Fabrication and Characteristics of Porous Hydroxyapatite-CaO Composite Nanofibers for Biomedical Applications

Abstract

Hydroxyapatite (HAp), a major inorganic and essential component of normal bone and teeth, is a promising biomaterial due to its excellent biocompatibility, bioactivity, and osteoconductivity. Therefore, synthetic HAp has been widely used as a bone substitute, cell carrier, and delivery carrier of therapeutic genes or drugs. Mesoporous materials have attracted considerable attention due to their relatively high surface area, large pore volume, high porosity, and tunable pore size. Recently, mesoporous HAp has also been successfully synthesized by the traditional template-based process and has been demonstrated to possess better drug-loading and release efficiencies than traditional HAp. It is widely accepted that cell adhesion and most cellular activities, including spreading, migration, proliferation, gene expression, surface antigen display, and cytoskeletal functioning, are sensitive to the topography and molecular composition of the matrix. The native extracellular matrix is a porous, nanofibrous structure. The major focus of this study is the fabrication of porous hydroxyapatite-CaO composite nanofibers (p-HApFs) and the investigation of its drug-release property. In this study, nanofibers were prepared by the sol-gel route and an electrospinning technique to mimic the three-dimensional structure of the natural extracellular matrix. We analyzed the components of fibers using X-ray diffraction and determined the morphology of fibers using scanning and transmission electron microscopy. The average diameter of the nanofibers was approximately 461 ± 186 nm. The N2 adsorption–desorption isotherms were type IV isotherms. Moreover, p-HApFs had better drug-loading efficiency and could retard the burst release of tetracycline and maintain antibacterial activity for a period of 7 days. Hence, p-HApFs have the potential to become a new bone graft material.

Fabrication and Characterization of Strontium-Substituted Hydroxyapatite-CaO-CaCO3 Nanofibers with a Mesoporous Structure as Drug Delivery Carriers

“…In this study, CTAB-induced mSrHANFs showed a nonordered orientation of the mesopores within the nanocrystals (Figure 2). The microstructure is same as that observed in Pluronic P123-induced p-HApFs [23].…”

“…In our previous work, we fabricated mesoporous hydroxyapatite-CaO composite nanofibers (p-HApFs) via the sol–gel process by using Pluronic P123 as a porogen and an electrospinning technique and found that the p-HApFs possessed good drug loading efficiency and could retard the burst release of tetracycline (TC). [23] The formation of CaO may have been due to the incomplete pyrolysis of Pluronic P123 and the absorption of CO 2 from the atmosphere during the calcination process. Lopatin et al have also reported a similar result regarding the formation of CaO in the sol–gel processing of HAp [24].…”

Collagen Scaffolds Containing Hydroxyapatite-CaO Fiber Fragments for Bone Tissue Engineering

“…The HANFs used in the present work were synthesized based on our previously reported method [20]. First, 1.0 g of poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (P123, MW = 5800, Sigma-Aldrich Chemical Company, St. Louis, MO, USA) and 6.172 mL of triethyl phosphite (TEP, Merck, Darmstadt, Germany) were dissolved in 10 mL of aqueous ethanol solution (50% v/v) until a clear solution was obtained.…”

“…Eight weeks after implantation, the condylar bone defect was not completely regenerated, and the COL-HANF scaffold had been completely absorbed. From our past research, HANFs have a high drug-loading efficiency due to their mesoporous structure [20]. Wang et al demonstrated that COL-HAp with bone morphogenetic proteins (BMPs) promoted faster and more extensive new bone formation than COL-HAp [45].…”

“…In our past research, hydroxyapatite-CaO fibers (HANFs) fabricated by a sol-gel/electrospinning technique were demonstrated to have improved drug-loading efficiency and to retard the burst release of tetracycline and maintain antibacterial activity for a period of seven days [20]. However, the effect of HANFs on the osteogenic differentiation of osteoblast cells has not been evaluated.…”