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Hydroxyapatite nano and microparticles: Correlation of particle properties with cytotoxicity and biostability

Paper ID Volume ID Publish Year Pages File Format Full-Text
10010 658 2009 11 PDF Available
Title
Hydroxyapatite nano and microparticles: Correlation of particle properties with cytotoxicity and biostability
Abstract

Synthetic colloid and gel hydroxyapatite (HA) nanoparticles (NPs) were spray dried to form microparticles (MPs). These are intended for use as slow release vaccine vectors. The physico-chemical properties of gel and colloid NPs and MPs were compared to those of HA obtained commercially. Their cytotoxicity to human monocytes'-derived macrophages (HMMs) was assessed in vitro using a range of techniques. These included the MTT assay, LDH leakage and a confocal based live–dead cell assay. Cytotoxicity differed significantly between preparations, with the suspended gel preparation being the most toxic (31–500 μg/ml). Other preparations were also toxic but only at higher concentrations (>250 μg/ml). Transmission electron microscopy (TEM) and stereology showed variable cellular uptake and subsequent dissolution of the various forms of HA. We have demonstrated that HA particle toxicity varied considerably and that it was related to their physico-chemical properties. Cell death correlated strongly with particle load. The intracellular dissolution of particles as a function of time in HMM suggests that increased cytoplasmic calcium load is likely to be the cause of cell death. Some HA NPs eluded the phagocytic pathway and a few were even seen to enter the nuclei through nuclear pores.

Keywords
Hydroxyapatite; Nanoparticles; Cytotoxicity; Slow release; Vaccine delivery; Transfection
First Page Preview
Hydroxyapatite nano and microparticles: Correlation of particle properties with cytotoxicity and biostability
Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 30, Issue 19, July 2009, Pages 3307–3317
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering