The use of gold nanowires conjugated with cytokine has been demonstarted as a transport and delivery agent at the subcellular level by a team led by C. L. Chien and Andre Levchenko, Johns Hopkins University, USA.

They used electrophoretic and dielectrophoretic forces to guide the nanowire along a prescribed trajectory to a specific location. The nanowires could be transported forwards and backwards along a zig-zag trajectory and restored to their original locations within microns.

The tumor-necrosis factor-alpha activated canonical nuclear factor-kappaB signalling in a single cell and stimulation was shown to be highly localized to the nanowire vicinity.

This precise delivery of molecular doses of biologically active chemicals to a pre-specified single cell among many could allow individual cell manipulation and targeted intervention.

• Subcellular-resolution delivery of a cytokine through precisely manipulated nanowires
  D. Fan, Z. Yin, R. Cheong, F. Q. Zhu, R. C. Cammarata, C. L. Chien, A. Levchenko,
  Nat. Nanotechnol. 2010, 5.
   DOI: 10.1038/nnano.2010.104