Vinay Chauhan - Academia.edu (original) (raw)
Papers by Vinay Chauhan
Journal of Colloid and Interface Science, 2017
New ester-functionalized surface active ionic liquids (SAILs) based on nicotine, [C n ENic][Br] (... more New ester-functionalized surface active ionic liquids (SAILs) based on nicotine, [C n ENic][Br] (n = 8, 10 and 12), with bromide counterions have been synthesized, characterized and investigated for their self-assembly behavior in aqueous medium. Conductivity measurements in aqueous solutions of the investigated SAILs have provided information about their critical micelle concentration (cmc), and degree of counterion binding (β), where cmc was found to be 2-3 fold lower than homologous SAILs or conventional cationic surfactants. The inherent fluorescence of SAILs in the absence of any external fluorescent probe have shed light on cmc as well as interactions prevailing between the monomers in micelle at molecular level. The thermodynamic parameters related to micellization have been deduced from isothermal titration calorimetry (ITC) and conductivity measurements. 1 H NMR, spin-lattice (T 1) relaxation time and 2D 1 H-I H ROESY measurements have been exploited to get detailed account of internal structure of micelle. The size and shape of the micelles have been explored using dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. The synthesized SAILs have been found to be non-cytotoxic towards C6-Glioma cell line, which adds to the possible utility of these SAILs for diverse biological applications.
Langmuir, 2015
New gemini pyridinium amphiphiles having alkyl chain lengths of C10, C12, C14 , and C16 and appen... more New gemini pyridinium amphiphiles having alkyl chain lengths of C10, C12, C14 , and C16 and appended with hydroxyl-substituted spacers have been synthesized, characterized, and investigated for their self-assembly as well as adsorption behavior by state-of-the-art techniques such as conductometry, tensiometry, isothermal titration calorimetry (ITC), and spectrofluorometry. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) have provided excellent acumen with respect to the micellar size distribution of investigated dicationics in aqueous media. Furthermore, the interaction of these dicationics with plasmid DNA, at different charge ratios (N/P), has been studied by DLS, agarose gel electrophoresis, and ethidium bromide exclusion measurements. The cytotoxicity of these geminis has been evaluated by using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on BV2 (microglial) and C6 glioma cell lines. It was found that the varying alkyl chain length, fashioned by ether linkage close to the headgroup, and the presence of a polar linker significantly altered the physicochemical properties of these new dicationics as compared to the properties of nonfunctionalized gemini surfactants.
![Research paper thumbnail of Corrigendum to, “Self-assembly, DNA binding and cytotoxicity trends of ether functionalized gemini pyridinium amphiphiles” [J. Colloid Interface Sci. 417 (2014) 385–395]](https://attachments.academia-assets.com/113382775/thumbnails/1.jpg)
](Journal of Colloid and Interface Science, 2014
Journal of colloid and interface science, Jan 15, 2014
Four new amide functionalized N-methylpiperazinium amphiphiles having tetradecyl, hexadecyl alkyl... more Four new amide functionalized N-methylpiperazinium amphiphiles having tetradecyl, hexadecyl alkyl chain lengths and counterions; chloride or bromide have been synthesized and characterized by various spectroscopic techniques. These new surfactants have been investigated in detail for their self-assembling behavior by surface tension, conductivity and fluorescence measurements. The thermodynamic parameters of these surfactants indicate that micellization is exothermic and entropy-driven. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) experiments have been performed to insight the aggregate size of these cationics. Thermal degradation of these new surfactants has also been evaluated by thermal gravimetric analysis (TGA). These new surfactants form stable complexes with DNA as acknowledged by agarose gel electrophoresis, ethidium bromide exclusion and zeta potential measurements. They have also been found to have low cytotoxicity by MTT (3-(4,5-dimethylth...
Langmuir, 2014
Morpholinium-based amide-functionalized ionic liquids (ILs) [C n AMorph][Br], where n = 8, 12, an... more Morpholinium-based amide-functionalized ionic liquids (ILs) [C n AMorph][Br], where n = 8, 12, and 16, have been synthesized and characterized for their micellization behavior in aqueous medium using a variety of state of the art techniques. The adsorption and micellization behavior of [C n AMorph][Br] ILs at the air−solution interface and in the bulk, respectively, has been found to be much better compared to that observed for nonfunctionalized homologous ILs and conventional cationic surfactants, as shown by the comparatively higher adsorption efficiency, lower surface tension at the critical micelle concentraiton (γ cmc), and much lower critical micelle concentration (cmc) for [C n AMorph][Br] ILs. Conductivity measurements have been performed to obtain the cmc, degree of counterion binding (β), and standard free energy of micellization (ΔG m°). Isothermal titration calorimetry has provided information specifically about the thermodynamics of micellization, whereas steady-state fluorescence has been used to obtain the cmc, micropolarity of the cybotactic region, and aggregation number (N agg) of the micelles. Both dynamic light scattering and atomic force microscopy have provided insights into the size and shape of the micelles. 2D 1 H− 1 H nuclear Overhauser effect spectroscopy experiments have provided insights into the structure of the micelle, where [C 16 AMorph][Br] has shown distinct micellization behavior as compared to [C 8 AMorph][Br] and [C 12 AMorph][Br] in corroboration with observations made from other techniques.
Physical chemistry chemical physics : PCCP, Jan 21, 2014
Amide-functionalized surface active ionic liquids (SAILs), 1-methyl-1-dodecyl piperidinium chlori... more Amide-functionalized surface active ionic liquids (SAILs), 1-methyl-1-dodecyl piperidinium chloride, [C12APip][Cl]; 1-methyl-1-dodecyl pyrrolidinium chloride, [C12APyrr][Cl]; 1-methyl-3-dodecyl imidazolium chloride, [C12Amim][Cl], and 1-methyl-1-dodecyl morpholinium chloride, [C12AMorph][Cl], have been synthesized, characterized and investigated for thermal stability, and micellization behavior in aqueous medium. The introduction of an amide moiety in the alkyl chain decreased the thermal stability of the functionalized SAILs compared to non-functionalized SAILs bearing a simple alkyl chain. A variety of state of the art techniques, viz. tensiometry, conductometry, steady-state fluorescence, isothermal titration calorimetry (ITC), dynamic light scattering (DLS) and atomic force microscopy (AFM), have been employed to investigate the micellization behavior. Amide-functionalized SAILs have shown much lower critical micelle concentration, cmc, and better surface active properties as co...
Langmuir : the ACS journal of surfaces and colloids, Jan 16, 2014
Colloid and Polymer Science, 2013
N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by variou... more N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by various spectroscopic techniques. Self-assembling properties of these amphiphiles have been studied by surface tension, conductivity, and fluorescence measurements. Basic micellization parameters like critical micelle concentration (cmc), surface tension at the cmc (γ cmc), adsorption efficiency (pC 20), effectiveness of surface tension reduction (Π cmc), maximum surface excess concentration (Γ max) and minimum surface area/molecule (A min), and Gibbs free energy of the micellization (ΔG 0 mic) have also been determined. The micellization of these 3alkyloxypyridinium halides in aqueous phase have been found to be exothermic and entropy-driven as assessed by conductivity measurements at different temperatures. Thermal degradation of these surfactants has also been assessed by thermal gravimetric analysis under nitrogen atmosphere. Further, 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of these surfactants on C6 glioma cells show them to be less toxic than conventional cationic surfactants.
Journal of Colloid and Interface Science, 2015
Ester functionalized surface active ionic liquids (SAILs), [C n EMorph][Br], where n = 8, 12 and ... more Ester functionalized surface active ionic liquids (SAILs), [C n EMorph][Br], where n = 8, 12 and 16, comprising of long hydrophobic chain appended with ester functionality connected to N-methylmorpholine group have been synthesized and investigated for their aggregation behavior and cytotoxicity. A variety of state of art techniques viz. tensiometry, conductometry, isothermal titration calorimetry (ITC), spectrofluorometry, dynamic light scattering (DLS) and atomic force microscopy (AFM) have been employed to get insight into the various aspects of aggregation behavior. The investigated SAILs have been found to possess lower critical aggregation concentration (cac) and greater adsorption efficacy at air-solution interface as compared to earlier reported non-functionalized SAILs or conventional ionic surfactants. Further, the thermal stability of these morpholinium cationics has been evaluated by thermal gravimetric analysis (TGA). These SAILs have been found to be non-cytotoxic in the concentration range generally required for different biological applications as judged by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on the C6 glioma cell line. The dependence of characteristic properties of aggregation on alkyl chain length has been established.
Journal of Colloid and Interface Science, 2017
New ester-functionalized surface active ionic liquids (SAILs) based on nicotine, [C n ENic][Br] (... more New ester-functionalized surface active ionic liquids (SAILs) based on nicotine, [C n ENic][Br] (n = 8, 10 and 12), with bromide counterions have been synthesized, characterized and investigated for their self-assembly behavior in aqueous medium. Conductivity measurements in aqueous solutions of the investigated SAILs have provided information about their critical micelle concentration (cmc), and degree of counterion binding (β), where cmc was found to be 2-3 fold lower than homologous SAILs or conventional cationic surfactants. The inherent fluorescence of SAILs in the absence of any external fluorescent probe have shed light on cmc as well as interactions prevailing between the monomers in micelle at molecular level. The thermodynamic parameters related to micellization have been deduced from isothermal titration calorimetry (ITC) and conductivity measurements. 1 H NMR, spin-lattice (T 1) relaxation time and 2D 1 H-I H ROESY measurements have been exploited to get detailed account of internal structure of micelle. The size and shape of the micelles have been explored using dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. The synthesized SAILs have been found to be non-cytotoxic towards C6-Glioma cell line, which adds to the possible utility of these SAILs for diverse biological applications.
Langmuir, 2015
New gemini pyridinium amphiphiles having alkyl chain lengths of C10, C12, C14 , and C16 and appen... more New gemini pyridinium amphiphiles having alkyl chain lengths of C10, C12, C14 , and C16 and appended with hydroxyl-substituted spacers have been synthesized, characterized, and investigated for their self-assembly as well as adsorption behavior by state-of-the-art techniques such as conductometry, tensiometry, isothermal titration calorimetry (ITC), and spectrofluorometry. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) have provided excellent acumen with respect to the micellar size distribution of investigated dicationics in aqueous media. Furthermore, the interaction of these dicationics with plasmid DNA, at different charge ratios (N/P), has been studied by DLS, agarose gel electrophoresis, and ethidium bromide exclusion measurements. The cytotoxicity of these geminis has been evaluated by using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on BV2 (microglial) and C6 glioma cell lines. It was found that the varying alkyl chain length, fashioned by ether linkage close to the headgroup, and the presence of a polar linker significantly altered the physicochemical properties of these new dicationics as compared to the properties of nonfunctionalized gemini surfactants.
Journal of Colloid and Interface Science, 2014
Journal of colloid and interface science, Jan 15, 2014
Four new amide functionalized N-methylpiperazinium amphiphiles having tetradecyl, hexadecyl alkyl... more Four new amide functionalized N-methylpiperazinium amphiphiles having tetradecyl, hexadecyl alkyl chain lengths and counterions; chloride or bromide have been synthesized and characterized by various spectroscopic techniques. These new surfactants have been investigated in detail for their self-assembling behavior by surface tension, conductivity and fluorescence measurements. The thermodynamic parameters of these surfactants indicate that micellization is exothermic and entropy-driven. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) experiments have been performed to insight the aggregate size of these cationics. Thermal degradation of these new surfactants has also been evaluated by thermal gravimetric analysis (TGA). These new surfactants form stable complexes with DNA as acknowledged by agarose gel electrophoresis, ethidium bromide exclusion and zeta potential measurements. They have also been found to have low cytotoxicity by MTT (3-(4,5-dimethylth...
Langmuir, 2014
Morpholinium-based amide-functionalized ionic liquids (ILs) [C n AMorph][Br], where n = 8, 12, an... more Morpholinium-based amide-functionalized ionic liquids (ILs) [C n AMorph][Br], where n = 8, 12, and 16, have been synthesized and characterized for their micellization behavior in aqueous medium using a variety of state of the art techniques. The adsorption and micellization behavior of [C n AMorph][Br] ILs at the air−solution interface and in the bulk, respectively, has been found to be much better compared to that observed for nonfunctionalized homologous ILs and conventional cationic surfactants, as shown by the comparatively higher adsorption efficiency, lower surface tension at the critical micelle concentraiton (γ cmc), and much lower critical micelle concentration (cmc) for [C n AMorph][Br] ILs. Conductivity measurements have been performed to obtain the cmc, degree of counterion binding (β), and standard free energy of micellization (ΔG m°). Isothermal titration calorimetry has provided information specifically about the thermodynamics of micellization, whereas steady-state fluorescence has been used to obtain the cmc, micropolarity of the cybotactic region, and aggregation number (N agg) of the micelles. Both dynamic light scattering and atomic force microscopy have provided insights into the size and shape of the micelles. 2D 1 H− 1 H nuclear Overhauser effect spectroscopy experiments have provided insights into the structure of the micelle, where [C 16 AMorph][Br] has shown distinct micellization behavior as compared to [C 8 AMorph][Br] and [C 12 AMorph][Br] in corroboration with observations made from other techniques.
Physical chemistry chemical physics : PCCP, Jan 21, 2014
Amide-functionalized surface active ionic liquids (SAILs), 1-methyl-1-dodecyl piperidinium chlori... more Amide-functionalized surface active ionic liquids (SAILs), 1-methyl-1-dodecyl piperidinium chloride, [C12APip][Cl]; 1-methyl-1-dodecyl pyrrolidinium chloride, [C12APyrr][Cl]; 1-methyl-3-dodecyl imidazolium chloride, [C12Amim][Cl], and 1-methyl-1-dodecyl morpholinium chloride, [C12AMorph][Cl], have been synthesized, characterized and investigated for thermal stability, and micellization behavior in aqueous medium. The introduction of an amide moiety in the alkyl chain decreased the thermal stability of the functionalized SAILs compared to non-functionalized SAILs bearing a simple alkyl chain. A variety of state of the art techniques, viz. tensiometry, conductometry, steady-state fluorescence, isothermal titration calorimetry (ITC), dynamic light scattering (DLS) and atomic force microscopy (AFM), have been employed to investigate the micellization behavior. Amide-functionalized SAILs have shown much lower critical micelle concentration, cmc, and better surface active properties as co...
Langmuir : the ACS journal of surfaces and colloids, Jan 16, 2014
Colloid and Polymer Science, 2013
N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by variou... more N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by various spectroscopic techniques. Self-assembling properties of these amphiphiles have been studied by surface tension, conductivity, and fluorescence measurements. Basic micellization parameters like critical micelle concentration (cmc), surface tension at the cmc (γ cmc), adsorption efficiency (pC 20), effectiveness of surface tension reduction (Π cmc), maximum surface excess concentration (Γ max) and minimum surface area/molecule (A min), and Gibbs free energy of the micellization (ΔG 0 mic) have also been determined. The micellization of these 3alkyloxypyridinium halides in aqueous phase have been found to be exothermic and entropy-driven as assessed by conductivity measurements at different temperatures. Thermal degradation of these surfactants has also been assessed by thermal gravimetric analysis under nitrogen atmosphere. Further, 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of these surfactants on C6 glioma cells show them to be less toxic than conventional cationic surfactants.
Journal of Colloid and Interface Science, 2015
Ester functionalized surface active ionic liquids (SAILs), [C n EMorph][Br], where n = 8, 12 and ... more Ester functionalized surface active ionic liquids (SAILs), [C n EMorph][Br], where n = 8, 12 and 16, comprising of long hydrophobic chain appended with ester functionality connected to N-methylmorpholine group have been synthesized and investigated for their aggregation behavior and cytotoxicity. A variety of state of art techniques viz. tensiometry, conductometry, isothermal titration calorimetry (ITC), spectrofluorometry, dynamic light scattering (DLS) and atomic force microscopy (AFM) have been employed to get insight into the various aspects of aggregation behavior. The investigated SAILs have been found to possess lower critical aggregation concentration (cac) and greater adsorption efficacy at air-solution interface as compared to earlier reported non-functionalized SAILs or conventional ionic surfactants. Further, the thermal stability of these morpholinium cationics has been evaluated by thermal gravimetric analysis (TGA). These SAILs have been found to be non-cytotoxic in the concentration range generally required for different biological applications as judged by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on the C6 glioma cell line. The dependence of characteristic properties of aggregation on alkyl chain length has been established.