Abstract

Noble metal immunolabels targeted at specific cell surface receptors have traditionally been used in electron microscopy to map spatial receptor distributions. Herein, we introduce a multispectral imaging approach to obtain information about the spatial organization of the nanoparticle labels in an optical microscope. The assay utilizes the fact that the optical far-field response of the labels encode information about the interparticle separation due to distance dependent plasmon coupling interactions. A calibration of the multispectral response of nanoparticle clusters of defined sizes enables an approximate sizing of nanoparticle clusters on the cellular surface and provides quantitative information about the spatial organization of the nanoparticle labels and thus of the labeled receptors on the cell surface.

© 2011 Optical Society of America