Accelerated degradation of HAP/PLLA bone scaffold by PGA blending facilitates bioactivity and osteoconductivity

Abstract

The incorporation of hydroxyapatite (HAP) into poly- l -lactic acid (PLLA) matrix serving as bone scaffold is expected to exhibit bioactivity and osteoconductivity to those of the living bone. While too low degradation rate of HAP/PLLA scaffold hinders the activity because the embedded HAP in the PLLA matrix is difficult to contact and exchange ions with body fluid. In this study, biodegradable polymer poly (glycolic acid) (PGA) was blended into the HAP/PLLA scaffold fabricated by laser 3D printing to accelerate the degradation. The results indicated that the incorporation of PGA enhanced the degradation rate of scaffold as indicated by the weight loss increasing from 3.3% to 25.0% after immersion for 28 days, owing to the degradation of high hydrophilic PGA and the subsequent accelerated hydrolysis of PLLA chains. Moreover, a lot of pores produced by the degradation of the scaffold promoted the exposure of HAP from the matrix, which not only activated the deposition of bone like apatite on scaffold but also accelerated apatite growth. Cytocompatibility tests exhibited a good osteoblast adhesion, spreading and proliferation, suggesting the scaffold provided a suitable environment for cell cultivation. Furthermore, the scaffold displayed excellent bone defect repair capacity with the formation of abundant new bone tissue and blood vessel tissue, and both ends of defect region were bridged after 8 weeks of implantation.

Bone physiological microenvironment and healing mechanism: Basis for future bone-tissue engineering scaffolds

“…And the blend of biodegradable polymer PGA could make the scaffold exhibit tunable biodegradability which facilitated the exposure of HA during the degradation process. It's confirmed that this scaffold displayed desirable cytocompatibility in vitro and excellent bone repair capacity in vivo [ 271 ]. Feng et al incorporated biodegradable polymer PLLA into Polyetheretherketone (PEEK)/β-TCP scaffold to facilitate the exposure of β-TCP during scaffold degradation.…”

Synthesis and Characterization of Silver-Coated Polymeric Scaffolds for Bone Tissue Engineering: Antibacterial and In Vitro Evaluation of Cytotoxicity and Biocompatibility

“…We have still reported the grafting of ARX with acrylic acid (AAc) as there is relative research available on ARX- co -AAc. 21 , 22 …”

Main 3D Manufacturing Techniques for Customized Bone Substitutes. A Systematic Review

“…Biocomposites can result from the polymer-ceramic bonding of calcium phosphate (HA or TCP) or bioactive polymer-glass, facilitating cell adhesion and proliferation [ 20 , 32 ] and, as a result, bone regeneration/reparation [ 15 ]. In this regard, it has recently been reported that the incorporation of hydroxyapatite (HAP) into a biodegradable polymer (i.e., poly l-lactic acid) (PLLA) matrix exhibit bioactivity and osteoconductivity showing excellent bone defect repair capacity with the formation of abundant new bone tissue and blood vessel tissue [ 53 ]. Moreover, authors such as Gendviliene I [ 18 ] proved that biocomposites achieved higher printing accuracy than pure polymers.…”