Depolarization signatures map GNRs in tissue in vivo
Lippok et al.
Owing to their electromagnetic properties, tunability and biocompatibility, gold nanorods are being investigated as multifunctional probes for a range of biomedical applications. However, detection beyond the reach of traditional fluorescence and two-photon approaches and quantitation of their concentration in biological tissue remain challenging tasks in microscopy. Here, we show how the size and aspect ratio that impart gold nanorods with their plasmonic properties also make them a source of entropy. We report on how depolarization can be exploited as a strategy to visualize gold nanorod diffusion and distribution in biologically relevant scenarios ex vivo, in vitro and in vivo. We identify a deterministic relation between depolarization and nanoparticle concentration. As a result, some of the most stringent experimental conditions can be relaxed, and susceptibility to artefacts is reduced, enabling microscopic and macroscopic applications.
N. Lippok, M. Villiger, A. Albanese, E. F. J. Meijer, K. Chung, T. P. Padera, S. N. Bhatia, B. E. Bouma, “Depolarization signatures map gold nanorods within biological tissue,” Nature Photonics 11, 583 (2017).