Engineering Porous Poly(lactic acid) Scaffolds with High Mechanical Performance via a Solid State Extrusion/Porogen Leaching Approach.

Hua-Mo Yin,Jin Zhang,Jing Qian,Jian-Shu Li,Zhong-Ming Li,Jia-Zhuang Xu,Zai-Fu Lin

doi:10.3390/polym8060213

Abstract

A knotty issue concerning the poor mechanical properties exists in the porogen leaching approach to porous scaffolds, despite its advantage in tuning pore structure. To address this hurdle, solid state extrusion (SSE) combined with porogen leaching was utilized to engineer porous scaffolds of poly(lactic acid) (PLA). Advances introduced by poly(ethylene glycol) (PEG) caused the PLA ductile to be processed and, on the other hand, enabled the formation of interconnected pores. Thus, a well-interconnected porous architecture with high connectivity exceeding 97% and elevated porosity over 60% was obtained in the as-prepared PLA scaffolds with the composition of NaCl higher than 75.00 wt % and PEG beyond 1.25 wt %. More strikingly, the pore walls of macropores encompassed countless micropores and rough surface topography, in favor of transporting nutrients and metabolites as well as cell attachment. The prominent compressive modulus of the PLA scaffolds was in the range of 85.7–207.4 MPa, matching the normal modulus of human trabecular bone (50–250 MPa). By means of alkaline modification to improve hydrophilicity, biocompatible porous PLA scaffolds exhibited good cell attachment. These results suggest that the SSE/porogen leaching approach provides an eligible clue for fabricating porous scaffolds with high mechanical performance for use as artificial extracellular matrices.

Highlights

A foremost strategy to substitute autografts is the utilization of three-dimensional porous scaffold, which serves as a temporary template for cell adhesion, proliferation, along with differentiation to form a functional tissue [1,2] and effectively overcomes the problems of lacking availability and allografts suffering from existent complications
This is because the presence of poly(ethylene glycol) (PEG) in the ternary blends is conducive to a decrease in viscosity and the improvement in flowability [40]
Interconnected porous poly(lactic acid) (PLA) scaffolds were successfully developed via a solid state extrusion (SSE)/water-soluble

Summary

Introduction

A foremost strategy to substitute autografts is the utilization of three-dimensional porous scaffold, which serves as a temporary template for cell adhesion, proliferation, along with differentiation to form a functional tissue [1,2] and effectively overcomes the problems of lacking availability and allografts suffering from existent complications. Of particular importance is the fabrication method, since it endows scaffolds with the required physical and biological properties for tissue regeneration [3,4,5,6]. A wide spectrum of techniques have been proposed to engineer porous scaffolds, including fiber bonding [7], porogen leaching [8,9,10,11,12,13,14], emulsion freeze drying [15], gas foaming [16,17], thermally induced phase separation [18], electrospinning [19,20], and rapid prototyping [21]. Porogen leaching is perceived as the most expedient and economic access to porous structures. Despite its distinct convenience, potential toxicity from residual organic solvents poses an intrinsic limitation to bone repair [22]

Methods

Results

Conclusion