posted on 2020-10-28, 18:35authored byJingjing Fu, Xiao Bai Li, Lin Xiang Wang, Xiao Hui Lv, Zhisong Lu, Feng Wang, Qingyou Xia, Ling Yu, Chang Ming Li
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.