3D exploration of light scattering from live cells in the presence of gold nanomarkers using holographic microscopy

In this paper, we explore the 3D structure of light scattering from dark-field illuminated live 3T3 cells in the presence of 40 nm gold nanomarkers. For this purpose, we use a high resolution holographic microscope combining the off-axis heterodyne geometry and the phase-shifting acquisition of the digital holograms. A comparative study of the 3D reconstructions of the scattered fields allows us to locate the gold markers which yield, contrarily to the cell structures, well defined bright scattering patterns that are not angularly tilted and clearly located along the optical axis (z). This characterization is an unambiguous signature of the presence of gold biological nanomarkers, and validates the capability of digital holographic microscopy to discriminate them from background signals in live cells. F. Joud Laboratoire Kastler Brossel, École Normale Supérieure, 24 Rue Lhomond, 75005 Paris, France Tel.: +33-1-44-32-35-12 Fax: +33-1-44-32-34-34 E-mail: [email protected] N. Warnasooriya Institut Langevin, ESPCI, 10 Rue Vauquelin, 75005 Paris, France Present address: Dept. of Biomedical Engineering, Texas A&M University, College Station, TX 77843, U.S.A. P. Bun Institut Jacques Monod, Université Paris-Diderot, 15 Rue Hélène Brion, 75205 Paris, France