  We present an electrophoretic platform based on 3D hollow nanoelectrodes
capable of controlling and quantifying the intracellular delivery of single
nanoparticles in single selected cells by surface-enhanced Raman spectroscopy
(SERS). The gold-coated hollow nanoelectrode has a sub-femtoliter inner volume
that allows the confinement and enhancement of electromagnetic fields upon
laser illumination to distinguish the SERS signals of a single nanoparticle
flowing through the nanoelectrode. The tight wrapping of cell membranes around
the nanoelectrodes enables effective membrane electroporation such that single
gold nanorods are delivered into a living cell with a delivery rate subject to
the applied bias voltage. The capability of the 3D hollow nanoelectrodes to
porate cells and reveal single emitters from the background under live flow is
promising for the analysis of both intracellular delivery and sampling.
