Biodegradable bead-on-spring nanofibers releasing β-carotene for bone tissue engineering.

Bead-on-string mats based on poly(lactide-co-glycolide) (PLGA) releasing β-carotene (βC) as a natural osteogen were fabricated and used for bone tissue engineering. Mesenchymal stem cells (MSCs) seeded on the scaffolds successfully differentiated to osteoblasts without using any a differential medium. The mats showed a small burst of β-carotene (24-27%) during the first day and a sustained slow release up to 21 days. The MTT and SEM results indicated good attachment and proliferation of MSCs on the scaffolds. Calcination of scaffolds and expression of RUNX2, SOX9, and osteonectin genes approved the differentiation of seeded MSCs to osteoblasts without using any external osteogenic differential agent. The scaffold loaded with 4% β-carotene not only induced the early phase of osteogenesis but also advanced the differentiation to the osteoblast maturation phase. Thus, these bead-on-string scaffolds can be used as a substrate for direct bone tissue engineering.