High signal-to-noise, non-bleaching imaging with plasmonic nanoparticles

Conventional biological imaging typically relies on either spatial or temporal modulation which are limited by fluorophores undergoing photobleaching. As a result, imaging of biological processes for extended periods of time remains a challenge. To overcome this limitation, we introduce polarization modulation combined with nonbleaching plasmonic nanoparticles to boost signal-to-noise ratio and to eliminate strong background scattering. We show plasmonic nanoparticles can be extracted from the noisy background and cellular environment, where the visualization of nanoparticles has been previously hindered by the strongly scattering biological components. We demonstrate that such a reduction of background noise level greatly enhances the overall signal-to-noise ratio of nanoparticles within biological structures.