Selenium Nanorod Chemical Template-Directed Synthesis of Several Unique Nanostructures & Two Biomedical Applications of Gold/Silver Nanoparticles

• Main Authors: Ming-han Liu, 劉明翰
• Other Authors: Churng-ren Chris Wang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/43448139432157246973

碩士 === 國立中正大學 === 化學所 === 96 === We have successfully developed a two-step temperature controlled synthetic method to prepare one-dimensional selenium nanoparticles under CMC (Carboxymethyl-cellulose, sodium salt) stabilized system. In the synthetic process, we also control the nucleation rate by manipulating reduction time at room temperature to obtain selenium nanowires and nanorods with the aspect ratio from 12.2±3.1 to 55.2±22.2. By means of the characterizations from HRTEM, XRD and Raman, the 1D nanoselenium was identified as a mix-crystalline nanostructure (segamented SeNRs/SeNWs) containing monoclinic and trigonal crystalline phases (t-Se-m-Se-t-Se). Furthermore, the segmented nanoselenium is regarded as a fine “chemical-template” to drive the synthesis of SeNR@MPTMS nanofloats and others, such as SeNR@SiO2 and SeNR@TiO2 nanofloats. The formation of nanofloat composites is due to the crystalline difference that causes the selective chemisorption of MPTMS on m-Se. To further expand the diversity of such nanostructure system, we utilized SeNR@SiO2 as a starting material for the preparations of various nanofloats (e.g., hollow silica and AuNP-deposited SeNR@SiO2). The synthetic strategy for them relies on the post-synthetic treatments of hydrazine (N2H4) and hydrogen tetrachloroaurate(III) (HAuCl4), respectively. In addition, the CMC-stabilized selenium nanorods exhibit an anisotropic blocking on the body side of nanorods so that they provide good template for the preparation of hybrid nanodumbbell under aqueous solution. In the second part, we apply spherical gold nanoparticles through its fine biocompatibility to the biomedical applications in MALDI MS detection and therapy of dentin hypersensitivity. How to improve the S/N ratio and suppress the influence of matrix is a major task during MALDI MS analysis. We prepare high surface area and negative charged silver nanoparticles via silver-stain technique on nano-gold seeds. General organic matrix substituted by such Au@Ag nanoparticles were proven to be an effective matrix, a material for analyte preconcentration and selective binding of biomolecules in MALDI-MS analysis. In addition, for the treatment of dentin hypersensitivity we demonstrate two occlusion protocols to the exposed dentinal tubules with the aid of gold nanoparticles: (i) the inner tubular walls were pre-adsorbed by sub-monolayered gold nanoparticles, followed by a silver stain process to achieve tubular occlusion. (ii) highly concentrated gold nanoparticles were brushed into the exposed ends of dentinal tubules, followed by a laser irradiation which promoted a sintering process of gold nanoparticle aggregates to occur via photothermal conversion.