Development of Magnetic Hydroxyapatite Nanoparticles as a Non-viral Gene Carrier
Date Issued
2009
Date
2009
Author(s)
Wu, Hsi-Chin
Abstract
Gene therapy has great potential to revolutionize the treatment of human diseases in both genetic and acquired origin. Of the was that, the successful transfer of genetic materials (such as nucleic acid) into living cells is the most important issue depending on the development of the gene delivery carrier. In the study, nanoparticles (NPs) of synthetic hydroxyapatite (Hap) were rendered magnetic by treatment with iron ions using a wet-chemical process. During Hap precipitation processes, two kinds of magnetized Hap (mHap) NPs (mHap-Inter and mHap-Post) were fabricated by iron precursor addition at different time points (inter- and post-) in various ratios of Fe:Ca (XFe/ Ca) and were used to compare with magnetic natural bone mineral (mNBM). he physical and chemical properties of two types of mHap NPs were, respectively, evaluated the crystal structure and cell parameters by X-ray diffraction; morphology and lattice arrangement by scanning electron microscopy, atomic force microscopy and (high-resolution) transmission electron microscopy; composition analysis by inductively coupled plasma; functional groups by Fourier transform infrared spectroscopy; magnetization by superconducting quantum interference device. The mHap-Inter NPs, which iron substituted for calcium in Hap, was remained unaltered lattice constants without collapse phenomenon. The size distribution of mHap-Inter was around 20 to 50 nm with sphere shape. On the other hand, the mHap-Post and mNBM NPs were the result of the hetero-epitaxial growth of magnetite on the Hap and NBM crystallites. The magnetic NPs with sphere shape less than 10 nm in diameters were tightly surrounded on Hap or NBM crystallites which were revealed randomly in rod and needle-like shape. The magnetization of all groups of mHap NPs increased with the increasing of XFe/ Ca and possessed superparamagnetic property. Moreover, all the mHap NPs were examined with good biocompatibility using the analysis of lactate dehydrogenase assay.he mHap NPs displayed a high binding affinity with plasmid DNA (pDNA) and appeared to exert a protective effect on the bound plasmid against enzymatic degradation compared to magnetite NPs. The mHap-Inter, mHap-Post and mNBM NPs showed substantial increases in the glial cell line-derived neurotrophic factor (GDNF) gene transfection for rat marrow-derived mesenchymal stem cells (MSCs) under an applied magnetic field, and were shown to be non-cytotoxic. The amount of GDNF recovered in the medium approached therapeutic levels despite the small amount of plasmid delivered by the mHap NPs. he hydroxyapatite-based magnetic NPs were synthesized in two different types: iron-substitution and hetero-epitaxial growth during precipitation processes by iron addition. The mHap-Inter and mHap-Post NPs possessed the appropriate physico-chemical and biological properties with great promising to be applied in the biomedical applications. The mHap NPs were demonstrated to possess binding affinity with pDNA and protected the plasmid against enzymatic digestion. The mHap-Inter, mHap-Post and mNBM NPs significantly increased GDNF expression in rat MSCs transfection when magnetic field was applied (P<0.05). GDNF could be maintained for as long as two weeks and the accumulated amount achieved therapeutic levels even for low pDNA loading. According to the above facts, we believe that the mHap NPs have great potential as a novel non-viral vector for gene therapy.
Subjects
hydroxyapatite
magnetic
bioceramics
gene therapy
non-viral delivery vector
SDGs
Type
thesis
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