Aggregation and photobleaching of merocyanine 540 as probed by resonance light scattering

Kozhinova, E. A.; Tikhomirova, Anna; Kozyr, L. A.; Kyagova, Alla A.; Potapenko, A. Ya.

doi:10.1134/s0036024407080286

Cited by 4 publications

(7 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, control experiments assessing differences in probe excited-state lifetimes at long and short wavelengths (as well as high and low temperature) confirmed that the changes in steady-state anisotropy observed in Figures 1 and 2 were explained mostly by differences in probe rotational rates (rather than lifetime). Although these observations and those regarding emission spectra (Figures 1, 2, and 4) corroborate the previous idea that MC540 dimers are fluorescent only in highly packed interfaces [16,17,36], they introduce the novel finding of strong dependence on the L c ' phase.…”

Section: Discussionsupporting

confidence: 86%

“…Merocyanine 540 has a negatively-charged sulfate group that creates a permanent dipole moment which affects the binding locations of the probe and its tendency to exist as either monomers or dimers in the membrane [36]. The monomeric form of MC540 resides near the lipid head groups at an orientation parallel to the phospholipid chains [16].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Combined Use of Steady-State Fluorescence Emission and Anisotropy of Merocyanine 540 To Distinguish Crystalline, Gel, Ripple, and Liquid Crystalline Phases in Dipalmitoylphosphatidylcholine Bilayers

Franchino

Bell

2010

Biophysical Journal

View full text Add to dashboard Cite

The various lamellar phases of dipalmitoylphosphadtidylcholine bilayers with and without cholesterol were used to assess the versatility of the fluorescent probe merocyanine 540 through simultaneous measurements of emission intensity, spectral shape, and steady-state anisotropy. Induction of the crystalline phase (L c ') by preincubation at 4°C produced a wavelength dependence of anisotropy which was strong at 15 and 25°C, weak at 38°C, and minimal above the main transition (>~41.5°C) or after returning the temperature from 46 to 25°C. The profile of anisotropy values across this temperature range revealed the ability of the probe to detect crystalline, gel (L β '), and liquid crystalline (L α ) phases. The temperature dependence of fluorescence intensity was additionally able to distinguish between the ripple (P β ') and gel phases. In contrast, the shape of the emission spectrum, quantified as the ratio of merocyanine monomer and dimer peaks (585 and 621 nm), was primarily sensitive to the crystalline and gel phases because dimer fluorescence requires a highly-ordered environment. This requirement also explained the diminution of anisotropy wavelength dependence above 25°C. Repetition of experiments with vesicles containing cholesterol allowed creation of a phase map. Superimposition of data from the three simultaneous measurements provided details about the various phase regions in the map not discernible from any one of the three alone. The results were applied to assessment of calcium-induced membrane changes in living cells.

show abstract

Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Combined Use of Steady-State Fluorescence Emission and Anisotropy of Merocyanine 540 To Distinguish Crystalline, Gel, Ripple, and Liquid Crystalline Phases in Dipalmitoylphosphatidylcholine Bilayers

Franchino

Bell

2010

Biophysical Journal

View full text Add to dashboard Cite

show abstract

“…Moreover, control experiments assessing differences in probe excited-state lifetimes at long and short wavelengths (as well as high and low temperature) confirmed that the changes in steady-state anisotropy observed in Figures 1 and 2 were explained mostly by differences in probe rotational rates (rather than lifetime). Although these observations and those regarding emission spectra (Figures 1 , 2 , and 4 ) corroborate the previous idea that MC540 dimers are fluorescent only in highly packed interfaces [ 16 , 17 , 36 ], they introduce the novel finding of strong dependence on the L c ' phase.…”

Section: Discussionsupporting

confidence: 86%

“…Merocyanine 540 has a negatively-charged sulfate group that creates a permanent dipole moment which affects the binding locations of the probe and its tendency to exist as either monomers or dimers in the membrane [ 36 ]. The monomeric form of MC540 resides near the lipid head groups at an orientation parallel to the phospholipid chains [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Combined use of steady-state fluorescence emission and anisotropy of merocyanine 540 to distinguish crystalline, gel, ripple, and liquid crystalline phases in dipalmitoylphosphatidylcholine bilayers

et al. 2010

View full text Add to dashboard Cite

The various lamellar phases of dipalmitoylphosphadtidylcholine bilayers with and without cholesterol were used to assess the versatility of the fluorescent probe merocyanine 540 through simultaneous measurements of emission intensity, spectral shape, and steady-state anisotropy. Induction of the crystalline phase (Lc') by pre-incubation at 4°C produced a wavelength dependence of anisotropy which was strong at 15 and 25°C, weak at 38°C, and minimal above the main transition (>~41.5°C) or after returning the temperature from 46 to 25°C. The profile of anisotropy values across this temperature range revealed the ability of the probe to detect crystalline, gel (Lβ'), and liquid crystalline (Lα) phases. The temperature dependence of fluorescence intensity was additionally able to distinguish between the ripple (Pβ') and gel phases. In contrast, the shape of the emission spectrum, quantified as the ratio of merocyanine monomer and dimer peaks (585 and 621 nm), was primarily sensitive to the crystalline and gel phases because dimer fluorescence requires a highly-ordered environment. This requirement also explained the diminution of anisotropy wavelength dependence above 25°C. Repetition of experiments with vesicles containing cholesterol allowed creation of a phase map. Superimposition of data from the three simultaneous measurements provided details about the various phase regions in the map not discernible from any one of the three alone. The results were applied to assessment of calcium-induced membrane changes in living cells.PACS Codes: 87.16.dt

show abstract

“…Then the recorded RLS spectra were corrected for internal light filter effect and for the sensitivity of the spectrofluorimeter (27). A 5 μ m aqueous solution of merocyanine 540 (MC540, Sigma) was used as an aggregation positive control (27,29).…”

mentioning

confidence: 99%

Fully Protected Glycosylated Zinc (II) Phthalocyanine Shows High Uptake and Photodynamic Cytotoxicity in MCF‐7 Cancer Cells

Kimani

Shmigol

Hammond

et al. 2012

Photochem & Photobiology

View full text Add to dashboard Cite

Phthalocyanine photosensitizers are effective in anticancer photodynamic therapy (PDT) but suffer from limited solubility, limited cellular uptake and limited selectivity for cancer cells. To improve these characteristics, we synthesized isopropylidene-protected and partially deprotected tetra β-glycosylated zinc (II) phthalocyanines and compared their uptake and accumulation kinetics, subcellular localization, in vitro photocytotoxicity and reactive oxygen species generation with those of disulfonated aluminum phthalocyanine. In MCF-7 cancer cells, one of the compounds, zinc phthalocyanine {4}, demonstrated 10-fold higher uptake, 5-fold greater PDT-induced cellular reactive oxygen species concentration and 2-fold greater phototoxicity than equimolar (9 μm) disulfonated aluminum phthalocyanine. Thus, isopropylidene-protected β-glycosylation of phthalocyanines provides a simple method of improving the efficacy of PDT.

show abstract

Aggregation and photobleaching of merocyanine 540 as probed by resonance light scattering

Cited by 4 publications

References 17 publications

Combined Use of Steady-State Fluorescence Emission and Anisotropy of Merocyanine 540 To Distinguish Crystalline, Gel, Ripple, and Liquid Crystalline Phases in Dipalmitoylphosphatidylcholine Bilayers

Combined Use of Steady-State Fluorescence Emission and Anisotropy of Merocyanine 540 To Distinguish Crystalline, Gel, Ripple, and Liquid Crystalline Phases in Dipalmitoylphosphatidylcholine Bilayers

Combined use of steady-state fluorescence emission and anisotropy of merocyanine 540 to distinguish crystalline, gel, ripple, and liquid crystalline phases in dipalmitoylphosphatidylcholine bilayers

Fully Protected Glycosylated Zinc (II) Phthalocyanine Shows High Uptake and Photodynamic Cytotoxicity in MCF‐7 Cancer Cells

Contact Info

Product

Resources

About