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. 2024 Jan 3;25(1):621.
doi: 10.3390/ijms25010621.

Comparative In Vitro Dissolution Assessment of Calcined and Uncalcined Hydroxyapatite Using Differences in Bioresorbability and Biomineralization

Woo Young Jang  1   2 , Jae Chul Pyun  2 , Jeong Ho Chang  1
Affiliations

Comparative In Vitro Dissolution Assessment of Calcined and Uncalcined Hydroxyapatite Using Differences in Bioresorbability and Biomineralization

Woo Young Jang et al. Int J Mol Sci. .

Abstract

This study reports the effect of the not-calcining process on the bioresorption and biomineralization of hydroxyapatite through in vitro dissolution assessment. The prepared calcined hydroxyapatite (c-HAp) and uncalcined hydroxyapatite (unc-HAp) have a particle size of 2 μm and 13 μm, surface areas of 4.47 m2/g and 108.08 m2/g, and a Ca/P ratio of 1.66 and 1.52, respectively. In vitro dissolution assessments of c-HAp and unc-HAp were performed for 20 days at 37 °C in a citric acid buffer according to ISO 10993-14. During the dissolution, the c-HAp and unc-HAp confirmed an increase in weight, and the calcium and phosphorous ions were rapidly released. The calcium ions released from c-HAp formed rod-shaped particles with a longer and thinner morphology, while in unc-HAp, they appeared thicker and shorter. In the ICP-OES results, the concentrations of calcium elements were initially increased and then decreased by this formation. The rod-shaped particles identified as calcium citrate (Ca-citrate) through the XRD pattern. The calcium content of Ca-citrate particles from unc-HAp was higher than that from c-HAp. The unc-HAp demonstrated non-toxic properties in a cytotoxicity evaluation. Therefore, due to its higher bioresorption and biomineralization, unc-HAp exhibits enhanced biocompatibility compared to c-HAp.

Keywords: biomineralization; bioresorption; calcium citrate; dissolution; uncalcined hydroxyapatite.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Comparison of c-HAp and unc-HAp characterizations. (a) TEM images, (b) particle size distribution and SEM image, and (c) XRD pattern.
Figure 2
Figure 2
(a) Nitrogen adsorption–desorption isotherms, (b) BET parameters of surface areas, pore volume, and pore size, (c) contents of calcium and phosphorous elements and Ca/P molar ratios, (d) cell viability, and (e) compressive strength–stain curve and fracture strength of the c-HAp and unc-HAp.
Figure 3
Figure 3
Comparison of in vitro dissolution assessments of c-HAp and unc-HAp. (a) Weight of powder, (b) calcium and phosphorus elements concentrations in the eluted filtrate by ICP-OES analysis, (c) XRD pattern and crystallinity, (d) dissolution efficiency, (e) dissolution rate, and (f) SEM images as a function of the time.
Figure 4
Figure 4
(a) FIB-SEM images showing cross-sectional views, aspect ratio, and EDS results of rod-shaped particles, (b) XRD pattern and molecular modeling of the c-HAp and unc-HAp at 20 days, and (c) schematic representations of c-HAp and unc-HAp in citric acid.
Figure 4
Figure 4
(a) FIB-SEM images showing cross-sectional views, aspect ratio, and EDS results of rod-shaped particles, (b) XRD pattern and molecular modeling of the c-HAp and unc-HAp at 20 days, and (c) schematic representations of c-HAp and unc-HAp in citric acid.
Figure 5
Figure 5
(a) Cell viability through an MTT assay observed during in vitro dissolution assessment of c-HAp and unc-HAp at 20 days, and (b) calcium/carbon contents of Ca-citrate-1 and Ca-citrate-2.
Figure 6
Figure 6
Changes in calcium ion concentration with bioresorption and biomineralization of c-HAp and unc-HAp.
See this image and copyright information in PMC

References

    1. Lu X., Kolzow J., Chen R.R., Du J. Effect of solution condition on hydroxyapatite formation in evaluating bioactivity of B2O3 containing 45S5 bioactive glasses. Bioact. Mater. 2019;4:207–214. doi: 10.1016/j.bioactmat.2019.05.002. - DOI - PMC - PubMed
    1. Alorku K., Manoj M., Yuan A. A plant-mediated synthesis of nanostructured hydroxyapatite for biomedical applications: A review. RSC Adv. 2020;10:40923–40939. doi: 10.1039/D0RA08529D. - DOI - PMC - PubMed
    1. Pramanik S., Agarwal A.K., Rai K.N., Garg A. Development of high strength hydroxyapatite by solid-state-sintering process. Ceram. Int. 2007;33:419–426. doi: 10.1016/j.ceramint.2005.10.025. - DOI
    1. Koonawoot R., Saelee C., Thiansem S., Punyanitya S. Synthesis control and characterization of hydroxyapatite ceramic using a solid state reaction; Proceedings of the 1st Mae Fah Luang University International Conference; Chiang Rai, Thailand. 29 November–1 December 2012.
    1. Cai S., Wang Y., Lv H., Peng Z., Yao K. Synthesis of carbonated hydroxyapatite nanofibers by mechanochemical methods. Ceram. Int. 2005;31:135–138. doi: 10.1016/j.ceramint.2004.04.012. - DOI

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