title: Laser-targeted photofabrication of gold nanoparticles inside cells.
abstract: Nanoparticle manipulation is of increasing interest, since they can report single molecule-level measurements of the cellular environment. Until now, however, intracellular nanoparticle locations have been essentially uncontrollable. Here we show that by infusing a gold ion solution, focused laser light-induced photoreduction allows in situ fabrication of gold nanoparticles at precise locations. The resulting particles are pure gold nanocrystals, distributed throughout the laser focus at sizes ranging from 2 to 20 nm, and remain in place even after removing the gold solution. We demonstrate the spatial control by scanning a laser beam to write characters in gold inside a cell. Plasmonically enhanced molecular signals could be detected from nanoparticles, allowing their use as nano-chemical probes at targeted locations inside the cell, with intracellular molecular feedback. Such light-based control of the intracellular particle generation reaction also offers avenues for in situ plasmonic device creation in organic targets, and may eventually link optical and electron microscopy.
authors.affiliation: 1] Biophotonics Laboratory, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan [2] PRESTO, Japan Science and Technology Agency (JST), Chiyodaku, Tokyo 102-0075, Japan.
authors.forename: Nicholas I
authors.initials: NI
authors.lastname: Smith
authors.affiliation: Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Mochizuki
authors.affiliation: Department of Mechanical Science and Bioengineering, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Niioka
authors.affiliation: Institute for NanoScience Design, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ichikawa
authors.affiliation: Biophotonics Laboratory, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Pavillon
authors.affiliation: Biophotonics Laboratory, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Hobro
authors.affiliation: Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ando
authors.affiliation: Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Host Defense Laboratory, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Kumagai
mesh_terms: D006046:Gold; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction
chemical_list: D006046:Gold