title: Long-wavelength, photostable, two-photon excitable BODIPY fluorophores readily modifiable for molecular probes.
abstract: Near-infrared (NIR) fluorescent probes are increasingly popular in biological imaging and sensing, as long-wavelength (650-900 nm) excitation and emission have the advantages of minimum photodamage, deep tissue penetration, and minimum interference from autofluorescence in living systems. Here, a series of long-wavelength BODIPY dyes SPC, DC-SPC, DPC, and DC-DPC are synthesized conveniently and efficiently. They exhibit excellent photophysical properties in far red to near-infrared region, including large extinction coefficients, high fluorescence quantum yields, good photostability, and reasonable two-photon absorption cross section. Comparison of single-molecular imaging confirms that DPC is a much more efficient and more photostable NIR fluorophore than the commonly used Cy5. Also importantly, two kinds of convenient functionalization sites have been reserved: the aryl iodide for organometallic couplings and the terminal alkyne groups for click reactions. Further derivatives DC-SPC-PPh3 exhibit specificity to localize in mitochondria. The introduction of triphenylphosphonium (TPP) moieties mediates its hydrophilic-lipophilic balance and makes DC-SPC-PPh3 appropriate for cell labeling. Their long-wavelength emission at ∼650 nm can efficiently avoid the spectral crosstalk with other probes emitting in the visible light region. Superior photostability, low cytotoxicity, and two-photon excitable properties demonstrate its utility as a standard colocalizing agent to estimate the other probes' local distribution.
authors.affiliation: State Key Laboratory of Fine Chemicals, Dalian University of Technology , 2 Linggong Road, Dalian 116024, People's Republic of China.
authors.forename: Xinfu
authors.initials: X
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
authors.forename: Jing
authors.initials: J
authors.lastname: Qi
authors.forename: Junle
authors.initials: J
authors.lastname: Qu
authors.forename: Bosung
authors.initials: B
authors.lastname: Kim
authors.forename: Xiling
authors.initials: X
authors.lastname: Yue
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Belfield
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D015394:Molecular Structure; D055668:Photochemical Processes; D017785:Photons
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D005456:Fluorescent Dyes