Osteoconductive visible light-crosslinkable nanocomposite for hard tissue engineering

Acceleration of bone regeneration using nanocomposite hydrogels that provide the biomechanical, and osteoconductivity criteria of bone tissue engineering is emerging as an appealing approach but challenging. Here, we designed an osteoconductive and high-strength nanocomposite hydrogels based on visible-light crosslinkable gelatin methacryloyl (GelMA) reinforced with various concentrations of bioactive glass (BG, 0, 2, 5, 10 wt%). We investigated the physical and mechanical properties of GelMA/BG composites, as well as their in vitro bioactivity, cytocompatibility and osteoconductivity. We found that BG nanoparticles significantly increased mechanical characteristics of GelMA matrix, as a function of BG content. Remarkably, incorporation of 5 wt%BG in GelMA hydrogels significantly enhanced elastic modulus (two times) and compressive strength (1.8 times) of GelMA hydrogel. Moreover, it was found that, the swelling ratio, degradability and bioactivity of GelMA/BG hydrogels were improved by increasing the BG content. The findings also revealed GelMA/BG drastically promoted cell attachment and proliferation and alkaline phosphatase (ALP) activity. Noticeably, our results indicated that incorporation of 10 wt% BG content significantly improved MG63 cell proliferation and ALP activities (2.3 fold), compared to GelMA, after 7 days of cell culture. Altogether, the engineered GelMA-BG hydrogels may have great potential in low-bearing craniomaxillofacial applications. However, further in vitro studies along with in vivo studies are necessary.