Wavelength-dependent differential interference contrast microscopy: selectively imaging nanoparticle probes in live cells.
Gold and silver nanoparticles display extraordinarily large apparent refractive indices near their plasmon resonance (PR) wavelengths. These nanoparticles show good contrast in a narrow spectral band but are poorly resolved at other wavelengths in differential interference contrast (DIC) microscopy. The wavelength dependence of DIC contrast of gold/silver nanoparticles is interpreted in terms of Mie's theory and DIC working principles. We further exploit this wavelength dependence by modifying a DIC microscope to enable simultaneous imaging at two wavelengths. We demonstrate that gold/silver nanoparticles immobilized on the same glass slides through hybridization can be differentiated and imaged separately. High-contrast, video-rate images of living cells can be recorded both with and without illuminating the gold nanoparticle probes, providing definitive probe identification. Dual-wavelength DIC microscopy thus presents a new approach to the simultaneous detection of multiple probes of interest for high-speed live-cell imaging.
Ames Laboratory, U.S. Department of Energy, and Department of Chemistry, Iowa State University, Ames, Iowa, 50011, USA.
Wei
W
Sun
Gufeng
G
Wang
Ning
N
Fang
Edward S
ES
Yeung
D006046:Gold / Q000032:analysis*; D006367:HeLa Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000032:analysis*; D008857:Microscopy, Interference / Q000379:methods*; D010446:Peptide Fragments / Q000737:chemistry*; D012834:Silver / Q000032:analysis*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry*
D010446:Peptide Fragments; D054322:tat Gene Products, Human Immunodeficiency Virus; C497137:tat peptide (47-57), Human immunodeficiency virus 1; D012834:Silver; D006046:Gold