glycol (PEG) alternative, via the ring-opening polymerization (ROP) of N-carboxyanhydride (NCA) is rare and challenging. Here, we report the well-controlled ROP of sarcosine NCA (Sar-NCA) that is catalyzed by various carboxylic acids, which accelerate the polymerization rate up to 50 times, and enables the robust synthesis of pSar with an unprecedented ultrahigh molecular weight (UHMW) up to 586 kDa (DP ∼ 8200) and exceptionally narrow dispersity (D̵) below 1.05. Mechanistic experiments and density functional theory calculations together elucidate the role of carboxylic acid as a bifunctional catalyst that significantly facilitates proton transfer processes and avoids charge separation and suggest the ring opening of NCA, rather than decarboxylation, as the rate-determining step. UHMW pSar demonstrates improved thermal and mechanical properties over the low-molecular-weight counterparts. This work provides a simple yet highly efficient approach to UHMW pSar and generates a new fundamental understanding useful not only for the ROP of Sar-NCA but also for other NCAs.

[Research progress on pharmacological effects of separation and combination methods based on traditional Chinese medicine property and flavor].

The theory of medicinal properties of traditional Chinese medicine (TCM) is one of the core theories of TCM, which is an important basis for guiding the clinical application of TCM and the key supporting point for the modernization of TCM. How to study the modernization of TCM under the guidance of traditional Chinese medicine theory has become a great challenge for modern researchers. Currently, the researches in TCM mainly focus on chemical studies such as on active ingredients and effective components, lacking the guidance of traditional Chinese medicine theory, and losing the inherent characteristics of TCM. Therefore, the combination of the theory of TCM and the modernization of TCM and the establishment of research mode that is in line with the characteristics of modernization of traditional Chinese medicine under guidance by the theory of medicinal properties of TCM shall be the top priority in modern Chinese medicine research. The property and flavor of TCM are closely related to its chemical compositions, and also have certain regularity. The researches on the chemical components of TCM, systematic design of property and flavor, as well as the separation and combination of TCM property and flavor are beneficial to the overall analysis of the characteristics of TCM, showing great significance to inherit and carry forward TCM. The pharmacological effects about separation and combination methods based on TCM property and flavor were reviewed in this study, providing theoretical reference for the development of new drugs and the application of TCM.