One-Step Dip-Coating-Fabricated Core–Shell Silk Fibroin Rice Paper Fibrous Scaffolds for 3D Tumor Spheroid Formation

Abstract

Bioscaffolds are important substrates for supporting threedimensional (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.

Preparation of Degradable Superhydrophobic Mg/P/Z/F/H Composite Materials and Their Anticorrosion

“…By the Cassie-Baxter state, the air trapped of the micro/nanostructured surface can improve the hydrophobicity and corrosion resistance of Mg/P/Z/F/H materials. [40,41] The Mg/P/Z/F/H materials had the best corrosion resistance and the corrosion rate of Mg/P/Z/F/H was 1.9152×10 -3 mm/y. Here we found that with the addition of ZnO the corrosion resistance of…”

“…As a widely applied and simple surface treatment technology, dip-coating can produce a relatively adherent, stable and uniform films on the surface of materials. [39][40][41][42] Using dip-coating method the rough Mg/P/Z/F/H structure was constructed, which can be prepared simply and protect the magnesium alloy better. Furthermore, 30minutes' heating process at 50 o C can not only repair defects of the composite Mg/P/Z/F materials' surface but also rearrange the PCL and PFDTES molecules to make the composite surface from hydrophobic (96.5 o ) to superhydrophobic (159.0 o ).…”

Recent Advances in Multicellular Tumor Spheroid Generation for Drug Screening

“…[34]. Copyright 2019, American Chemical Society; Reprinted with permission from [35]. Copyright 2020, American Chemical Society.…”

“…Some researchers reported a self-assembling peptide, bQ13, that can be useful for obtaining the 3D culture of prostate cancer cells [36]. These self-assembled peptides have been known to help stabilize 3D culture and provide Copyright 2019, American Chemical Society; Reprinted with permission from [35]. Copyright 2020, American Chemical Society.…”

Emerging Biofabrication Techniques: A Review on Natural Polymers for Biomedical Applications

“…Normally, these systems do not present a good integration between cells and the polymer matrix, and their efficacy for tissue regeneration depends on the physical properties of the polymer matrix such as hydrophobicity, degradation rate, or stiffness [14,27]. Among the most used techniques, we can highlight layer-by-layer [28,29], melt molding [30], photolithography [31], and self-assembling [32].…”