A fluorescent probe for alkanes, surfactants, lipids and self-organized molecular aggregates (original) (raw)
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Coralyne cation, a fluorescent probe for general detection in planar chromatography
Journal of Chromatography A, 2007
A large number of analytes, including non-fluorescent ones, can be sensitively detected by 15 fluorescence scanning densitometry using silica gel HPTLC plates impregnated with a solution of coralyne cation. This is carried out by the variation, increase or decrease, that the corresponding analyte induces on native coralyne emission at a given excitation wavelength. A similar phenomenon was previously described for berberine cation, and Reichardt's dye probes. However, the sensitivity of coralyne in HPTLC detection of non-20 fluorescent, structurally different analytes (e.g., long-chain alkanes, alcohols, alkylbromides, neutral lipids) is superior to that of the above-mentioned probes.
2006
Many chemical compounds, including non-fluorescent ones, induce changes (either increase in emission or quenching) in the fluorescence spectra of coralyne cation, in absence and presence of solvent. We have applied this phenomenon to HPTLC with fluorescence scanning densitometry, using coralyne as a revealing agent, as a general detection system for analytes. It does not involve covalent interactions. Alkanes in presence of coralyne provide an enhancement of the fluorescent signal, which depends on alkane concentration and structure, when the system is irradiated with UV light. Responses of compounds other than alkanes are structure-dependent. A model has been proposed to explain results. Non-specific interactions between alkane and coralyne create a microenvironment that prevents non-fluorescent decay mechanisms, giving increases in emission. Changes in dielectric constant, and a balance between non-specific and specific interactions between the analyte and coralyne determine the variation of emission when analytes are other than alkanes. Moreover, chromatographic fluorescent response and detection sensitivity depend on coralyne concentration
Journal of Photochemistry and Photobiology A: Chemistry, 2011
The micellar aggregation behavior and micropolarity characteristics of a series of N,N-bisalkyl-N,N-bis[(3-d-aldonylamido)propyl]ethylenediamines referred to as gemini bis(C n X) surfactants (where C n = n-butyl, n-octyl, n-decyl and n-dodecyl; X = gluconyl and lactobionyl, denoted as GA and LA, respectively) has been investigated by steady-state fluorescence, SSF (by emission spectra of pyrene) and time-resolved fluorescence quenching, TRFQ (using pyrene as the fluorescence probe and cetylpyridinium ion as the fluorescence quencher). Remarkably low magnitude cmc values were found for the studied aldonamide-type gemini surfactants, in a range from 4.5 × 10 −6 M (bis(C 12 GA)) to 2.3 × 10 −3 M (bis(C 4 LA)). The variation of cmc for bis(C n LA) (n = 4, 8, 10 and 12) follows a linear semi-logarithmic pattern. The obtained I 1 /I 3,c > cmc ratios from 1.41 to 1.5 indicate a considerable high polarity sensed by pyrene in micelles of bis(C n X), dependent upon both the kind of aldonyl entity, and the length of hydrophobic tail. According to TRFQ, all studied systems display micellar growth (demonstrated by values of an average aggregation number of surfactant chains per micelle) with increasing surfactant concentration typically from 100 up to 1000 times more than the cmc. The aggregation numbers, N agg (N tail) and the "polydispersity index", /N ω (less than ∼0.3), show that micelles of bis(C n LA)'s of up to ca. 500cmc, are nearly spherical and almost monodisperse. Their spheroidal micelle growth and enhanced micellar polydispersity is observed as the surfactant concentration increases. Such a behavior was found to be strictly related to geometric aspects of a given surfactant dimeric structure.
Fluorescence Characteristics of some Flavones Probes in Different Micellar Media
Journal of Fluorescence, 2014
The fluorescence characteristics of five hydroxiflavones (HFs) (some typical models of flavonols), (3 -HF, 6 -HF, 7-HF, 3, 6 -diHF and 3, 7-diHF) in the micellar media of non-ionic surfactant (Triton X-100), anionic surfactant (SDS) and the block copolymer Pluronic F127, have been investigated by means of UV-Vis and steadystate and time resolved fluorescence spectroscopies. Attention is paid to both excited-state intra-molecular proton transfer (ESIPT) as well as ground-state intermolecular proton transfer. The influence of the -OH groups as well as the effect of temperature on the dual fluorescence emission, the Normal and Tautomer emissions, are also investigated. The fluorescence quantum yield of the HFs in mentioned micellar media has been also determined. The results are discussed with relevance to the local environment of HFs as sensitive fluorescence probe in biological membrane systems.
Detection of biomacromolecules with fluorescent light-up probes
Pure and Applied Chemistry, 2006
The emission properties of selected benzo[b]quinolizinium (acridizinium) derivatives in the presence of double-stranded DNA and proteins are presented. Spectrophotometric studies and linear dichroism (LD) spectroscopic experiments reveal that benzo[b]quinolizinium derivatives bind to DNA, mainly by intercalation. In contrast to the 9-aminobenzo[b]quinolizinium, which exhibits a moderate emission quantum yield in water, the 6-aminobenzo[b]quinolizinium ion as well as N-phenyl-9-aminobenzo[b]quinolizinium derivatives are almost nonfluorescent. The low intrinsic fluorescence quantum yields of the latter compounds are caused by conformational changes in the excited state, as shown by a linear double-logarithmic plot of the emission quantum yield vs. the solvent viscosity. Most notably, the fluorescence intensities of these dyes increase significantly by a factor of 10 to 50 upon addition of double-stranded DNA or proteins such as human serum albumin (HSA) or chicken egg albumin (CEA). Thus, these compounds exhibit ideal properties to be used as DNA-or protein-sensitive light-up probes.
Chemical Physics Letters, 2011
Berberine and coralyne experience either fluorescence enhancement or quenching when long hydrocarbon chain compounds (e.g., n-alkanes or alcohols) are added to their solutions, depending on solvent polarity. In polar solvents, as methanol or acetonitrile, the added compounds provide an apolar microenvironment that hinders alternative relaxation mechanisms, favouring fluorescence emission. However, alkane additions produce quenching in dichloromethane, which has been explained taking into account ion pairing between cationic fluorophore and counterion. The strong quenching measured after alcohol additions in dichloromethane suggests reversed micelle formation. Procedures and results described here may find practical applications in the development of analytical methods.
INTERACTION OF 3-HYDROXY PYRIDINE AND SURFACTANT MICELLES: A FLUORESCENCE STUDIES
Asian Journal of Pharmaceutical and Clinical Research Journal, 2021
Objective: Micellar solubilization is a powerful alternative for dissolving hydrophobic compound in aqueous environment. 3-hydroxy pyridine (3-HP) derivatives are the potential endogenous photosensitizers. 3-HP derivatives show protective effect in clinical extreme condition such as hypoxia, hyperthermia, hypokinesia. Micellization of 3-HP followed by solubilization would catalyze its pharmaceutical activities which may serve better results in medicinal and analytical fields. Methods: Fluorescence and absorption spectroscopy techniques are used to monitor the micellar solubilization studies of 3-HP. Solubilization studies of 3-HP with various anionic, cationic and nonionic surfactants have been performed in aqueous medium around 23-25°C temperature. The solubilization action of the surfactant has also been determined by theoretical calculated spectral parameters such as empirical fluorescence coefficient, quantum yield, stokes, shift and molar absorption coefficient. Results: 3-HP shows fluorescence excitation peak at 315 nm and emission peak at 390 nm respectively while the absorbance of 3-HP has been found to be maximum at 305 nm. The fluorescence as well as the theoretically calculated spectral data has been used to characterize the hetero environment of the micelles in terms of their polarity, probe solubilization site and critical micelle concentration. Conclusion: This article briefly discusses the importance of surfactants in biological system model as well as the use of micelles in pharmacy as an important tool that finds numerous applications.