Nanoclay and nano-hydroxyapatite chitosan-based scaffold for bone regeneration: Morphological, spectral, structural, thermal, in vitro, and in vivo studies

The present work evaluates chitosan/sodium alginate blended with two nanomaterials of hydroxyapatite (HA) and commercial nanoclay-Cloisite20A for improving bone regeneration. The free nano-HA, nanoclay, and their scaffolds were characterized via TEM, SEM, EDX, FTIR, XRD, and TGA analyses. In vitro bioactivity, degradation, swelling, and cytotoxicity were investigated. For the in vivo studies, two groups of rats were used (n = five) in the study period (37 days). The scaffolds were implanted in the rat’s back. TEM analysis showed the nanorods of HA have a particle length of around 107 nm and a width around 17 nm, which is crystalline in nature, as XRD demonstrated. However, the SEM images showed the formation of honeycomb-like scaffolds. The in vitro bioactivity results through the changes of PBS ions and SEM/EDX analysis after immersion in PBS detected the formation of a calcium phosphate layer which is important for bone regeneration. The cell viability results proved IC50 > 670 µg/mL and IC50: 116 µg/mL for HA and nanoclay, respectively. Furthermore, the histological analysis revealed the highest calcification after 1 month for the nano-HA-containing scaffold supporting them as promising substitute biomaterials for treating bone loss.