Thymoquinone-releasing collagen/chitosan/nano-hydroxyapatite composite scaffold for enhanced bone regeneration

Thymoquinone (TQ) has osteogenic properties. Loading TQ into scaffolds improves release, increases local bioavailability, and reduces toxicity. This study developed a TQ-loaded collagen-chitosan-nano hydroxyapatite (Col-Chi-nHAp) scaffold for bone regeneration.

Collagen, chitosan, and nano-hydroxyapatite were blended in acetic acid, followed by TQ (10, 25, and 50 μM) loading and cross-linked using glutaraldehyde. Scaffolds were fabricated via freeze-drying. Physicochemical properties were assessed through scanning electron microscopy (SEM), shrinkage, degradation rate, porosity, water absorption, mechanical testing, Fourier-transform infrared spectroscopy (FTIR), and TQ release rate. Biocompatibility was evaluated via Human adipose-derived mesenchymal stem cells (ASC) proliferation, while osteoconductivity was determined by alkaline phosphatase (ALP) activity.

The scaffold exhibited a porous microstructure with an average pore size of 85 ± 3.23 μm, porosity of 96 ± 1.93 %, and water absorption capacity of 5368 ± 181.46 %, with minimal shrinkage or degradation. TQ (25 μM)-loaded scaffold revealed a significantly higher Young's modulus than other groups in Mechanical testing. Sustained TQ release was observed over a 21 days. The 3D scaffold environment enhanced ASC proliferation 4.2-fold over monolayers, underscoring its biomimetic potential, and improved ALP activity (114.6 ± 26.88 %) vs monolayers control.

The TQ-loaded Col-Chi-nHAp scaffold exhibits optimal physicochemical, mechanical, and biological properties, making it promising for bone tissue engineering.