title: Imaging of Biological Cells Using Luminescent Silver Nanoparticles.
abstract: The application of luminescent silver nanoparticles as imaging agents for neural stem and rat basophilic leukemia cells was demonstrated. The experimental size dependence of the extinction and emission spectra for silver nanoparticles were also studied. The nanoparticles were functionalized with fluorescent glycine dimers. Spectral position of the resonance extinction and photoluminescence emission for particles with average diameters ranging from 9 to 32 nm were examined. As the particle size increased, the spectral peaks for both extinction and the intrinsic emission of silver nanoparticles shifted to the red end of the spectrum. The intrinsic photoluminescence of the particles was orders of magnitude weaker and was spectrally separated from the photoluminescence of the glycine dimer ligands. The spectral position of the ligand emission was independent of the particle size; however, the quantum yield of the nanoparticle-ligand system was size-dependent. This was attributed to the enhancement of the ligand's emission caused by the local electric field strength's dependence on the particle size. The maximum quantum yield determined for the nanoparticle-ligand complex was (5.2 ± 0.1) %. The nanoparticles were able to penetrate cell membranes of rat basophilic leukemia and neural stem cells fixed with paraformaldehyde. Additionally, toxicity studies were performed. It was found that towards rat basophilic leukemia cells, luminescent silver nanoparticles had a toxic effect in the silver atom concentration range of 10-100 μM.
authors.affiliation: Physics Department, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. verakravez@gmail.com.|Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. verakravez@gmail.com.|Taras Shevchenko National University of Kyiv, 4 Academic Glushkov Prospect, Kyiv, 01601, Ukraine. verakravez@gmail.com.
authors.forename: Vira
authors.initials: V
authors.lastname: Kravets
authors.affiliation: Mechanical and Aerospace Engineering Department, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. zamawang.almemar@gmail.com.
authors.forename: Zamavang
authors.initials: Z
authors.lastname: Almemar
authors.affiliation: Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. kjiang@uccs.edu.
authors.forename: Ke
authors.initials: K
authors.lastname: Jiang
authors.affiliation: Physics Department, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. kculhane@uccs.edu.|Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. kculhane@uccs.edu.
authors.forename: Kyle
authors.initials: K
authors.lastname: Culhane
authors.affiliation: Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. rmachado@uccs.edu.
authors.forename: Rosa
authors.initials: R
authors.lastname: Machado
authors.affiliation: Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. ghagen@uccs.edu.
authors.forename: Guy
authors.initials: G
authors.lastname: Hagen
authors.affiliation: I.M. Frantsevich Institute for Problems of Material Science, 3 Krzhizhanovsky str., 03680, Kyiv, Ukraine. a.kotko@mail.ru.
authors.forename: Andriy
authors.initials: A
authors.lastname: Kotko
authors.affiliation: Taras Shevchenko National University of Kyiv, 4 Academic Glushkov Prospect, Kyiv, 01601, Ukraine. igor_dmitruk@univ.kiev.ua.
authors.forename: Igor
authors.initials: I
authors.lastname: Dmytruk
authors.affiliation: Physics Department, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. kspendie@uccs.edu.|Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. kspendie@uccs.edu.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Spendier
authors.affiliation: Physics Department, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. apinchuk@uccs.edu.|Center for Biofrontiers Institute, University of Colorado, 1420, Austin Bluffs Parkway, 80918, Colorado Springs, CO, USA. apinchuk@uccs.edu.
authors.forename: Anatoliy
authors.initials: A
authors.lastname: Pinchuk
keywords: Bio-imaging; Nanoparticles; Neural stem cells; Photoluminescence; Plasmon radiative decay; Rat basophilic leukemia cells; Surface plasmon resonance; Surface-enhanced photoluminescence