Publications by authors named "Sayaree Dhar"

A unique pH-driven Förster resonance energy transfer (FRET) based biosensor emission by a pyrazoline-doxorubicin pair has been deciphered with a bioimaging application in a live HepG2 cell whereas conformational switching of both molecules at elevated pH reveals a fascinating twist (FRET-OFF) via strong fluorescent exciplex formation.

View Article and Find Full Text PDF

The principal intent of the present contribution is to decipher the binding domain and structural changes of trypsin (TPS), a proteolytic globular enzyme and two serum proteins, namely, bovine serum albumin (BSA), human serum albumin (HSA) association with a newly synthesized bioactive isoquinolindione derivative (ANAP) by employing steady state, time resolved fluorescence and circular dichroism (CD) techniques. Intramolecular charge transfer emission (ICT) of ANAP is found to be responsible for the commendable sensitivity of the probe as an extrinsic fluorescent marker to the protein environments. A sharp distinctive feature of determined micropolarities in proteinous media clearly demarcates the differential extent of hydrophobicity around the encapsulated ANAP.

View Article and Find Full Text PDF

Polycrystalline lanthanum oxalate (LaOX) nanorods (NRs) were succesfully synthesized using reverse micellar (RM) method. The study espouses the versatility of the reverse micellar method forming monodisperse, stable nanorods at room temperature. The as-synthesized LaOX nanorods were characterised by different techniques.

View Article and Find Full Text PDF

Spectroscopic studies of Naproxen (NP), a nonsteroidal drug have been carried out in well characterized, micellar media of cationic surfactants of a homologous series having general formula C(n)TAB (alkyl trimethyl ammonium bromide) and of nonionic surfactants of Igepal (Ig) series (poly(oxyethylene) nonyl phenol). The fluorescence behavior of the drug molecule in C(n)TAB micelles has been found to be opposite to that in Igepal micelles. The binding constants during probe micelle binding have been evaluated from relevant fluorescence data.

View Article and Find Full Text PDF

This paper investigates how solution conditions, especially solvent polarity and hydrogen bonding, influence the fluorescence of an anticancer drug, doxorubicin hydrochloride (DOX). When excited at 480 nm, this molecule shows single fluorescence. However, when excited at 346 nm, it shows dual fluorescence.

View Article and Find Full Text PDF

The solvatochromic behavior of two newly synthesized naphthalimide derivatives (I and II) which have potential antioxidative activities in anticarcinogenic drug development treatment, has been monitored in protic and aprotic solvents of different polarity applying steady-state and time-resolved fluorescence techniques. The compounds exhibit unique photophysical response in different solvent environments. The spectral trends do not appear to originate only from changes in the solvent polarity but also indicate that hydrogen bonding interactions and intramolecular charge transfer (ICT) influence the energy of electronic excitation of the compounds.

View Article and Find Full Text PDF