title: Etchable plasmonic nanoparticle probes to image and quantify cellular internalization.
abstract: There is considerable interest in using nanoparticles as labels or to deliver drugs and other bioactive compounds to cells in vitro and in vivo. Fluorescent imaging, commonly used to study internalization and subcellular localization of nanoparticles, does not allow unequivocal distinction between cell surface-bound and internalized particles, as there is no methodology to turn particles 'off'. We have developed a simple technique to rapidly remove silver nanoparticles outside living cells, leaving only the internalized pool for imaging or quantification. The silver nanoparticle (AgNP) etching is based on the sensitivity of Ag to a hexacyanoferrate-thiosulphate redox-based destain solution. In demonstration of the technique we present a class of multicoloured plasmonic nanoprobes comprising dye-labelled AgNPs that are exceptionally bright and photostable, carry peptides as model targeting ligands, can be etched rapidly and with minimal toxicity in mice, and that show tumour uptake in vivo.
authors.affiliation: 1] Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA [2] Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Gary B
authors.initials: GB
authors.lastname: Braun
authors.affiliation: 1] Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA [2] Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Tomas
authors.initials: T
authors.lastname: Friman
authors.affiliation: Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Pang
authors.affiliation: Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Alessia
authors.initials: A
authors.lastname: Pallaoro
authors.affiliation: Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Hurtado de Mendoza
authors.affiliation: Laboratory of Cancer Biology, Institute of Biomedicine, Centre of Excellence for Translational Medicine, University of Tartu, Tartu 50411, Estonia.
authors.forename: Anne-Mari A
authors.initials: AM
authors.lastname: Willmore
authors.affiliation: 1] Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA [2] Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Venkata Ramana
authors.initials: VR
authors.lastname: Kotamraju
authors.affiliation: Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
authors.forename: Aman P
authors.initials: AP
authors.lastname: Mann
authors.affiliation: Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: She
authors.affiliation: Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
authors.forename: Kazuki N
authors.initials: KN
authors.lastname: Sugahara
authors.affiliation: Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Norbert O
authors.initials: NO
authors.lastname: Reich
authors.affiliation: 1] Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA [2] Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA [3] Laboratory of Cancer Biology, Institute of Biomedicine, Centre of Excellence for Translational Medicine, University of Tartu, Tartu 50411, Estonia.
authors.forename: Tambet
authors.initials: T
authors.lastname: Teesalu
authors.affiliation: 1] Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA [2] Center for Nanomedicine and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA.
authors.forename: Erkki
authors.initials: E
authors.lastname: Ruoslahti
mesh_terms: D000818:Animals; D001360:Avidin / Q000737:chemistry; D001692:Biological Transport; D045744:Cell Line, Tumor; D002477:Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D053768:Metal Nanoparticles; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D015335:Molecular Probes / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D011092:Polyethylene Glycols / Q000737:chemistry; D012834:Silver / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity
chemical_list: D015335:Molecular Probes; C093483:neutravidin; D001360:Avidin; D012834:Silver; D011092:Polyethylene Glycols