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Sánchez-Cepeda A, Cedeño E, Marín E, Pazos MC, Ingrid SC, Muñoz EDJ, Vera-Graziano R. Evaluation of the dispersion properties of graphene oxide/cetyltrimethylammonium bromide for application in nanocomposite materials. RSC Adv 2024; 14:3267-3279. [PMID: 38249673 PMCID: PMC10798003 DOI: 10.1039/d3ra04689c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
The properties of thermal diffusivity and Z potential of the GONPs/CTAB nanofluid were studied as a function of GO concentration (in the range between 4 and 12% w/v), temperature (35 and 50 °C) and time (30 and 60 min) under ultrasound. In turn, the structural properties of GONPs/CTAB were measured by XRD, Raman, SEM and TEM. The GO previously modified with CTAB was used to obtain a PLA/GO nanocomposite. It was found that the behavior of thermal diffusivity provides information in situ on the dispersion properties of the nanofluid, finding values from 0.0013 to 0.0024 cm2 s-1. The hydrodynamic diameter of the GONP dispersions was also determined to range from 75.83 to 360.3 nm with an increase in Z potential from 17 to 30 mV. The most stable GONPs/CTAB dispersion conditions were 6% w/v GO, 50 °C and 30 min. Under these conditions, the GONPs/CTAB materials present an increase in the spacing between GO layers, associated with a greater multilayer stacking of the GO and CTAB layers. The Raman spectrum allowed us to demonstrate that the modification with CTAB did not affect the crystallinity of GO, which was verified by the intensity ratio of the D band and the G band (ID/IG) for the GO/CTAB samples, with the exception of the GO 6% sample, where an increase in the ID/IG ratio (0.9) was observed compared to GO (0.82), associated with greater intercalation of CTAB between the GO sheets. Finally, an SEM analysis of the PLA/GO nanocomposite was carried out and the homogeneous distribution of GO in PLA was demonstrated when it is used as a filler in proportions of 0.1%. This treatment, in turn, contributed to improving the mechanical flexural properties of the nanocomposite materials.
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Affiliation(s)
- Angela Sánchez-Cepeda
- Facultad de Ciencias Básicas, Escuela de Posgrados, Universidad Pedagógica y Tecnológica de Colombia UPTC Avda. Central del Norte, Vía Paipa 150001 Tunja Boyacá Colombia
| | - E Cedeño
- Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Av. Legaria # 694, Col. Irrigación, Del. Miguel Hidalgo 11500 Ciudad de México Mexico
| | - E Marín
- Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Av. Legaria # 694, Col. Irrigación, Del. Miguel Hidalgo 11500 Ciudad de México Mexico
| | - M Carolina Pazos
- Escuela de Ciencias Química, Facultad de Ciencias, Universidad Pedagógica y Tecnológica de Colombia UPTC Avda. Central del Norte, Vía Paipa Tunja Boyacá Colombia
| | - Silva-Cote Ingrid
- Unidad de Terapia Celular, Instituto Distrital de Ciencia, Biotecnología e Innovación en salud. IDCBIS Cra 32 #12-81 0571 Bogotá Colombia
| | - Efrén de Jesús Muñoz
- Facultad de Ciencias Básicas, Escuela de Posgrados, Universidad Pedagógica y Tecnológica de Colombia UPTC Avda. Central del Norte, Vía Paipa 150001 Tunja Boyacá Colombia
| | - Ricardo Vera-Graziano
- Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México UNAM Avda Universidad, C.U., Coyoacán 04510 Ciudad de México Mexico
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Patil R, Ray D, Aswal VK, Bussy C, Bahadur P, Tiwari S. Adsorption of P103 Nanoaggregates on Graphene Oxide Nanosheets: Role of Electrostatic Forces in Improving Nanosheet Dispersion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:867-873. [PMID: 33400877 DOI: 10.1021/acs.langmuir.0c03206] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Graphene oxide (GO) nanosheet suspension is not stable in physiological ionic fluids. To improve stability, surfactants such as Pluronic 103 (P103) have been tested. Going further, this work investigated whether conferring positive surface charge to the surfactant may improve the adsorption ability of P103 micelles on GO sheets. Positive charge on the surfactant was induced by adding dodecyltrimethylammonium bromide (DTAB, a cationic surfactant) in P103 micelles. Subsequent changes in aggregation parameters were investigated through dynamic light scattering and small-angle neutron scattering studies. DTAB incorporation was accompanied by a steady increase in the ζ potential and mixed micelle formation. At high surface charge density, the interaction between adjacent head groups was distorted, which led to dissociation of mixed micelles. Structural developments during the adsorption of mixed micelles on the sheet surface (mass fractal formation) were monitored in terms of changes in the scattering features of aggregates. These fractals emerged as a result of electrostatic interactions. Our observations point toward the existence of small-sized building blocks at low DTAB concentration (≤4 mM). With a superior adsorption, mixed micelles are expected to occupy the intersheet space and maintain a hydration layer. However, at a higher DTAB concentration (≥10 mM), micelles dissociate to produce DTAB-rich unimers and P103-rich loose aggregates. At this point, sheets tend to aggregate in the solvent, regardless of fractal formation.
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Affiliation(s)
- Rahul Patil
- Maliba Pharmacy College, UKA Tarsadia University, Gopal-Vidyanagar Campus, Surat 394350, India
| | - Debes Ray
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Cyrill Bussy
- Nanomedicine Lab, School of Biological Sciences, and Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PR, U.K
- National Graphene Institute, The University of Manchester, Manchester M13 9PR, U.K
| | - Pratap Bahadur
- Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India
| | - Sanjay Tiwari
- Maliba Pharmacy College, UKA Tarsadia University, Gopal-Vidyanagar Campus, Surat 394350, India
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Das S, Behera S, Balasubramanian S. Orientational Switch of the Lipase A Enzyme at the Oil-Water Interface: An Order of Magnitude Increase in Turnover Rate with a Single Surfactant Tag Explained. J Phys Chem Lett 2020; 11:2977-2982. [PMID: 32202805 DOI: 10.1021/acs.jpclett.0c00470] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Interfacially active lipases can be immobilized at a biphasic interface to enhance turnover recyclability and to facilitate product separation. Extensive coarse-grained molecular dynamics simulations of lipase A (LipA) from Bacillus subtilis show a bimodal orientational distribution of the enzyme at an oil-water interface, arising from its ellipsoidal Janus particle-like character. The relative orientational preference can be tuned by pH. The simulations rationalize a rare experimental observation of an order of magnitude increase in the turnover rate of this lipase upon its noncovalent tagging by a single surfactant molecule at the interface, compared to its rate in bulk water. The adsorption free energy, the interfacial activation, a decrease in the number of orientational fluctuations, and an increased rate of translational diffusion, to all of which the Janus character of LipA contributes, are the factors responsible for this enhancement. This study can spur further investigations of the Janus behavior of enzymes to enhance their activity as well as to stabilize the biphasic emulsion needed for interfacial catalysis.
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Affiliation(s)
- Sudip Das
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064, India
| | - Sudarshan Behera
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064, India
| | - Sundaram Balasubramanian
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064, India
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4
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Choudhury P, Dinda S, Kumar Das P. Fabrication of soft-nanocomposites from functional molecules with diversified applications. SOFT MATTER 2020; 16:27-53. [PMID: 31693041 DOI: 10.1039/c9sm01304k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
With the increasing demand for new soft materials having excellent physical and biological characteristics and functionality, the design of hybrid materials offers a simple, yet versatile platform for the development of materials with specific and tunable properties. By definition a "soft-nanocomposite" is the combination of supramolecular self-assemblies with nanomaterials of different origins (inorganic/metallic nanoparticles and carbonaceous allotropes like carbon nanotubes and graphene) through covalent/non-covalent interactions. Dynamic supramolecular self-assemblies can serve as excellent hosts for the incorporation of these dimensionally different nanomaterials. Nanomaterials within the matrix of supramolecular self-assemblies can give rise to new characteristics due to the synergistic contribution of both materials. Although the very initial work intended to use molecular gels as media for the preparation and stabilization of nanoparticles, recent reports have suggested that amalgamation of different supramolecular self-assemblies with nanoparticles is advantageous for both constituents. These newly developed soft-nanocomposites have interesting properties including electrical conductivity, viscoelasticity, thermal robustness, magnetic, phase-selective, redox and near-infrared radiation sensitive properties and so on. This review will focus on some of the most recent advancements in the development of novel soft-nanocomposites. In particular, we intend to correlate various design strategies for synthesis as well as composite preparation from functional molecules with interesting applications in the area of supercapacitors, nanoelectronics, photovoltaic devices, chemical and biosensors, biomedicine and so on. We expect that this article will be a general and conceptual demonstration of various approaches to develop different soft-nanocomposites and will highlight their applications across disciplines.
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Affiliation(s)
- Pritam Choudhury
- School of Biological Sciences, Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032, India.
| | - Soumik Dinda
- School of Biological Sciences, Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032, India.
| | - Prasanta Kumar Das
- School of Biological Sciences, Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032, India.
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5
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Sun X, Bandara N. Applications of reverse micelles technique in food science: A comprehensive review. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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6
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Efficient preparation of cetyltrimethylammonium bromide-graphene oxide composite and its adsorption of Congo red from aqueous solutions. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.06.048] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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7
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Gao W, Li J, Yan X, Zhu B, Jia J, Huang A, Xie K, Bai Y. Accordion-like graphene by a facile and green synthesis method reinforcing polyolefin nanocomposites. RSC Adv 2017. [DOI: 10.1039/c7ra04139j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Scalable synthesis of accordion-like graphene via low temperature (below 170 °C) thermal expansion exfoliation of alkylated graphite oxide without any auxiliary equipment.
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Affiliation(s)
- Wensheng Gao
- MOE Key Laboratory for Magnetism and Magnetic Materials
- Institute of Material Science and Engineering
- Lanzhou University
- Lanzhou 730000
- PR China
| | - Jiangong Li
- MOE Key Laboratory for Magnetism and Magnetic Materials
- Institute of Material Science and Engineering
- Lanzhou University
- Lanzhou 730000
- PR China
| | - Xiaojie Yan
- MOE Key Laboratory for Magnetism and Magnetic Materials
- Institute of Material Science and Engineering
- Lanzhou University
- Lanzhou 730000
- PR China
| | - Bochao Zhu
- Lanzhou Petrochemical Research Center
- Petro China
- Lanzhou 730000
- PR China
| | - Junji Jia
- Lanzhou Petrochemical Research Center
- Petro China
- Lanzhou 730000
- PR China
| | - Anping Huang
- Lanzhou Petrochemical Research Center
- Petro China
- Lanzhou 730000
- PR China
| | - Kefeng Xie
- Lanzhou Petrochemical Research Center
- Petro China
- Lanzhou 730000
- PR China
| | - Yongxiao Bai
- MOE Key Laboratory for Magnetism and Magnetic Materials
- Institute of Material Science and Engineering
- Lanzhou University
- Lanzhou 730000
- PR China
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8
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9
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Sarkar S, Das K, Das PK. Hydrophobically Tailored Carbon Dots toward Modulating Microstructure of Reverse Micelle and Amplification of Lipase Catalytic Response. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3890-3900. [PMID: 27035762 DOI: 10.1021/acs.langmuir.5b04750] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This article delineates the modulation of microstructure of cationic reverse micelle utilizing hydrophobically modified carbon dots (CDs) with varying surface functionalizations. Citric acid was used as the source of the carbon core, and Na-salt of glycine, glycine, Na-salt of 11-aminoundecanoic acid, 11-aminoundecanoic acid, and n-hexadecylamine were used for the surface fabrication of CDs to produce CD 1s, CD 1a, CD 2s, CD 2a, and CD 3, respectively. All these CDs having dimension of 5-7 nm were characterized by spectroscopic and microscopic techniques. The hydrodynamic diameter of cetyltrimethylammonium bromide (CTAB) reverse micelle (CTAB/isooctane/n-hexanol/water) at z ([cosurfactant]/[surfactant]) = 6.4 and W0 ([water]/[surfactant]) = 44 is around 15-20 nm. Interestingly, the size of the water-in-oil (w/o) microemulsions dramatically increased up to 120-200 nm upon doping hydrophobic surface functionalized CD 2a and CD 3. This is possibly due to change in the micellar exchange dynamics and reorganization of the micellar aggregates via hydrophobic interaction between surfactant (CTAB) tail and hydrophobic surface modifier of the carbon dots. However, no alteration in the size of reverse micelles was noted in the presence of carbon dots CD 1s, CD 1a, and CD 2s. Spectroscopic and microscopic investigations confirmed that the hydrophobic CD 2a and CD 3 were localized at the interface of reverse micelles whereas CD 1s, CD 1a, and CD 2s were possibly located in the water pool (away from interface). The activity of Chromobacterium viscosum lipase encapsulated within CD 3 and CD 2a doped significantly large CTAB reverse micelles showed remarkable improvement (3.7-fold and 3.4-fold) in its catalytic response. However, hydrophilic carbon dots CD 1s and CD 2s as well as moderately hydrophobic CD 1a had no significant effect on the microstructure of reverse micelles as well as on the lipase activity.
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Affiliation(s)
- Saheli Sarkar
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
| | - Krishnendu Das
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
| | - Prasanta Kumar Das
- Department of Biological Chemistry, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India
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10
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Yang YJ, Yu X. Cetyltrimethylammonium bromide assisted self-assembly of phosphotungstic acid on graphene oxide nanosheets for selective determination of tryptophan. J Solid State Electrochem 2016. [DOI: 10.1007/s10008-016-3178-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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11
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Zhong X, Qian Y, Huang J, Yang D, Deng Y, Qiu X. Fabrication of Lignosulfonate Vesicular Reverse Micelles to Immobilize Horseradish Peroxidase. Ind Eng Chem Res 2016. [DOI: 10.1021/acs.iecr.5b04939] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiaowen Zhong
- School
of Chemistry and Chemical
Engineering, State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, People’s Republic of China
| | - Yong Qian
- School
of Chemistry and Chemical
Engineering, State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, People’s Republic of China
| | - Jinhao Huang
- School
of Chemistry and Chemical
Engineering, State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, People’s Republic of China
| | - Dongjie Yang
- School
of Chemistry and Chemical
Engineering, State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, People’s Republic of China
| | - Yonghong Deng
- School
of Chemistry and Chemical
Engineering, State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, People’s Republic of China
| | - Xueqing Qiu
- School
of Chemistry and Chemical
Engineering, State Key Lab of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, People’s Republic of China
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12
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Nooralian Z, Parvinzadeh Gashti M, Ebrahimi I. Fabrication of a multifunctional graphene/polyvinylphosphonic acid/cotton nanocomposite via facile spray layer-by-layer assembly. RSC Adv 2016. [DOI: 10.1039/c6ra00296j] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dispersibility and zeta potential of functionalized graphene in water with CTAB.
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Affiliation(s)
- Zoha Nooralian
- Young Researchers and Elites Club
- Yadegar-e-Imam Khomeini (RAH) Branch
- Islamic Azad University
- Tehran
- Iran
| | | | - Izadyar Ebrahimi
- Young Researchers and Elites Club
- Yadegar-e-Imam Khomeini (RAH) Branch
- Islamic Azad University
- Tehran
- Iran
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13
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Carmona-Ribeiro AM, Prieto T, Nantes IL. Nanostructures for peroxidases. Front Mol Biosci 2015; 2:50. [PMID: 26389124 PMCID: PMC4558528 DOI: 10.3389/fmolb.2015.00050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 08/19/2015] [Indexed: 11/13/2022] Open
Abstract
Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese, and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design, and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting, and reusability.
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Affiliation(s)
- Ana M Carmona-Ribeiro
- Biocolloids Laboratory, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo São Paulo, Brazil
| | - Tatiana Prieto
- NanoBioMav, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC Santo André, Brazil
| | - Iseli L Nantes
- NanoBioMav, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC Santo André, Brazil
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Bardhan S, Kundu K, Chakraborty G, Saha SK, Paul BK. The Schulman Method of Cosurfactant Titration of the Oil/Water Interface (Dilution Method): A Review on a Well-Known Powerful Technique in Interfacial Science for Characterization of Water-in-Oil Microemulsions. J SURFACTANTS DETERG 2015. [DOI: 10.1007/s11743-015-1694-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Yu X, Zou F, Yao P, Huang X, Qu Y. Gold nanoparticles tune the activity of laccase in anionic reverse micelles. SOFT MATTER 2014; 10:6425-6432. [PMID: 25046816 DOI: 10.1039/c4sm01127a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interfacial property of reverse micelles is an important factor affecting the catalytic activity of enzymes hosted in the micelles. In this article, the effect of gold nanoparticles (GNPs) on the catalytic activity of laccase (non-surface-active enzyme) and the related mechanism are reported. It was found that laccase activity was dependent on the size of the particle and its concentration as well as on the water content and the concentration of AOT. It was shown that there existed several types of micelles in the present reverse micellar system in the presence of GNPs. The population of the various micelles depended on the concentrations of both GNPs and AOT. Fluorescence and circular dichroism spectra of laccase at different water contents and GNP concentrations indicated that the conformation of laccase and its activity were tuned by GNPs via changing the structure of the reverse micelles. Analysis showed that changes in the thickness of the water layer (Lw) and in the apparent occupied area of individual AOT molecules (AAOT) caused by GNPs were the main parameters affecting the activity of laccase. The present work extends and deepens the understanding of the tuning mechanism of GNPs on enzymatic performance in reverse micelles and provides guidance for rational design of the optimal microenvironment of laccase.
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Affiliation(s)
- Xinxin Yu
- Key Laboratory of Colloid & Interface Chemistry of the Education Ministry of China, Shandong University, No. 27 Shanda Nanlu, Jinan 250100, PR China.
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16
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Das K, Maiti S, Das PK. Probing enzyme location in water-in-oil microemulsion using enzyme-carbon dot conjugates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2448-59. [PMID: 24528191 DOI: 10.1021/la403835h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This article delineates the formation and characterization of different enzyme-carbon dot conjugates in aqueous medium (pH = 7.0). We used soybean peroxidase (SBP), Chromobacterium viscosum (CV) lipase, trypsin, and cytochrome c (cyt c) for the formation of conjugate either with cationic carbon dot (CCD) or anionic carbon dot (ACD) depending on the overall charge of the protein at pH 7.0. These nanobioconjugates were used to probe the location of enzymes in water-in-oil (w/o) microemulsion. The size of the synthesized water-soluble carbon dots were of 2-3 nm with distinctive emission property. The formation of enzyme/protein-carbon dot conjugates in aqueous buffer was confirmed via fluorescence spectroscopy and zeta potential measurement, and the structural alteration of enzyme/protein was monitored by circular dichroism spectroscopy. Biocatalytic activities of protein/enzymes in conjugation with carbon dots were found to be decreased in aqueous phosphate buffer (pH 7.0, 25 mM). Interestingly, the catalytic activity of the nanobioconjugates of SBP, CV lipase, and cyt c did not reduce in cetyltrimethylammonium bromide (CTAB)-based reverse micelle. It indicates different localization of carbon dots and the enzymes inside the reverse micelle. The hydrophilic carbon dots always preferred to be located in the water pool of reverse micelle, and thus, enzyme must be located away from the water pool, which is the interface. However, in case of trypsin-carbon dot conjugate, the enzyme activity notably decreased in reverse micelle in the presence of carbon dot in a similar way that was observed in water. This implies that trypsin and carbon dots both must be located at the same place, which is the water pool of reverse micelle. Carbon dot induced deactivation was not observed for those enzymes which stay away from the water pool and localized at the interfacial domain while deactivation is observed for those enzymes which reside at the water pool. Thus, the location of enzymes in the microdomain of w/o microemulsion can be predicted by comparing the activity profile of enzyme-carbon dot conjugate in water and w/o microemulsion.
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Affiliation(s)
- Krishnendu Das
- Department of Biological Chemistry, Indian Association for the Cultivation of Science Jadavpur , Kolkata 700 032, India
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17
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Mondal P, Ghosal K, Bhattacharyya SK, Das M, Bera A, Ganguly D, Kumar P, Dwivedi J, Gupta RK, Martí AA, Gupta BK, Maiti S. Formation of a gold–carbon dot nanocomposite with superior catalytic ability for the reduction of aromatic nitro groups in water. RSC Adv 2014. [DOI: 10.1039/c4ra02837f] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Probing on the synthesis of gold-carbon dot nanocomposite for catalytic reduction of aromatic nitrogroup.
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Affiliation(s)
- Pritiranjan Mondal
- Department of Applied Chemistry and Industrial Chemistry
- Ramakrishna Mission Vidyamandira
- Howrah-711 202, India
| | - Krishanu Ghosal
- Department of Applied Chemistry and Industrial Chemistry
- Ramakrishna Mission Vidyamandira
- Howrah-711 202, India
| | | | - Mithun Das
- Department of Applied Chemistry and Industrial Chemistry
- Ramakrishna Mission Vidyamandira
- Howrah-711 202, India
| | - Abhijit Bera
- Department of Applied Chemistry and Industrial Chemistry
- Ramakrishna Mission Vidyamandira
- Howrah-711 202, India
| | - Debabrata Ganguly
- Department of Applied Chemistry and Industrial Chemistry
- Ramakrishna Mission Vidyamandira
- Howrah-711 202, India
| | - Pawan Kumar
- National Physical Laboratory (CSIR)
- New Delhi 110012, India
| | - Jaya Dwivedi
- National Physical Laboratory (CSIR)
- New Delhi 110012, India
| | - R. K. Gupta
- Department of Chemistry
- Pittsburg State University
- Pittsburg, USA
| | - Angel A. Martí
- Dept. of Chemistry and Bioengineering
- Rice University
- Houston, USA
| | | | - Subhabrata Maiti
- Department of Applied Chemistry and Industrial Chemistry
- Ramakrishna Mission Vidyamandira
- Howrah-711 202, India
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18
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Bardhan S, Kundu K, Saha SK, Paul BK. Physicochemical investigation of mixed surfactant microemulsions: water solubilization, thermodynamic properties, microstructure, and dynamics. J Colloid Interface Sci 2013; 411:152-61. [PMID: 24064004 DOI: 10.1016/j.jcis.2013.08.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/19/2013] [Accepted: 08/20/2013] [Indexed: 10/26/2022]
Abstract
In this contribution, we report on a systematic investigation of phase behavior and solubilization of water in water-in-heptane or decane aggregates stabilized by mixtures of polyoxyethylene (20) cetyl ether (Brij-58) and cetyltrimethylammonium bromide (CTAB) surfactants with varying compositions in conjugation with 1-pentanol (Pn) at fixed surfactant(s)/Pn ratio and temperature. Synergism in water solubilization was evidenced by the addition of CTAB to Brij-58 stabilized system in close proximity of equimolar composition in both oils. An attempt has been made to correlate composition dependent water solubilization and volume induced conductivity studies to provide insight into the solubilization mechanism of these mixed systems. Conductivity studies reveal the ascending curve in water solubilization capacity-(Brij-58:CTAB, w/w) profile as the interdroplet interaction branch indicating percolation of conductance and the descending curve is a curvature branch due to the rigidity of the interface in these systems. The microstructure of these systems as a function of surfactant composition has been determined by dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR) measurements. FTIR study reveals increase and decrease in relative population of bound and bulk-like water, respectively, with increase in Brij-58:CTAB (w/w). DLS measurements showed that the droplet hydrodynamic diameter (Dh) decreases significantly with the increase in Brij-58:CTAB (w/w). Further, the interfacial composition and energetic parameters for the transfer of Pn from bulk oil to the interface were evaluated by the dilution method. Formation of temperature-insensitive microemulsions and temperature invariant droplet sizes are evidenced in the vicinity of the equimolar composition. The results are interpreted in terms of a proposed mechanism.
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Affiliation(s)
- Soumik Bardhan
- Department of Chemistry, University of North Bengal, Darjeeling 734 013, India
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