Construction of crosslinked chitosan/nitrogen-doped graphene quantum dot nanocomposite for hydroxyapatite biomimetic mineralization.

Crosslinked Chitosan/nitrogen doped-graphene quantum dot nanocomposites (CCS/NGQD NC) with 10 wt% of glutaraldehyd as crosslinker were fabricated under ultrasonic cavitation. Structure and physicochemical properties of the prepared nanocomposites (NC) were systematically characterized by a number of techniques. The swelling capacity of the crosslinked films in the simulated intestinal (pH 7.4) media was evaluated. However, rate of water ingress of specimens was nearly same, but, the CCS/NGQD NC 8 wt% showed the more water absorption ability than the CCS. Bioactivity of the CCS and CCS/NGQD NCs were evaluated by studying their ability to form of apatite on their surface after soaking in a simulated body fluid (SBF) for 30 days. In images of field emission scan electron microscopy, small island-like agglomerated apatite deposited on the sample surface. Also, the pH fluctuation displayed that the hydroxyapatite was formed on the surface of the samples after one month of immersion in SBF. The finding showed that the CCS/NGQD NCs immersed into SBF had a better apatite-forming bioactivity compared with the CCS, which may be due to the high surface area, adequate function groups and appropriate swelling of the NCs. Such improved behaviors of CCS/NGQD NCs may have potential use in the bone tissue engineering.