Ivy Sarkar

Bio: Ivy Sarkar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Pyrene & Denaturation (biochemistry). The author has an hindex of 6, co-authored 8 publications receiving 85 citations.

Photophysical behavior of a new cholesterol attached coumarin derivative and fluorescence spectroscopic studies on its interaction with bile salt systems and lipid bilayer membranes

Abstract: A new fluorescent-cholesterol (Cum-Chl) molecule has been synthesized by attaching 3-acetyl-7-(diethylamino)-2H-chromen-2-one (Cum) to cholesterol via cholesterol bound β-keto ester. The β-keto ester was synthesized from the corresponding nitrile by applying the Blaise reaction. The molecule forms H-aggregates in solutions. The efficiency of aggregation is high in water. The H-aggregates are non-fluorescent in non-aqueous solvents but fluorescent in water. Aqueous bile salt media suppress the formation of H-aggregates, this effect being more pronounced for sodium deoxycholate (NaDC) which is more hydrophobic. With increasing bile salt concentration, the enhancement of monomeric fluorescence intensity of Cum-Chl generally follows the progressive miceller aggregation of bile salts. Incorporation of Cum-Chl into the dimyristoylphosphatidylcholine (DMPC) lipid bilayer membrane results in a significant enhancement of monomeric fluorescence intensity. The variation of fluorescence intensity is also sensitive to the thermotropic phase transition of the bilayer. It is seen that in such aqueous micro- and nanoscale organized media like bile salts and lipid bilayer membranes the monomer-to-aggregate fluorescence intensity ratio reflects the state of organization of the medium.

Fluorophore tagged bio-molecules and their applications: A brief review

Abstract: Bio-molecules are principal building blocks of living species and their inter-play is the cause of bio-activities. Various sophisticated experimental techniques as well as theoretical studies have ...

Introduction of an α,β-unsaturated carbonyl conjugated pyrene–lactose hybrid as a fluorescent molecular probe for micro-scale anisotropic media

Abstract: A new fluorescent lactose molecule (pyd-lact) (E)-1-(galactose-β-(1→4)-β-D-glucopyranosyl)-4-(1-pyrene)-but-3-en-2-one, has been synthesized by attaching 1-pyrene-but-3-ene-2-one to lactose. Extended π-conjugation removes the emission forbiddenness of pyrene, which results in the broad spectrum. Detailed photo-physical studies in homogeneous media show the sensitivity of ICT (intra molecular charge transfer) emission towards medium polarity. Unlike pyrene, pyd-lact is more soluble in water at a probe concentration of 10 μM, because of the attached disaccharide. Thus, the usage of pyd-lact as an aqueous probe is found to be advantageous over pyrene. Using the polarity sensitivity of fluorescence parameters (intensity, shift of emission maximum, anisotropy, lifetime), the micro-heterogeneity of anisotropic media such as β-CD, bile salts, and Pluronic P123 have been monitored. In contrast to pyrene-3-carboxaldehyde, which is often used as a hydrophobic fluorescent molecular probe, pyd-lact reports from the interfacial regions of micro-heterogeneous media.

Review on Methylene Blue: Its Properties, Uses, Toxicity and Photodegradation

Abstract: The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

Topics In Fluorescence Spectroscopy

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Chitosan Glutamate-Coated Niosomes: A Proposal for Nose-to-Brain Delivery.

Abstract: The aim of this in vitro study is to prepare and characterize drug free and pentamidine loaded chitosan glutamate coated niosomes for intranasal drug delivery to reach the brain through intranasal delivery. Mucoadhesive properties and stability testing in various environments were evaluated to examine the potential of these formulations to be effective drug delivery vehicles for intranasal delivery to the brain. Samples were prepared using thin film hydration method. Changes in size and ζ-potential of coated and uncoated niosomes with and without loading of pentamidine in various conditions were assessed by dynamic light scattering (DLS), while size and morphology were also studied by atomic force microscopy (AFM). Bilayer properties and mucoadhesive behavior were investigated by fluorescence studies and DLS analyses, respectively. Changes in vesicle size and ζ-potential values were shown after addition of chitosan glutamate to niosomes, and when in contact with mucin solution. In particular, interactions with mucin were observed in both drug free and pentamidine loaded niosomes regardless of the presence of the coating. The characteristics of the proposed systems, such as pentamidine entrapment and mucin interaction, show promising results to deliver pentamidine or other possible drugs to the brain via nasal administration.