Investigations on the Use of Laser Dyes as Quantum Counters for Obtaining Corrected Fluorescence Spectra in the Near Infrared

Duggan, JX; DiCesare, Joseph L.; Williams, JF

doi:10.1520/stp31871s

Cited by 11 publications

(11 citation statements)

References 4 publications

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“…73 The relative QE of dye-encapsulating ICG-CPNPs in phosphate buffered 0.15 M saline (PBS) was compared to that of free ICG molecules in the same environment, measured against the near-infrared laser dye hexamethylindotricarbocyanine (HITC) as a reference of known quantum yield (0.28). 74 The measured free ICG QE in high ionic strength, pH 7.4 PBS (0.028 Ϯ 0.001), is likely a result of significant dimerization, consistent with similar reports on aggregate formation. 21 Physically bound ground-state dimers and oligomers act as quenching centers of fluorescence due to the energy transfer between excited and nonexcited states.…”

Section: Resultssupporting

confidence: 89%

Near-Infrared Emitting Fluorophore-Doped Calcium Phosphate Nanoparticles for In Vivo Imaging of Human Breast Cancer

Altınoğlu¹,

et al. 2008

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Early detection is a crucial element for the timely diagnosis and successful treatment of all human cancers but is limited by the sensitivity of current imaging methodologies. We have synthesized and studied bioresorbable calcium phosphate nanoparticles (CPNPs) in which molecules of the near-infrared (NIR) emitting fluorophore, indocyanine green (ICG), are embedded. The ICG-CPNPs demonstrate exceptional colloidal and optical characteristics. Suspensions consisting of 16 nm average diameter particles are colloidally stable in physiological solutions (phosphate buffered 0.15 M saline (PBS), pH 7.4) with carboxylate or polyethylene glycol (PEG) surface functionality. ICG-doped CPNPs exhibit significantly greater intensity at the maximum emission wavelength relative to the free constituent fluorophore, consistent with the multiple molecules encapsulated per particle. The quantum efficiency per molecule of the ICG-CPNPs is 200% greater at 0.049 +/- 0.003 over the free fluorophore in PBS. Photostability based on fluorescence half-life of encapsulated ICG in PBS is 500% longer under typical clinical imaging conditions relative to the free dye. PEGylated ICG-CPNPs accumulate in solid, 5 mm diameter xenograft breast adenocarcinoma tumors via enhanced retention and permeability (EPR) within 24 h after systemic tail vein injection in a nude mouse model. Ex situ tissue imaging further verifies the facility of the ICG-CPNPs for deep-tissue imaging with NIR signals detectable from depths up to 3 cm in porcine muscle tissue. Our ex vivo and in vivo experiments verify the promise of the NIR CPNPs for diagnostic imaging in the early detection of solid tumors.

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Section: Resultssupporting

confidence: 89%

Near-Infrared Emitting Fluorophore-Doped Calcium Phosphate Nanoparticles for In Vivo Imaging of Human Breast Cancer

Altınoğlu¹,

et al. 2008

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“…To minimize the inner filter effects, the optical densities of dye solutions in fluorescence measurements did not exceed 0.1 in the absorption maximum. The fluorescence quantum yields (Φ f ) were determined relative to rhodamine 6G (Φ R = 0.95, ethanol), rhodamine 101 (Φ R = 0.91, acidified EtOH), indodicarbocyanine iodide (Φ R = 0.4, methanol), and indotricarbocyanine iodide (Φ R = 0.28, EtOH) . The values of Φ f were corrected taking into account refractive indexes of the solvents, , where Φ R is the fluorescence quantum yield of a fluorescent standard, I and I R are the fluorescence intensities of a tested compound and the fluorescent standard correspondingly (the areas of their fluorescence bands), A and A R are the optical densities of two solutions at the excitation wavelength, η and η R are refractive indexes of two solutions.…”

Section: Methodsmentioning

confidence: 99%

“…The fluorescence quantum yields (Φ f ) were determined relative to rhodamine 6G (Φ R = 0.95, ethanol), 22 rhodamine 101 (Φ R = 0.91, acidified EtOH), 23 indodicarbocyanine iodide (Φ R = 0.4, methanol), 24 and indotricarbocyanine iodide (Φ R = 0.28, EtOH). 25 The values of Φ f were corrected taking into account refractive indexes of the solvents,…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Highly Fluorescent Dianionic Polymethines with a 1,3,2-Dioxaborine Core

et al. 2021

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The difluoroboron β-diketonate ring is ever more used for creating bright polymethine-type fluorophores for the visible and NIR range. Here, we report the synthesis and spectral properties of a series of dianionic cyanine dyes of the rare A1–π–A−π–A1 type, with the central dioxaborine ring (A) embedded into the polymethine chain and various electron-acceptor terminal groups A1. Depending on the nature of the end group, the maxima of their intensive (with molar extinctions up to 380 000 M–1 cm–1) and narrow long-wavelength absorption band lie in the range of 530–770 nm. Their absorption and fluorescence bands are nearly mirror-like and characterized by weak solvatochromism; the marked hypsochromic shifts are observed only when going from polar aprotic solvents to methanol. The designed dianionic dyes have fluorescence quantum yields up to 92 % in the visible range, and even for the NIR dyes, the values of 18–37 % are observed in DMF.

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“…Fluorescence and excitation spectra were recorded with a Shimadzu RF‐500 spectrofluorimeter with appropriate filters to eliminate scattered light. Fluorescence quantum yields ( Φ F ) were determined by use of free‐base tetraphenylporphyrin in benzene ( Φ F = 0.11),46a tetra‐ tert ‐butylated tetrabenzoporphyrin in chloroform ( Φ F = 0.57),46b or 1,3,3,1′,3′,3′‐hexamethylindotricarbocyanine in DMSO ( Φ F = 0.28)46c as standards. Data were obtained by a comparative calibration method, by use of the same excitation wavelength and absorbance for the metal‐free samples and the calibrants, as well as the same emission energies.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, Spectroscopy, and Electrochemistry of Tetra‐tert‐butylated Tetraazaporphyrins, Phthalocyanines, Naphthalocyanines, and Anthracocyanines, together with Molecular Orbital Calculations

Kobayashi

Nakajima

Ogata

et al. 2004

Chemistry A European J

171

149

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Tetraazaporphyrins (TAPs), phthalocyanines (Pcs), naphthalocyanines (Ncs), and anthracocyanines (Acs) with four tert-butyl groups attached at similar positions have been synthesized, and their electronic absorption, magnetic circular dichroism (MCD), IR, and voltammetric properties were studied and interpreted with the help of quantum-mechanical calculations. Through the preparation of a series of compounds with the same number of the same substituent, the effects of the increase in the size of the ring system were clearly derived. The main results may be summarized as follows. 1) The Q band shifts to longer wavelength and its intensity increases, but with decreasing degree of change with increasing molecular size. If the size of the effect of benzene directly fused to the TAP skeleton is set at unity, the effects of the second and third benzene units are roughly 0.8 and 0.5, respectively. 2) The splitting of the Q bands in metal-free compounds decreases with increasing molecular size, so that the Q bands of H2Nc and H2Ac appear as single bands. 3) The magnitude of the orbital angular momentum of the excited state of the ligand decreases with increasing molecular size. 4) Interestingly, the ring current, as judged from the positions of pyrrole proton signals in the 1H NMR spectrum, appears to decrease with increasing molecular size. 5) The first reduction potential becomes less negative, but only slightly, whereas the first oxidation potential shows a marked shift to less positive values with increasing molecular size, indicating that the HOMO destabilizes significantly as the molecule becomes larger. 6) In 5), the extent of the HOMO destabilization with molecular size differs depending on the central metal, so metals producing smaller destabilization effects can allow larger macrocycles. Of the metals studied, the most effective is cobalt, and the practical size limit is represented by the Acs. 7) The IR spectra become simpler the larger the molecule, and the main bands were assigned by DFT calculations. 8) The trend in experimentally determined redox potentials and electronic absorption and MCD spectra were reasonably reproduced by MO calculations using the ZINDO/S Hamiltonian. 9) EPR data for several metallocomplexes are also reported.

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Investigations on the Use of Laser Dyes as Quantum Counters for Obtaining Corrected Fluorescence Spectra in the Near Infrared

Cited by 11 publications

References 4 publications

Near-Infrared Emitting Fluorophore-Doped Calcium Phosphate Nanoparticles for In Vivo Imaging of Human Breast Cancer

Near-Infrared Emitting Fluorophore-Doped Calcium Phosphate Nanoparticles for In Vivo Imaging of Human Breast Cancer

Highly Fluorescent Dianionic Polymethines with a 1,3,2-Dioxaborine Core

Synthesis, Spectroscopy, and Electrochemistry of Tetra‐tert‐butylated Tetraazaporphyrins, Phthalocyanines, Naphthalocyanines, and Anthracocyanines, together with Molecular Orbital Calculations

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