Thin Film Phosphate Based Bioactive Substrates

Abstract

Calcium phosphate based thin films prepared by colloidal sol-gel slow draw dipping of quartz substrates are bioactive to both osteoclast resorption and osteoblast deposition. The bioactivity is related to the presence of mixed crystalline phases in the films generated under different sintering conditions. As the sintering temperature was increased from 800°C to 1000°C, a transition in film composition from calcium hydroxylapatite to alpha-tricalcium phosphate is achieved.

Effect of β-TCP ceramic on the total protein of osteoblasts

“…Coomassie brilliant blue is a sulfonic acid salt which results in blue staining when the dye anion is bound to certain cations [12] . It is frequently used for the staining of soluble proteins or protein bands in various protein separation procedures.…”

Silicon-Containing Apatites

“…An initial study reported the formation of a biphasic mixture of a HA phase and a silicon-containing a-TCP-phase at the interface when a thin calcium phosphate colloid layer on a quartz substrate was heated at 1000 C. 114 Following this observation, the same group used this concept to produce biphasic thin film coatings (with a thickness of 0.5-1 mm) of HA and a siliconstabilized a-TCP (Si-a-TCP) by dip-coating a quartz substrate into a HA suspension, 115 followed by heating at 800-1000 C. They also produced ceramics by mixing HA powder processed from the HA suspension and Si from either TEOS or tetraprolpyl orthosilicate (TPOS), followed by sintering at 1000 C. Characterization of the coatings heated at 800, 900, and 1000 C by XRD gave phase mixtures of HA (%):Si-a-TCP (%) of 94:6, 62:38, and 33:67, respectively. An initial study reported the formation of a biphasic mixture of a HA phase and a silicon-containing a-TCP-phase at the interface when a thin calcium phosphate colloid layer on a quartz substrate was heated at 1000 C. 114 Following this observation, the same group used this concept to produce biphasic thin film coatings (with a thickness of 0.5-1 mm) of HA and a siliconstabilized a-TCP (Si-a-TCP) by dip-coating a quartz substrate into a HA suspension, 115 followed by heating at 800-1000 C. They also produced ceramics by mixing HA powder processed from the HA suspension and Si from either TEOS or tetraprolpyl orthosilicate (TPOS), followed by sintering at 1000 C. Characterization of the coatings heated at 800, 900, and 1000 C by XRD gave phase mixtures of HA (%):Si-a-TCP (%) of 94:6, 62:38, and 33:67, respectively.…”

Surface and adsorption properties of α-tricalcium phosphate

“…2 Si-TCP, a phase mixture of calcium phosphates containing Si, which has an ␣-TCP-like phase as its majority component shows great promise as a bone substitute that takes part in the body's natural bone remodeling process. [3][4][5][6][7][8] Ab initio methods based on density functional theory have been used to investigate the atomic arrangements and electronic structures of ␣-and ␤-TCPs. 9 The findings support the picture of robust tetrahedral PO 4 ions linked in complicated ways by Ca ions.…”

“…The body fluid is overwhelmingly water, but other physiologically important constituents are Ca and P. The adsorption of an H 2 O molecule and a Ca atom on surfaces of TCP is therefore of interest. In addition, the reasons for the bioactivity of Si-doped TCP are important because of its bone remodeling properties, 7,8,10 and so the interaction of a SiO 2 fragment with TCP surfaces is also investigated. Although the interactions of ceramic calcium phosphate surfaces with these species in aqueous solutions are the biological effects of interest, a first computational step is the study of in vacuo adsorption, and this is our objective here.…”