Synthesis and in vitro biological evaluation of hydroxyapatite-zeolite containing silver, zinc, fluoride for medical applications
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Date
2014
Authors
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Publisher
Universiti Teknologi Malaysia
Abstract
Hydroxyapatite (HA) (Ca10(P04)6(OH)2) is a basic mineral component of natural hard tissues (bone, enamel etc.) and has been used in a wide range of applications such as bone filler, coating on metal prostheses and drug delivery. However, pure HA implants have several limitations such as slow osseointegration rate and requiring long-term implant stability in bone tissues. Moreover, it still exhibits poor antibacterial activities. Therefore, the implant associated with bacterial infections poses a threat to host life in spite of sterilized operating conditions. In view of the aforementioned condition, considerable effort is currently conducted to develop a new biomedical material with enhanced bioactivity properties and should be effected in resisting the bacterial biofilm formation. In this present work, the synthesis of hydroxyapatite containing ions (Ag+, Zn2+ and F¯) and its bioactive composites with zeolites (Y and ZSM-5) were done using a microwave process. Then, hydroxyapatite-zeolite (ZSM-5) containing ions composites were prepared by mechanical mixing and sintering process. The phase composition, functional groups, surface morphology, and elemental composition of the synthesized bioceramics were examined by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The XRD, FTIR and EDS results confirmed the incorporation of ions and zeolite into the HA structure. The FESEM and TEM results revealed that the particles were in nanosize with a spherical morphology. The antibacterial activity using the disk diffusion method showed that the samples were active against gram-positive and gram-negative bacteria. The antibacterial effect was found to increase with the ions contents. The in vitro bioactivity results after soaking in simulated body fluid (SBF) solution proved that hydroxyapatite containing ions showed the apatite layer formation within 28 days, whereas the hydroxyapatite-zeolite and its ions containing composites showed apatite formation within 14 days, indicating the improvement in bioactivity which was due to the presence of zeolites. Furthermore, the MTT assay and cell adhesion results confirmed good proliferation and attachment of normal human osteoblast (NHOst) cells on the surface of composites. In conclusion, these results indicated that the low concentrations of hydroxyapatite-zeolite containing ions (Ag+, Zn2+ and F¯) exhibited good bioactivity and biocompatibility with sufficient antibacterial activity. Therefore, these composites can be used as bone substitute in bone implant applications
Description
Thesis (PhD. (Biomedical Engineering))
Keywords
Biosciences and medical engineering