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Ze Xiang Shen

Publications and source records attributed to Ze Xiang Shen.

2 recordsLinked to original sources
PubMed2005

Deposition method for preparing SERS-active gold nanoparticle substrates.

Surface-enhanced Raman scattering or SERS, discovered some 20 years ago, has recently become a promising tool for routine biofluid assays in a clinical setting. Many attempts have been made to produce cheap and reproducible SERS-active substrates. In this study, we report on the fabrication of SERS-active substrates through the convective assembly of gold (Au) particles on electrostatically charged glass slides. We show that, by a proper control of the initial particle concentration in an evaporating Au suspension droplet, it is possible to obtain a closely packed colloidal film capable of generating SERS activity. Finally, AFM and SERS measurements of the resulting films reveal comparability in performance with previous silane-immobilized Au colloidal films. The minimum electromagnetic enhancement factor of our films is estimated to be about 2 x 10(4).

Colloids↗
PubMed2004

Complexation between PVP and Gantrez polymer and its effect on release and bioadhesive properties of the composite PVP/Gantrez films.

Complexation between poly(methyl vinyl ether-maleic anhydride) copolymer (Gantrez AN 169) and polyvinylpyrrolidone (PVP K-90D) in aqueous solutions were investigated using a viscometric method and Raman spectroscopy. The composite films with different weight ratios of PVP to Gantrez were prepared in the presence of N-methyl-2-pyrrolidone. The release profiles of diclofenac sodium (DS) from these films were determined and the bioadhesive properties measured. An interpolymer complex was formed through hydrogen bonding between the carbonyl groups of PVP and the hydroxyl groups of Gantrez. The formation of interpolymer hydrogen bonds reduced the interaction of the polymers with water molecules, thus resulting in a lower solubility of the complex in water and a further retarded release of DS from the composite films. The interpolymer complexation was also found to increase the bioadhesive properties of the composite films to a silicone elastomer substrate. The complexation of PVP and the Gantrez copolymer in the composite films was a critical factor affecting the release of DS from the films and the bioadhesive properties of the films.

Adhesives↗