Water Transport‐Induced Liquid–Liquid Phase Separation Facilitates Gelation for Controllable and Facile Fabrication of Physically Crosslinked Microgels

• Published in: Advanced materials (Weinheim) 2024-08, Vol.36 (35), p.e2405109-n/a
• Main Authors: Chen, Michael W, Fan, Dongdong, Liu, Xiangjian, Han, Dongbo, Jin, Yuhong, Ao, Yanxiao, Chen, Yuyang, Liu, Zhiqiang, Feng, Yiting, Ling, Sida, Liang, Kaini, Kong, Wenyu, Xu, Jianhong, Du, Yanan
• Format: Article
• Language: English
• Subjects: Animals; Biocompatibility; Biocompatible Materials - chemistry; Biomedical materials; Controllability; Cross-Linking Reagents - chemistry; Crosslinking; Emulsions; Emulsions - chemistry; Encapsulation; Gelation; Liquid phases; liquid–liquid phase separation; Lymphocytes; Mechanical properties; Microgels; Microgels - chemistry; Phase Separation; Phase Transition; physical crosslink; Sol-gel processes; T-Lymphocytes - cytology; Water - chemistry; water transport
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202405109

Physically crosslinked microgels (PCMs) offer a biocompatible platform for various biomedical applications. However, current PCM fabrication methods suffer from their complexity and poor controllability, due to their reliance on altering physical conditions to initiate gelation and their dependence on specific materials. To address this issue, a novel PCM fabrication method is devised, which employs water transport‐induced liquid–liquid phase separation (LLPS) to trigger the intermolecular interaction‐supported sol–gel transition within aqueous emulsion droplets. This method enables the controllable and facile generation of PCMs through a single emulsification step, allowing for the facile production of PCMs with various materials and sizes, as well as controllable structures and mechanical properties. Moreover, this PCM fabrication method holds great promise for diverse biomedical applications. The interior of the PCM not only supports the encapsulation and proliferation of bacteria but also facilitates the encapsulation of eukaryotic cells after transforming the system into an all‐aqueous emulsion. Furthermore, through appropriate surface functionalization, the PCMs effectively activate T cells in vitro upon coculturing. This work represents an advancement in PCM fabrication and offers new insights and perspectives for microgel engineering. Water transport within the emulsion system is found to be able to trigger not only the liquid–liquid phase separation within aqueous droplets, but also a consecutive sol–gel transition. This phenomenon enables the invention of a physically crosslinked microgel fabrication system, which is controllable, facile, and possesses high potential for biomedical applications.