© 2020, The Author(s).In this research, hWJ-MSCs were grown on silk scaffolds and induced towards chondrogenesis by supplementation with L-ascorbic acid (LAA) or platelet rich plasma (PRP). Silk scaffolds were fabricated with salt leaching method by mixing silk fibroin (SF) with silk spidroin (SS). The silk fibroin was obtained from Bombyx mori cocoon that had been degummed, and the silk spidroin was obtained from wild-type spider Argiope appensa. The effect of scaffold composition and inducer on cell proliferation was observed through MTT assay. The most optimal treatment then continued to be used to induce hWJ-MSC towards chondrogenic differentiation for 7 and 21 days. Scaffolds characterization showed that the scaffolds produced had 3D structure with interconnected pores, and all were biocompatible with hWJ-MSCs. Scaffold with the addition of 10% SS + 90% SF showed higher compressive strength and better pore interconnectivity in comparison to 100% silk fibroin scaffold. After 48 h, cells seeded on scaffold with spidroin and fibroin mix had flattened morphology in comparison to silk fibroin scaffold which appeared to be more rounded on the scaffold surface. Scaffold with 10% (w/w) of silk spidroin (SS) + 90% (w/w) of silk fibroin (SF) was the most optimal composition for cell proliferation. Immunocytochemistry of integrin β1 and RGD sequence, showed that scaffold with SS 10% provide better cell attachment with the presence of RGD sequence from the spidroin silk which could explain the higher cell proliferation than SF100% scaffold. Based on Alcian Blue staining and Collagen Type II immunocytochemistry (ICC), cells grown on 10% SS + 90% SF scaffold with 10% PRP supplementation were the most optimal to support chondrogenesis of hWJ-MSCs. These results showed that the addition of spidroin silk from A. appensa. had impact on scaffold compressive strength and chondrogenic differentiation of hWJ-MSC and had the potential for further development of bio-based material scaffold in cartilage tissue engineering.

Animals,Ascorbic Acid,Bombyx,Cell Differentiation,Cell Proliferation,Cells, Cultured,Chondrogenesis,Collagen Type II,Fibroins,Humans,Mesenchymal Stem Cells,Microscopy, Electron, Scanning,Platelet-Rich Plasma,Silk,Spectroscopy, Fourier Transform Infrared,Spiders,Tissue Engineering,Tissue Scaffolds,Wharton Jelly

This current work were financially supported by Indonesian Ministry of Research and Technology/National Research and Innovation Agency (Risetdikti No.3143/I1.CO2.2/KU/2018). We would like to thank Dr. Veinardi Suendo for his help on FTIR analysis and Mr. Hutomo Tanoto for helping with compressive strength measurement. We also would like to thank Olympus for the help in using and operating confocal microscope Olympus Fv1200.

https://doi.org/10.1038/s41598-020-76466-8