Synergistic Effect of Reinforced Multiwalled Carbon Nanotubes and Boron Nitride Nanosheet-Based Hybrid Piezoelectric PLLA Scaffold for Efficient Bone Tissue Regeneration

Electrospun poly(L-lactic acid) nanofibers (PLLANFs) have been receiving considerable attention in bone tissue engineering (BTE) due to their tunable biodegradability and remarkable in vitro and in vivo biocompatibility. However, deterioration in the mechanical strength of PLLANFs during the regeneration process leads to low osteoinductive performances. Additionally, their high hydrophobicity and limited piezoelectric properties have to be addressed concerning BTE. Herein, we report an efficient approach for fabricating high-performance PLLANF hybrid scaffolds for BTE by reinforcing amphiphilic triblock copolymer pluronic F-127 (PL)-functionalized nanofillers (PL-functionalized carboxylated multiwalled carbon nanotubes (PL-cMWCNTs) and PL-functionalized exfoliated boron nitride nanosheets (PL-EBN)). The synergistic reinforcement effect from one-dimensional (1D) electrically conducting PL-cMWCNTs and two-dimensional (2D) piezoelectric PL-EBN was remarkable in PLLANFs, and the obtained PL-Hybrid (PL-cMWCNTs + PL-EBN) reinforced scaffolds have outperformed the mechanical strength, wettability, and piezoelectric performances of pristine PLLANFs. Consequently, in vitro biocompatibility results reveal the enhanced proliferation of MC3T3-E1 cells on PL-Hybrid nanofiber scaffolds. Furthermore, the ALP activity, ARS staining, and comparable osteogenic gene expression results demonstrated significant osteogenic differentiation of MC3T3-E1 cells on PL-Hybrid nanofiber scaffolds than on the pristine PLLANF scaffold. Thus, the reported approach for constructing high-performance piezoelectric biodegradable scaffolds for BTE by the synergistic effect of PL-cMWCNTs and PL-EBN holds great promise in tissue engineering applications.