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Li T, Bandari VK, Schmidt OG. Molecular Electronics: Creating and Bridging Molecular Junctions and Promoting Its Commercialization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209088. [PMID: 36512432 DOI: 10.1002/adma.202209088] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/28/2022] [Indexed: 06/02/2023]
Abstract
Molecular electronics is driven by the dream of expanding Moore's law to the molecular level for next-generation electronics through incorporating individual or ensemble molecules into electronic circuits. For nearly 50 years, numerous efforts have been made to explore the intrinsic properties of molecules and develop diverse fascinating molecular electronic devices with the desired functionalities. The flourishing of molecular electronics is inseparable from the development of various elegant methodologies for creating nanogap electrodes and bridging the nanogap with molecules. This review first focuses on the techniques for making lateral and vertical nanogap electrodes by breaking, narrowing, and fixed modes, and highlights their capabilities, applications, merits, and shortcomings. After summarizing the approaches of growing single molecules or molecular layers on the electrodes, the methods of constructing a complete molecular circuit are comprehensively grouped into three categories: 1) directly bridging one-molecule-electrode component with another electrode, 2) physically bridging two-molecule-electrode components, and 3) chemically bridging two-molecule-electrode components. Finally, the current state of molecular circuit integration and commercialization is discussed and perspectives are provided, hoping to encourage the community to accelerate the realization of fully scalable molecular electronics for a new era of integrated microsystems and applications.
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Affiliation(s)
- Tianming Li
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Vineeth Kumar Bandari
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Oliver G Schmidt
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
- Nanophysics, Dresden University of Technology, 01069, Dresden, Germany
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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.
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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.
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Moreira LG, Almeida AM, Nield T, Camacho SA, Aoki PHB. Modulating photochemical reactions in Langmuir monolayers of Escherichia coli lipid extract with the binding mechanisms of eosin decyl ester and toluidine blue-O photosensitizers. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 218:112173. [PMID: 33799010 DOI: 10.1016/j.jphotobiol.2021.112173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 02/08/2023]
Abstract
Photodynamic damage to the cell envelope can inactivate microorganisms and may be applied to combat super-resistance phenomenon, empowered by the indiscriminate use of antibiotics. Efficiency in microbial inactivation is dependent on the incorporation of photosensitizers (PS) into the bacterial membranes to trigger oxidation reactions under illumination. Herein, Langmuir monolayers of Escherichia coli lipid extract were built to determine the binding mechanisms and oxidation outcomes induced by eosin decyl ester (EosDEC) and toluidine blue-O (TBO) PSs. Surface-pressure isotherms of the E. coli monolayers were expanded upon EosDEC and TBO, suggesting incorporation of both PSs. Fourier-transform infrared spectroscopy (FTIR) of Langmuir-Schaefer (LS) films reveled that the EosDEC and TBO binding mechanisms are dominated by electrostatic interactions with the anionic polar groups, with limited penetration into the chains. Light-irradiation reduced the relative area of E. coli monolayer on TBO, indicating an increased loss of material to the subphase owing to the chain cleavage, generated by contact-dependent reactions with excited states of TBO. In contrast, the increased relative area of E. coli monolayers containing EosDEC suggests lipid hydroperoxidation, which is PS contact-independent. Even considering a small chain penetration, the saturated EosDEC may have partitioned towards saturated reach domains, avoiding direct contact with membrane unsaturations.
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Affiliation(s)
- Lucas G Moreira
- Saõ Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil
| | - Alexandre M Almeida
- Saõ Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil
| | - Tyler Nield
- Saõ Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil; Faculty of Engineering, University of Victoria, Victoria, BC V8P 5C2, Canada
| | - Sabrina A Camacho
- Saõ Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil; IFSC, São Carlos Institute of Physics, University of São Paulo (USP), São Carlos, SP 13566-590, Brazil
| | - Pedro H B Aoki
- Saõ Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil.
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Awasthi N, Kopec W, Wilkosz N, Jamróz D, Hub JS, Zatorska M, Petka R, Nowakowska M, Kepczynski M. Molecular Mechanism of Polycation-Induced Pore Formation in Biomembranes. ACS Biomater Sci Eng 2018; 5:780-794. [PMID: 33405839 DOI: 10.1021/acsbiomaterials.8b01495] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Polycations are an attractive class of macromolecules with promising applications as drug/gene carriers and biocides. The chemical structure and concentration of a polycation determine its interaction with cellular membranes and, hence, are crucial parameters for designing efficient nontoxic polycations. However, the interaction of polycations with biomembranes at the molecular level and the corresponding free-energy landscape is not well understood. In this work, we investigate the molecular mechanism of interaction between a strong polycation substituted with alkyl moieties and zwitterionic membranes via long-time-scale all-atom molecular dynamics simulations and free-energy calculations combined with Langmuir monolayer, atomic force microscopy, and calcein-release experimental measurements. We found that the membrane activity of the polycation and its ability to induce pores in the membranes can be attributed to the polycation-induced changes in the bilayer organization, such as reduced membrane thickness, increased disorder of the acyl chains, reduced packing, and electrostatic field gradients between membrane leaflets. These changes facilitate the penetration of water into the membrane and the formation of aqueous defects/pores. The calculated free-energy profiles indicate that the polycation lowers the nucleation barrier for pore opening and the free energy for pore formation in a concentration-dependent manner. Above the critical coverage of the membrane, the polycation nucleates spontaneous pores in zwitterionic membranes. Our work demonstrates the potential of combining enhanced sampling methods in MD simulations with experiments for a quantitative description of various events in the polycation-membrane interaction cycle, such as strong adsorption on the membrane due to hydrophobic and electrostatic interactions, and pore formation.
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Affiliation(s)
- Neha Awasthi
- Institute for Microbiology and Genetics, Georg-August-Universität, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Wojciech Kopec
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Natalia Wilkosz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Dorota Jamróz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Jochen S Hub
- Institute for Microbiology and Genetics, Georg-August-Universität, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Maria Zatorska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Rafał Petka
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Maria Nowakowska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Mariusz Kepczynski
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
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Ruiz-Rincón S, González-Orive A, de la Fuente JM, Cea P. Reversible Monolayer-Bilayer Transition in Supported Phospholipid LB Films under the Presence of Water: Morphological and Nanomechanical Behavior. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7538-7547. [PMID: 28691823 DOI: 10.1021/acs.langmuir.7b01268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mixed monolayer Langmuir-Blodgett (LB) films of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol (Chol) in the 1:1 ratio have been prepared onto solid mica substrates. Upon immersion in water or in an aqueous HEPES solution (pH 7.4) the monolayer LB films were spontaneously converted into well-organized bilayers leaving free mica areas. The process has been demonstrated to be reversible upon removal of the aqueous solution, resulting in remarkably free of defects monolayers that are homogeneously distributed onto the mica. In addition, the nanomechanical properties exhibited by the as-formed bilayers have been determined by means of AFM breakthrough force studies. The bilayers formed by immersion of the monolayer in an aqueous media exhibit nanomechanical properties and stability under compression analogous to those of DPPC:Chol supported bilayers obtained by other methods previously described in the literature. Consequently, the hydration of a monolayer LB film has been revealed as an easy method to produce well-ordered bilayers that mimic the cell membrane and that could be used as model cell membranes.
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Affiliation(s)
| | | | - Jesús M de la Fuente
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC , 50009 Zaragoza, Spain
- Networking Biomedical Research Center of Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), Zaragoza, Spain
| | - Pilar Cea
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza , 50009, Zaragoza, Spain
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Aoki PH, Alessio P, Volpati D, Paulovich FV, Riul A, Oliveira ON, Constantino CJ. On the distinct molecular architectures of dipping- and spray-LbL films containing lipid vesicles. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 41:363-71. [DOI: 10.1016/j.msec.2014.04.067] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/02/2014] [Accepted: 04/26/2014] [Indexed: 11/30/2022]
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Volpati D, Aoki PHB, Alessio P, Pavinatto FJ, Miranda PB, Constantino CJL, Oliveira ON. Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces. Adv Colloid Interface Sci 2014; 207:199-215. [PMID: 24530000 DOI: 10.1016/j.cis.2014.01.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/28/2013] [Accepted: 01/13/2014] [Indexed: 01/26/2023]
Abstract
Investigation into nanostructured organic films has served many purposes, including the design of functionalized surfaces that may be applied in biomedical devices and tissue engineering and for studying physiological processes depending on the interaction with cell membranes. Of particular relevance are Langmuir monolayers, Langmuir-Blodgett (LB) and layer-by-layer (LbL) films used to simulate biological interfaces. In this review, we shall focus on the use of vibrational spectroscopy methods to probe molecular-level interactions at biomimetic interfaces, with special emphasis on three surface-specific techniques, namely sum frequency generation (SFG), polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and surface-enhanced Raman scattering (SERS). The two types of systems selected for exemplifying the potential of the methods are the cell membrane models and the functionalized surfaces with biomolecules. Examples will be given on how SFG and PM-IRRAS can be combined to determine the effects from biomolecules on cell membrane models, which include determination of the orientation and preservation of secondary structure. Crucial information for the action of biomolecules on model membranes has also been obtained with PM-IRRAS, as is the case of chitosan removing proteins from the membrane. SERS will be shown as promising for enabling detection limits down to the single-molecule level. The strengths and limitations of these methods will also be discussed, in addition to the prospects for the near future.
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Affiliation(s)
- Diogo Volpati
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | - Pedro H B Aoki
- Faculty of Science and Technology, UNESP, Presidente Prudente, CEP 19060-900 SP,Brazil
| | - Priscila Alessio
- Faculty of Science and Technology, UNESP, Presidente Prudente, CEP 19060-900 SP,Brazil
| | - Felippe J Pavinatto
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | - Paulo B Miranda
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | | | - Osvaldo N Oliveira
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil.
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Duarte AA, Gomes PJ, Ribeiro JHF, Ribeiro PA, Hoffmann SV, Mason NJ, Oliveira ON, Raposo M. Characterization of PAH/DPPG layer-by-layer films by VUV spectroscopy. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:98. [PMID: 24008406 DOI: 10.1140/epje/i2013-13098-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/03/2013] [Accepted: 07/03/2013] [Indexed: 06/02/2023]
Abstract
The spectroscopic characterization of layer-by-layer (LbL) films containing liposomes is essential not only for determining the precise film architecture but also to guide the design of drug delivery systems. In this study we provide the first report of vacuum ultraviolet spectroscopy (VUV) characterization of LbL films made with liposomes from 1.2-dipalmitoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (Sodium Salt) (DPPG) alternated with poly(allylamine hydrochloride) (PAH). Measurements in the 6.0-9.5eV range allowed us to identify the electronic transitions responsible for the spectra, which were assigned to carboxyl, hydroxyl and phosphate groups in DPPG while the PAH spectra were governed by electronic transitions in the amino groups. The surface mass density of the LbL films could be determined, from which the formation of a DPPG bilayer was inferred. This rupture of the liposomes into bilayers was confirmed with atomic force microscopy measurements. In subsidiary experiments we ensured that the UV irradiation in vacuum had negligible damage in the DPPG liposomes during the course of the VUV measurements. In addition to demonstrating the usefulness of VUV spectroscopy, the results presented here may be exploited in biological applications of liposome-containing films.
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Affiliation(s)
- Andreia A Duarte
- CEFITEC, Departamento de Fısica, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
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Tuning the nanostructure of DODAB/nickel tetrasulfonated phthalocyanine bilayers in LbL films. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:2937-46. [DOI: 10.1016/j.msec.2013.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 02/11/2013] [Accepted: 03/12/2013] [Indexed: 01/27/2023]
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Aoki PHB, Carreon EGE, Volpati D, Shimabukuro MH, Constantino CJL, Aroca RF, Oliveira ON, Paulovich FV. SERS mapping in Langmuir-Blodgett films and single-molecule detection. APPLIED SPECTROSCOPY 2013; 67:563-569. [PMID: 23643046 DOI: 10.1366/12-06909] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Plasmon-enhanced spectroscopic techniques have expanded single-molecule detection (SMD) and are revolutionizing areas such as bio-imaging and single-cell manipulation. Surface-enhanced (resonance) Raman scattering (SERS or SERRS) combines high sensitivity with molecular-fingerprint information at the single-molecule level. Spectra originating from single-molecule SERS experiments are rare events, which occur only if a single molecule is located in a hot-spot zone. In this spot, the molecule is selectively exposed to a significant enhancement associated with a high, local electromagnetic field in the plasmonic substrate. Here, we report an SMD study with an electrostatic approach in which a Langmuir film of a phospholipid with anionic polar head groups (PO4(-)) was doped with cationic methylene blue (MB), creating a homogeneous, two-dimensional distribution of dyes in the monolayer. The number of dyes in the probed area of the Langmuir-Blodgett (LB) film coating the Ag nanostructures established a regime in which single-molecule events were observed, with the identification based on direct matching of the observed spectrum at each point of the mapping with a reference spectrum for the MB molecule. In addition, advanced fitting techniques were tested with the data obtained from micro-Raman mapping, thus achieving real-time processing to extract the MB single-molecule spectra.
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Affiliation(s)
- Pedro H B Aoki
- Faculdade de Ciências e Tecnologia, UNESP Universidade Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil
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Torrano AA, Pereira ÂS, Oliveira ON, Barros-Timmons A. Probing the interaction of oppositely charged gold nanoparticles with DPPG and DPPC Langmuir monolayers as cell membrane models. Colloids Surf B Biointerfaces 2013; 108:120-6. [PMID: 23528608 DOI: 10.1016/j.colsurfb.2013.02.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 12/19/2022]
Abstract
The growing use of nanoparticles in a variety of applications calls for detailed studies of their toxicology, which in turn require understanding the interactions between nanoparticles and living cells. Since simulating the interaction with real cell membranes is rather complex, Langmuir monolayers (LMs) have been used to mimic the first barrier encountered by a nanoparticle as it approaches a biological membrane to assess molecular-level interactions. In this study, we show how oppositely charged gold nanoparticles (Au-NPs) interact with monolayers of the zwitterionic dipalmitoylphosphatidyl choline (DPPC) and negatively charged dipalmitoylphosphatidyl glycerol (DPPG). The monolayers were spread on subphases containing two concentrations of either negatively charged Au-NPs coated with citrate anions or positively charged Au-NPs functionalized with the cationic polyelectrolyte poly(allylamine hydrochloride) (PAH). For DPPG, electrostatic effects dominated which depended strongly on the NPs capping agent, being obviously larger for the positive nanoparticles. The in-plane elasticity for DPPG monolayers within the surface pressure range corresponding to real cell membranes increased with adsorption of positively charged NPs, but decreased with the negative ones. For the zwitterionic DPPC, on the other hand, significant effects only occurred for negatively charged NPs, including a decrease in elasticity. Therefore, it is concluded that the nature, namely the charge of the capping agents, is crucial for the interaction of charged NPs with the cell membrane.
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Affiliation(s)
- Adriano A Torrano
- Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
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13
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Spray layer-by-layer films based on phospholipid vesicles aiming sensing application via e-tongue system. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2012.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Volpati D, Aoki PHB, Dantas CAR, Paulovich FV, de Oliveira MCF, Oliveira ON, Riul A, Aroca RF, Constantino CJL. Toward the optimization of an e-tongue system using information visualization: a case study with perylene tetracarboxylic derivative films in the sensing units. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:1029-1040. [PMID: 22103862 DOI: 10.1021/la203641a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The wide variety of molecular architectures used in sensors and biosensors and the large amount of data generated with some principles of detection have motivated the use of computational methods, such as information visualization techniques, not only to handle the data but also to optimize sensing performance. In this study, we combine projection techniques with micro-Raman scattering and atomic force microscopy (AFM) to address critical issues related to practical applications of electronic tongues (e-tongues) based on impedance spectroscopy. Experimentally, we used sensing units made with thin films of a perylene derivative (AzoPTCD acronym), coating Pt interdigitated electrodes, to detect CuCl(2) (Cu(2+)), methylene blue (MB), and saccharose in aqueous solutions, which were selected due to their distinct molecular sizes and ionic character in solution. The AzoPTCD films were deposited from monolayers to 120 nm via Langmuir-Blodgett (LB) and physical vapor deposition (PVD) techniques. Because the main aspects investigated were how the interdigitated electrodes are coated by thin films (architecture on e-tongue) and the film thickness, we decided to employ the same material for all sensing units. The capacitance data were projected into a 2D plot using the force scheme method, from which we could infer that at low analyte concentrations the electrical response of the units was determined by the film thickness. Concentrations at 10 μM or higher could be distinguished with thinner films--tens of nanometers at most--which could withstand the impedance measurements, and without causing significant changes in the Raman signal for the AzoPTCD film-forming molecules. The sensitivity to the analytes appears to be related to adsorption on the film surface, as inferred from Raman spectroscopy data using MB as analyte and from the multidimensional projections. The analysis of the results presented may serve as a new route to select materials and molecular architectures for novel sensors and biosensors, in addition to suggesting ways to unravel the mechanisms behind the high sensitivity obtained in various sensors.
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Affiliation(s)
- Diogo Volpati
- Faculdade de Ciências e Tecnologia, UNESP Univ Estadual Paulista, Presidente Prudente/SP, 19060-900, Brazil
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Alessio P, Aoki PHB, De Saja Saez JA, Rodríguez-Méndez ML, Constantino CJL. Combining SERRS and electrochemistry to characterize sensors based on biomembrane mimetic models formed by phospholipids. RSC Adv 2011. [DOI: 10.1039/c1ra00141h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Romão RIS, Ferreira Q, Morgado J, Martinho JMG, Gonçalves da Silva AMPS. Microphase separation in mixed monolayers of DPPG with a double hydrophilic block copolymer at the air-water interface: a BAM, LSCFM, and AFM study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:17165-17177. [PMID: 20964300 DOI: 10.1021/la103029d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Phase separation and interactions in mixed monolayers of dipalmitoylphosphatidylglycerol (DPPG) with the rhodamine B end-labeled double-hydrophilic block copolymer (DHBC), poly(N,N-dimethylacrylamide)-block-poly(N,N-diethylacrylamide) (RhB-PDMA(207)-b-PDEA(177)), was studied at the air-water interface. Surface pressure versus area isotherms indicate that both components behave almost independently. Brewster angle microscopy (BAM) images show a random distribution of liquid condensed (LC) domains of DPPG in an apparent homogeneous matrix of DHBC, excluding the macroscopic phase separation. The laser scanning confocal fluorescence microscopy (LSCFM) of the rhodamine dye at the end of the PDMA chain showed how the DHBC is distributed in Langmuir-Blodgett (LB) mixed monolayers. The high spatial resolution of atomic force microscopy (AFM) combined with the LCSFM images indicates that DHBC incorporates in the expanded phase of DPPG to form mixed domains, being excluded from the condensed regions. Upon compression, nanosized LC domains of DPPG nucleate inside the mixed domains corralled in the nanopatterning of pure DHBC. The negatively charged polar group of DPPG inhibits rhodamine aggregation, while the long polymer chains promote the formation of corralled nanodomains of DPPG in two dimensions.
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Affiliation(s)
- Rute I S Romão
- Centro de Química Estrutural, Instituto Superior Técnico, Avenida Rovisco Pais, P-1049-001 Lisboa, Portugal
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Sołoducho J, Cabaj J. Biocatalysts immobilized in ultrathin ordered films. SENSORS (BASEL, SWITZERLAND) 2010; 10:10298-313. [PMID: 22163470 PMCID: PMC3230983 DOI: 10.3390/s101110298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 11/02/2010] [Accepted: 11/10/2010] [Indexed: 11/17/2022]
Abstract
The immobilization of enzymes and other proteins into ordered thin materials has attracted considerable attention over the past few years. This research has demonstrated that biomolecules immobilized in different [Langmuir-Blodgett (LB)/Langmuir-Schaefer (LS)] matrixes retain their functional characteristics to a large extent. These new materials are of interest for applications as biosensors and biocatalysts. We review the growing field of oxidases immobilized onto ordered Langmiur-Blodgett and Langmuir-Schaefer films. Strategies for the preparation of solid supports and the essential properties of the resulting materials with respect to the envisaged applications are presented. Basic effects of the nature of the adsorption and various aspects of the application of these materials as biosensors, biocatalysts are discussed. Outlook of potential applications and further challenges are also provided.
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Affiliation(s)
- Jadwiga Sołoducho
- Department of Medicinal Chemistry and Microbiology, Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland; E-Mail:
| | - Joanna Cabaj
- Department of Medicinal Chemistry and Microbiology, Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland; E-Mail:
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Sarkar R, Pal P, Mahato M, Kamilya T, Chaudhuri A, Talapatra GB. On the origin of iron-oxide nanoparticle formation using phospholipid membrane template. Colloids Surf B Biointerfaces 2010; 79:384-9. [PMID: 20493675 DOI: 10.1016/j.colsurfb.2010.04.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 04/20/2010] [Accepted: 04/27/2010] [Indexed: 11/16/2022]
Abstract
In this report, we have studied the formation of iron-oxide nanoparticle at biologically relevant phospholipids, DPPC Langmuir monolayer at air/water interface. Water subphase contains FeCl(3). Adsorption and agglomeration of Fe(3+) ions at DPPC head group have being monitored by Langmuir and Langmuir Blodgett (LB) technique. Adsorption kinetics (pi-t) as well as the surface pressure area (pi-A) isotherms measurement demonstrate the incorporation of Fe(3+) ion at DPPC monolayer. The amount of incorporation of Fe(3+) to the DPPC monolayer is FeCl(3) concentration and time dependent. This reaction kinetics is well fitted by single exponential association equation. The composite monolayers transferred to different substrates are characterized by UV-vis absorption spectroscopy and electron microscopy (FE-SEM and HR-TEM). Study shows the formation of monodisperse Fe(3)O(4) nanoparticle having size approximately 20 nm coated with DPPC mono or multilayer. The overall study indicates that the formation as well as assembly of iron-oxide nanoparticle in two dimensions is possible using lipid monolayer as a template.
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Affiliation(s)
- Ratan Sarkar
- Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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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
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20
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Pavinatto A, Pavinatto FJ, Barros-Timmons A, Oliveira ON. Electrostatic interactions are not sufficient to account for chitosan bioactivity. ACS APPLIED MATERIALS & INTERFACES 2010; 2:246-251. [PMID: 20356241 DOI: 10.1021/am900665z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Recent studies involving chitosan interacting with phospholipid monolayers that mimic cell membranes have brought molecular-level evidence for some of the physiological actions of chitosan, as in removing a protein from the membrane. This interaction has been proven to be primarily of electrostatic origin because of the positive charge of chitosan in low pH solutions, but indirect evidence has also appeared of the presence of hydrophobic interactions. In this study, we provide definitive proof that model membranes are not affected merely by the charges in the amine groups of chitosan. Such a proof was obtained by comparing surface pressure and surface potential isotherms of dipalmitoyl phosphatidyl choline (DPPC) and dipalmitoyl phosphatidyl glycerol (DPPG) monolayers incorporating either chitosan or poly(allylamine hydrochloride) (PAH). As the latter is also positively charged and with the same charged functional group as chitosan, similar effects should be observed in case the electrical charge was the only relevant parameter. Instead, we observed a large expansion in the surface pressure isotherms upon interaction with chitosan, whereas PAH had much smaller effects. Of particular relevance for biological implications, chitosan considerably reduced the monolayer elasticity, whereas PAH had almost no effect. It is clear therefore that chitosan action depends strongly either on its functional uncharged groups and/or on its specific conformation in solution.
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Affiliation(s)
- Adriana Pavinatto
- Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, CP 369, 13566-590, Sao Carlos, Sao Paulo, Brazil
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