Abstract
This article presents the construction of scaffolds composed of polylactic acid (PLA) with different concentrations of hydroxyapatite (HA) by electrospinning, which were superficially modified with polypyrrole (PPy/I) by plasma polymerization. A preliminary study was conducted of the biological and mechanical behavior of the scaffolds when they were implanted in the back of rabbits for 30 days; bone cells differentiated from mesenchymal stem cells (MSCs) were used. The bone cell and scaffold structures were characterized by histological, immunohistochemical, and mechanical stress tests. Hematoxylin–eosin staining showed good tissue conformation. The immunohistochemical tests highlighted the presence of the main bone tissue proteins, such as collagen, osteocalcin, and osteopontin. The PLA/HA scaffolds were observed to exhibit cell adhesion and proliferation properties; however, the response was much better in the scaffolds that had a higher concentration of HA and that were coated with PPy/I. The results of the mechanical tests of the scaffolds indicated that the plasma treatment improved the adhesion and cell proliferation properties and contributed to the mechanical support, allowing the formation of neotissues with good viability of cell growth.
Highlights
In bone tissue engineering, scaffolds serve as tissue formation matrices, and it is desirable that they meet basic characteristics that allow cell adhesion, differentiation and proliferation, mechanical integrity, osteoconductivity and biocompatibility, vascularization, and nutrients and bioactive factors (de Witte et al, 2018; Hosseinpour et al, 2017; Motamedian et al, 2015; Venkatesan et al, 2017)
Polymeric matrices with higher values of Young’s modulus and yield strength were obtained in M1 polylactic acid (PLA)/HA (18.1%) and M2 PLA/HA (18.1%)/PPy/I than in M3 PLA/HA (35.7%) and M4 PLA/HA (35.7%)/PPy/I. These differences are attributed to the amount of HA present and the surface modification induced by PPy/I
It was observed that these neotissues show vascularization, absence of necrosis, and good conformation
Summary
Scaffolds serve as tissue formation matrices, and it is desirable that they meet basic characteristics that allow cell adhesion, differentiation and proliferation, mechanical integrity, osteoconductivity and biocompatibility, vascularization, and nutrients and bioactive factors (de Witte et al, 2018; Hosseinpour et al, 2017; Motamedian et al, 2015; Venkatesan et al, 2017). Proliferation and even promoting cell regeneration (AlvarezMejia et al, 2015; Olayo et al, 2008). Another important aspect in this study was the incorporation of bioactive cells into the three-dimensional porous scaffold from mesenchymal stem cells (MSCs). MSCs are present in many human tissues and can be derived directly from bone marrow and isolated, grown, and proliferated in the laboratory. These cells are capable of giving rise to various tissues, such as bone, muscles, and other tissues of mesenchymal origin. MSCs do not appear to be rejected by the immune system (Chuenjitkuntaworn and Pavasant 2015; Hoda et al, 2016; Elkhenany et al, 2014; Yousefi et al, 2016)
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