1
|
Rimoli CV, de Oliveira Pedro R, Miranda PB. Interaction mechanism of chitosan oligomers in pure water with cell membrane models studied by SFG vibrational spectroscopy. Colloids Surf B Biointerfaces 2022; 219:112782. [PMID: 36063719 DOI: 10.1016/j.colsurfb.2022.112782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/10/2022] [Accepted: 08/17/2022] [Indexed: 11/20/2022]
Abstract
Chitosan is a versatile and biocompatible cationic antimicrobial polymer obtained from sustainable sources that is effective against a wide range of microorganisms. Although it is soluble only at low pH, chitosan oligomers (ChitO) are soluble in pure water and thus more appropriate for antibacterial applications. Although there is a vast literature on chitosan's antimicrobial activity, the molecular details of its interaction with biomembranes remain unclear. Here we investigate these molecular interactions by resorting to phospholipid Langmuir films (zwitterionic DPPC and anionic DPPG) as simplified membrane models (for mammalian and bacterial membranes, respectively), and using SFG vibrational spectroscopy to probe lipid tail conformation, headgroup dynamics and interfacial water orientation. For comparison, we also investigate the interactions of another simple cationic antimicrobial polyelectrolyte, poly(allylamine) hydrochloride - PAH. By forming the lipid films over the polyelectrolyte solutions, we found that both have only a very small interaction with DPPC, but PAH adsorption is able to invert the interfacial water orientation (membrane potential). This might explain why ChitO is compatible with mammalian cells, while PAH is toxic. In contrast, their interaction with DPPG films is much stronger, even more so for ChitO, with both insertion within the lipid film and interaction with the oppositely charged headgroups. Again, PAH adsorption inverts the membrane potential, while ChitO does not. Finally, ChitO interaction with DPPG is weaker if the antimicrobial is injected underneath a pre-assembled Langmuir film, and its interaction mode depends on the time interval between end of film compression and ChitO injection. These differences between ChitO and PAH effects on the model membranes highlight the importance of molecular structure and intermolecular interactions for their bioactivity, and therefore this study may provide insights for the rational design of more effective antimicrobial molecules.
Collapse
Affiliation(s)
- Caio Vaz Rimoli
- Sao Carlos Physics Institute, University of Sao Paulo, CP 369, Sao Carlos CEP 13560-970, SP, Brazil; Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
| | - Rafael de Oliveira Pedro
- Sao Carlos Physics Institute, University of Sao Paulo, CP 369, Sao Carlos CEP 13560-970, SP, Brazil; Department of exact and earth sciences, Minas Gerais State University (UEMG), Ituiutaba CEP 38302-192, MG, Brazil
| | - Paulo B Miranda
- Sao Carlos Physics Institute, University of Sao Paulo, CP 369, Sao Carlos CEP 13560-970, SP, Brazil.
| |
Collapse
|
2
|
Tran E, Mapile AN, Richmond GL. Peeling back the layers: Investigating the effects of polyelectrolyte layering on surface structure and stability of oil-in-water nanoemulsions. J Colloid Interface Sci 2021; 599:706-716. [PMID: 33984763 DOI: 10.1016/j.jcis.2021.04.115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/14/2021] [Accepted: 04/21/2021] [Indexed: 12/21/2022]
Abstract
HYPOTHESIS Layer-by-layer deposition of polyelectrolytes is a useful technique for modifying surface functionalities. For drug delivery systems, alternating layers of biopolymers coat nanoemulsions, which house and protect the cargo until the time and destination of delivery. Here, we investigate molecular factors contributing to the stability and interfacial properties of nanoemulsions prepared by a co-adsorption of polymers poly(styrene sulfonate) and polyethylenimine (PEI), and surfactant dodecyltrimethylammonium bromide. We hypothesize the interplay between electrosteric and hydrophobic effects upon multi-polymer co-adsorption contributes to both macroscopic and molecular-level interfacial properties of nanoemulsions. EXPERIMENTS To probe interfacial layering properties, we use vibrational sum frequency scattering spectroscopy with ζ-potential measurements to determine the adsorptive behavior and molecular conformational arrangement of the polymer layers. Complementing these interfacial studies are dynamic light scattering experiments measuring the nanoemulsion size distribution and polydispersity index over a 30-day period. FINDINGS Our light scattering, ζ-potential, and spectroscopic results of the nanoemulsion surface show that the duration of droplet stability and the degree of molecular orientation of adsorbed polymers can be tuned by surfactant concentration, PEI concentration, and pH. These results illustrate how molecular surface properties of multi-polymer coated nanoemulsions contribute to synergistic effects and droplet stability, enabling advancements in applications surrounding biopharmaceuticals, cosmetics, and food sciences.
Collapse
Affiliation(s)
- Emma Tran
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403, United States.
| | - Ashley N Mapile
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403, United States.
| | - Geraldine L Richmond
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403, United States.
| |
Collapse
|
3
|
Guzmán E, Rubio RG, Ortega F. A closer physico-chemical look to the Layer-by-Layer electrostatic self-assembly of polyelectrolyte multilayers. Adv Colloid Interface Sci 2020; 282:102197. [PMID: 32579951 DOI: 10.1016/j.cis.2020.102197] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/06/2020] [Accepted: 06/08/2020] [Indexed: 01/08/2023]
Abstract
The fabrication of polyelectrolyte multilayer films (PEMs) using the Layer-by-Layer (LbL) method is one of the most versatile approaches for manufacturing functional surfaces. This is the result of the possibility to control the assembly process of the LbL films almost at will, by changing the nature of the assembled materials (building blocks), the assembly conditions (pH, ionic strength, temperature, etc.) or even by changing some other operational parameters which may impact in the structure and physico-chemical properties of the obtained multi-layered films. Therefore, the understanding of the impact of the above mentioned parameters on the assembly process of LbL materials plays a critical role in the potential use of the LbL method for the fabrication of new functional materials with technological interest. This review tries to provide a broad physico-chemical perspective to the study of the fabrication process of PEMs by the LbL method, which allows one to take advantage of the many possibilities offered for this approach on the fabrication of new functional nanomaterials.
Collapse
|
4
|
Carr O, Raymundo-Pereira PA, Shimizu FM, Sorroche BP, Melendez ME, de Oliveira Pedro R, Miranda PB, Carvalho AL, Reis RM, Arantes LMRB, Oliveira ON. Genosensor made with a self-assembled monolayer matrix to detect MGMT gene methylation in head and neck cancer cell lines. Talanta 2019; 210:120609. [PMID: 31987176 DOI: 10.1016/j.talanta.2019.120609] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 11/28/2019] [Accepted: 11/30/2019] [Indexed: 12/24/2022]
Abstract
DNA methylation is involved in the oncogenesis of head and neck squamous cell carcinoma and could be used for early detection of cancer to increase the chances of cure, but unfortunately diagnosis is usually made at late stages of the disease. In this work we developed genosensors to detect DNA methylation of the MGMT gene in head and neck cancer cell lines. The probe for MGMT promoter methylation was immobilized on gold electrodes modified with 11-mercaptoundecanoic acid (11-MUA) self-assembled monolayers (SAM). Detection was performed with electrochemical impedance spectroscopy, with clear distinction between methylated and non-methylated DNA from head and neck cell lines. The genosensor is sensitive with a low detection limit of 0.24 × 10-12 mol L-1. In addition, the cell lines FaDu, JHU28 and SCC25 for the MGMT gene, could be distinguished from the HN13 cell line which has a high degree of MGMT methylation (97%), thus confirming the selectivity. Samples with different percentages of MGMT DNA methylation could be separated in multidimensional projections using the visualization technique interactive document mapping (IDMAP). The genosensor matrix and the immobilization procedures are generic, and can be extended to other DNA methylation biomarkers.
Collapse
Affiliation(s)
- Olivia Carr
- São Carlos Institute of Physics, University of São Paulo, 13566-590, São Carlos, Brazil
| | | | - Flávio M Shimizu
- São Carlos Institute of Physics, University of São Paulo, 13566-590, São Carlos, Brazil
| | - Bruna Pereira Sorroche
- Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil
| | - Matias Eliseo Melendez
- Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil
| | | | - Paulo B Miranda
- São Carlos Institute of Physics, University of São Paulo, 13566-590, São Carlos, Brazil
| | - André Lopes Carvalho
- Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil
| | - Rui M Reis
- Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil; Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Lídia M R B Arantes
- Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil
| | - Osvaldo N Oliveira
- São Carlos Institute of Physics, University of São Paulo, 13566-590, São Carlos, Brazil.
| |
Collapse
|
5
|
Silva HS, Miranda PB. Probing the Molecular Ordering and Thermal Stability of Azopolymer Layer-by-Layer Films by Second-Harmonic Generation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:9950-9959. [PMID: 27666122 DOI: 10.1021/acs.langmuir.6b02486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Polyelectrolyte layer-by-layer (LbL) films have many applications, but several parameters and procedures during film fabrication determine their morphology and molecular arrangement, with important practical consequences. Here we have used optical second-harmonic generation (SHG) to investigate the molecular ordering of LbL films containing the anionic azopolymer PS-119 and the cationic polyelectrolyte PAH. We show that spontaneous drying leads to laterally homogeneous and isotropic films, while the opposite occurs for nitrogen-flow drying. The effect of film thickness and pH of the assembling/rinsing solutions on the molecular ordering was also investigated. The optical nonlinearity tends to significantly decrease for thicker films (∼10 bilayers), and a slight alternation of SHG intensity for films with odd or even number of layers (complete vs incomplete bilayers) was also observed, which results from the reorientation of azopolymer groups in the last layer after adsorption of an additional PAH layer. We propose a qualitative electrostatic model to explain the pH dependence of film growth and azopolymer orientation, which is based on changes of the charge density of the substrate and PAH and on different ionic screening of electrostatic interactions at various pH values. We also found that the nonlinear response presents a gradual and significant reduction upon heating, which is inconsistent with a glass transition temperature for these ultrathin LbL films. The thermal stability is improved with a combination of low ionic strength and higher charge density of the polyelectrolytes and substrate, which promotes better interlayer complexation. The SHG signal is recovered upon cooling, although for some conditions the molecular arrangement became anisotropic after a heating/cooling cycle. Such detailed information about the structural order of thin nonlinear optical azopolymer LbL films demonstrates that SHG is a powerful technique to probe the film structure at the molecular level, with important consequences for their applications in optical devices.
Collapse
Affiliation(s)
- Heurison S Silva
- Universidade Federal do Piauí, Campus Universitário Ministro Petrônio Portella, Bairro: Ininga, CEP, 64049-550 Teresina, PI, Brazil
| | - Paulo B Miranda
- Instituto de Física de São Carlos, Universidade de São Paulo , CP 369, São Carlos, SP 13566-590, Brazil
- Center for Nano Science and Technology (CNST@POLIMI), Istituto Italiano di Tecnologia , Via Pascoli 70/3, Milan, MI 20133, Italy
- Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, Milan, MI 20133, Italy
| |
Collapse
|
6
|
Silva HS, Lopes FJS, Miranda PB. Molecular ordering of PAH/MA-co-DR13 azopolymer layer-by-layer films probed by second-harmonic generation. J Chem Phys 2016; 145:104902. [PMID: 27634274 DOI: 10.1063/1.4962341] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Molecular orientation within azopolymer thin films is important for their nonlinear optical properties and photonic applications. We have used optical second-harmonic generation (SHG) to study the molecular orientation of Layer-by-Layer (LbL) films of a cationic polyelectrolyte (poly(allylamine hydrochloride)) and an anionic polyelectrolyte containing azochromophore side groups (MA-co-DR13) on a glass substrate. The SHG measurements indicate that there is a preferential orientation of the azochromophores in the film, leading to a significant optical nonlinearity. However, both the signal strength and its anisotropy are not homogeneous throughout the sample, indicating the presence of large orientational domains. This is corroborated with Brewster angle microscopy. The average SHG signal does not increase with film thickness, in contrast to some reports in the literature, indicating an independent orientational order for successive bilayers. Analyzing the SHG signal as a function of the input and output polarizations, a few parameters of the azochromophore orientational distribution can be deduced. Fitting the SHG signal to a simple model distribution, we have concluded that the chromophores have an angular distribution with a slight in-plane anisotropy and a mean polar angle ranging from 45° to 80° with respect to substrate normal direction, with a relatively large width of about 25°. These results show that SHG is a powerful technique for a detailed investigation of the molecular orientation in azopolymer LbL films, allowing a deeper understanding of their self-assembling mechanism and nonlinear optical properties. The inhomogeneity and anisotropy of these films may have important consequences for their applications in nonlinear optical devices.
Collapse
Affiliation(s)
- Heurison S Silva
- Universidade Federal do Piauí - Campus Universitário Ministro Petrônio Portella, Bairro: Ininga, CEP: 64049-550 Teresina, PI, Brazil
| | - Fábio J S Lopes
- Universidade de São Paulo, Instituto de Pesquisa Energética e Nucleares, Cidade Universitária-IPEN, Av. Lineu Prestes 2242, CEP: 05508-000 São Paulo, SP, Brazil
| | - Paulo B Miranda
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal: 369, CEP: 13566-590 São Carlos, SP, Brazil
| |
Collapse
|
7
|
Ge A, Matsusaki M, Qiao L, Akashi M, Ye S. Salt Effects on Surface Structures of Polyelectrolyte Multilayers (PEMs) Investigated by Vibrational Sum Frequency Generation (SFG) Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3803-3810. [PMID: 27045932 DOI: 10.1021/acs.langmuir.5b04765] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy was employed to investigate the surface structures of polyelectrolyte multilayers (PEMs) constructed by sequentially alternating adsorption of poly(diallyldimethylammonium chloride) (PDDA) and poly(styrenesulfonate) (PSS). It was found that the surface structures and surface charge density of the as-deposited PEMs of PDDA/PSS significantly depend on the concentration of sodium chloride (NaCl) present in the polyelectrolyte solutions. Furthermore, it was found that the surface structure of the as-deposited PEMs is in a metastable state and will reach the equilibrium state by diffusion of the polyelectrolyte chain after an aging process, resulting in a polyelectrolyte mixture on the PEM surfaces.
Collapse
Affiliation(s)
- Aimin Ge
- Institute for Catalysis, Hokkaido University , Sapporo 001-0021, Japan
| | - Michiya Matsusaki
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University , Osaka 565-0871, Japan
| | - Lin Qiao
- Institute for Catalysis, Hokkaido University , Sapporo 001-0021, Japan
| | - Mitsuru Akashi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University , Osaka 565-0871, Japan
| | - Shen Ye
- Institute for Catalysis, Hokkaido University , Sapporo 001-0021, Japan
| |
Collapse
|
8
|
Gustafsson E, Hedberg J, Larsson PA, Wågberg L, Johnson CM. Vibrational Sum Frequency Spectroscopy on Polyelectrolyte Multilayers: Effect of Molecular Surface Structure on Macroscopic Wetting Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4435-4442. [PMID: 25859709 DOI: 10.1021/la5046207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adsorption of a single layer of molecules on a surface, or even a reorientation of already present molecules, can significantly affect the surface properties of a material. In this study, vibrational sum frequency spectroscopy (VSFS) has been used to study the change in molecular structure at the solid-air interface following thermal curing of polyelectrolyte multilayers of poly(allylamine hydrochloride) and poly(acrylic acid). Significant changes in the VSF spectra were observed after curing. These changes were accompanied by a distinct increase in the static water contact angle, showing how the properties of the layer-by-layer molecular structure are controlled not just by the polyelectrolyte in the outermost layer but ultimately by the orientation of the chemical constituents in the outermost layers.
Collapse
Affiliation(s)
- Emil Gustafsson
- †KTH Royal Institute of Technology, School of Chemical Science and Engineering, Wallenberg Wood Science Center, Teknikringen 42, SE-100 44 Stockholm, Sweden
- ‡KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - Jonas Hedberg
- §KTH Royal Institute of Technology, School of Chemical Science and Engineering, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Per A Larsson
- ‡KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - Lars Wågberg
- †KTH Royal Institute of Technology, School of Chemical Science and Engineering, Wallenberg Wood Science Center, Teknikringen 42, SE-100 44 Stockholm, Sweden
- ‡KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden
| | - C Magnus Johnson
- §KTH Royal Institute of Technology, School of Chemical Science and Engineering, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| |
Collapse
|
9
|
Ge A, Peng Q, Qiao L, Yepuri NR, Darwish TA, Matsusaki M, Akashi M, Ye S. Molecular orientation of organic thin films on dielectric solid substrates: a phase-sensitive vibrational SFG study. Phys Chem Chem Phys 2015; 17:18072-8. [DOI: 10.1039/c5cp02702k] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phase-sensitive SFG spectroscopy is employed to determine the absolute molecular orientation on the solid/air and solid/liquid interfaces.
Collapse
Affiliation(s)
- Aimin Ge
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Qiling Peng
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Lin Qiao
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Nageshwar R. Yepuri
- National Deuteration Facility
- Australian Nuclear Science and Technology Organization (ANSTO)
- Kirrawee DC
- Australia
| | - Tamim A. Darwish
- National Deuteration Facility
- Australian Nuclear Science and Technology Organization (ANSTO)
- Kirrawee DC
- Australia
| | - Michiya Matsusaki
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Osaka 565-0871
- Japan
| | - Mitsuru Akashi
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Osaka 565-0871
- Japan
| | - Shen Ye
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| |
Collapse
|
10
|
Costa RR, Testera AM, Arias FJ, Rodríguez-Cabello JC, Mano JF. Layer-by-layer film growth using polysaccharides and recombinant polypeptides: a combinatorial approach. J Phys Chem B 2013; 117:6839-48. [PMID: 23662646 DOI: 10.1021/jp4028518] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nanostructured films consisting of polysaccharides and elastin-like recombinamers (ELRs) are fabricated in a layer-by-layer manner. A quartz-crystal microbalance with dissipation monitoring (QCM-D) is used to follow the buildup of hybrid films containing one polysaccharide (chitosan or alginate) and one of several ELRs that differ in terms of amino acid content, length, and biofunctionality in situ at pH 4.0 and pH 5.5. The charge density of the ingredients at each pH is determined by measuring their ζ-potential, and the thickness of a total of 36 different films containing five bilayers is estimated using the Voigt-based viscoelastic model. A comparison of the values obtained reveals that thicker films can be obtained when working at a pH close to the acidity constant of the polysaccharide used (near-pKa conditions), suggesting that the construction of such films is more favorable when based on the presence of hydrophobic interactions between ELRs and partially neutralized polysaccharides. Further analysis shows that the molecular weight of the ELRs plays only a minor role in defining the growth tendency. When taken together, these results point to the most favorable conditions for constructing nanostructured films from natural and distinct recombinant polypeptides that can be tuned to exhibit specialized biofunctionality for tissue-engineering, drug-delivery, and biotechnological applications.
Collapse
Affiliation(s)
- Rui R Costa
- University of Minho, 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark, 4806-909 Caldas das Taipas, Guimarães, Portugal
| | | | | | | | | |
Collapse
|
11
|
Hong J, Han JY, Yoon H, Joo P, Lee T, Seo E, Char K, Kim BS. Carbon-based layer-by-layer nanostructures: from films to hollow capsules. NANOSCALE 2011; 3:4515-31. [PMID: 21845276 DOI: 10.1039/c1nr10575b] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Over the past years, the layer-by-layer (LbL) assembly has been widely developed as one of the most powerful techniques to prepare multifunctional films with desired functions, structures and morphologies because of its versatility in the process steps in both material and substrate choices. Among various functional nanoscale objects, carbon-based nanomaterials, such as carbon nanotubes and graphene sheets, are promising candidates for emerging science and technology with their unique physical, chemical, and mechanical properties. In particular, carbon-based functional multilayer coatings based on the LbL assembly are currently being actively pursued as conducting electrodes, batteries, solar cells, supercapacitors, fuel cells and sensor applications. In this article, we give an overview on the use of carbon materials in nanostructured films and capsules prepared by the LbL assembly with the aim of unraveling the unique features and their applications of carbon multilayers prepared by the LbL assembly.
Collapse
Affiliation(s)
- Jinkee Hong
- The National Creative Research Initiative Center for Intelligent Hybrids, The WCU Program of Chemical Convergence for Energy & Environment, School of Chemical and Biological Engineering, Seoul National University, Seoul, 151-744, Korea
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Chen Z. Investigating buried polymer interfaces using sum frequency generation vibrational spectroscopy. Prog Polym Sci 2010; 35:1376-1402. [PMID: 21113334 DOI: 10.1016/j.progpolymsci.2010.07.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This paper reviews recent progress in the studies of buried polymer interfaces using sum frequency generation (SFG) vibrational spectroscopy. Both buried solid/liquid and solid/solid interfaces involving polymeric materials are discussed. SFG studies of polymer/water interfaces show that different polymers exhibit varied surface restructuring behavior in water, indicating the importance of probing polymer/water interfaces in situ. SFG has also been applied to the investigation of interfaces between polymers and other liquids. It has been found that molecular interactions at such polymer/liquid interfaces dictate interfacial polymer structures. The molecular structures of silane molecules, which are widely used as adhesion promoters, have been investigated using SFG at buried polymer/silane and polymer/polymer interfaces, providing molecular-level understanding of polymer adhesion promotion. The molecular structures of polymer/solid interfaces have been examined using SFG with several different experimental geometries. These results have provided molecular-level information about polymer friction, adhesion, interfacial chemical reactions, interfacial electronic properties, and the structure of layer-by-layer deposited polymers. Such research has demonstrated that SFG is a powerful tool to probe buried interfaces involving polymeric materials, which are difficult to study by conventional surface sensitive analytical techniques.
Collapse
Affiliation(s)
- Zhan Chen
- Department of Chemistry, 930 North University Avenue, University of Michigan, Ann Arbor, MI 48109, United States
| |
Collapse
|
13
|
Abstract
This minireview describes the main developments of electronic tongues (e-tongues) and taste sensors in recent years, with a summary of the principles of detection and materials used in the sensing units. E-tongues are sensor arrays capable of distinguishing very similar liquids employing the concept of global selectivity, where the difference in the electrical response of different materials serves as a fingerprint for the analysed sample. They have been widely used for the analysis of wines, fruit juices, coffee, milk and beverages, in addition to the detection of trace amounts of impurities or pollutants in waters. Among the various principles of detection, electrochemical measurements and impedance spectroscopy are the most prominent. With regard to the materials for the sensing units, in most cases use is made of ultrathin films produced in a layer-by-layer fashion to yield higher sensitivity with the advantage of control of the film molecular architecture. The concept of e-tongues has been extended to biosensing by using sensing units capable of molecular recognition, as in films with immobilized antigens or enzymes with specific recognition for clinical diagnosis. Because the identification of samples is basically a classification task, there has been a trend to use artificial intelligence and information visualization methods to enhance the performance of e-tongues.
Collapse
Affiliation(s)
- Antonio Riul
- UFScar, campus Sorocaba, 18052-780 Sorocaba, SP, Brazil
| | | | | | | |
Collapse
|
14
|
Aoki PHB, Alessio P, Riul A, De Saja Saez JA, Constantino CJL. Coupling Surface-Enhanced Resonance Raman Scattering and Electronic Tongue as Characterization Tools to Investigate Biological Membrane Mimetic Systems. Anal Chem 2010; 82:3537-46. [DOI: 10.1021/ac902585a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pedro H. B. Aoki
- Faculdade de Ciências e Tecnologia, Unesp Univ Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil, Faculty of Science, University of Valladolid, Valladolid 47011, Spain, and Universidade Federal de São Carlos, campus Sorocaba/SP, 18043-970, Brazil
| | - Priscila Alessio
- Faculdade de Ciências e Tecnologia, Unesp Univ Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil, Faculty of Science, University of Valladolid, Valladolid 47011, Spain, and Universidade Federal de São Carlos, campus Sorocaba/SP, 18043-970, Brazil
| | - Antonio Riul
- Faculdade de Ciências e Tecnologia, Unesp Univ Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil, Faculty of Science, University of Valladolid, Valladolid 47011, Spain, and Universidade Federal de São Carlos, campus Sorocaba/SP, 18043-970, Brazil
| | - J. A. De Saja Saez
- Faculdade de Ciências e Tecnologia, Unesp Univ Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil, Faculty of Science, University of Valladolid, Valladolid 47011, Spain, and Universidade Federal de São Carlos, campus Sorocaba/SP, 18043-970, Brazil
| | - Carlos J. L. Constantino
- Faculdade de Ciências e Tecnologia, Unesp Univ Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil, Faculty of Science, University of Valladolid, Valladolid 47011, Spain, and Universidade Federal de São Carlos, campus Sorocaba/SP, 18043-970, Brazil
| |
Collapse
|