Controlled degradation and kinetics response in calcium silicate doped with sodium alginate/functionalized multi-walled carbon nanotube composite 3D scaffolds for cartilage regeneration

Abstract

Development of bio-mimetic scaffolds with controlled degradation is a key research area in cartilage regeneration. Therefore, novel scaffold composites and favorable techniques to fabricate essential 3D scaffolds are crucial. In this investigation, we achieved controlled biodegradation of composite scaffolds by incorporating calcium silicate (CS) into sodium alginate (SA)/functionalized with multi-walled carbon nanotubes (f-MWCNT). The SA/f-MWCNT and scaffolds with various amounts of CS (5, 10, and 15%) were shown to enhance scaffold properties. We conducted analyses of the composites using X-ray diffraction and scanning electron microscopy. The findings indicated that CS was successfully loaded onto SA/f-MWCNT, and after inclusion the CS crystal structure remained unaltered. We also evaluated the composites using differential scanning calorimetry, and we determined the mechanical strength, swelling, porosity, degradation, and pH properties. The 15% CS-SA/f-MWCNT scaffolds demonstrated improved mechanical properties, controlled degradation and swelling ratio, increased material density, and strengthened bonds that resulted in a more compact structure and better control of porosity. Furthermore, kinetic investigations of the composite scaffolds to potentially absorb water could be accurately modeled using the pseudo-first-order, pseudo-second-order, Elovich, and diffusion kinetic models. The gradual water absorption rate observed in 15% CS-SA/f-MWCNT could be attributed to controlled intraparticle and micropore diffusion. Further biocompatibility studies showed that the scaffold encouraged chondrocyte attachment, spreading, and division. Additionally, collagen deposition and biomineralization of the 15% CS-SA/f-MWCNT scaffolds were slightly higher compared to the SA/f-MWCNT, 5% CS-SA/f-MWCNT, and 10% CS-SA/f-MWCNT scaffolds. The results indicated that the 15% CS-SA/f-MWCNT fabricated scaffolds are the most suitable for cartilage regeneration.