Evaluation of the Effects of Halloysite Nanotubes on Physical, Mechanical, and Biological Properties of Polyhydroxy Butyrate Electrospun Scaffold for Cartilage Tissue Engineering Applications

Nano clays, such as halloysite nanotubes (HNT), has recently become a popular additive for improving the physicochemical properties of polymeric scaffolds used in tissue engineering. This study investigates the effect of HNT on the physical, mechanical, and biological properties of polyhydroxy butyrate (PHB)-based scaffolds for cartilage regeneration. Fibrous scaffolds made of PHB/HNT were prepared via electrospinning using 1-7 wt% HNT, and their properties were analyzed. Our results indicate that the scaffold containing 5 wt% HNT (P-5H) represents superior properties compared to PHB. Morphological studies showed that HNT incorporation decreased fiber diameter from 1017 & PLUSMN; 295.95 nm to 878.66 & PLUSMN; 128 nm. Also, HNT improved the scaffold's mechanical properties in terms of ultimate strength and strain by 92% and 46% respectively. Moreover, differential scanning calorimetry and X-Ray Diffraction evaluations confirmed that HNT had increased crystallinity from 42.9 to 48.2%. Furthermore, the analysis of atomic force microscopy revealed that HNT has significantly increased surface roughness. According to our findings, HNT enhanced the structure's resistance to degradation, which would benefit cartilage regeneration as a slow-healing tissue. Additionally, MTT analysis revealed that chondrocytes proliferated and grew with an increasing trend on the P-5H scaffold over seven days, which indicates HNT biocompatibility. Overall, the results of this study suggest that the incorporation of 5 wt% HNT positively enhance the properties of PHB-based electrospun scaffolds for cartilage tissue engineering.