Publications by authors named "V Aswal"

Compaction of calf thymus DNA (ct-DNA) by two single-head-double-tailed surfactants with variable tail lengths , Dihexadecyldimethylammonium bromide (DDAB16) and Dioctadecyldimethylammonium bromide (DDAB18), and one triple-head-double-tailed surfactant -dodecyl--(2-(dodecyldimethylammonio)ethyl)-,,,-tetramethylethane-1,2-diaminium (MQAS12) has been studied. DDAB18 is found to be the most efficient, while MQAS12 is the least efficient for cellular uptake. Hybrid materials of surfactants and silica nanoparticles have better compaction efficiency due to the cooperative binding.

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Hybrid nanoparticles formed by Silica (SiO) coated with cationic gemini surfactants with variable hydroxyl group substituted spacers, 12-4(OH)-12,2Br and 12-4(OH)-12,2Br have shown a great extent of compaction of calf thymus DNA (ct-DNA) compared to conventional counterpart cationic surfactant, dodecyl trimethylammonium bromide (DTAB). Study shows not only the hydrophobicity of the spacer but also the hydrogen bonding interactions between the hydroxyl group substituted spacer and DNA have a great role in DNA compaction. 12-4(OH)-12,2Br is more efficient in compacting ct-DNA compared to 12-4(OH)-12,2Br due to the stronger binding of the former with ct-DNA than the latter.

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Fundamental investigations into the photophysical properties and microenvironmental features of pluronic-zwitterionic surfactant mixed assemblies are essential for advancing our understanding of molecular interactions at the nanoscale, setting the stage for innovative solutions in drug delivery, diagnostics, and other applications of pluronic-zwitterionic surfactant assemblies. This investigation explores the intricate photophysics of pluronic-zwitterionic surfactant mixed assemblies, utilizing the twisted intramolecular charge transfer state forming styryl dye trans-2-[(4-dimethylamino) styryl] benzothiazole as a probe. By comparing the behaviors of two distinct poly(ethylene oxide)--poly(propylene oxide)--poly(ethylene oxide) block copolymers with block composition of (PEO)(PPO)-(PEO) [F108] and (PEO)-(PPO)-(PEO) [F127] at concentrations of 5 and 10 wt %, this study systematically examines the impact of the addition of zwitterionic surfactants.

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An interesting evolution of the re-entrant interaction has been observed in an anionic silica nanoparticle (NP)-block copolymer (P85) dispersion due to mutually competing effects of temperature and polymer concentration. It has been demonstrated that a rise in the temperature leads to an evolution of attraction in the system, which interestingly diminishes on increasing the polymer concentration. Consequently, the system exhibits a re-entrant transition from repulsive to attractive and back to repulsive at a given temperature but with respect to the increasing polymer concentration, within a selected region of concentration and temperature.

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The effects of two ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF) and 1-butyl-1-methyl pyrrolidinium tetrafluoroborate ([bmp]BF), on a mixture of phospholipids (PLs) 1,2-dipalmitoyl--glycero-3-phosphatidylcholine (DPPC), 1,2-dipalmitoyl--glycero-3-phosphoethanolamine (DPPE), and 1,2-dipalmitoyl--glycero-3-phosphoglycerol (DPPG) (6:3:1, M/M/M, 70% PL) in combination with 30 mol % cholesterol (CHOL) were investigated in the form of a solvent-spread monolayer and bilayer (vesicle). Surface pressure (π)-area () isotherm studies, using a Langmuir surface balance, revealed the formation of an expanded monolayer, while the cationic moiety of the IL molecules could electrostatically and hydrophobically bind to the PLs on the palisade layer. Turbidity, dynamic light scattering (size, ζ-potential, and polydispersity index), electron microscopy, small-angle X-ray/neutron scattering, fluorescence spectroscopy, and differential scanning calorimetric studies were carried out to evaluate the effects of IL on the structural organization of bilayer in the vesicles.

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