title: FRET enhanced fluorescent nanodiamonds.
abstract: Fluorescent nanodiamonds (FNDs) are one of the new and very promising biocompatible nanomaterials that can be used both as a fluorescence imaging agent and a highly versatile platform for controlled functionalization to target and deliver a wide spectrum of therapeutic agents. Among the remarkable fluorescence properties are excellent photostability, emission between 600-700nm, quantum yield of 1 and moderately long fluorescence lifetimes. However the low absorption cross section of fluorescent (N-V)(-) centers limits FNDs' brightness. In this work we show that an approach based on the Forster resonance energy transfer (FRET) may significantly enhance the fluorescence signal observed from a single ND. We demonstrate that organic dyes (fluorophores) attached to the FND surface can efficiently transfer the excitation energy to (N-V)(-) centers. Multiple dyes positioned in close proximity to the ND facile surface may serve as harvesting antennas transferring excitation energy to the fluorescent centers. We propose that, with the help of some of the functional groups present on the FND surface, we can either directly link flurophores or use scalable dendrimer chemistry to position many organic dyes at a calibrated distance. Also, the remaining multiple functional groups will be still available for particle targeting and drug delivery. This opens a new way for designing a new type of theranostics particles of ultrahigh brightness, high photostability, specific targeting, and high capacity for drug delivery.
authors.forename: Rafal
authors.initials: R
authors.lastname: Fudala
authors.forename: Sangram
authors.initials: S
authors.lastname: Raut
authors.forename: Badri P
authors.initials: BP
authors.lastname: Maliwal
authors.forename: T W
authors.initials: TW
authors.lastname: Zerda
authors.forename: Ignacy
authors.initials: I
authors.lastname: Gryczynski
authors.forename: Eric
authors.initials: E
authors.lastname: Simanek
authors.forename: Julian
authors.initials: J
authors.lastname: Borejdo
authors.forename: Ryan
authors.initials: R
authors.lastname: Rich
authors.forename: Irina
authors.initials: I
authors.lastname: Akopova
authors.affiliation: Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129, USA. zgryczynski@tcu.edu.
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Gryczynski
mesh_terms: D018130:Diamond / Q000737:chemistry*; D016650:Fluorescein-5-isothiocyanate; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes; D018613:Microscopy, Confocal; D049329:Nanostructures / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005456:Fluorescent Dyes; D012710:Serum Albumin, Bovine; D018130:Diamond; D016650:Fluorescein-5-isothiocyanate