Intracellular p53 detection in a single living HeLa cell with FTP.
(a), Schematic set-up of the FTP system. The probe, consisting of a nanorod immobilized on the sub-100 nm tapered tip of an optical fiber, is inserted into a single living cell at designated positions using a three-axis micromanipulator. (b), Sequence of EMCCD images of a FTP penetrating a single HeLa cell, viewed from below. The FTP was first positioned outside the cell with its tip lying slightly flat against the petri dish substrate. It is then punctured into the side of the cell. Without background illumination, we could clearly see the LSPR signal from the nanorod glowing inside the cell. (c), p53 dynamics in the intact, UV exposed and NCS treated HeLa cells. The p53 showed sustained concentration increase under UV and pulsed oscillation under NCS. (d), Phase-contrast and fluorescent image of cells that have been punctured by FTP. A cell in the green circle fluoresced in green after treatment with calcein viability dye and thus was alive after a series of measurement (8 hours long) with nanosize FTP. The cell showed similar levels of green fluorescence intensity indicating the viability of both poked and intact cells. However, a cell in the white circle was dead after being punctured once by a FTP with 5-micrometer tip in diameter.