Tailoring Si-substitution level of Si-hydroxyapatite nanowires via regulating Si-content of calcium silicates as hydrothermal precursors

Abstract The silicon (Si) substituted hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 , Si-HAp] nanowires with different Si-substitution levels were synthesized via a hydrothermal reaction of the different Si containing precursors of CaSiO 3 (CS), Ca 2 SiO 4 (C 2 S) and Ca 3 SiO 5 (C 3 S) ceramic powders in trisodium phosphate (Na 3 PO 4 ) aqueous solution, in the absence of any surfactants and organic solvents. The results showed that the morphology transformation trend of particle shaped CS to Si-HAp nanowires is stronger than that of C 2 S and C 3 S. After hydrothermal treatment of the precursors at 180 °C for 7 days, the particle shape precursors transformed into Si-HAp nanowires with a width of ~100 nm and length up to 3 μm. Moreover, the Si-substitution amount (0.318–3.75 wt%) of the Si-HAp nanowires could be facilely tailored by regulation of the Si-content of the precursors. Our study suggested that the hydrothermal transformation of the calcium silicate precursors with different Si-contents provides a facile approach to regulate the Si-substitution level of the Si-HAp nanowires, and the synthetic Si-HAp nanowires might be used as bioactive materials for hard tissue regeneration applications.