Reinforced nanohydroxyapatite/polyamide66 scaffolds by chitosan coating for bone tissue engineering

High porosity in tissue engineering scaffolds often compromises mechanical strength. Prior research has shown that porous structures are essential for cell infiltration and nutrient transport but may lack sufficient rigidity. No prior work had resolved how to balance porosity with mechanical performance. This gap motivated the exploration of surface modifications to enhance scaffold properties. It was already known that chitosan can interact with hydroxyapatite surfaces. However, the effect of chitosan on mechanical reinforcement remained unclear. This study addresses the challenge of maintaining porosity while improving mechanical characteristics. The findings offer insights into optimizing scaffold design for biomedical use.

The aim was to evaluate whether chitosan coating could reinforce a nanohydroxyapatite/polyamide66 scaffold without significantly reducing its porosity. The specific problem addressed was the trade-off between high porosity and poor mechanical strength in tissue engineering scaffolds. The motivation stemmed from the need for scaffolds that can support bone regeneration while withstanding physiological loads. The study focused on the role of chitosan as a reinforcing agent. It was already known that chitosan could improve surface properties of biomaterials. The researchers propose that chitosan might enhance mechanical performance without compromising porosity. This approach could lead to better scaffold designs for bone tissue engineering. The study sought to quantify the mechanical and cytological effects of chitosan coating.

The study used a nanohydroxyapatite/polyamide66 scaffold as the base material. Chitosan was applied as a coating to modify the scaffold surface. The coated and uncoated scaffolds were compared for mechanical properties. Compression modulus and strength were measured to assess reinforcement. Porosity was evaluated using standard imaging techniques. Cytocompatibility was tested using MG63 osteoblast-like cells in vitro. The scaffolds were analyzed for interconnected pore structures. The effect of chitosan content on physical and biological properties was systematically investigated.

Chitosan coating significantly increased the compressive modulus of the scaffold to 32.71 MPa. The compressive strength reached 2.38 MPa, about five times higher than uncoated samples. The porosity remained at 78%, slightly lower than the 84% of uncoated scaffolds. The interconnected porous structure was preserved despite the coating. Cytological tests showed no significant difference in cell viability between coated and uncoated scaffolds. MG63 cells adhered and proliferated similarly on both types of scaffolds. The mechanical properties met the basic requirements for bone tissue engineering. The results suggest that chitosan can reinforce scaffolds without compromising cell compatibility.

The authors state that chitosan coating can effectively reinforce n-HA/PA66 scaffolds. The mechanical properties of the coated scaffolds meet the minimum standards for bone tissue engineering. The porosity remains high enough to support cell infiltration and nutrient transport. The cytocompatibility of the reinforced scaffolds is comparable to uncoated scaffolds. The study suggests that chitosan is a viable option for improving scaffold performance. The findings support the potential use of these scaffolds in bone reconstruction and repair. The authors propose that this approach could lead to better scaffold designs for biomedical applications. The results do not suggest any essential role for chitosan beyond its observed effects.