Mechanical and biological properties of photocurable oligolactide-HA composites investigated under accelerated degradation

Abstract

The major concern related to biodegradable bone substitute materials is the loss of mechanical strength which can be undesirable when occurring too quickly before new bone formation. In this study, the multifunctional lactide oligomers having 2, 3, and 4 arms end capped with methacrylate groups were synthesized with the aim of improving the degradation properties. Their composites with hydroxyapatite (HA) were photopolymerized and subjected to accelerated degradation at 60 °C. The results showed that increasing number of arms significantly improved thermal and mechanical properties as well as biocompatibility of the composites. All composites although varying in number of arms had similar levels of bone-specific gene expression and calcification indicating their equal bioactivity in supporting bone formation. The high HA content in the composites was proposed to be responsible for enhanced osteoblast response, and this tended to suppress the effects of polymeric structure.

Gentamicin Released from Porous Scaffolds Fabricated by Stereolithography

“…In this study, woodpile scaffolds with highly interconnected pores were designed and fabricated by the SLA technique. The oligolactide/HA composites which have been previously reported on their biocompatibility [ 16 – 18 ] were used as the scaffold material. All scaffolds, according to the CAD models, had a pore size of 500 μ m and 71% porosity with a slight difference in the orientation of pores.…”

“…Scaffolds with a dimension of 5 × 5 × 3 mm were fabricated using a stereolithography apparatus equipped with 3W UV laser at 355 nm wavelength and 70 μ m laser spot size (model: SLL2020, RP Medical Lab, MTEC Thailand). The photocurable resin used as a scaffold material was (L)-4LM/T 55HA produced in our laboratory [ 18 ]. The resin was composed of the 4-arm-methacrylated oligolactide (Mn = 1420 g/mol) and triethylene glycol dimethacrylate (from Esschem Inc.) at the weight ratio of 1 : 1, added with HA (from Taihei Chemical Industrial, Japan) at 55% wt of the resin.…”

“…In our previous work, the composite resins of oligolactide and hydroxyapatite (HA) that can be crosslinked by photoinitiated polymerization were developed to obtain scaffolds with designed patterns via SLA fabrication process [ 16 – 18 ]. The fabricated scaffolds appeared to provide appropriate conditions to support the growth of bone cells and their differentiation, making them potentially suitable for bone tissue engineering.…”

“…It reduces the time of delivery, avoids fluctuations of the antibiotic concentration through the blood circulation, and eliminates administration of high doses of systemic antibiotics with potential for adverse side effects and systemic toxicity. Although various scaffolds generated using SLA have been reported to support cell proliferation [ 8 , 9 , 17 , 18 , 22 ], there were only a few reports on investigating these controlled structural scaffolds as carriers for drug delivery.…”

Heat-curing polylactide for bone implants: Preparation and investigation on properties relevant to degradation

“…10,22,23 In our previous works, the photocurable star PLA that hardened by light was prepared as a tentative material for 3D printing fabrication. 24 Owing to the star architecture, the thermal and mechanical stability, as well as biocompatibility of the star PLA, were significantly improved in comparison with those of the linear PLA with the same molecular weight. The 3D-printed scaffolds of our star PLA composites exhibited high mechanical properties associated with bone scaffolding applications with complimentary local drug delivery.…”