This paper describes an imaging microscopic technique based on heterodyne
digital holography where subwavelength-sized gold colloids can be imaged in
cell environment. Surface cellular receptors of 3T3 mouse fibroblasts are
labeled with 40 nm gold nanoparticles, and the biological specimen is imaged in
a total internal reflection configuration with holographic microscopy. Due to a
higher scattering efficiency of the gold nanoparticles versus that of cellular
structures, accurate localization of a gold marker is obtained within a 3D
mapping of the entire sample's scattered field, with a lateral precision of 5
nm and 100 nm in the x,y and in the z directions respectively, demonstrating
the ability of holographic microscopy to locate nanoparticles in living cells
environments