title: Application of luminescent Eu:Gd2O3 nanoparticles to the visualization of protein micropatterns.
abstract: Nanoparticle phosphors made of lanthanide oxides are a promising new class of tags in biochemistry because of their large Stokes shift, sharp emission spectra, long luminescence lifetime, and good photostability. We demonstrate the application of these nanoparticles to the visualization of protein micropatterns. Luminescent europium-doped gadolinium oxide (Eu:Gd2O3) nanoparticles are synthesized by spray pyrolysis. The size distribution is from 5 to 200 nm. The particles are characterized by means of laser-induced fluorescent spectroscopy and transmission electron microscopy (TEM). The main emission peak is at 612 nm. The nanoparticles are coated with avidin through physical adsorption. biotinylated bovine serum albumin (BSA-b) is patterned on a silicon wafer using a microcontact printing technique. The wafer is then incubated in a solution of avidin-coated nanoparticles. Fluorescent microscopic images reveal that the nanoparticles are organized onto designated area, as defined by the microcontact printing process. The luminescent nanoparticles do not suffer photobleaching during the observation, which demonstrates their suitability as luminescent labels for fluorescence microscopy studies. More detailed studies are preformed using atomic-force microscopy (AFM) at a single nanoparticle level. The specific and the nonspecific binding densities of the particles are qualitatively evaluated.
authors.affiliation: University of California Davis, Department of Mechanical and Aeronautical Engineering, Davis, California 95616, USA.
authors.forename: Dosi
authors.initials: D
authors.lastname: Dosev
authors.forename: Mikaela
authors.initials: M
authors.lastname: Nichkova
authors.forename: Maozi
authors.initials: M
authors.lastname: Liu
authors.forename: Bing
authors.initials: B
authors.lastname: Guo
authors.forename: Gang-Yu
authors.initials: GY
authors.lastname: Liu
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hammock
authors.forename: Ian M
authors.initials: IM
authors.lastname: Kennedy
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry; D005063:Europium / Q000737:chemistry; D005456:Fluorescent Dyes; D005682:Gadolinium / Q000032:analysis / Q000737:chemistry*; D007089:Image Enhancement / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods*; D008164:Luminescent Proteins / Q000032:analysis* / Q000648:ultrastructure*; D008856:Microscopy, Fluorescence / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D020099:Coated Materials, Biocompatible; D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D005063:Europium; C030581:gadolinium oxide; D005682:Gadolinium