*Article* **The Preparation of Novel P(OEGMA-co-MEO2MA) Microgels-Based Thermosensitive Hydrogel and Its Application in Three-Dimensional Cell Scaffold**

**Yang Liu \* , Yu-Ning Luo, Pei Zhang, Wen-Fei Yang, Cai-Yao Zhang and Yu-Li Yin**

Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, School of Pharmacy, Hengyang Medical School, University of South China, Hengyang 421001, China; luo1748058392@163.com (Y.-N.L.); zp1832711702@163.com (P.Z.); yang18138800314@163.com (W.-F.Y.); caiyao.zhang@nuclover.com (C.-Y.Z.); yinyulimy@163.com (Y.-L.Y.) **\*** Correspondence: liuyanghxl@126.com; Tel.: +86-0734-8281296

**Abstract:** Thermosensitive hydrogel scaffolds have attracted particular attention in three-dimensional (3D) cell culture. It is very necessary to develop a type of thermosensitive hydrogel material with low shrinkage, and excellent biocompatibility and biodegradability. Here, five types of thermosensitive microgels with different volume phase transition temperature (VPTT) or particle sizes were first synthesized using 2-methyl-2-propenoic acid-2-(2-methoxyethoxy) ethyl ester (MEO2MA) and oligoethylene glycol methyl ether methacrylate (OEGMA) as thermosensitive monomers by free radical polymerization. Their VPTT and particle sizes were investigated by a nanometer particle size meter and an ultraviolet spectrophotometer. The feasibility of using these P(OEGMA-co-MEO2MA) microgels to construct thermosensitive hydrogel by means of the thermal induction method is discussed for the first time. The prepared thermosensitive hydrogel with the optimum performance was screened for in situ embedding and three-dimensional (3D) culture of MCF-7 breast cancer cells. The experimental results of AO/EB and MTT methods indicate that the pioneering scaffold material has prominent biocompatibility, and cells grow rapidly in the 3D scaffold and maintain high proliferative capacity. At the same time, there is also a tendency to aggregate to form multicellular spheres. Therefore, this original P(OEGMA-co-MEO2MA) thermosensitive hydrogel can serve as a highly biocompatible and easily functionalized 3D cell culture platform with great potential in the biomedical area.

**Keywords:** thermosensitive; hydrogel; P(OEGMA-co-MEO2MA); microgel; scaffold; 3D culture
