title: Study of gold nanoparticles and live cells interactions by using planar evanescent wave excitation.
abstract: We present a planar evanescent wave (PEW) technique combined with phase contrast optical microscopy to study the interactions between cells and gold nanoparticles (AuNPs). The PEW method employs a dual-fiber-line guide to couple light into a thin glass slide. It produces a uniform and long evanescent wave near the glass surface, as verified by the optical near-field measurement. High-contrast AuNP images are obtained by the PEW illumination. At the same time, cells are observed only by using the phase contrast microscopy. The nanoparticles and cell images indicated that unmodified AuNPs had no interactions with cells, possibly due to the negative surface charges on both cells and nanoparticles. The electrostatic concept was further verified by coating AuNPs with positively charged poly (L-lysine). DNA aptamers for surface mucin glycoprotein were coated on AuNPs to demonstrate the application for single nanoparticle tracking.
authors.affiliation: Academia Sinica, Research Center for Applied Sciences, 128, Section 2, Academia Road, Nankang, Taipei 11529, Taiwan.
authors.forename: Chia-Wei
authors.initials: CW
authors.lastname: Lee
authors.forename: En-Hong
authors.initials: EH
authors.lastname: Lin
authors.forename: Ji-Yen
authors.initials: JY
authors.lastname: Cheng
authors.forename: Pei-Kuen
authors.initials: PK
authors.lastname: Wei
mesh_terms: D003287:Contrast Media; D006046:Gold; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008858:Microscopy, Phase-Contrast / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009369:Neoplasms / Q000473:pathology*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D003287:Contrast Media; D006046:Gold