Sub-Cellular Resolution Delivery of a Cytokine via Precisely Manipulated Nanowires

Precise delivery of molecular doses of biologically active chemicals to a pre-specified single cell among many, or a specific sub-cellular location, is still a largely unmet challenge hampering our understanding of cell biology. Overcoming this could allow unprecedented levels of cell manipulation and targeted intervention. Here, we show that gold nanowires conjugated with cytokine, such as tumour necrosis factor-alpha (TNFα), can be transported along any prescribed trajectory or orientation using electrophoretic and dielectrophoretic forces to a specific location with subcellular resolution. The nanowire, 6 μm long and 300 nm in diameter, delivered the cytokine and activated canonical nuclear factor-kappaB signaling in a single cell. Combined computational modeling and experimentation indicated that cell stimulation was highly localized to the nanowire vicinity. This targeted delivery method has profound implications for controlling signaling events on the single cell level.