TiO2/hydroxyapatite (TiO2/HA) composite nanofiber mats were fabricated using an electrospinning technique. Subsequently, pamidronic acid (PDA) was immobilized on the surface of the TiO2/HA nanofiber mat to improve osseointegration. X-ray photoelectron microscopy and scanning electron microscopy (SEM) were used to characterize the structure and morphology of the PDA-immobilized TiO2/HA composite nanofiber mat (TiO2/HA-P). The potential of TiO2/HA-P as a bone scaffold was assessed by examining the cell adhesion and proliferation of osteoblasts and osteoclasts. The adhesion and proliferation of osteoblasts on the TiO2/HA-P composite nanofiber mat were slightly higher than those on the TiO2/HA composite nanofiber mat, whereas the viability of osteoclasts on the TiO2/HA-P nanofiber mat was significantly suppressed. These results suggest that the TiO2/HA-P nanofiber mat has the potential for use as a therapeutic bone implant. 1. Introduction Titanium (Ti) and some of its alloys are the most widely used metallic materials for biomedical applications. Their inherent biocompatibility, excellent mechanical properties, and corrosion resistance make them suitable for biomaterials in tissue engineering [1, 2]. Over the past few decades, a range of materials and designs have been used to improve the osseointegration of titanium implants [3–7]. Hydroxyapatite (HA), a major inorganic component of natural bone and teeth, has been studied extensively and used in biomedical implant applications and bone regeneration owing to its good osteoconductivity and bone binding ability to natural bone [8–11]. The addition of hydroxyapatite (HA) to titanium implants has attracted considerable interest because of its potential use as a biomaterial with a range of treatments, such as sol-gel and hydrolysis and hydrothermal treatment [12]. Many researchers have examined TiO2/HA composites [13, 14]. Ramires et al. investigated the biocompatibility of TiO2/HA composite coatings and reported that they are bioactive and effective in improving the growth of osteoblasts [15]. Bigi et al. reported that hydroxyapatite-coated nanostructured titanium alloys induce the differentiation of mesenchymal cells (MSCs) towards a phenotypic osteoblast lineage [16]. Recently Kim et al. prepared TiO2/HA composite nanofiber mats using an electrospinning technique and immobilized collagen on the surface of the mats to improve the tissue compatibility. They showed that the collagen-immobilized TiO2/HA composite nanofiber mats induced better adhesion, proliferation, and differentiation of osteoblasts than the
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