Green Gemini Surfactants Research Articles

Synthesis, properties, and applications of an anionic–nonionic Gemini surfactant for highly efficient remediation of perchloroethylene-contaminated aquifers

Monomeric surfactants are currently used for the remediation of dense non-aqueous phase liquid-contaminated groundwater. However, they result in low remediation efficiency because of their high adsorption loss and low temperature and salt resistance. In this study, a novel and green Gemini surfactant, SNE(10)SID (sodium nonylphenol ethoxylate (10) sulfoitaconate diester), was synthesized for subsurface environment characteristics through esterification and sulfonation. This surfactant consisted of two long and straight hydrophobic chains, two selfsame non-ionic portions, and two anionic moieties covalently connected to each other by an itaconic acid spacer. The critical micelle concentration was ∼10−4 M. The interfacial tension between SNE(10)SID and perchloroethylene (PCE) was significantly low, and the value was found to be 1.0 mN/m. SNE(10)SID exhibited excellent activity under conditions of low temperature and in high salt systems. The solubility of PCE was up to 8863 mg/L in a 4 wt% SNE(10)SID solution, which was two orders of magnitude higher than the solubility recorded in pure water. SNE(10)SID exhibited a low adsorption loss (only 0.8 mg/g at a concentration of 2 g/L in medium sand). The PCE desorption ability of the surfactant was far significantly higher than the PCE desorption abilities of other monomeric surfactants in various aquifer media. Under conditions of dynamic flushing, the low-viscosity SNE(10)SID solution exhibited excellent remediation ability when PCE-contaminated simulated aquifers were used for the studies. The total PCE removal rate reached was 87.5% after the flushing of 10 pore volumes. These results revealed that SNE(10)SID was an excellent surfactant that could be used to realize efficient aquifer remediation.

Investigation of micellar and interfacial phenomenon of amitriptyline hydrochloride with cationic ester-bonded gemini surfactant mixture in different solvent media.

Herein, the interaction among the antidepressant drug amitriptyline hydrochloride (AMT) and a green gemini surfactant, ethane-1, 2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14), via numerous techniques such as tensiometry, fluorimetry, FT-IR and UV-visible spectroscopy in three different media (aqueous 0.050 mol·kg-1 NaCl, 0.50 and 1.0 mol·kg-1 urea) were investigated. AMT is used to treat mental illness or mood problems, such as depression. The aggregation of biologically active ingredients can enhance the bioavailability of hydrophobic drugs. A significant interaction between AMT and 14-E2-14 was detected by tensiometric study as the critical micelle concentration (cmc) of AMT+14-E2-14 is reduced upon an increase of mole fraction (α1) of 14-E2-14. The decrease in cmc indicates the nonideality of studied mixtures of different compositions. Although, employed drug AMT is freely soluble in the aqueous and non-aqueous system but is not hydrophobic enough to act as its carrier. Instead, gemini surfactant formed spherical micelles in an aqueous system and their high solubilization capability, as well as their relatively lower cmc value, makes them highly stable in vivo. The cmc values of AMT+14-E-14 mixtures in all cases were further decreased and increased in NaCl and urea solutions respectively as compared with the aqueous system. Numerous micellar, interfacial, and thermodynamic parameters have been measured by applying various theoretical models. The obtained changes in the physicochemical assets of AMT upon adding of 14-E2-14 are likely to enhance the industrial and pharmaceutical applications of gemini surfactants. The negative interaction parameters (βm and βσ), indicate synergistic attraction is occurring in the mixed systems. The aggregation number (Nagg), Stern–Volmer constant (Ksv), etc. are attained through the fluorescence method, also supporting the attractive interaction behavior of AMT+14-E2-14 mixtures in all solvents. The Nagg was found to increase in the salt solution and decrease in the urea system compared with the aqueous solution. FT-IR and UV-visible analysis also depict the interaction between the constituent alike tensiometry and fluorimetry methods. The results suggested that gemini surfactants may serve as a capable drug delivery agent for antidepressants, improving their bioavailability.

Aggregation and interfacial phenomenon of amphiphilic drug under the influence of pharmaceutical excipients (green/biocompatible gemini surfactant).

In the current study, we have examined the interaction amongst an antidepressant drug amitriptyline hydrochloride (AMH) and ethane-1, 2-diyl bis(N,N-dimethyl-N-cetylammoniumacetoxy) dichloride (16-E2-16, a green gemini surfactant) through tensiometric and fluorimetric techniques in aqueous/electrolyte/urea solutions. Significant variations are observed in the various evaluated parameters in the present study. Gemini 16-E2-16 has outstanding surface properties along with a much lower cmc value, demonstrating very little toxicity as well as considerable antimicrobial activity. The cmc values of mixtures decrease through increase in mole fraction (α1) of 16-E2-16, which specifies the nonideality of the solution mixtures, along with demonstrating the occurrence of mixed micellization too. Negative βRub values signify on the whole attractive force of interaction between constituents of mixed micelles. Owing to the incidence of electrolyte NaCl (50 mmol.kg–1), lowering of the micelles’ surface charge happens, resulting in aggregation taking place at lower concentration while the presence of urea (NH2CONH2) halts micellization taking place, which means the cmc value increases in the attendance of urea. The values for all systems were negative along with the presence of electrolyte/urea. The excess free energy (Gex) of studied mixed systems was also estimated and found to be negative for all the systems. Using the fluorescence quenching method, the micelle aggregation number (Nagg) was evaluated and it was found that the contribution of gemini surfactant was always more than that of the AMH and their value enhances in the existence of electrolyte while decreasing in the attendance of NH2CONH2 in the system. In addition, other fluorescence parameters such as micropolarity (I1/I3), dielectric constant (Dexp) as well as Stern–Volmer binding constants (Ksv) of mixed systems were evaluated and the results showed the synergistic performance of the AMH + 16-E2-16 mixtures. Along with tensiometric and fluorimetric techniques, FT-IR spectroscopy was also engaged to reveal the interaction among constituents.

Analyzing the interaction between porcine serum albumin (PSA) and ester-functionalized cationic gemini surfactants

Green gemini surfactants (m-E2-m) containing cleavable ester functionalities were allowed to interact with porcine serum albumin (PSA) and the binding mechanism along with concomitant physicochemical changes were analyzed using a multi-technique approach. Intrinsic fluorescence study reveals that the concerned gemini surfactants have a substantial affinity for PSA at a pH well above its isoelectric point. Static quenching is indicated by the relevant value of bimolecular quenching constant (kq). Synchronous, three-dimensional and pyrene fluorescence data depict the PSA−m-E2-m complex formation together with significant conformational changes induced in PSA. UV–vis studies are also indicative of ground state complexation involving the biomolecule and the amphiphile. Far-UV CD spectra indicate the stabilization of protein structure as deciphered by the increased α-helical content, whereas near-UV CD spectra signify a tertiary structure close to that of the native state. In order to validate the results obtained by fluorescence, cyclic voltammetry is employed, which unveils the formation of electrochemically inactive PSA−m-E2-m complex. Moreover, it is revealed that gemini with longer chain interacts more efficiently than the one with shorter chain owing to stronger hydrophobic forces. All these findings suggest that in future, the m-E2-m geminis may be potentially utilized as excipients in drug, skincare and immunoassay reagent formulations. Furthermore, results of this research work will also contribute in understanding the physicochemical effect of surfactant architecture on its interaction with biomacromolecules.

Unraveling the interaction of hemoglobin with a biocompatible and cleavable oxy-diester-functionalized gemini surfactant

Surfactant-protein mixtures have attracted considerable research interest in recent years at the interface of chemical biology and medicinal chemistry. Herein, the interaction between a green gemini surfactant (C16-E2O-C16) and a redox protein hemoglobin was examined through a series of in vitro experimental techniques with an attempt to provide a comprehensive knowledge of the surfactant-protein binding interactions. Quantitative appraisal of the fluorescence/CV data showed that the binding of C16-E2O-C16 to Hb leads to the formation of thermodynamically favorable non-covalent adduct with 1:1 stoichiometry. UV–vis spectra demonstrated that the effect of C16-E2O-C16 on Hb is highly concentration dependent. Far-UV and near-UV CD spectra together elucidated the formation of molten globule state of Hb upon C16-E2O-C16 addition. Temperature dependent CD explicated the effect of C16-E2O-C16 on the thermal stability of Hb. Furthermore, the structural investigation of Hb via pyrene/synchronous/three-dimensional fluorescence and FT-IR spectroscopy provided the complementary information related to its microenvironmental and conformational changes. Computational studies delineated that C16-E2O-C16 binds in the vicinity of β-37 Trp at the α1β2 interface of Hb. Overall, this study is expected to clarify the binding mechanism between Hb/other congeners and surfactant at the molecular level that are known to have immense potential in biomedical and industrial areas.

Effect of salt counterions on the physicochemical characteristics of novel green surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride

Abstract In this research article we have examined the effect of chloride (Cl−), sulphate (SO42−), phosphate (PO43−), anthranilate (An−) and tosylate (Tos−) counterions on the physicochemical characteristics of green gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14) through a multidimensional approach. Substantial changes were observed in the physicochemical parameters. Counterions were found to cause reduction in critical micellar concentration (CMC) and minimum area per head group ( A min ) of the 14-E2-14 gemini surfactant. However, increase in aggregation number (Ng) and surface excess concentration ( Γ max ) of the 14-E2-14 surfactant was observed upon increasing the counterion concentrations. The Gibbs free energies of micellization (ΔG°mic) and adsorption (ΔG°ads) were found to be negative, indicating that 14-E2-14 micellization is spontaneous. The order of efficacy of counterions to influence the micellar characteristics was: An− > Tos− > PO43− > SO42− > Cl−. Further, 1H NMR results demonstrated morphological transitions (sphere-to-rod) and newer phase formation. The UV–vis and FT-IR results delineate intercalation of organic counterions (An− and Tos−) into the palisade layer of 14-E2-14 micelles. TEM micrographs show emergence of non-spheroidal micelles at higher counterion concentrations. This study could be significant to surfactant science scientists in tailoring green surfactants with desirable physicochemical characteristics, so that special-characteristic-tailored surfactants could be exploited in designing and compilation of environmentally benign industrial, cosmetic and biomedical products.

Interaction of a green ester-bonded gemini surfactant with xanthine oxidase: Biophysical perspective

A multi technique approach was utilized to explore the interaction between a novel green gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14), with bovine milk xanthine oxidase (XO). Tensiometric, spectroscopic, microscopic and molecular modeling results demonstrate significant interaction and structural change of native xanthine oxidase upon 14-E2-14 combination. The results obtained in this study may be beneficial for scientists to calibrate conformation of the enzyme by novel biodegradable/green microstructures; consequently, it would likely add new impetus in understanding the treatment modes of various diseases like gout, hyperuricemia, liver and brain necrosis. Moreover, the 14-E2-14–XO interaction assists to unfurl new routes in the designing/selection of green-surfactant–protein mixtures widely used in food processing, cosmetics, and pharmaceutical industries.