Electrospun ultrathin PBAT/nHAp fibers influenced the in vitro and in vivo osteogenesis and improved the mechanical properties of neoformed bone

• Autor(a) principal: Santana-Melo, Gabriela F. [UNESP]
• Data de Publicação: 2017
• Outros Autores: Rodrigues, Bruno V. M., Silva, Edmundo da, Ricci, Ritchelli, Marciano, Fernanda R., Webster, Thomas J., Vasconcellos, Luana M. R. [UNESP], Lobo, Anderson O.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.colsurfb.2017.04.053; http://hdl.handle.net/11449/162896
• topic: Electrospinning; PBAT; Nanohydroxyapatite; Gene expression; Micro-computed tomography; Bone regeneration

Combining polyester scaffolds with synthetic nanohydroxyapatite (nHAp), which is bioactive and osteoconductive, is a plausible strategy to improve bone regeneration. Here, we propose the combination of PBAT [poly(butylene-adipate-co-terephthalate)] and synthetic nHAp (at 3 and 5 wt%). PBAT is a relatively a new polymer with low crystallinity and attractive biodegradability and mechanical properties for orthopedic applications, however, with a still underexplored potential for in vivo applications. Then, we performed a careful biological in vitro and in vivo set of experiments to evaluate the influence of PBAT containing two different nHAp loads. For in vitro assays, osteoblast-like MG63 cells were used and the bioactivity and gene expression related to osteogenesis were evaluated by qRT-PCR. For in vivo experiments, twenty-four male rats were used and a tibial defect model was applied to insert the scaffolds. Micro-computed tomography (Micro-CT) and histological analysis were used to assess e bone neoformation after 6 weeks of implantation. Three point flexural tests measured the mechanical properties of the neoformed bone. All scaffolds showed promising in vitro properties, since they were not cytotoxic against MG-63 cells and promoted high cell proliferation and formation of mineralized nodules. From a mechanistic point-of-view, nHAp loading increased hydrophilicity, which in turn allowed for a better adsorption of proteins and consequent changes in the phenotypic expression of osteoblasts. nHAp induced better cellular responses on/in the scaffolds, which was mainly attributed to its osteoconductive and osteoinductive properties. Micro-CT images showed that nHAp at 3% and 5 wt% led to more effective bone formation, presenting the highest bone volume after 6 weeks of implantation. Considering the three point flexural tests, 5 wt% of nHAp positively influenced the flexural mode of the neoformed bone, but the stiffness was similar between the 3% and 5 wt% groups. In summary, this investigation demonstrated great potential for the application of these novel scaffolds towards bone regeneration and, thus, should be further studied. (C) 2017 Elsevier B.V. All rights reserved,