Fabrication of nanostructured hydroxyapatite and analysis of human osteoblastic cellular response

Abstract

Nano-sized hydroxyapatite (HA) powders were produced by a hydrothermal method and a precipitation method. Spark plasma sintering (SPS) was used to fabricate nanostructured HA (NHA) using nano-sized HA powders as a precursor. Conventional sintering was employed to produce microstructured HA (MHA). Characteristics of HA powders and HA bulk ceramics after sintering were investigated by XRD, FTIR, SEM, TEM, particle size distribution, and AFM. Dense compacts consisting of equiaxed grains with an average grain size of approximately 100 nm were obtained by SPS. Human osteoblasts were cultured on both NHA and MHA and cell attachment, proliferation, and mineralization were evaluated. After 90 min incubation, the cell density on NHA surface was significantly higher than that of MHA and glass control, whereas average cell area of a spread cell was significantly lower on NHA surface compared to MHA and glass control after 4 h incubation. Matrix mineralization was determined after 7 and 14 days incubation by using alizarin red assay combined with cetylpyridinium chloride extraction. NHA shows significant enhancement (p < 0.05) in mineralization compared to MHA. Results from this study suggest that NHA may be a much better candidate for clinical use in terms of bioactivity.

Nanodimensional and Nanocrystalline Calcium Orthophosphates

“…The prepared nanodimensional apatites might be consolidated to transparent bioceramics [330]. A hydrothermal synthesis [69,72,156,157,257,258,288,322,323, seems to be the second most popular preparation technique of the nanodimensional and/or nanocrystalline apatites. The term "hydrothermal" refers to a chemical reaction of substances in a sealed heated solution above ambient temperature and pressure [358] and this process allows synthesis of highly pure fine-grained single crystals, with controlled morphology and narrow size distribution [333].…”

“…As the nanodimensional and nanocrystalline calcium orthophosphates tend to agglomerate at heating (Fig. 8) [313,[593][594][595], normally a low-temperature [169,371] and/or a rapid consolidation [169,258,323,[596][597][598][599][600][601][602] techniques must be employed. The low-temperature approach comprises gel hardening (at 4 ºC) [371] and uni-axial pressing at 150 -200 ºC [169].…”

Biocomposite nanofibrous strategies for the controlled release of biomolecules for skin tissue regeneration

“…44 The SEM images ( Figure 9) showed normal cell morphology on TCP, PLACL, PLACL/SF, PLACL/SF/VE, and PLACL/SF/VE/ Cur scaffolds on day 6 and 9, respectively. Compared to day 6 nanofibrous scaffolds ( Figure 9A-E), on day 9 ( Figure 9F-I), the cells penetrate into the nanofibrous scaffolds with improved migration and cellular connections to form a dermal substitute.…”

The Biomimetic Approach to Design Apatites for Nanobiotechnological Applications

“…These are: wet chemical precipitation (Wang & Shaw 2007;Huang et al, 2004;Liou et al, 2004;Ganesan & Epple 2008;Zhang & Lu 2007), sol-gel synthesis (Sun et al, 2007;Chai & Ben-Nissan 1999;Ben-Nissan & Choi 2006;Choi & Ben-Nissan 2007), co-precipitation (Lopez-Macipe et al, 1998;Tas 2000), hydrothermal synthesis (Guo et al, 2007;Chaudhry et al, 2006), mechanochemical synthesis (Yeon et al, 2001), microwave processing (Siva Rama Krishna et al, 2007;Liu et al, 2005;Rameshbabu et al, 2005), vapour diffusion (Iafisco et al, 2010a), silica gel template (Iafisco et al, 2009a), emulsion-based syntheses (Phillips et al, 2003) and several other methods by which nanocrystals of various shapes and sizes can be obtained (Layrolle & Lebugle 1994;Ye et al, 2008). In general, the shape, size and specific surface area of the apatite nanocrystals appear to be very sensitive to both the reaction temperature and both the reactant addition rate.…”