KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Chaopanich, PakviparHas files: No

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Sodium polystyrene sulfonate template assisted hydrothermal synthesis of hydroxyapatite nanorods
    (2016-09-01)
    Chaopanich, Pakvipar
    ;
    Siriphannon, Punnama
    Hydroxyapatite nanoparticles (nHAp) have been synthesized by benign hydrothermal reaction from the aqueous mixture of Ca(NO<inf>3</inf>)<inf>2</inf>·4H<inf>2</inf>O and (NH<inf>4</inf>)<inf>2</inf>HPO<inf>4</inf> solutions in the presence of non-toxic sodium polystyrene sulfonate (PSS) template. The pH of starting precursors has been adjusted to 10.5 before hydrothermal treatment at 100°C for 1, 2 and 3 h. The added PSS template generates the largely negative surface of dicalcium phosphate dihydrate (DCPD) precursor, resulting in minimization of precursor agglomeration and promoting the hydrothermal growth of nHAp along preferential c-axis as rod-shaped crystals. The crystallite sizes along 002-plane of nHAp synthesized with and without PSS template are 47.1 and 29.5 nm, respectively. With longer hydrothermal treatment time, larger crystallite size of nHAp is obtained. In vitro cytotoxicity of the synthesized nHAp has been evaluated by MTT assay using African green monkey kidney fibroblast cells, in which the nHAp exhibits low cytotoxicity. Antibacterial activities of the synthesized nHAp against S.aureus and E.coli have been tested. Due to the presence of largely negative surface, the nHAp could inhibit only the grampositive S.aureus, creating a clear zone of about 9.5 mm.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Facile Refluxing Synthesis of Hydroxyapatite Nanoparticles
    (2015-01-01)
    Chaopanich, Pakvipar
    ;
    Siriphannon, Punnama
    Hydroxyapatite (HAp) nanoparticles were successfully synthesized from an aqueous mixture of Ca(NO<inf>3</inf>)<inf>2</inf>·4H<inf>2</inf>O and (NH<inf>4</inf>)2HPO<inf>4</inf> by a facile single-step refluxing method using polystyrene sulfonate (PSS) as a template. The effects of reaction times, pH, and PSS concentration on the HAp formation were investigated. It was found that the crystalline HAp was obtained under all conditions after refluxing the precursors for 3 and 6h. The longer refluxing time, the greater the crystallinity and the larger the crystallite size of the HAp nanoparticles. The HAp with poor crystallinity was obtained at pH 8.5; however, the well-crystallized HAp was obtained when reaction pH was increased to 9.5 and 10.5. In addition, the X-ray diffraction patterns revealed that the presence of PSS template caused the reduction of HAp crystallite size along the (002) plane from 52.6nm of non-template HAp to 43.4nm and 41.4nm of HAp with 0.05 and 0.2wt-% PSS template, respectively. Transmission electron microscopy images of the synthesized HAp revealed the rod-shaped crystals of all samples. The synthesized HAp nanoparticles were modified by l-aspartic acid (Asp) and l-arginine (Arg), having negative and positive charges, respectively. It was found that the zeta potential of HAp was significantly changed from +5.46 to -24.70mV after modification with Asp, whereas it was +4.72mV in the Arg-modified HAp. These results suggested that the negatively charged amino acid was preferentially adsorbed onto the synthesized HAp surface.