Electrospun CHIR99021-loaded cellulose acetate scaffolds stimulate osteogenic differentiation and mineralization in vitro

Abstract

Glycogen synthase kinase-3 (GSK-3) inhibitors are a diverse class of small molecules known to promote osteogenic differentiation in cell monolayers. However, the osteoinductive capacity of GSK-3 inhibitors loaded into scaffolds remains underexplored. To address this, the study first evaluated three GSK-3 inhibitors—DIPQUO, 1-Azakenpaullone (Azak), and CHIR99021 (CHIR)—for their ability to enhance matrix mineralization in pre-osteoblast monolayers. The results showed that only Azak and CHIR induced a significant osteogenic response. Consequently, these two inhibitors were incorporated separately into cellulose acetate solutions to fabricate electrospun scaffolds. The physicochemical properties, molecular integrity, and release profiles of Azak and CHIR from the membranes were next characterized. Subsequently, biocompatibility and osteoinductive potential of the GSK-3 inhibitor-loaded membranes were assessed. In terms of scaffold characteristics, CHIR loading significantly reduced the water contact angle. Both inhibitors exhibited a burst release profile consistent with first-order kinetics. Pre-osteoblasts demonstrated comparable growth on unloaded and GSK-3 inhibitor-loaded scaffolds, with no evidence of cytotoxicity. Importantly, CHIR-loaded mats enhanced cell adhesion, proliferation, and osteogenic differentiation, whereas Azak-loaded membranes inhibited matrix mineralization. Taken together, these findings indicate that CHIR-loaded scaffolds possess in vitro bioactivity and may be promising for bone tissue engineering applications.

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