title: Nanoparticle-enhanced infrared neural  stimulation.
abstract: OBJECTIVE
  Recent research has demonstrated that nerves can be stimulated by transient heating associated with the absorption of infrared light by water in the tissue. There is a great deal of interest in using this technique in neural prostheses, due to the potential for increased localization of the stimulus and minimization of contact with the tissue. However, thermal modelling suggests that the full benefits of increased localization may be reduced by cumulative heating effects when multiple stimulus sites and/or high repetition rates are used.
  
  
  METHODS
  Here we review recent in vitro and in vivo results suggesting that the transient heating associated with plasmon absorption in gold nanorods can also be used to stimulate nerves.
  
  
  RESULTS
  Patch clamp experiments on cultured spiral ganglion neurons exhibited action potentials when exposed to 780 nm light at the plasmon absorption peak, while the amplitude of compound action potentials in the rat sciatic nerve were increased by laser irradiation of gold nanorods in the vicinity of the plasma membrane. Similarly, calcium imaging studies of NG108-15 neuronal cells incubated with Au nanorods revealed an increased level of intracellular calcium activity synchronized with laser exposure.
  
  
  CONCLUSIONS
  Given that the plasmon absorption peak of gold nanorods can be matched with the transparency window of biological tissues, these results demonstrate that nanorod absorbers hold great promise to enhance the process of infrared neural stimulation for future applications in neural prostheses and fundamental studies in neuroscience.
authors.forename: Chiara
authors.initials: C
authors.lastname: Paviolo
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Thompson
authors.forename: Jiawey
authors.initials: J
authors.lastname: Yong
authors.forename: William G A
authors.initials: WG
authors.lastname: Brown
authors.forename: Paul R
authors.initials: PR
authors.lastname: Stoddart
mesh_terms: D000818:Animals; D006046:Gold / Q000008:administration & dosage*; D006801:Humans; D007259:Infrared Rays / Q000627:therapeutic use*; D053685:Laser Therapy / Q000379:methods* / Q000639:trends; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D020349:Surface Plasmon Resonance / Q000379:methods* / Q000639:trends
chemical_list: D006046:Gold