Fig. 1.

Optical stimulation of neuron using surface-modified GNRs. (a) Streptavidin coated gold nanorods (GNRs) are delivered to the neuron by biotinylated anti-Thy-1 antibody that bind to an epitope from external neuronal membrane. Localized heat from strongly bound GNRs could elicit neuronal depolarization. (b) TEM image reveals that average geometric dimensions of GNRs are 80.4 nm in length and 15.3 nm in width. Optical extinction spectrum of GNRs shows a longitudinal absorption peak at λ = 977 nm. (c) The phase contrast microscope image shows a typical hippocampal neural cell after 18 days in vitro. Cell bodies as well as axons can be distinguished morphologically. (d) After neuronal membrane is tagged by biotinylated anti-Thy1.1 antibody, streptavidin-coated GNRs are incubated to form a strong binding with biotinylated antibody. Biotinylated FITC is used to observe the distribution of streptavidin-coated GNRs. Scale bar, 100 μm in (c) and (d).