3D Scaffold Designing based on Conductive/Degradable Tetrapolymeric Nanofibers of PHEMA-co-PNIPAAm-co-PCL/PANI for Bone Tissue Engineering

Abstract

The hydrophilic, conducting, biocompatible and porous scaffolds were designed using poly(2-hydroxy ethyl methacrylate)-co-poly(N-isopropylacrylamide)-co-poly(ε-caprolactone) (P(HEMA-b-NIPAAm-b-CL))/polyaniline (PANI) for the osteoblast applications. To this end, the PHEMA and P(HEMA-b-NIPAAm) were synthesized via reversible addition of fragmentation chain transfer (RAFT) polymerization, and in next step, the ε-caprolactone was polymerized from –OH group of PHEMA segments through the ring opening polymerization (ROP). The electroactivity, mechanical properties, and hydrophilicity of designed scaffolds played an important role in the adhesion, differentiation, and proliferation of MG63 cells. By using the PHEMA and PNIPAAm, the hydrophilicity and biocompatibility, and by employing the PCL, the appropriate mechanical properties were acquired. The addition of PANI in the composition induced the conductivity to scaffolds. The morphology, electrical conductivity, biocompatibility, hydrophilicity and mechanical characteristics of the nanofibers were thoroughly investigated. The scaffolds possessed a porous nanostructure (nanofiber diameter ranged in 60–130 nm) with a large surface area, electrical conductivity of 0.03 S cm–1 and contact angle of 49 ± 5 ͦ , which imitated the natural microenvironment of extra cellular matrix (ECM) to regulate the cell attachment, proliferation and differentiation. In vitro cytocompatibility studies were performed over 168 h and indicated that the nanofibers were non-toxic to MG63 cells and potent to the artificial nanostructured osteoblasting.

Keywords

• Scaffold
• osteoblast
• electrospun nanofiber
• poly(2-hydroxyethylmethaacrylate), poly(N-isopropylacrylamide)
• polycaprolactone