Biomimetic porous tetracycline loaded PLGA/Silk Fibroin/Ascorbic acid/n‐HA hybrid scaffolds for adipose derived stem cells differentiation into Osteogenic lineage (LB32)

Abstract

The objective of this study is to fabricate poly (D,L‐lactide‐co‐glycolide) (PLGA)/Silk fibroin(SF)/Ascorbic acid(AA)/Tetracycline (TC) nanofibrous scaffolds and nanohydroxyapatite (n‐HA) was deposited by calcium phosphate dipping method. These nanofibrous scaffolds were characterized using scanning electron microscopy (SEM), surface wettability, functional groups analysis, porosity and tensile properties. Adipose derived stem cells (ADSCs) were cultured on these nanofibrous scaffolds and were made to undergo osteogenic differentiation in the presence of TC/n‐HA. Osteogenic differentiation of ADSCs was confirmed using alkaline phosphatase activity (ALP), mineralization (ARS) and immunofluorescent staining using both ADSC specific marker protein CD105 and osteoblast specific marker protein osteocalcin. SEM micrographs of PLGA/SF/AA/TC/n‐HA fabricated electrospun fiber diameters measured around 430 ± 26 nm to 220 ± 27 nm and FT‐IR analysis showed the amide I, II and III groups. The obtained PLGA/SF/AA/TC/n‐HA scaffolds were hydrophilic, having water contact angle of 0° compared to PLGA nanofibers (119.2 ± 12.11°). Resulting nanofibrous scaffolds were highly porous (85‐91%) and provided desirable architecture for transport of nutrients and metabolic waste and facilitate neovascularization. The PLGA/SF/AA/TC/n‐HA scaffolds had mechanical properties comparable to that of native bone with tensile break of 28.52% and Young’s modulus of 2.94 MPa, while that of PLGA nanofibers was comparatively lower at 1.96 ± 0.68 MPa. Cell culture studies performed on the bioactive AA/TC/n‐HA molecules were incorporated on the nanofibers to develop specific biological functions like proliferation, mineralization and differentiation of ADSCs into osteogenic lineage. The results proved that the ADSCs differentiated cells showed osteoblast‐like morphology, expression of osteocalcin and mineralization. Overall the data suggest that the abundance and accessibility of biodegradable PLGA/SF/AA/TC/n‐HA nanofibrous scaffolds can be used as a carrier for the sustained release of biomolecules and promote greater osteogenic differentiation of ADSCs, proving them to be potential scaffolds for bone tissue engineering.Grant Funding Source: This work was supported, in part by the Ministry of Education SUG (SD Kumar), LKCMedicine, NTU