Development and Characterization of Functional Polylactic Acid/Chitosan Porous Scaffolds for Bone Tissue Engineering

Abstract

In this study, we developed and characterized various open-cell composite scaffolds for bone regeneration. These scaffolds were made from Polylactic acid (PLA) as the scaffold matrix biopolymeric phase, and chitosan (CS) and chitosan-grafted-PLA (CS-g-PLA) copolymer as the dispersed biopolymeric phase. As a first step, successful grafting of PLA onto CS backbone was executed and confirmed by both FTIR and XPS. Mechanical characterization confirmed that adding CS or CS-g-PLA to the intrinsically rigid PLA made their corresponding PLA/CS and PLA/CS-g-PLA composite scaffolds more flexible under compression. This flexibility was higher for the latter due to the improved compatibility between PLA and CS-g-PLA copolymer. The hydrolytic stability of both PLA/CS and PLA/CS-g-PLA composite scaffolds inside phosphate-buffered saline (PBS) solution, as well as MG-63 osteoblast cell adhesion and proliferation inside both scaffolds, were characterized. The corresponding results revealed that PLA/CS composite scaffolds showed hydrolytic degradation due to the cationic properties of CS. However, modified PLA/CS-g-PLA scaffolds were hydrolytically stable due to the improved interfacial adhesion between the PLA matrix and CS-g-PLA copolymer. Finally, biological characterization was done for both PLA/CS and PLA/CS-g-PLA composite scaffolds. Contrarily to what was observed for uncompatibilized PLA/CS scaffolds, compatibilized PLA/CS-g-PLA scaffolds showed a high MG-63 osteoblast cell proliferation after three and five days of cell culture. Moreover, it was observed that cell proliferation increased with CS-g-PLA content. This suggests that the PLA/CS-g-PLA composite scaffolds could be a potential solution for bone regeneration.

A novel foaming technique to develop functional open‐cell polylactic acid scaffolds for bone tissue engineering

“…In this study, we produced a CS-g-PLA copolymer by following the same procedure and using the same grades of CS and PLA as described in our previous research. 31 The grafting of PLA onto the CS backbone was assessed by means of ATR-FTIR, and the spectra presented in Figure 1 exhibit the same behavior as those discussed in the aforementioned publication, thus confirming the effective grafting of PLA onto the CS backbone.…”

“…MG63 osteoblast cells were cultured in Dulbecco's Modified Eagle's medium (DMEM), as previously described. 31 Upon reaching 80% confluence, cells were detached from the culture flasks using trypsin treatment, washed twice with the medium, and resuspended to a concentration of 10 6 cells/mL. To prepare for cell seeding, both pure PLA scaffold control sample and PLA/CFCO scaffolds were distributed at one scaffold per well into a low adherence plate and pre-incubated in DMEM at 37 C for 30 min under a 5% CO 2 humid atmosphere.…”

“…Despite having a 30% lower content of CS-g-PLA copolymer, the immobilization of CS-g-PLA copolymer on the surface of the pores led to a 26% higher MG-63 cell proliferation compared to the uniform dispersion of CS-g-PLA copolymer throughout the entire PLA matrix. In our previous study, 31 CS-g-PLA copolymer was uniformly dispersed within the entire PLA matrix to develop open-cell scaffolds. However, in this study, we took a different approach and immobilized the CS-g-PLA copolymer on the surface of the pores to make them available for osteoblast cell proliferation and growth factor adhesion.…”

“…However, this often results in residual undesirable solvents deeply embedded within the scaffold matrix. 31 The primary objective of this study was to address this issue by developing a solventfree PLA open-cell porous scaffold matrix using a novel compression-foaming technique that eliminates the need for solvents. To achieve this, a new chemical foaming compound (CFCO) composed of chitosan-grafted polylactic acid (CS-g-PLA) copolymer blended with PLA and a chemical foaming agent (azodicarbonamide, ADA) was prepared under a mixing temperature below the ADA decomposition temperature.…”

“…In order to promote bone cell adhesion on the surface of scaffold pores and their adequate proliferation, many scaffolds produced using the aforementioned techniques require additional solvent treatment to introduce biocompatible materials into the pores. However, this often results in residual undesirable solvents deeply embedded within the scaffold matrix 31 . The primary objective of this study was to address this issue by developing a solvent‐free PLA open‐cell porous scaffold matrix using a novel compression‐foaming technique that eliminates the need for solvents.…”