Hyperspectral molecular imaging of multiple receptors using immunolabeled plasmonic nanoparticles

This work presents simultaneous imaging and detection of three types of cell receptors using three types of plasmonic nanoparticles. The size, shape, and composition-dependent scattering profiles of these particles allow for a system of multiple distinct molecular markers using a single optical source. With this goal in mind, a system of tags consisting of anti-EGFR gold nanorods, anti-IGF1R silver nanospheres, and anti-HER-2 gold nanospheres was developed for monitoring the expression of three commonly overexpressed receptors in cancer cells. These labels were chosen because they each scatter strongly in a distinct spectral window. A hyperspectral dark-field microscope was developed to record the scattering spectra of cells labeled with these molecular tags. The ability to monitor multiple tags simultaneously may lead to applications such as profiling the immunophenotype of cell lines and gaining better knowledge of receptor signaling pathways. Single, dual, and triple tag experiments were performed to analyze the specificity of the nanoparticle tags as well as their effect on one another. While distinct resonance peaks in these studies show the ability to characterize cell lines using conjugated nanoparticles, shifts in these peaks also indicate changes in the cellular dielectric environment which may not be distinct from plasmon coupling between nanoparticles bound to proximal receptors.