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1.
J Environ Manage ; 367: 122069, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39098071

RESUMO

Studying the adsorption behavior of cationic surfactants can help to develop more effective strategies to limit their dispersion in the environment. However, there have few studies on the adsorption of cationic surfactants from the perspective of critical micelle concentration (CMC). In this study, with cetyltrimethylammonium bromide (CTAB) and octadecyl trimethylammonium bromide (OTAB) serving as the model cationic surfactants, the effect of CMC on the adsorption behavior of cationic surfactant onto the surface of sodium alginate/silica (SA/SiO2) microspheres was systematically revealed. The adsorption mechanism relative to CMC was investigated under different conditions, including surfactant concentration, pH, temperature, and adsorption time. The results suggest that at identical concentrations, the smaller the CMC value of the cationic surfactants, the greater the adsorption amount (qt). qt for CTAB and OTAB were 583.2 and 678.0 mg/g respectively, with the concentration higher than their CMC value. When the concentration was lower than the CMC value of the cationic surfactants, qt for CTAB and OTAB were 123.2 and 138.7 mg/g, respectively. The CMC value of CTAB was lower than that of OTAB under identical conditions, suggesting that the adsorption of cationic surfactants is related to their CMC. These results are beneficial for the removal of cationic surfactants by adsorption methods.


Assuntos
Cátions , Micelas , Microesferas , Dióxido de Silício , Tensoativos , Tensoativos/química , Adsorção , Dióxido de Silício/química , Cátions/química , Cetrimônio/química , Compostos de Cetrimônio/química , Alginatos/química , Concentração de Íons de Hidrogênio
2.
Chemistry ; 30(48): e202401144, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-38924574

RESUMO

We report a simple and versatile method for effectively replacing the toxic ligands, such as cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC), on the surface of Au nanospheres with different sizes by citrate. The method involves the deposition of an ultrathin shell of fresh Au in the presence of sodium citrate at an adequate concentration. After the ligand exchange process, multiple techniques are used to confirm that the surface of the resultant Au nanospheres is covered by citrate while there is no sign of aggregation. We also demonstrate the mitigation of cell toxicity after exchanging the surface-bound CTAB/CTAC with citrate, opening the door to a range of biomedical applications.


Assuntos
Cetrimônio , Ouro , Nanopartículas Metálicas , Nanosferas , Ouro/química , Cetrimônio/química , Nanosferas/química , Nanopartículas Metálicas/química , Humanos , Ácido Cítrico/química , Compostos de Cetrimônio/química , Tamanho da Partícula , Ligantes , Propriedades de Superfície , Sobrevivência Celular/efeitos dos fármacos
3.
J Nanobiotechnology ; 22(1): 254, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755625

RESUMO

AIM: The antifungal activity was studied on sessile and persister cells (PCs) of Candida tropicalis biofilms of gold nanoparticles (AuNPs) stabilized with cetyltrimethylammonium bromide (CTAB-AuNPs) and those conjugated with cysteine, in combination with Amphotericin B (AmB). MATERIALS/METHODS: The PC model was used and synergistic activity was tested by the checkerboard assay. Biofilms were studied by crystal violet and scanning electron microscopy. RESULTS/CONCLUSIONS: After the combination of both AuNPs and AmB the biofilm biomass was reduced, with significant differences in architecture being observed with a reduced biofilm matrix. In addition, the CTAB-AuNPs-AmB combination significantly reduced PCs. Understanding how these AuNPs aid in the fight against biofilms and the development of new approaches to eradicate PCs has relevance for chronic infection treatment.


Assuntos
Anfotericina B , Antifúngicos , Biofilmes , Candida tropicalis , Sinergismo Farmacológico , Ouro , Nanopartículas Metálicas , Testes de Sensibilidade Microbiana , Candida tropicalis/efeitos dos fármacos , Ouro/química , Ouro/farmacologia , Biofilmes/efeitos dos fármacos , Anfotericina B/farmacologia , Anfotericina B/química , Nanopartículas Metálicas/química , Antifúngicos/farmacologia , Antifúngicos/química , Cetrimônio/química , Compostos de Cetrimônio/farmacologia , Compostos de Cetrimônio/química
4.
J Virol Methods ; 327: 114918, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38556176

RESUMO

Wastewater-based epidemiology has allowed tracking the magnitude and distribution of SARS-CoV-2 in communities, allowing public health officials to prepare for impending outbreaks. While many factors influence recovery of SARS-CoV-2 from wastewater, proper extraction, concentration, and purification of RNA are key steps to ensure accurate detection of viral particles. The aim of this study was to compare the efficiency of four commonly used RNA extraction methods for detection of the SARS-CoV-2 RNA genome in sewage samples artificially inoculated with the virus, in order to identify a protocol that improves viral recovery. These methods included CTAB-based, TRIzol-based, and guanidinium thiocyanate (GTC)-based extraction procedures coupled with silica spin column-based purification, and an automated extraction/purification protocol using paramagnetic particles. Following RNA extraction, virus recovery rates were compared using RT-qPCR-based detection. The CTAB-based approach yielded the highest recovery rates and was the only method to consistently demonstrate stable virus recovery percentages regardless of the specific physicochemical characteristics of the samples tested. The TRIzol method proved to be the second most effective, yielding significantly higher recovery rates compared to both the GTC-based and the automated extraction methods. These results suggest that the CTAB-based approach could be a useful tool for the recovery of viral RNA from complex wastewater matrices.


Assuntos
Cetrimônio , RNA Viral , SARS-CoV-2 , Águas Residuárias , Águas Residuárias/virologia , RNA Viral/isolamento & purificação , RNA Viral/genética , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/genética , Cetrimônio/química , Humanos , Compostos de Cetrimônio/química , COVID-19/virologia , COVID-19/diagnóstico , Tiocianatos , Esgotos/virologia , Guanidinas
5.
Electrophoresis ; 45(15-16): 1307-1315, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38342679

RESUMO

Cationic surfactant coatings (e.g., CTAB) are commonly used in CE to control EOF and thereby improve separation efficiencies. However, our understanding of surfactant adsorption and desorption dynamics under EOF conditions is limited. Here, we apply automated zeta potential analysis to study the adsorption and desorption kinetics of CTAB in a capillary under different transport conditions: diameter, length, voltage alternation pattern and frequency, and applied pressure. In contrast to other studies, we observe slower kinetics at distinct capillary wall zeta potential ranges. Within these ranges, which we call "stagnant regimes," the EOF mobility significantly counteracts the electrophoretic (EP) mobility of CTA+ and hinders the net transport. By constructing a numerical model to compare with our experiments and recasting our experimental data in terms of the net CTA+ transport volume normalized by surface area, we reveal that the EP mobility of CTA+ and the capillary surface-area-to-volume ratio dictate the zeta potential range and the duration of the stagnant regime and thereby govern the overall reaction kinetics. Our results indicate that further transport-oriented studies can significantly aid in the understanding and design of electrokinetic systems utilizing CTAB and other charged surfactants.


Assuntos
Compostos de Cetrimônio , Cetrimônio , Eletroforese Capilar , Cetrimônio/química , Adsorção , Eletroforese Capilar/métodos , Compostos de Cetrimônio/química , Cinética , Tensoativos/química , Modelos Químicos , Eletro-Osmose/métodos
6.
ACS Sens ; 9(1): 337-343, 2024 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-38194413

RESUMO

Selective and sensitive detection of nitrite has important medical and biological implications. In the present work, to obtain an enhanced electrochemiluminescence (ECL) determination of nitrite, a novel nano-ECL emitter CoBIM/cetyltrimethylammonium bromide (CTAB) was prepared via a micelle-assisted, energy-saving, and ecofriendly method based on benzimidazole (BIM) and CTAB. Unlike conventional micelle assistance, the deprotonated BIM (BIM-) preferential placement was in the palisade layer of cationic CTAB-based micelles. Enriching the original CTAB micelle with BIM- disrupted its stability and resulted in the formation of considerably smaller BIM/CTAB-based micelles, providing a confined coordination environment for BIM- and Co2+. As a result, the growth of CoBIM/CTAB was also limited. Owing to the unusual nitration reaction between BIM and nitrite, the prepared CoBIM/CTAB was successfully applied as a novel ECL probe for the detection of nitrite with a wide linear range of 1-1500 µM and a low detection limit of 0.67 µM. This work also provides a promising ECL platform for ultrasensitive monitoring of nitrite and it was applied with sausages and pickled vegetables.


Assuntos
Compostos de Cetrimônio , Nitritos , Cetrimônio , Micelas , Benzimidazóis
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 309: 123770, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38157746

RESUMO

In this study, the complexation of potential chemo-therapeutic antibacterial drug, ciprofloxacin (CIP) with varying concentrations of surface active compounds (SACs) i.e., (N-(2-hydroxyethyl)-N,N-dimethyl-1-dodecanaminium bromide (12Cho.Br) and cetyltrimethylammonium bromide (CTAB) has been studied. Multispectroscopic techniques were exploited to carry out the study. The higher binding constant (Kb) value for CIP-CTAB than CIP-12Cho.Br obtained from fluorescence data revealed stronger binding of CTAB than 12Cho.Br, owing to the stronger hydrophobic-hydrophobic interaction betweeen CIP and CTAB compared to CIP and 12Cho.Br. The time resolve fluorescence decay shows changes in average lifetime (τavg) with the increasing concentration of 12Cho.Br and CTAB. The changes in τavg suggests that complex formation is taking place between CIP and 12Cho.Br / CTAB. Further, the formation of micelles by 12Cho.Br / CTAB and the effect of alkyl chain length was studied by dynamic light scattering (DLS) and zeta potential to confirm the drug complexation with 12Cho.Br and CTAB. The antibacterial activity has been performed for CIP and 12Cho.Br and CTAB. It was observed that in presence of lower concentrations of 12Cho.Br/ CTAB, the activity of the drug increased. The activity was also found cationic alkyl chain length dependent. Moreover, in-vitro cytotoxicity of CIP and its combinations with 12Cho.Br and CTAB was performed using MTT assay on HEK293 (Human embryonic kidney cells).


Assuntos
Ciprofloxacina , Líquidos Iônicos , Humanos , Cetrimônio , Ciprofloxacina/farmacologia , Líquidos Iônicos/química , Tensoativos/química , Colina , Células HEK293 , Compostos de Cetrimônio/farmacologia , Compostos de Cetrimônio/química , Micelas , Antibacterianos/farmacologia
8.
Water Res ; 246: 120738, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37866246

RESUMO

Traditional research on biodegradation of emerging organic pollutants involves slow and labor-intensive experimentation. Currently, fast-developing metagenome, metatranscriptome, and metabolome technologies promise to expedite mechanistic research on biodegradation of emerging organic pollutants. Integrating the metagenome, metatranscriptome, and metabolome (i.e., tri-omics) makes it possible to link gene abundance and expression with the biotransformation of the contaminant and the formation of metabolites from this biotransformation. In this study, we used this tri-omics approach to study the biotransformation pathways for cetyltrimethylammonium bromide (CTAB) under aerobic conditions. The tri-omics analysis showed that CTAB undergoes three parallel first-step mono-/di-oxygenations (to the α, ß, and ω-carbons); intermediate metabolites and expressed enzymes were identified for all three pathways, and the ß-carbon mono-/di-oxygenation is a novel pathway; and the genes related to CTAB biodegradation were associated with Pseudomonas spp. Four metabolites - palmitic acid, trimethylamine N-oxide (TMAO), myristic acid, and betaine - were the key identified biodegradation intermediates of CTAB, and they were associated with first-step mono-/di-oxygenations at the α/ß-C. This tri-omics approach with CTAB demonstrates its power for identifying promising paths for future research on the biodegradation of complex organics by microbial communities.


Assuntos
Poluentes Ambientais , Metagenoma , Cetrimônio , Compostos de Cetrimônio , Metaboloma
9.
Indian J Med Microbiol ; 46: 100478, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37769586

RESUMO

BACKGROUND: Most studies on biocide resistance and its genetic determinants arise from environmental or food-borne microbial isolates and only a few from clinically relevant isolates. OBJECTIVES: This study determines the proportion of biocide resistance against five commonly used biocides and detects biocide resistance genes among MDR bacterial isolates using PCR. METHODS: Consecutive MDR isolates (n â€‹= â€‹180) were included (30 each of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, and Enterococcus species) from clinical specimens of various inpatient units at JIPMER. The isolates were challenged at 0.5,1 and 2 Macfarland (McF) inoculum with discrete dilutions of disinfectants. The minimum bactericidal concentrations (MBCs) for 70% Ethanol, 1.5% Cresol, 2% Glutaraldehyde, 1% Cetrimide, and 1% Chlorhexidine were determined for the isolates using ATCC reference strains as controls. PCR was performed targeting qac A/B, G; smr; and nfx B genes. RESULTS: For all biocides, MDR isolates had MBCs less than the maximum MBCs of ATCC strains. For MDR K. pneumoniae, A. baumannii, and P. aeruginosa, the highest MBCs of chlorhexidine and cetrimide were ≥75 and â€‹≥ â€‹150 â€‹µg/ml respectively at 0.5 McF inoculum; whereas these organisms grew at higher inoculum (2McF) even at commercially recommended biocidal concentration (1%) corresponding to 750 and 1500 â€‹µg/ml of chlorhexidine and cetrimide respectively. Meanwhile, the highest MBCs of MDR E. coli were 75 and 150 â€‹µg/ml for chlorhexidine and cetrimide respectively. Interestingly, the Gram-positive cocci survived the action of up to 35% ethanol. The nfxB and qacG genes were detected in 87% and 6.67% of MDR P. aeruginosa isolates respectively with no biocide resistance genes detected among the other organisms. CONCLUSIONS: Biocide dilutions challenged with higher inoculum indicated a narrow margin of effectiveness for certain biocides. Although a significant proportion of clinical MDR isolates of P. aeruginosa harbored biocide resistance genes, this finding had no phenotypic correlation.


Assuntos
Desinfetantes , Humanos , Desinfetantes/farmacologia , Clorexidina , Escherichia coli , Centros de Atenção Terciária , Testes de Sensibilidade Microbiana , Etanol , Compostos de Cetrimônio , Antibacterianos/farmacologia
10.
Environ Sci Pollut Res Int ; 30(41): 94474-94484, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37535279

RESUMO

Cocoa shell was modified whit sodium hydroxide (NaOH) and cationic surfactant cetyltrimethylammonium bromide (CTAB) to increase surface functionality, surface area, and positive charge density. The prepared adsorbent CC-OH-CTAB was used to remove indigo carmine (IC) and bromocresol green (BCG) dyes from water. The optimal pH for IC and BCG adsorption were 2 and 4, respectively. The equilibrium was attained after a contact time of 30 min for IC and 120 min for BCG. The maximum adsorption capacity (Qmax) of IC and BCG obtained was 85.1 mg g-1 and 192.7 mg g-1, respectively. The Liu isotherm model best described the equilibrium results. The adsorption kinetics model showed that IC and BCG adsorption onto CC-OH-CTAB followed the pseudo-first-order and pseudo-second-order model, respectively. The regeneration and reusability experiments indicated that CC-OH-CTAB had much stability and excellent performance meanwhile repeatedly used. Finally, the insertion of CTAB on the CC-OH surface proved to be an excellent way to improve the adsorption performance of this material concerning dyes.


Assuntos
Corantes , Poluentes Químicos da Água , Cetrimônio , Corantes/química , Adsorção , Compostos de Cetrimônio/química , Índigo Carmim , Cinética , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio
11.
Aust Endod J ; 49(3): 530-536, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37464569

RESUMO

The objective of this research was to evaluate the efficacy of diclofenac sodium solutions, with or without cetrimide (CTR) added, against polymicrobial root canal biofilms grown in dentin specimens. The study groups were: (1) 5% diclofenac sodium (DCS); (2) 2.5% DCS; (3) 2.5% DCS + 0. 2% CTR; (4) 2.5% DCS + 0.4% CTR and (5) 0.9% saline solution (SS) as the control. After 5 min of solution contact with the biofilms, the antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay as well as confocal laser scanning microscopy (CLSM). Microbial quantification was indicated as the percentage reduction of relative light units (RLUs) for the ATP assay, the Log10 total biovolume and the viability percentage (green cells) for CLSM. Solutions of 2.5% DCS + 0.4% CTR and 5% DCS showed the highest antimicrobial efficacy. Cetrimide increased the antibiofilm activity of diclofenac sodium against endodontic biofilms.


Assuntos
Anti-Infecciosos , Diclofenaco , Diclofenaco/farmacologia , Cavidade Pulpar , Hipoclorito de Sódio/farmacologia , Irrigantes do Canal Radicular/farmacologia , Cetrimônio , Compostos de Cetrimônio , Biofilmes , Trifosfato de Adenosina , Enterococcus faecalis , Microscopia Confocal , Dentina
12.
Soft Matter ; 19(7): 1429-1439, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36723251

RESUMO

Catanionic surfactant vesicles (SVs) composed of sodium dodecylbenzenesulfonate (SDBS) and cetyltrimethylammonium tosylate (CTAT) have potential applications as targeted drug delivery systems, vaccine platforms, and diagnostic tools. To facilitate these applications, we evaluated various methods to attach proteins to the surface of SDBS/CTAT vesicles. Acid phosphatase from wheat germ was used as a model protein. Acid phosphatase was successfully conjugated to vesicles enriched with a Triton-X 100 derivative containing an unsaturated ester. Enzymatic activity of acid phosphatase attached to vesicles was assessed using an acid phosphatase assay. Results from the acid phosphatase assay indicated that 15 ± 3% of the attached protein remained functional but the presence of vesicles interferes with the assay. DLS and zeta potential results correlated with the protein functionalization studies. Acid phosphatase functionalized vesicles had an average diameter of 175 ± 85 nm and an average zeta potential of -61 ± 5 mV in PBS. As a control, vesicles enriched with Triton-X 100 were prepared and analyzed by DLS and zeta potential measurements. Triton X-100 enriched vesicles had an average diameter of 140 ± 67 nm and an average zeta potential of -49 ± 2 mV in PBS. Functionalizing the surface of SVs with proteins may be a key step in developing vesicle-based technologies. For drug delivery, antibodies could be used as targeting molecules; for vaccine formulation, functionalizing the surface with spike proteins may produce novel vaccine platforms.


Assuntos
Compostos de Cetrimônio , Tensoativos , Sistemas de Liberação de Medicamentos , Fosfatase Ácida
13.
Chemistry ; 29(27): e202203764, 2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-36808662

RESUMO

The emergence of catalytic activity associated with a disassembly process is reported, reminiscent of complex biological systems. A cystine derivative with pendant imidazole groups self-assembles into cationic nanorods in the presence of the cationic surfactants cetylpyridinium chloride (CPC) or cetyltrimethylammonium bromide (CTAB). Disulfide reduction triggers nanorod disassembly and the generation of a simple cysteine protease mimic, which shows a dramatically improved catalytic efficiency in the hydrolysis of p-nitrophenyl acetate (PNPA).


Assuntos
Cisteína Proteases , Nanotubos , Cetrimônio , Tensoativos , Compostos de Cetrimônio , Cátions
14.
Dalton Trans ; 52(4): 1052-1061, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36602082

RESUMO

The spectrum and size controllable synthesis of gold nanorods is of great value for their widely applicable aspect ratio dependence of anisotropic surface plasmon resonance. Herein, 1,7-dihydroxynaphthalene with a relatively strong reducibility is proposed as a reducing agent for the controllable synthesis of gold nanorods. The result indicated that gold nanorods with high monodispersity, high shape yield, relatively small diameters, and maximum plasmon resonance wavelength of above 1000 nm can be acquired. More importantly, by virtue of the reducing agent used, fine and precise controls over the plasmon wavelength and diameter of the rod can be achieved via changes in experimental conditions. In particular, increases in the concentration of both silver ions and cetyltrimethylammonium bromide (CTAB) can increase the plasmon wavelength from around 600 nm to 1000 nm but respectively show a decreased diameter with the smallest value of around 14.3 nm and a mildly increased diameter from around 9.0 nm to 14.3 nm; moreover, increasing the concentration of reducing agents and gold seeds can simultaneously cause decreases in the plasmon wavelength from around 1000 nm to 800 nm and the diameters from around 14.3 nm to 9.0 and 7.3 nm, respectively. This powerful and efficient method of controllable synthesis of AuNRs could be valuable and attractive for the application of the as-obtained particles.


Assuntos
Nanotubos , Substâncias Redutoras , Ouro , Cetrimônio , Compostos de Cetrimônio
15.
J Colloid Interface Sci ; 631(Pt A): 202-211, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36375300

RESUMO

HYPOTHESIS: Quatsome nanovesicles, formed through the self-assembly of cholesterol (CHOL) and cetyltrimethylammonium bromide (CTAB) in water, have shown long-term stability in terms of size and morphology, while at the same time exhibiting high CHOL-CTAB intermolecular binding energies. We hypothesize that CHOL/CTAB quatsomes are indeed thermodynamically stable nanovesicles, and investigate the mechanism underlying their formation. EXPERIMENTS: A systematic study was performed to determine whether CHOL/CTAB quatsomes satisfy the experimental requisites of thermodynamically stable vesicles. Coarse-grain molecular dynamics simulations were used to investigate the molecular organization in the vesicle membrane, and the characteristics of the simulated vesicle were corroborated with experimental data obtained by cryo-electron microscopy, small- and wide-angle X-ray scattering, and multi-angle static light scattering. FINDINGS: CHOL/CTAB quatsomes fulfill the requisites of thermodynamically stable nanovesicles, but they do not exhibit the classical membrane curvature induced by a composition asymmetry between the bilayer leaflets, like catanionic nanovesicles. Instead, CHOL/CTAB quatsomes are formed through the association of intrinsically planar bilayers in a faceted vesicle with defects, indicating that distortions in the organization and orientation of molecules can play a major role in the formation of thermodynamically stable nanovesicles.


Assuntos
Compostos de Cetrimônio , Simulação de Dinâmica Molecular , Cetrimônio , Microscopia Crioeletrônica , Compostos de Cetrimônio/química , Colesterol/química , Bicamadas Lipídicas/química
16.
Langmuir ; 38(48): 14768-14778, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36437713

RESUMO

A catanionic surfactant system is an aqueous solution or dispersion of cationic and anionic surfactants that spontaneously self-assemble into structures such as micelles, vesicles, and coacervates. Their structural diversity varies depending on the ratios of cationic and anionic surfactants (compositions), the chemical structure of the constituent molecules, etc. Herein, two types of catanionic surfactant systems were systematically characterized: (i) cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), both typical ionic surfactants; and (ii) dodecylmethylimidazolium ammonium bromide ([C12mim]Br) and SDS, where the former is an ionic liquid. By observing the sample appearance, turbidity, and particle size, the phase state of each system was analyzed according to the total concentration of surfactants and the molar ratio of cationic surfactants to the total concentration. Especially, for specific compositions of catanionic surfactant vesicles (cataniosome), the closed structure of the vesicles was confirmed through calcein entrapment and release detected with a fluorescence assay. The polarities of the interface of the prepared self-assemblies were evaluated using a fluorescence probe, Laurdan. The packing state of the molecules in the formed self-assembly structure was estimated using Raman spectroscopy. The results clearly indicate consistent phase-transition behavior for the CTAB-SDS (i) and [C12mim]Br-SDS (ii) systems, depending on the total surfactant concentration and composition, while the membrane properties of the two systems differed. The cataniosome formed in the CTAB-SDS system was in a tightly packed membrane state and more hydrophobic than that formed in the [C12mim]Br-SDS system owing to the difference in the structure of the constituting molecule: [C12mim]Br has a larger head group and shorter acyl chain than CTAB. The self-assembly properties evaluated in this study were compared with those of typical lipid membranes, liposomes (lipid vesicles), to determine a possible application of the catanionic systems with various self-assembly formulations.


Assuntos
Surfactantes Pulmonares , Tensoativos , Tensoativos/química , Cetrimônio , Dodecilsulfato de Sódio/química , Compostos de Cetrimônio/química , Cátions/química , Excipientes
17.
Molecules ; 27(14)2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35889205

RESUMO

In recent years, there has been increasing interest in daily-use chemical products providing a pleasant scent. The added fragrance molecules may induce microstructural transitions of surfactant aggregates, which further affect the physical and chemical properties of the products. Here, the effects of four types of aromatic alcohols (cinnamyl alcohol, phenyl ethanol, phenyl methanol and anisyl alcohol) on cetyltrimethylammonium bromide (CTAB)/KBr aggregates were studied. The combined results from rheology, dynamic light scattering, and transmission electron microscopy measurements showed that cinnamyl alcohol induced significant micellar growth, while increases in micellar growth were less obvious for the other aromatic alcohols. The changes in the interfacial molarities of water, aromatic alcohol, and bromide ions during such transitions were studied using the chemical trapping method. Transitions resulting from added cinnamyl alcohol were accompanied by significant declines in interfacial water and bromide ion molarities, and a rise in interfacial alcohol molarity. The marked decrease in interfacial water molarity was not observed in previous studies of the octanol induced formation of wormlike micelles and vesicles, indicating that a different mechanism was presented in the current system. Nuclear magnetic resonance investigation showed that π-π stacking between cinnamyl alcohols, but not cation-π interactions between alcohols and CTAB headgroups, facilitated the tight packing of alcohol molecules in CTAB aggregates and the repulsion of water from the interfacial region. The current study may provide a theoretical basis for the morphological regulation of surfactant aggregates in the presence of additives.


Assuntos
Surfactantes Pulmonares , Tensoativos , Brometos , Cetrimônio , Compostos de Cetrimônio/química , Excipientes , Micelas , Odorantes , Tensoativos/química , Água/química
18.
Appl Opt ; 61(10): 2864-2868, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35471371

RESUMO

The major goal of this study was to find predictors of plasmon positions in silver nanorod (NR) optical absorption spectra. The goal of this study is to use an adaptive neural fuzzy inference system to identify the various input parameters for longitudinal surface plasmon resonance (LSPR) and transverse surface plasmon resonance (TSP). A seed strategy has been used for preparation of the silver NRs. During the preparation, the seed particles are synthesized in the presence of cetyltrimethylammonium bromide (CTAB). To produce the silver NRs, metal salt (AgNO3) has been added, as well as ascorbic acid (AA) and CTAB. Skillful prediction could play a pivotal role in the plasmon NR production management. The combination of CTAB and the seeds has the largest influence on the TSPR. The combination of CTAB and AA has the largest influence on the LSPR. The study considering different input parameters simultaneously, to the best of our knowledge, is the first on a small scale and should attract great general interest.


Assuntos
Nanotubos , Prata , Cetrimônio , Compostos de Cetrimônio , Ouro
19.
Langmuir ; 38(8): 2486-2494, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35164504

RESUMO

Although worm-like micelles were invented 35 years ago, its formation pathway remains unclear. Inspired by the fact that a single molecular level experiment could provide meaningful and additional information, especially in a heterogeneous subpopulation, herein, we present a single molecular level study on the formation of wormlike micelles by cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) in water. Our results indicated a coexistence of normal spherical micelles along with a big wormlike micelle in its formation path. More interestingly, we have two unique insights into the formation mechanism, which are inaccessible in ensemble averaged experiments: (i) at extremely low concentrations of the surfactant, [CTAB]/[NaSal] ∼ 0.06, the wormlike micelle attains the highest size; and (ii) the relative concentration of wormlike micelles is highest when [CTAB]/[NaSal] ∼ 2.


Assuntos
Compostos de Cetrimônio , Micelas , Cetrimônio , Compostos de Cetrimônio/química , Espectrometria de Fluorescência , Tensoativos/química
20.
J Colloid Interface Sci ; 610: 785-795, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34876264

RESUMO

HYPOTHESIS: Molecular interactions between 4-OH-cinnamate and cetrimonium in solution result in improved adsorption of the cinnamate on mild steel, developing a protective mechanism against the diffusion of corrosive chloride to the oxide surface. Fundamental understanding of this mechanism should allow new design routes for the development of eco-friendly corrosion inhibitors. EXPERIMENTS: Via classic molecular dynamics, simulations were carried out for cetrimonium and 4-OH-cinnamate in aqueous solutions at different ionic strengths and the results were validated with experimental SAXS data. Self-aggregation of cetrimonium 4-OH-cinnamate on a hydrated hematite surface was then simulated and results were compared with cryo-TEM imaging for the same compound. Finally, the effect of the adsorbed aggregates on chloride diffusion to the oxide surface was modelled. FINDINGS: Simulations showed the encapsulation of 4-OH-cinnamate into cetrimonium micelles, consistent with experiments. The newly formed micelles adsorb onto a hydrated iron oxide surface by forming hydrogen bonds between their carboxylate outer-shell groups and the surface hydroxyls. As the adsorbate concentrations increase, there is a morphological transition from spherical to wormlike adsorbed aggregates. The wormlike structure can block chloride ions, demonstrating a synergistic inhibitory mechanism between both cetrimonium and 4-OH-cinnamate. Encapsulation and delivery of active compounds to certain targets, such as carcinogenic tumors, have been well studied in biochemistry research, we demonstrate that the same mechanism can be applied to the design of efficient corrosion inhibitors, optimizing their delivery to the metal surface.


Assuntos
Cinamatos , Micelas , Cetrimônio , Compostos de Cetrimônio , Compostos Férricos , Espalhamento a Baixo Ângulo , Tensoativos , Difração de Raios X
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