Formation of oriented fishbone-like pores in biodegradable polymer scaffolds using directional phase-separation processing

Young Gun Ko

doi:10.1038/s41598-020-71581-y

Abstract

The scaffold is a dreamed biomaterial of tissue engineers which can culture cells three-dimensionally outgrowing the two-dimensional cell culture in a petri dish to repair or regenerate tissues and organs. To maximize the performance of this dreamed material, complex three-dimensional (3D) structures should be generated with a simple technique and nontoxic ingredients. Many tissues have tubular or fibrous bundle architectures such as nerve, muscle, tendon, ligament, blood vessel, bone and teeth. The concept of mimicking the extracellualr matrix in real tissue has recently been applied to scaffold development. In this study, a novel method for preparing the poly(l-lactic acid) (PLLA) scaffold with a tubular architecture is presented. Solid–liquid phase-separation was applied to form tubular pores in the scaffold using the directional freezing apparatus. Pores formed in this manner exhibited a fishbone like morphology due to the two crystalline phases of 1,4-dioxane. A tubular diameter of ca. 60–250 μm was achieved by regulating the PLLA concentration and the cooling rate. The compressive modulus of the fishbone-like porous scaffold showed higher values than that of non-directional porous scaffold.

Highlights

The scaffold is a dreamed biomaterial of tissue engineers which can culture cells three-dimensionally outgrowing the two-dimensional cell culture in a petri dish to repair or regenerate tissues and organs
The design and fabrication of synthetic biodegradable scaffolds is driven by two materials categories: (1) biodegradable and bioresorbable polymers, which have been effectively used for clinically established products, including polyglic acid (PGA)[1], poly (l-lactic acid) (PLLA)[2], poly (d,l-lactic acid) (PDLLA)[3], and polycaprolactone (PCL)[4]; (2) novel di- and tri-block copolymers which predominantly incorporated PGA, PLA, and PCL in different chain arrangements which confer both degradation and mechanical property c ustomization[5]
Solid–liquid phase separation can be achieved by lowering the temperature to induce solvent crystallization from a polymer solution

Summary

Introduction

The scaffold is a dreamed biomaterial of tissue engineers which can culture cells three-dimensionally outgrowing the two-dimensional cell culture in a petri dish to repair or regenerate tissues and organs. The design and fabrication of synthetic biodegradable scaffolds is driven by two materials categories: (1) biodegradable and bioresorbable polymers, which have been effectively used for clinically established products, including polyglic acid (PGA)[1], poly (l-lactic acid) (PLLA)[2], poly (d,l-lactic acid) (PDLLA)[3], and polycaprolactone (PCL)[4]; (2) novel di- and tri-block copolymers which predominantly incorporated PGA, PLA, and PCL in different chain arrangements which confer both degradation and mechanical property c ustomization[5] Various techniques such as salt leaching[6], fibrous fabric processing[7], woven fabric processing[8], gas forming[9], emulsion freeze-drying[10], electro spinning[11], three dimensional printing[12], and phase separation[13] have been developed to fabricate porous biodegradable polymer scaffolds. The fabricated tubular scaffold showed higher compressive modulus values in comparison with the non-directional scaffold when the load was applied parallel to the tubular axis

Methods

Results

Conclusion