Evaluation of Hydroxyl Groups on Hydroxyapatite and Calcium Metaphosphate by Grafting TEOS and APTES

Abstract:

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OH groups on hydroxyapatite (HA) and calcium metaphosphate (CMP) were evaluated by grafting tetraethyl orthosilicate (TEOS) and 3-aminopropyltriethyloxysilane (3-APTES) which can bond covalently with OH group of ceramic biomaterials. The prepared HA and CMP disks were soaked in pH 2 and 5 of acidic water and ethanol solution respectively, where pH change of each solution was measured during soaking of samples. After grafting TEOS and 3-APTES on HA and CMP disks, samples were ultrasonically cleaned in distilled water and soaked in pH 5 of ethanol solution, and pH measurement was carried out in the same manner. The pH value of HA and CMP in aqueous solution at pH 2 increased with time continuously, resulting from dissolution of HA and CMP by acidic condition on surface. At pH 5 in aqueous solution, it was the same though the pH increase was smaller. In case of ethanol at pH 5 with HA, though pH value went up slightly, the curve became saturated with time, while there was no change in pH with CMP. After grafting TEOS and 3-APTES, pH values were stabilized with few changes, indicating that there was no direct chemical reaction between the acidic media and the surface of samples due to covalently grafted TEOS and 3-APTES layer. In conclusion, it was confirmed that OH group on the surface of HA was crystallographic and chemical one rather than physically adsorbed one by grafting TEOS or 3-APTES and it will serve an effective binding site for calcium and phosphate ions, or minerals.

Info:

Periodical:

Key Engineering Materials (Volumes 342-343)

Edited by:

Young-Ha Kim, Chong-Su Cho, Inn-Kyu Kang, Suk Young Kim and Oh Hyeong Kwon

Pages:

677-680

DOI:

10.4028/www.scientific.net/KEM.342-343.677

Citation:

C. K. You et al., "Evaluation of Hydroxyl Groups on Hydroxyapatite and Calcium Metaphosphate by Grafting TEOS and APTES", Key Engineering Materials, Vols. 342-343, pp. 677-680, 2007

Online since:

July 2007

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Price:

$35.00

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