Formation of fluorescent H-aggregates of a cyanine dye in ultrathin film and its effect on energy transfer

Chakraborty, Santanu; Debnath, Pintu; Dey, Dibyendu; Bhattacharjee, D.; Hussain, Syed Arshad

doi:10.1016/j.jphotochem.2014.07.018

Cited by 41 publications

(13 citation statements)

References 39 publications

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“…This 410 nm absorption band in the NK LB films has been assigned as due to H-dimer absorption by several other authors (Hussain and Schoonheydt, 2010a;and Yamaguchi et al, 2005). It is worthwhile to mention in this context that in several other work using cyanine dyes, high-energy shoulder of H-dimer along with the monomeric band was observed (Kushida et al, 2008 andChakraborty et al, 2014). On the other hand, the absorption spectra of monolayer NK LB films possess a prominent peak at 461 nm and a weak hump at 433 nm.…”

Section: Spectroscopic Characterizationmentioning

confidence: 51%

Temperature and concentration dependence of J-aggregate of a cyanine dye in a Laponite film fabricated by Langmuir–Blodgett technique

Chakraborty

Bhattacharjee

Soda

et al. 2015

Applied Clay Science

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Section: Spectroscopic Characterizationmentioning

confidence: 51%

Temperature and concentration dependence of J-aggregate of a cyanine dye in a Laponite film fabricated by Langmuir–Blodgett technique

Chakraborty

Bhattacharjee

Soda

et al. 2015

Applied Clay Science

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“…Free DiR dispersed in mouse serum showed no fluorescence (Figure S2) due to the formation of H-aggregates. 21, 24-26 These results indicate that DiR fluorescence can represent NPs in physiological fluid such as serum and blood. Therefore, DiR was chosen as a fluorescence marker of NPs for tracking their distribution in tumor-bearing mice.…”

Section: Resultsmentioning

confidence: 87%

“…Upon incubation in mouse serum, ICG was quickly released from the NPs and detected in the supernatant as early as in 10 min, whereas DiR was stably retained in the NPs over 6 h (duration of the observation) (Figure S1). Free DiR dispersed in mouse serum showed no fluorescence (Figure S2) due to the formation of H-aggregates. ,− These results indicate that DiR fluorescence can represent NPs in physiological fluid such as serum and blood. Therefore, DiR was chosen as a fluorescence marker of NPs for tracking their distribution in tumor-bearing mice.…”

Section: Resultsmentioning

confidence: 94%

Quantitative Assessment of Nanoparticle Biodistribution by Fluorescence Imaging, Revisited

et al. 2018

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Fluorescence-based whole body imaging is widely used in the evaluation of nanoparticles (NPs) in small animals, often combined with quantitative analysis to indicate their spatiotemporal distribution following systemic administration. An underlying assumption is that the fluorescence label represents NPs and the intensity increases with the amount of NPs and/or the labeling dyes accumulated in the region of interest. We prepare DiR-loaded poly(lactic-co-glycolic acid) (PLGA) NPs with different surface layers (polyethylene glycol with and without folate terminus) and compare the distribution of fluorescence signals in a mouse model of folate-receptor expressing tumor by near infrared fluorescence whole body imaging. Unexpectedly, we observe that fluorescence distribution patterns differ far more dramatically with DiR loading than with the surface ligand, reaching opposite conclusions with the same type of NPs (tumor-specific delivery vs. predominant liver accumulation). Analysis of DiR-loaded PLGA NPs reveal that fluorescence quenching, dequenching and signal saturation, which occur with the increasing dye content and local NP concentration, are responsible for the conflicting interpretations. This study highlights the critical need for validating fluorescence labeling of NPs in the quantitative analysis of whole body imaging. In light of our observation, we make suggestions for future whole body fluorescence imaging in the in vivo evaluation of NP behaviors.

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“…Although H-aggregates are ideally non-fluorescent, intermediate arrangements can occur when dipoles form twisted H-aggregates. The imperfect stacking may result in partially allowed transitions responsible for the observed H-aggregate fluorescence [ [32] , [33] , [34] ].…”

Section: Resultsmentioning

confidence: 99%

Supramolecular zippers elicit interbilayer adhesion of membranes producing cell death

Almendro‐Vedia

García

Ahijado-Guzmán

et al. 2018

Biochimica et Biophysica Acta (BBA) - General Subjects

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BackgroundThe fluorescent dye 10-N-nonyl acridine orange (NAO) is widely used as a mitochondrial marker. NAO was reported to have cytotoxic effects in cultured eukaryotic cells when incubated at high concentrations. Although the biochemical response of NAO-induced toxicity has been well identified, the underlying molecular mechanism has not yet been explored in detail.MethodsWe use optical techniques, including fluorescence confocal microscopy and lifetime imaging microscopy (FLIM) both in model membranes built up as giant unilamellar vesicles (GUVs) and cultured cells. These experiments are complemented with computational studies to unravel the molecular mechanism that makes NAO cytotoxic.ResultsWe have obtained direct evidence that NAO promotes strong membrane adhesion of negatively charged vesicles. The attractive forces are derived from van der Waals interactions between anti-parallel H-dimers of NAO molecules from opposing bilayers. Semi-empirical calculations have confirmed the supramolecular scenario by which anti-parallel NAO molecules form a zipper of bonds at the contact region. The membrane remodeling effect of NAO, as well as the formation of H-dimers, was also confirmed in cultured fibroblasts, as shown by the ultrastructure alteration of the mitochondrial cristae.ConclusionsWe conclude that membrane adhesion induced by NAO stacking accounts for the supramolecular basis of its cytotoxicity.General significanceMitochondria are a potential target for cancer and gene therapies. The alteration of the mitochondrial structure by membrane remodeling agents able to form supramolecular assemblies via adhesion properties could be envisaged as a new therapeutic strategy.

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Formation of fluorescent H-aggregates of a cyanine dye in ultrathin film and its effect on energy transfer

Cited by 41 publications

References 39 publications

Temperature and concentration dependence of J-aggregate of a cyanine dye in a Laponite film fabricated by Langmuir–Blodgett technique

Temperature and concentration dependence of J-aggregate of a cyanine dye in a Laponite film fabricated by Langmuir–Blodgett technique

Quantitative Assessment of Nanoparticle Biodistribution by Fluorescence Imaging, Revisited

Supramolecular zippers elicit interbilayer adhesion of membranes producing cell death

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