Preparation and in vitro/in vivo evaluations of dimpled poly(l-lactic acid) fibers mixed/coated with hydroxyapatite nanocrystals

Abstract

A novel hydroxyapatite (HAp)/poly(L-lactic acid) (PLLA) nanocomposite nonwoven fabric, which was coated and mixed with calcined HAp nanocrystals, and has submicron-sized dimples on its surface, was fabricated. First, HAp-mixed PLLA fabric was prepared by electrospinning a HAp nanocrystal dispersion in dichloromethane (DCM)-dissolved PLLA. It was found that most of the HAp nanocrystals were not exposed on the HAp-mixed PLLA fiber surface but covered with the PLLA matrix. A HAp-nanocrystal coating was applied onto the surface of the HAp-mixed PLLA fabric after corona discharge treatment followed by ethanol washing. The submicron-sized dimples were enlarged after the ethanol washing. After the HAp-nanocrystal coating, the HAp-mixed PLLA fabric surface was uniformly coated with the HAp nanocrystals. In vitro cell spread tests showed that the rat osteoblasts spread more on HAp-nanocrystal-coated fabrics than on non-HAp-coated fabrics. Upon covering calvarial defects, the in vivo hard tissue responses suggested earlier restoration of the defects with HAp-nanocrystal-coated fabrics than those with non-HAp-coated fabrics.

Hydroxylapatite nanoparticles: fabrication methods and medical applications

“…For example, alkoxysilyl groups (silane coupling agents) [210,366] and isocyanate groups [367] can covalently react with surface hydroxyl groups of HAp, and carboxyl groups can interact ionically with calcium ions on the HAp surfaces. Polymer and metal substrates have been used [346][347][348][349][350][351][352][353][354][355]. After adsorption of HAp nanocrystals and reaction at the interface between HAp nanocrystals and substrate surfaces, the HAp-nanocrystal-coated substrates retained the mechanical properties of the substrates and showed improved cell adhesion properties owing to the presence of HAp crystals on the surface [349][350][351][352][353]355].…”

“…Polymer and metal substrates have been used [346][347][348][349][350][351][352][353][354][355]. After adsorption of HAp nanocrystals and reaction at the interface between HAp nanocrystals and substrate surfaces, the HAp-nanocrystal-coated substrates retained the mechanical properties of the substrates and showed improved cell adhesion properties owing to the presence of HAp crystals on the surface [349][350][351][352][353]355]. The HAp nanocrystal coating is applied to percutaneous devices [349,356], artificial blood vessels [357,358] and stents [352].…”

“…To coat well-crystallized HAp on a broad range of substrates, the nanocrystal coating has been developed [346][347][348][349][350][351][352][353][354][355]. This approach involves four steps: (i) preparation of calcined HAp nanocrystals (see section 2.2.6), (ii) surface modification of the substrate to react with HAp surfaces, (iii) adsorption of HAp nanocrystals onto the modified substrate, and (iv) reaction at the interface between the HAp nanoparticle and the substrate (figure 3).…”

Hydrothermal fabrication of hydroxyapatite/chitosan/carbon porous scaffolds for bone tissue engineering

“…Recently, fiber/HA composites have been fabricated by using poly(L-lactic acid) fibers, 13 silk fibers, 14 cellulose fibers, 15 or carbon fibers 16 as templates to induce the nucleation and growth of HA nanocrystals on their surfaces.…”

Scanning Electron Microscopy Analysis of Changes of Hydroxiapatite/Poly-L-Lactide with Different Molecular Weight of PLLAaAfter Intraperitoneal Implantation

“…Synthetic polymer poly-L-lactide (PLLA) is often used for combining with HAp [6,7]. Fibers of PLLA may strengthen HAp and its good bioresorbability provides space for tissue extension [8]. Composite biomaterial HAp/PLLA embodies good features of each of these biomaterials [9].…”