For optical diagnosis of the human body, using near infrared (NIR) has several advantages: NIR penetrates into the tissue deeper than UV or visible light, and in NIR most of the tissue-originated fluorescence may be avoided. Although NIR fluorophores are valuable, only a few can be used for humans and they have relatively low quantum yields. If the fluorescence emission of NIR fluorophores can be artificially enhanced, it can increase the sensitivity of optical diagnosis. In addition, conditionally emitted contrast agents as in Förster resonance energy transfer (FRET) or molecular beacon can be developed. One way of artificially changing fluorescence is by applying an electric field to the fluorophore. An excellent way of generating the field is via the plasmon field by gold nanoparticles (GNPs) upon the receipt of the excitation light of the fluorophore to be used. In this paper, the mechanism of the fluorescence manipulation for an NIR fluorophore, Cypate, by GNPs is studied both theoretically and experimentally.
Ethylene Glycol Hydrochloride Carbodiimide
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The authors acknowledge the financial support from the U.S. Army Breast Cancer Program.
Benson RC, Kues HA (1978) Fluorescence properties of indocyanine green as related to angiography. Phys Med Biol 23:159–163PubMedCrossRefGoogle Scholar
Kang KA, Hong B (2006) Biocompatible nano-metal particle fluorescence enhancers. Crit Rev Eukaryot Gene Expr 16:45–60PubMedCrossRefGoogle Scholar
Wang J, Nantz MH, Achilefu S, Kang KA (2010) FRET-like fluorophore-nanoparticle complex for highly specific cancer localization. Adv Exp Med Biol 662:407–414PubMedCrossRefGoogle Scholar
Neeves AE, Birnboim MH (1989) Composite structures for the enhancement of nonlinear-optical susceptibility. J Opt Soc Am B 6:787–796CrossRefGoogle Scholar
Bharadwaj P, Anger P, Novotny L (2007) Nanoplasmonic enhancement of single-molecule fluorescence. Nanotechnology 18:044017CrossRefGoogle Scholar
Achilefu S, Dorshow R, Bugaj J, Rajagopalan R (2000) Novel receptor-targeted fluorescent contrast agents for in vivo tumor imaging. Invest Radiol 35:479–485PubMedCrossRefGoogle Scholar
Schneider G, Decher G, Nerambourg N, Praho R, Werts MHV, Blanchard-Desce M (2006) Distance-dependent fluorescence quenching on gold nanoparticles ensheathed with layer-by-layer assembled polyelectrolytes. Nano Lett 6:530–536PubMedCrossRefGoogle Scholar
Anger P, Bharadwaj P, Novotny L (2006) Enhancement and quenching of single-molecule fluorescence. Phys Rev Lett 96:113002PubMedCrossRefGoogle Scholar
Davis ME, Chen Z, Shin DM (2008) Nanoparticle therapeutics: an emerging treatment modality for cancer. Nat Rev Drug Discov 7:771–782PubMedCrossRefGoogle Scholar
Jiang W, Kim BYS, Rutka JT, Chan WCW (2008) Nanoparticle-mediated cellular response is size-dependent. Nat Nanotechnol 3:145–150PubMedCrossRefGoogle Scholar
Tyagi S, Kramer FR (1996) Molecular beacons: probes that fluoresce upon hybridization. Nat Biotechnol 14:303–308PubMedCrossRefGoogle Scholar