This work uses the dynamics of the excited state proton transfer of 1-naphthol to water as a basis for understanding the temperature-dependent changes in the water accessibility of the niosome membrane domain. The decrease in the neutral form fluorescence intensity of membrane bound 1-naphthol, the significant drop in the membrane-bound anion form fluorescence lifetime, and the changes in the fluorescence lifetime distribution plots of the two prototropic forms of 1-naphthol indicate a regular increase in the water penetration in the interfacial region of the niosome membrane domain, whereas the dry core regions appear unaffected with increasing temperature (10-60 °C). Unlike some liposomes and niosomes, these niosomes do not show thermotropic phase transition behavior. © 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Ashok Kumar Mishra

Department Of Chemistry

Akanksha Singh

1 naphthol

anion

Cholesterol

liposome

NIOSOME

Water

article

controlled study

excitation

fluorescence analysis

Hydrophilicity

membrane

molecular dynamics

phase transition

priority journal

proton transport

temperature dependence

TROPISM

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

New Journal of Chemistry

This study demonstrates that significant perturbation of tween20:cholesterol(1:1) niosome membrane takes place even at premicellar concentration of bile salts. Here, 1-naphthol (1-NpOH), a known and sensitive excited state proton transfer (ESPT) probe, was used to understand the nature of perturbation of the membrane in an unbuffered medium. The significant decrease in 1-NpOH fluorescence intensity in niosome-bile salt mixed system at both lower (10 °C) and higher (50 °C) temperatures indicates the bile salts [sodium cholate (NaC) and sodium deoxycholate (NaDC)] induce perturbation of niosome membranes. Variations in the fluorescence lifetime values of both the prototropic emissions (neutral and anionic species) along with the proton transfer rate of 1-NpOH confirm the bile salts perturb up to the hydrophobic core domain of the niosomal membranes. Bile salts induce size change of the niosomal membrane is confirmed through dynamic light scattering study. © 2019 Elsevier B.V.

Colloids and Surfaces B: Biointerfaces

Significant bile salt induced perturbation of niosome membrane: A molecular level interaction study using 1-Naphthol fluorescence

Thermotropic microenvironmental changes and the level of hydration in different microenvironments of pluronic F127 (PF127), (PEO<inf>106</inf> PPO<inf>70</inf> PEO<inf>106</inf>, average molar mass 13 000) in aqueous media have been studied using 1-naphthol, which is an ESPT fluorescent molecular probe. The appearance of 1-naphthol neutral form fluorescence in aqueous PF127 (10% w/v) solution indicates the ability of 1-naphthol to sense hydrophobic domains in micellar aggregations. There is a marked enhancement of the neutral form fluorescence at and above the gelation temperature (20°C), which shows that the probe can accurately sense the sol-gel transition. In the temperature range of 10-40°C, with increase in temperature there is a progressive enhancement of the neutral form fluorescence and the blue shift of the neutral and anionic form fluorescence; a decrease in the deprotonation rate constant (k<inf>pt</inf>) indicates that the water-polymer interfacial region is progressively dehydrated. Because k<inf>pt</inf> is related to the availability of proton-accepting water in the microenvironment of 1-naphthol, the reduction of k<inf>pt</inf> indicates progressive dehydration. The thermotropic response of the I<inf>1</inf>/I<inf>3</inf> vibronic band ratio of pyrene-1-butyric acid fluorescence shows a progressive increase in the non-polarity of the interfacial domain with increasing temperature. The increase in non-polarity and the decrease of the hydration level are strongly correlated. This journal is © the Owner Societies.

Physical Chemistry Chemical Physics

1-Naphthol as an ESPT fluorescent molecular probe for sensing thermotropic microenvironmental changes of pluronic F127 in aqueous media

In this study, 1-naphthol has been used as a sensitive ESPT fluorescent molecular probe to investigate the interaction of submicellar concentrations of two physiologically important bile salts, sodium deoxycholate and sodium cholate, with dipalmitoylphosphatidylcholine small unilamellar vesicles in solid gel and liquid crystalline phases. Steady-state and time-resolved fluorescence of the two excited state prototropic forms of 1-naphthol indicate that the incorporation of monomeric bile salt molecules in the lipid bilayer membrane induces appreciable wetting of the bilayer up to the hydrocarbon core region, even at very low (≤1 mM) concentrations of the bile salts. © 2010 American Chemical Society.

Journal of Physical Chemistry B

1-naphthol as a sensitive fluorescent molecular probe for monitoring the interaction of submicellar concentration of bile salt with a bilayer membrane of DPPC, a lung surfactant

When 1-naphthol incorporated polyvinyl alcohol (PVA) films are allowed to swell in water, there is a loss of fluorescence intensity of the neutral form with a concomitant increase of the anionic form fluorescence intensity. This fluorescence response due to the excited state prototropism (ESPT) of 1-naphthol is very sensitive to the initial stage of hydration of the PVA. Using an existing model of hydrogel swelling and DSC experiments, it was reasoned that 1-naphthol senses the bound-water component of PVA hydration. Thus, 1-naphthol is proposed as an ESPT fluorescent sensor for the specific sensing of bound-water hydration of PVA hydrogel. © 2006 Elsevier B.V. All rights reserved.

Talanta

1-Naphthol as an excited state proton transfer fluorescent probe for sensing bound-water hydration of polyvinyl alcohol

The microenvironmental dependence of excited state prototropism of 1-naphthol and the corresponding changes in its fluorescence emission is utilized to monitor the acyl chain melting phase transition behavior of liposome membrane made from human erythrocyte lipids. A sharp increase in the ratio of neutral/anionic form fluorescence intensity is noticed at the phase transition temperature (19 °C). This provides a convenient method for obtaining phase transition temperature in lipid membranes. The membrane modifying effect of cholesterol on the erythrocyte liposome is successfully sensed by 1-naphthol fluorescence.

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

1-Naphthol as an excited state proton transfer fluorescent probe for erythrocyte membranes

1-Naphthol, an excited state acid, undergoes partial dissociation in the excited state in liposome membranes, giving rise to two peaks, as opposed to a single peak in water. The excited state prototropic equilibrium is affected by perturbations in the membrane system. This property can be used to probe the properties of biomembranes. In this respect, as a preliminary study, the partition coefficient of 1-naphthol in liposomes has been calculated.

Journal of Photochemistry and Photobiology A: Chemistry

Determination of the partition coefficient of 1-naphthol, an excited state acid, in DMPC membrane

Temperature-dependent water penetration in Tween20:cholesterol niosome membrane: A study using excited state prototropism of 1-naphthol

Journal	Data powered by TypesetNew Journal of Chemistry
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	11440546
Open Access	No