Fu Jingjing, Li Xiao Bai, Wang Lin Xiang, Lv Xiao Hui, Lu Zhisong, Wang Feng, Xia Qingyou, Yu Ling, Li Chang Ming
Institute for Clean Energy & Advanced Materials, School of Materials & Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China.
State Key Laboratory of Silkworm Genome Biology, Southwest University, 1 Tiansheng Road, Chongqing 400715, P. R. China.
ACS Appl Bio Mater. 2020 Nov 16;3(11):7462-7471. doi: 10.1021/acsabm.0c00679. Epub 2020 Oct 28.
Bioscaffolds are important substrates for supporting three-dimensional (3D) cell cultures. Silk fibroin (SF) is an attractive biomaterial in tissue engineering because of its good biocompatibility and mechanical properties. Electrospinning is one of the most often used approaches to fabricate SF fibrous scaffolds; yet, this technique still faces many challenges, such as low yield, residual organic solvents, limited extensibility of fibers, and a lack of spatial control over pore size. To circumvent these limitations, a core-shell SF on rice paper (SF@RP) fibrous scaffold was fabricated using a mild one-step dip-coating method. The cellulose fiber matrix of RP is the physical basis of the 3D scaffold, whereas the SF coating on the cellulose fiber controls the adhesion/spreading of the cells. The results indicated that by tuning the secondary structure of SF on the surface of a SF@RP scaffold, the cell behavior on SF@RP could be tuned. Tumor spheroids can be formed on SF@RP scaffolds with a dominant random secondary structure, in contrast to cells adhering and spreading on SF@RP scaffolds with a higher ratio of β-sheet secondary structures. Direct culturing of breast cancer MDA-MB-231 and MCF-7, lung cancer A549, prostate cancer DU145, and liver cancer HepG2 cells could spontaneously lead to corresponding tumor spheroids on SF@RP. In addition, the physiological characteristics of HepG2 tumor spheroids were investigated, and the results showed that compared with HepG2 monolayer cells, CYP3A4, CYP1A1, and albumin gene expression levels in HepG2 cell spheres formed on SF@RP scaffolds were significantly higher. Moreover, these spheroids showed higher drug resistance. In summary, these SF@RP scaffolds prepared by the dip-coating method are biocompatible substrates for cell culture, especially for tumor cell spheroid formation.
生物支架是支持三维（3D）细胞培养的重要基质。丝素蛋白（SF）因其良好的生物相容性和机械性能，在组织工程中是一种有吸引力的生物材料。静电纺丝是制备SF纤维支架最常用的方法之一；然而，该技术仍面临许多挑战，如产量低、残留有机溶剂、纤维延伸性有限以及缺乏对孔径的空间控制。为了克服这些限制，采用温和的一步浸涂法制备了一种在宣纸（SF@RP）上的核壳型SF纤维支架。RP的纤维素纤维基质是3D支架的物理基础，而纤维素纤维上的SF涂层控制细胞的黏附/铺展。结果表明，通过调节SF@RP支架表面SF的二级结构，可以调节细胞在SF@RP上的行为。与细胞在具有较高β-折叠二级结构比例的SF@RP支架上黏附并铺展相反，在具有主要随机二级结构的SF@RP支架上可以形成肿瘤球体。直接培养乳腺癌MDA-MB-231和MCF-7、肺癌A549、前列腺癌DU145和肝癌HepG2细胞，可在SF@RP上自发形成相应的肿瘤球体。此外，还研究了HepG2肿瘤球体的生理特性，结果表明，与HepG2单层细胞相比，在SF@RP支架上形成的HepG2细胞球体中CYP3A4、CYP1A1和白蛋白基因表达水平显著更高。而且，这些球体表现出更高的耐药性。总之，通过浸涂法制备的这些SF@RP支架是用于细胞培养的生物相容性基质，尤其适用于肿瘤细胞球体的形成。
