Development of drug-injection system using plasmonic endoscopy toward single cell study.

In biology and biomedical research, where the microscopic organization of proteins and other molecules play a key role in the functioning of cells and organisms, it is imperative to zoom into the single cell and look at the underlying processes. Fluorescence-based microscopy techniques have been developed to get superresolution images of the structural organization inside living cells with resolution down to 10-50 nm. But these techniques rely on labeling of the bio-system with suitable fluorophores, and so label-free techniques like Raman imaging etc are important although yet to be implemented. Mechanical insertion of a needle into single-cells, know as single cell endoscopy, has been recognized as a useful technique for gene/drug delivery, bio-sensing, and single-cell electrophysiology etc. While large conical pipettes or tapered optical fibers have been widely used for such purpose, their insertion through the plasma membrane often causes cell damage. Recently, researchers have found thin 1D nanowires to be useful alternative to avoid such damage. In this project, I propose to use nanometer-scaled 1D metal nanowire for single-cell endoscopy. Metal nanowires offer two main advantages: (1) possibility to reduce its diameter to < 100 nm with enough strength, (2) subwavelegth plasmonic waveguiding that allows for optical access to the inside a single cell. In this project, the applicants will establish molecular injection system using plasmonic waveguide-based endoscopy.