Feasibility evaluation of low-crystallinity β-tricalcium phosphate blocks as a bone substitute fabricated by a dissolution–precipitation reaction from α-tricalcium phosphate blocks

Abstract

Although sintered β-tricalcium phosphate blocks have been used clinically as artificial bone substitutes, the crystallinity of β-tricalcium phosphate, which might dominate biocompatibility, is extremely high. The objective of this study is to evaluate the feasibility of fabricating low-crystallinity β-tricalcium phosphate blocks, which are expected to exhibit good biocompatibility via a dissolution-precipitation reaction of α-tricalcium phosphate blocks as a precursor under hydrothermal conditions at 200°C for 24 h. Although β-tricalcium phosphate is a metastable phase, the presence of Mg in the reaction solution inhibits the formation of its corresponding stable phase and induces β-tricalcium phosphate formation under acidic conditions. It was found that low-crystallinity β-tricalcium phosphate blocks could be fabricated from α-tricalcium phosphate blocks immersed in 1.0 mol/L MgCl + 0.1 mol/L NaHPO solution while maintaining the shape of the α-tricalcium phosphate blocks. The crystallite size of the fabricated β-tricalcium phosphate blocks was 42 nm, which was substantially smaller than that of the sintered β-tricalcium phosphate blocks. When the fabricated β-tricalcium phosphate blocks were implanted into bone defects in rabbit femurs, they exhibited excellent tissue responses. In particular, the initial osteoconductivity (two and four weeks) was substantially greater than that of sintered β-tricalcium phosphate blocks.

Sodium Induces Octacalcium Phosphate Formation and Enhances Its Layer Structure by Affecting the Hydrous Layer Phosphate

“…Further, it is still unclear whether this phenomenon will allow for the incorporation of molecules such as drugs into the OCP unit lattice. Furthermore, OCP crystallinity and thermodynamic stability significantly affect its pharmacokinetic properties such as dissolution ratio and biocompatibility. , The technique described here, however, will significantly contribute to the development of uses for OCP in various industrial fields such as biomaterials and pharmacy.…”

In vivo stability evaluation of Mg substituted low crystallinity ß-tricalcium phosphate granules fabricated through dissolution–precipitation reaction for bone regeneration

“…The detailed fabrication of the implanted materials is described in [23]. Briefly, Mg-LC-β-TCP granules were fabricated from 0.1 g of sintered α-TCP granules ranging from 300 to 400 μm, immersed in 20 ml of a mixture of 1 mol l −1 MgCl 2 +0.1 mol l −1 NaH 2 PO 4 solution in a hydrothermal vessel at 200 °C for 24 h. The β-TCP granules as control materials were fabricated through a sintering process at 1100 °C for 10 h in atmosphere.…”

“…Likewise, in our previous studies, Mg-incorporated low crystallinity β-TCP granules could be fabricated through a solution mediated dissolutionprecipitation process from α-tricalcium phosphate [α-TCP: Ca 3 (PO 4 ) 2 ] immersed in Mg 2+ containing acidic solution [23]. The fabricated low crystallinity β-TCP contained Mg 2+ ; therefore, it is indicated that the fabricated Mg 2+ substituted β-TCP (Mg-LC-β-TCP) block might exhibit an improved tissue response originating from its low crystallinity (see scheme 1).…”

Sol–gel synthesis of calcium phosphate-based biomaterials—A review of environmentally benign, simple, and effective synthesis routes

“…Synthetic calcium phosphates (CP) are very important biomaterials due to their high bioactivity in human bones and dental biomineralized tissues. These CP bioceramics are widely used to treat bone defects due to their chemical similarity to bone minerals with well biocompatibility [1][2][3][4][5][6][7]. Interestingly, the mineral component in bones and teeth is a highly carbonate-substituted [8], hydroxyl-deficient form of calcium hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 , and CHAp [6].…”