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Williams-Pavlantos K, Brigham-Stinson NC, Becker ML, Wesdemiotis C. Application of surface-layer matrix-assisted laser desorption/ionization mass spectrometry imaging to pharmaceutical-loaded poly(ester urea) films. Anal Chim Acta 2023; 1283:341963. [PMID: 37977787 PMCID: PMC10657383 DOI: 10.1016/j.aca.2023.341963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/17/2023] [Accepted: 10/25/2023] [Indexed: 11/19/2023]
Abstract
Polymer thin films are often used in transdermal patches as a method of continuous drug administration for patients with chronic illness. Understanding the drug segregation and distribution within these films is important for monitoring proper drug release over time. Surface-layer matrix-assisted laser desorption/ionization mass spectrometry imaging (SL-MALDI-MSI) is a unique analytical technique that provides an optical representation of chemical compositions that exist at the surface of polymeric materials. Solvent-free sublimation is employed for application of matrix to the sample surface, so that only molecules in direct contact with the matrix layer are detected. Here, these methodologies are utilized to visualize variations in drug concentration at both the air and substrate interface in pharmaceutical-loaded polymer films.
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Affiliation(s)
| | | | - Matthew L Becker
- Department of Chemistry, Duke University, Durham, NC, 27708, USA; Thomas Lord Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC, 27708, USA; Departments of Biomedical Engineering and Orthopedic Surgery, Duke University, Durham, NC, 27708, USA
| | - Chrys Wesdemiotis
- Department of Chemistry, The University of Akron, Akron, OH, 44325, USA.
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2
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Aliakseyeu A, Shah PP, Ankner JF, Sukhishvili SA. Salt-Induced Diffusion of Star and Linear Polyelectrolytes within Multilayer Films. Macromolecules 2023; 56:5434-5445. [PMID: 38357536 PMCID: PMC10863069 DOI: 10.1021/acs.macromol.3c00777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/19/2023] [Indexed: 02/16/2024]
Abstract
This study explores the effect of salt on the diffusivity of polyelectrolytes of varied molecular architecture in layer-by-layer (LbL) films in directions parallel and perpendicular to the substrate using fluorescence recovery after photobleaching (FRAP) and neutron reflectivity (NR) techniques, respectively. A family of linear, 4-arm, 6-arm, and 8-arm poly(methacrylic acids) (LPMAA, 4PMAA, 6PMAA, and 8PMAA, respectively) of matched molecular weights were synthesized using atom transfer radical polymerization and assembled with a linear polycation, poly[2-(trimethylammonium)ethyl methacrylate chloride] (QPC). NR studies involving deuterated QPC revealed ∼10-fold higher polycation mobility for the 8PMAA/QPC system compared to all-linear LbL films upon exposure to 0.25 M NaCl solutions at pH 6. FRAP experiments showed, however, that lateral diffusion of star PMAAs was lower than LPMAA at NaCl concentrations below ∼0.22 M NaCl, with a crossover to higher mobility of star polymers in more concentrated salt solutions. The stronger response of diffusion of star PMAA to salt is discussed in the context of several theories previously suggested for diffusivity of polyelectrolyte chains in multilayer films and coacervates.
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Affiliation(s)
- Aliaksei Aliakseyeu
- Department
of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Parin Purvin Shah
- Department
of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - John F. Ankner
- Spallation
Neutron Source Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Svetlana A. Sukhishvili
- Department
of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
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3
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Sakthinathan I, Köhling J, Wagner V, McCormac T. Layer-by-Layer Construction of a Nanoarchitecture by Polyoxometalates and Polymers: Enhanced Electrochemical Hydrogen Evolution Reaction. ACS APPLIED MATERIALS & INTERFACES 2023; 15:2861-2872. [PMID: 36598164 DOI: 10.1021/acsami.2c17397] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In this contribution, a nanoarchitectural approach was employed to produce a nanolayer of polyoxometalate (POM) on the surface of a glassy carbon electrode (GCE) to achieve a higher surface area with higher electrocatalytic activity toward the electrochemical hydrogen evolution reaction (HER). To accomplish this, the well-known layer-by-layer (LbL) technique was employed, which involved the alternate adsorption of the POM, Na0.3[N(C4H9)4]7.7 [(Mo3O8)4(O3PC(O)(C3H6NH2CH2C4H3S)PO3)4], abbreviated as [(TBA)Mo12(AleThio)4], and polyethyleneimine (PEI) polymer. This nanolayered electrode exhibited catalytic properties toward the HER in 0.5 M H2SO4 with the resulting polarization curves indicating an increase in the HER activity with the increasing number of POM layers, and the overpotential required for this reaction was lowered by 0.83 V when compared with a bare GCE. The eighth PEI/[(TBA)Mo12(AleThio)4] bilayer exhibited a significantly lower HER overpotential of -0.077 V at a current density of 10 mA cm-2. Surface characterization of the LbL-assembled nanolayers was carried out using X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. We believe that the synergetic effect of the positively charged PEI polymer and the catalytically active molybdate POM is the cause for the successful response to the electrochemical HER.
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Affiliation(s)
- Indherjith Sakthinathan
- Electrochemistry Research Group, Department of Applied Science, Dundalk Institute of Technology, Dublin Road, Dundalk A91K584, County Louth, Ireland
| | - Jonas Köhling
- Physics & Earth Sciences, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany
| | - Veit Wagner
- Physics & Earth Sciences, Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany
| | - Timothy McCormac
- Electrochemistry Research Group, Department of Applied Science, Dundalk Institute of Technology, Dublin Road, Dundalk A91K584, County Louth, Ireland
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4
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Aliakseyeu A, Ankner JF, Sukhishvili SA. Impact of Star Polyacid Branching on Polymer Diffusion within Multilayer Films. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Aliaksei Aliakseyeu
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - John F. Ankner
- Spallation Neutron Source Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Svetlana A. Sukhishvili
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
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5
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Pahal S, Boranna R, Prashanth GR, Varma MM. Simplifying Molecular Transport in Polyelectrolyte Multilayer Thin Films. MACROMOL CHEM PHYS 2021. [DOI: 10.1002/macp.202100330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Suman Pahal
- Institute for Stem Cell Science and Regenerative Medicine (inStem) Bengaluru Karnataka 560065 India
- Centre for Nano Science and Engineering Indian Institute of Science Bengaluru Karnataka 560012 India
| | - Rakshith Boranna
- Department of Electronics and Communication Engineering National Institute of Technology Goa Farmagudi Ponda Goa 403401 India
| | - Gurusiddappa R. Prashanth
- Department of Electronics and Communication Engineering National Institute of Technology Goa Farmagudi Ponda Goa 403401 India
| | - Manoj M. Varma
- Centre for Nano Science and Engineering Indian Institute of Science Bengaluru Karnataka 560012 India
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6
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Abbett RL, Chen Y, Schlenoff JB. Self-Exchange of Polyelectrolyte in Multilayers: Diffusion as a Function of Salt Concentration and Temperature. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Rachel L. Abbett
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Yuhui Chen
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Joseph B. Schlenoff
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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7
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Hlushko R, Ankner JF, Sukhishvili S. Dynamics and Self-Healing of Layer-by-Layer Hydrogen-Bonded Films of Linear Synthetic Polyphenols. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Raman Hlushko
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - John F. Ankner
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Svetlana Sukhishvili
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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8
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Ciejka J, Grzybala M, Gut A, Szuwarzynski M, Pyrc K, Nowakowska M, Szczubiałka K. Tuning the Surface Properties of Poly(Allylamine Hydrochloride)-Based Multilayer Films. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2361. [PMID: 34062785 PMCID: PMC8125107 DOI: 10.3390/ma14092361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/24/2021] [Accepted: 04/29/2021] [Indexed: 11/17/2022]
Abstract
The layer-by-layer (LbL) method of polyelectrolyte multilayer (PEM) fabrication is extremely versatile. It allows using a pair of any oppositely charged polyelectrolytes. Nevertheless, it may be difficult to ascribe a particular physicochemical property of the resulting PEM to a structural or chemical feature of a single component. A solution to this problem is based on the application of a polycation and a polyanion obtained by proper modification of the same parent polymer. Polyelectrolyte multilayers (PEMs) were prepared using the LbL technique from hydrophilic and amphiphilic derivatives of poly(allylamine hydrochloride) (PAH). PAH derivatives were obtained by the substitution of amine groups in PAH with sulfonate, ammonium, and hydrophobic groups. The PEMs were stable in 1 M NaCl and showed three different modes of thickness growth: exponential, mixed exponential-linear, and linear. Their surfaces ranged from very hydrophilic to hydrophobic. Root mean square (RMS) roughness was very variable and depended on the PEM composition, sample environment (dry, wet), and the polymer constituting the topmost layer. Atomic force microscopy (AFM) imaging of the surfaces showed very different morphologies of PEMs, including very smooth, porous, and structured PEMs with micellar aggregates. Thus, by proper choice of PAH derivatives, surfaces with different physicochemical features (growth type, thickness, charge, wettability, roughness, surface morphology) were obtained.
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Affiliation(s)
- Justyna Ciejka
- Department of Engineering and Technology of Chemical Processes, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (A.G.); (M.N.)
- Virogenetics Laboratory of Virology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, 30-387 Krakow, Poland;
| | - Michal Grzybala
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland;
| | - Arkadiusz Gut
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (A.G.); (M.N.)
| | - Michal Szuwarzynski
- Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland;
| | - Krzysztof Pyrc
- Virogenetics Laboratory of Virology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, 30-387 Krakow, Poland;
| | - Maria Nowakowska
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (A.G.); (M.N.)
| | - Krzysztof Szczubiałka
- Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (A.G.); (M.N.)
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9
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Kienle DF, Schwartz DK. Single molecule characterization of anomalous transport in a thin, anisotropic film. Anal Chim Acta 2021; 1154:338331. [PMID: 33736806 DOI: 10.1016/j.aca.2021.338331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/01/2021] [Accepted: 02/14/2021] [Indexed: 01/07/2023]
Abstract
The diffusion of small, charged molecules incorporated in an anisotropic polyelectrolyte multilayer (PEM) was tracked in three dimensions by combining single-molecule fluorescence localization (to characterize lateral diffusion) with Förster resonance energy transfer (FRET) between diffusing molecules and the supporting surface (to measure diffusion in the surface-normal direction). Analysis of the surface-normal diffusion required model-based statistical analysis to account for the inherently noisy FRET signal. Combining these distinct single-molecule methods, which are inherently sensitive to different length-scales, permitted simultaneous characterization of severely anisotropic diffusion, which was more than three orders of magnitude slower in the surface-normal direction. We hypothesize that the anomalously slow surface-normal diffusion was related to the periodic distribution of charge in the PEM, which created electrostatic barriers. The motion was strongly subdiffusive, with anomalous temporal scaling exponents in lateral and normal directions, suggesting a connection to the transient, random fractal conformation of polymer chains in the film's matrix.
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Affiliation(s)
- Daniel F Kienle
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA.
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10
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Polyelectrolyte Multilayers on Soft Colloidal Nanosurfaces: A New Life for the Layer-By-Layer Method. Polymers (Basel) 2021; 13:polym13081221. [PMID: 33918844 PMCID: PMC8069484 DOI: 10.3390/polym13081221] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/04/2021] [Accepted: 04/05/2021] [Indexed: 02/07/2023] Open
Abstract
The Layer-by-Layer (LbL) method is a well-established method for the assembly of nanomaterials with controlled structure and functionality through the alternate deposition onto a template of two mutual interacting molecules, e.g., polyelectrolytes bearing opposite charge. The current development of this methodology has allowed the fabrication of a broad range of systems by assembling different types of molecules onto substrates with different chemical nature, size, or shape, resulting in numerous applications for LbL systems. In particular, the use of soft colloidal nanosurfaces, including nanogels, vesicles, liposomes, micelles, and emulsion droplets as a template for the assembly of LbL materials has undergone a significant growth in recent years due to their potential impact on the design of platforms for the encapsulation and controlled release of active molecules. This review proposes an analysis of some of the current trends on the fabrication of LbL materials using soft colloidal nanosurfaces, including liposomes, emulsion droplets, or even cells, as templates. Furthermore, some fundamental aspects related to deposition methodologies commonly used for fabricating LbL materials on colloidal templates together with the most fundamental physicochemical aspects involved in the assembly of LbL materials will also be discussed.
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11
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Campbell J, Vikulina AS. Layer-By-Layer Assemblies of Biopolymers: Build-Up, Mechanical Stability and Molecular Dynamics. Polymers (Basel) 2020; 12:E1949. [PMID: 32872246 PMCID: PMC7564420 DOI: 10.3390/polym12091949] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 12/18/2022] Open
Abstract
Rapid development of versatile layer-by-layer technology has resulted in important breakthroughs in the understanding of the nature of molecular interactions in multilayer assemblies made of polyelectrolytes. Nowadays, polyelectrolyte multilayers (PEM) are considered to be non-equilibrium and highly dynamic structures. High interest in biomedical applications of PEMs has attracted attention to PEMs made of biopolymers. Recent studies suggest that biopolymer dynamics determines the fate and the properties of such PEMs; however, deciphering, predicting and controlling the dynamics of polymers remains a challenge. This review brings together the up-to-date knowledge of the role of molecular dynamics in multilayers assembled from biopolymers. We discuss how molecular dynamics determines the properties of these PEMs from the nano to the macro scale, focusing on its role in PEM formation and non-enzymatic degradation. We summarize the factors allowing the control of molecular dynamics within PEMs, and therefore to tailor polymer multilayers on demand.
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Affiliation(s)
- Jack Campbell
- School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, UK;
| | - Anna S. Vikulina
- Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses, Am Mühlenberg 13, 14476 Potsdam-Golm, Germany
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12
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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.
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Yuan W, Weng GM, Lipton J, Li CM, Van Tassel PR, Taylor AD. Weak polyelectrolyte-based multilayers via layer-by-layer assembly: Approaches, properties, and applications. Adv Colloid Interface Sci 2020; 282:102200. [PMID: 32585489 DOI: 10.1016/j.cis.2020.102200] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 06/03/2020] [Accepted: 06/11/2020] [Indexed: 10/24/2022]
Abstract
Layer-by-layer (LbL) assembly is a nanoscale technique with great versatility, simplicity and molecular-level processing of various nanoscopic materials. Weak polyelectrolytes have been used as major building blocks for LbL assembly providing a fundamental and versatile tool to study the underlying mechanisms and practical applications of LbL assembly due to its pH-responsive charge density and molecular conformation. Because of high-density uncompensated charges and high-chain mobility, weak polyelectrolyte exponential multilayer growth is considered one of the fastest developing areas for organized molecular films. In this article, we systematically review the current status and developments of weak polyelectrolyte-based multilayers including all-weak-polyelectrolyte multilayers, weak polyelectrolytes/other components (e.g. strong polyelectrolytes, neutral polymers, and nanoparticles) multilayers, and exponentially grown weak polyelectrolyte multilayers. Several key aspects of weak polyelectrolytes are highlighted including the pH-controllable properties, the responsiveness to environmental pH, and synergetic functions obtained from weak polyelectrolyte/other component multilayers. Throughout this review, useful applications of weak polyelectrolyte-based multilayers in drug delivery, tunable biointerfaces, nanoreactors for synthesis of nanostructures, solid state electrolytes, membrane separation, and sensors are highlighted, and promising future directions in the area of weak polyelectrolyte-based multilayer assembly such as fabrication of multi-responsive materials, adoption of unique building blocks, investigation of internal molecular-level structure and mechanism of exponentially grown multilayers, and exploration of novel biomedical and energy applications are proposed.
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Encapsulation of Low-Molecular-Weight Drugs into Polymer Multilayer Capsules Templated on Vaterite CaCO 3 Crystals. MICROMACHINES 2020; 11:mi11080717. [PMID: 32722123 PMCID: PMC7463826 DOI: 10.3390/mi11080717] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 12/17/2022]
Abstract
Polyelectrolyte multilayer capsules (PEMCs) templated onto biocompatible and easily degradable vaterite CaCO3 crystals via the layer-by-layer (LbL) polymer deposition process have served as multifunctional and tailor-made vehicles for advanced drug delivery. Since the last two decades, the PEMCs were utilized for effective encapsulation and controlled release of bioactive macromolecules (proteins, nucleic acids, etc.). However, their capacity to host low-molecular-weight (LMW) drugs (<1–2 kDa) has been demonstrated rather recently due to a limited retention ability of multilayers to small molecules. The safe and controlled delivery of LMW drugs plays a vital role for the treatment of cancers and other diseases, and, due to their tunable and inherent properties, PEMCs have shown to be good candidates for smart drug delivery. Herein, we summarize recent progress on the encapsulation of LMW drugs into PEMCs templated onto vaterite CaCO3 crystals. The drug loading and release mechanisms, advantages and limitations of the PEMCs as LMW drug carriers, as well as bio-applications of drug-laden capsules are discussed based upon the recent literature findings.
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Abstract
Controlled drug delivery formulations have revolutionized treatments for a range of health conditions. Over decades of innovation, layer-by-layer (LbL) self-assembly has emerged as one of the most versatile fabrication methods used to develop multifunctional controlled drug release coatings. The numerous advantages of LbL include its ability to incorporate and preserve biological activity of therapeutic agents; coat multiple substrates of all scales (e.g., nanoparticles to implants); and exhibit tuned, targeted, and/or responsive drug release behavior. The functional behavior of LbL films can be related to their physicochemical properties. In this review, we highlight recent advances in the development of LbL-engineered biomaterials for drug delivery, demonstrating their potential in the fields of cancer therapy, microbial infection prevention and treatment, and directing cellular responses. We discuss the various advantages of LbL biomaterial design for a given application as demonstrated through in vitro and in vivo studies.
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Affiliation(s)
- Dahlia Alkekhia
- School of Engineering and Center for Biomedical Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - Paula T. Hammond
- Koch Institute for Integrative Cancer Research and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Anita Shukla
- School of Engineering and Center for Biomedical Engineering, Brown University, Providence, Rhode Island 02912, USA
- Institute for Molecular and Nanoscale Innovation, Brown University, Providence, Rhode Island 02912, USA
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Dos Santos de Macedo B, de Almeida T, da Costa Cruz R, Netto ADP, da Silva L, Berret JF, Vitorazi L. Effect of pH on the Complex Coacervation and on the Formation of Layers of Sodium Alginate and PDADMAC. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2510-2523. [PMID: 32050754 DOI: 10.1021/acs.langmuir.9b03216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, we investigated the thermodynamic features of a system based on oppositely charged polyelectrolytes, sodium alginate, and poly(diallyldimethylammonium chloride) (PDADMAC) at different pH values. Additionally, a comparison of the effects of the thermodynamic parameters on the growth of the layers based on the same polymers is presented. For this investigation, different techniques were combined to compare results from the association in solution and coassembled layers at the silicon surface. Dynamic light scattering (DLS) and isothermal titration calorimetry (ITC) were used for studies in solution, and the layer-by-layer technique was employed for the preparation of the polymer layers. Ellipsometry and atomic force microscopy (AFM) were used to characterize the layer thickness growth as a function of the solution pH, and interferometric confocal microscopy was employed to analyze the topography and roughness of the films. The titration of both polyelectrolytes in two different sequences of additions confirmed the mechanism; it involved a two-step process that was monitored by varying the enthalpy, as determined by ITC experiments, and the structural evolution of the aggregates into coacervates, according to DLS. The primary process is aggregation to form polyelectrolyte complexes having a smaller hydrodynamic diameter, which abruptly transit toward a secondary process because of the formation of coacervate particles that have a larger hydrodynamic diameter. Independent of pH and the sequence of addition, for the first process, both directions are entropically driven. However, the binding enthalpy (ΔHb) decreased with a decrease in the pH of the solution. The layers grown for the PDADMAC/sodium alginate system demonstrated pH sensitivity with either linear or exponential behavior, depending on the pH values of the polyelectrolyte solutions. The more endothermic process at pH 10 afforded layers with a smaller thickness and with linear growth according to the increase in the number of layers from 5 to 20. Decreases in the pH of the solution resulted in the layers growing exponentially; additionally, a decrease in the ΔHb of the association in the solution was observed. The layer thicknesses measured using ellipsometry and AFM data were in good agreement. Additionally, the influence of pH on the roughness and topography of the films was observed. Films from basic dipping solutions resulted in surfaces that were more homogeneous with less roughness; in contrast, films with more layers and those formed in a low-pH dipping solution were rougher and less homogeneous.
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Affiliation(s)
- Bruno Dos Santos de Macedo
- Laboratório de Quı́mica Analı́tica Fundamental e Aplicada, Instituto de Quı́mica - Universidade Federal Fluminense, R. Outeiro de São João Batista, s/n, Niterói, RJ CEP 24020-141, Brazil
| | - Tamiris de Almeida
- Programa de Pós-Graduação em Engenharia Metalúrgica, EEIMVR, Universidade Federal Fluminense, Avenida dos Trabalhadores, 420, Volta Redonda RJ CEP 27225-125, Brazil
| | | | - Annibal Duarte Pereira Netto
- Laboratório de Quı́mica Analı́tica Fundamental e Aplicada, Instituto de Quı́mica - Universidade Federal Fluminense, R. Outeiro de São João Batista, s/n, Niterói, RJ CEP 24020-141, Brazil
| | - Ladário da Silva
- Programa de Pós-Graduação em Engenharia Metalúrgica, EEIMVR, Universidade Federal Fluminense, Avenida dos Trabalhadores, 420, Volta Redonda RJ CEP 27225-125, Brazil
- Laboratório Multiusuários de Caracterização de Materiais, Instituto de Ciências Exatas - Universidade Federal Fluminense, R. Des. Ellis Hermydio Figueira, 783, Volta Redonda RJ CEP 27213-145, Brazil
| | - Jean-François Berret
- Laboratoire Matière et Systèmes Complexes, UMR 7057 CNRS Université Denis Diderot Paris-VII, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris, France
| | - Letícia Vitorazi
- Programa de Pós-Graduação em Engenharia Metalúrgica, EEIMVR, Universidade Federal Fluminense, Avenida dos Trabalhadores, 420, Volta Redonda RJ CEP 27225-125, Brazil
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17
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Hlushko R, Ankner JF, Sukhishvili SA. Layer-by-Layer Hydrogen-Bonded Antioxidant Films of Linear Synthetic Polyphenols. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02512] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Raman Hlushko
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - John F. Ankner
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Svetlana A. Sukhishvili
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
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18
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Al Husseini D, Zhou J, Willhelm D, Hastings T, Day GS, Zhou HC, Coté GL, Qian X, Gutierrez-Osuna R, Lin PT, Sukhishvili SA. All-nanoparticle layer-by-layer coatings for Mid-IR on-chip gas sensing. Chem Commun (Camb) 2020; 56:14283-14286. [DOI: 10.1039/d0cc05513a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Functionalization of optical waveguides with submicron all-nanoparticle coatings significantly enhanced the detection of acetone. Such coatings were enabled via precise control of the substrate withdrawal speed using the layer-by-layer deposition.
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Affiliation(s)
- Diana Al Husseini
- Department of Materials Science and Engineering
- Texas A&M University
- College Station
- USA
| | - Junchao Zhou
- Department of Electrical and Computer Engineering
- Texas A&M University
- College Station
- USA
| | - Daniel Willhelm
- Department of Materials Science and Engineering
- Texas A&M University
- College Station
- USA
| | - Trevor Hastings
- Department of Materials Science and Engineering
- Texas A&M University
- College Station
- USA
| | - Gregory S. Day
- Department of Chemistry
- Texas A&M University
- College Station
- USA
| | - Hong-Cai Zhou
- Department of Materials Science and Engineering
- Texas A&M University
- College Station
- USA
- Department of Chemistry
| | - Gerard L. Coté
- Department of Biomedical Engineering
- Texas A&M University
- College Station
- USA
| | - Xiaofeng Qian
- Department of Materials Science and Engineering
- Texas A&M University
- College Station
- USA
| | | | - Pao Tai Lin
- Department of Materials Science and Engineering
- Texas A&M University
- College Station
- USA
- Department of Electrical and Computer Engineering
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19
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Odd-even effects on hydration of natural polyelectrolyte multilayers: An in situ synchrotron FTIR microspectroscopy study. J Colloid Interface Sci 2019; 553:720-733. [DOI: 10.1016/j.jcis.2019.06.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 11/20/2022]
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20
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Delcea M, Helm CA. X-ray and Neutron Reflectometry of Thin Films at Liquid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8519-8530. [PMID: 30901219 DOI: 10.1021/acs.langmuir.8b04315] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the 1980s, Helmuth Möhwald studied lipid monolayers at the air/water interface to understand the thermodynamically characterized phases at the molecular level. In collaboration with Jens Als-Nielsen, X-ray reflectometry was used and further developed to determine the electron density profile perpendicular to the water surface. Using a slab model, parameters such as thickness and density of the individual molecular regions, as well as the roughness of the individual interfaces, were determined. Later, X-ray and neutron reflectometry helped to understand the coverage and conformation of anchored and adsorbed polymers. Nowadays, they resolve molecular properties in emerging topics such as liquid metals and ionic liquids. Much is still to be learned about buried interfaces (e.g., liquid/liquid interfaces). In this Article, a historical and theoretical background of X-ray reflectivity is given, recent developments of X-ray and neutron reflectometry for polymers at interfaces and thin layers are highlighted, and emerging research topics involving these techniques are emphasized.
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Affiliation(s)
- Mihaela Delcea
- Institute of Biochemistry , University of Greifswald , Felix-Hausdorff-Straße 4 , 17489 Greifswald , Germany
- ZIK HIKE- Zentrum für Innovationskompetenz , Humorale Immunreaktionen bei kardiovaskulären Erkrankungen , Fleischmannstraße 42 , 17489 Greifswald , Germany
| | - Christiane A Helm
- Institute of Physics , University of Greifswald , Felix-Hausdorff-Straße 4 , 17489 Greifswald , Germany
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21
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Ryzhkov NV, Nesterov P, Mamchik NA, Yurchenko SO, Skorb EV. Localization of Ion Concentration Gradients for Logic Operation. Front Chem 2019; 7:419. [PMID: 31245356 PMCID: PMC6562996 DOI: 10.3389/fchem.2019.00419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/21/2019] [Indexed: 11/13/2022] Open
Abstract
Adjustment of the environmental acidity is a powerful method for fine-tuning the outcome of many chemical processes. Numerous strategies have been developed for the modification of pH in bulk as well as locally. Electrochemical and photochemical processes provide a powerful approach for on-demand generation of ion concentration gradients locally at solid-liquid interfaces. Spatially organized in individual way electrodes provide a particular pattern of proton distribution in solution. It opens perspectives to iontronics which is a bioinspired approach to signaling, information processing, and storing by spatial and temporal distribution of ions. We prove here that soft layers allow to control of ion mobility over the surface as well as processes of self-organization are closely related to change in entropy. In this work, we summarize the achievements and discuss perspectives of ion gradients in solution for information processing.
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Affiliation(s)
- Nikolay V Ryzhkov
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint Petersburg, Russia
| | - Pavel Nesterov
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint Petersburg, Russia
| | - Natalia A Mamchik
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint Petersburg, Russia
| | | | - Ekaterina V Skorb
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint Petersburg, Russia
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22
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Selin V, Aliakseyeu A, Ankner JF, Sukhishvili SA. Effect of a Competitive Solvent on Binding Enthalpy and Chain Intermixing in Hydrogen-Bonded Layer-by-Layer Films. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00650] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Victor Selin
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Aliaksei Aliakseyeu
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - John F. Ankner
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Svetlana A. Sukhishvili
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843, United States
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23
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Lappan U, Rau C, Naas C, Scheler U. Odd–Even Effect on Rotational Dynamics of Spin-Labeled Polyacid Chain Segments in Polyelectrolyte Multilayers. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00101] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Uwe Lappan
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Cindy Rau
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Carolin Naas
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Ulrich Scheler
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
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24
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Selin V, Albright V, Ankner JF, Marin A, Andrianov AK, Sukhishvili SA. Biocompatible Nanocoatings of Fluorinated Polyphosphazenes through Aqueous Assembly. ACS APPLIED MATERIALS & INTERFACES 2018; 10:9756-9764. [PMID: 29505245 DOI: 10.1021/acsami.8b02072] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nonionic fluorinated polyphosphazenes, such as poly[bis(trifluoroethoxy)phosphazene] (PTFEP), display superb biocompatibility, yet their deposition to surfaces has been limited to solution casting from organic solvents or thermal molding. Herein, hydrophobic coatings of fluorinated polyphosphazenes are demonstrated through controlled deposition of ionic fluorinated polyphosphazenes (iFPs) from aqueous solutions using the layer-by-layer (LbL) technique. Specifically, the assemblies included poly[(carboxylatophenoxy)(trifluoroethoxy)phosphazenes] with varied content of fluorine atoms as iFPs (or poly[bis(carboxyphenoxy)phosphazene] (PCPP) as a control nonfluorinated polyphosphazene) and a variety of polycations. Hydrophobic interactions largely contributed to the formation of LbL films of iFPs with polycations, leading to linear growth and extremely low water uptake. Hydrophobicity-enhanced ionic pairing within iFP/BPEI assemblies gave rise to large-amplitude oscillations in surface wettability as a function of capping layer, which were the largest for the most fluorinated iFP, while control PCPP/polycation systems remained hydrophilic regardless of the film top layer. Neutron reflectometry (NR) studies indicated superior layering and persistence of such layering in salt solution for iFP/BPEI films as compared to control PCPP/polycation systems. Hydrophobicity of iFP-capped LbL coatings could be further enhanced by using a highly porous polyester surgical felt rather than planar substrates for film deposition. Importantly, iFP/polycation coatings displayed biocompatibility which was similar to or superior to that of solution-cast coatings of a clinically validated material (PTFEP), as demonstrated by the hemolysis of the whole blood and protein adsorption studies.
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Affiliation(s)
- Victor Selin
- Department of Materials Science & Engineering , Texas A&M University , College Station , Texas 77843 , United States
| | - Victoria Albright
- Department of Materials Science & Engineering , Texas A&M University , College Station , Texas 77843 , United States
| | - John F Ankner
- Spallation Neutron Source , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Alexander Marin
- Institute for Bioscience and Biotechnology Research , University of Maryland , Rockville , Maryland 20850 , United States
| | - Alexander K Andrianov
- Institute for Bioscience and Biotechnology Research , University of Maryland , Rockville , Maryland 20850 , United States
| | - Svetlana A Sukhishvili
- Department of Materials Science & Engineering , Texas A&M University , College Station , Texas 77843 , United States
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25
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Ghoussoub YE, Zerball M, Fares HM, Ankner JF, von Klitzing R, Schlenoff JB. Ion distribution in dry polyelectrolyte multilayers: a neutron reflectometry study. SOFT MATTER 2018; 14:1699-1708. [PMID: 29424853 DOI: 10.1039/c7sm02461d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ultrathin films of complexed polycation poly(diallyldimethylammonium), PDADMA, and polyanion poly(styrenesulfonate), PSS, were prepared on silicon wafers using the layer-by-layer adsorption technique. When terminated with PDADMA, all films had excess PDADMA, which was balanced by counterions. Neutron reflectivity of these as-made multilayers was compared with measurements on multilayers which had been further processed to ensure 1 : 1 stoichiometry of PDADMA and PSS. The compositions of all films, including polymers and counterions, were determined experimentally rather than by fitting, reducing the number of fit parameters required to model the reflectivity. For each sample, acetate, either protiated, CH3COO-, or deuterated, CD3COO-, served as the counterion. All films were maintained dry under vacuum. Scattering length density profiles were constrained to fit reflectivity data from samples having either counterion. The best fits were obtained with uniform counterion concentrations, even for stoichiometric samples that had been exposed to PDADMA for ca. 5 minutes, showing that surprisingly fast and complete transport of excess cationic charge occurs throughout the multilayer during its construction.
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Affiliation(s)
- Yara E Ghoussoub
- Department of Chemistry and Biochemistry, The Florida State University, Tallahassee, Florida 32306-4390, USA.
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26
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Sustr D, Hlaváček A, Duschl C, Volodkin D. Multi-Fractional Analysis of Molecular Diffusion in Polymer Multilayers by FRAP: A New Simulation-Based Approach. J Phys Chem B 2018; 122:1323-1333. [PMID: 29257689 DOI: 10.1021/acs.jpcb.7b11051] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Comprehensive analysis of the multifractional molecular diffusion provides a deeper understanding of the diffusion phenomenon in the fields of material science, molecular and cell biology, advanced biomaterials, etc. Fluorescence recovery after photobleaching (FRAP) is commonly employed to probe the molecular diffusion. Despite FRAP being a very popular method, it is not easy to assess multifractional molecular diffusion due to limited possibilities of approaches for analysis. Here we present a novel simulation-optimization-based approach (S-approach) that significantly broadens possibilities of the analysis. In the S-approach, possible fluorescence recovery scenarios are primarily simulated and afterward compared with a real measurement while optimizing parameters of a model until a sufficient match is achieved. This makes it possible to reveal multifractional molecular diffusion. Fluorescent latex particles of different size and fluorescein isothiocyanate in an aqueous medium were utilized as test systems. Finally, the S-approach has been used to evaluate diffusion of cytochrome c loaded into multilayers made of hyaluronan and polylysine. Software for evaluation of multifractional molecular diffusion by S-approach has been developed aiming to offer maximal versatility and user-friendly way for analysis.
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Affiliation(s)
- David Sustr
- Faculty of Science, University of Potsdam, Institute of Biochemistry and Biology , Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany.,Department of Molecular and Cellular Bioanalytics, Fraunhofer Institute for Cell Therapy and Immunology (Fraunhofer IZI) , Am Mühlenberg 13, 14476 Potsdam-Golm, Germany
| | - Antonín Hlaváček
- Institute of Analytical Chemistry of the Czech Academy of Sciences , v. v. i., Veveří 97, Brno 602 00, Czech Republic
| | - Claus Duschl
- Department of Molecular and Cellular Bioanalytics, Fraunhofer Institute for Cell Therapy and Immunology (Fraunhofer IZI) , Am Mühlenberg 13, 14476 Potsdam-Golm, Germany
| | - Dmitry Volodkin
- Department of Molecular and Cellular Bioanalytics, Fraunhofer Institute for Cell Therapy and Immunology (Fraunhofer IZI) , Am Mühlenberg 13, 14476 Potsdam-Golm, Germany.,School of Science and Technology, Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS, United Kingdom
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27
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Selin V, Ankner JF, Sukhishvili SA. Ionically Paired Layer-by-Layer Hydrogels: Water and Polyelectrolyte Uptake Controlled by Deposition Time. Gels 2018; 4:E7. [PMID: 30674783 PMCID: PMC6321383 DOI: 10.3390/gels4010007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 12/28/2017] [Accepted: 01/08/2018] [Indexed: 01/18/2023] Open
Abstract
Despite intense recent interest in weakly bound nonlinear ("exponential") multilayers, the underlying structure-property relationships of these films are still poorly understood. This study explores the effect of time used for deposition of individual layers of nonlinearly growing layer-by-layer (LbL) films composed of poly(methacrylic acid) (PMAA) and quaternized poly-2-(dimethylamino)ethyl methacrylate (QPC) on film internal structure, swelling, and stability in salt solution, as well as the rate of penetration of invading polyelectrolyte chains. Thicknesses of dry and swollen films were measured by spectroscopic ellipsometry, film internal structure-by neutron reflectometry (NR), and degree of PMAA ionization-by Fourier-transform infrared spectroscopy (FTIR). The results suggest that longer deposition times resulted in thicker films with higher degrees of swelling (up to swelling ratio as high as 4 compared to dry film thickness) and stronger film intermixing. The stronger intermixed films were more swollen in water, exhibited lower stability in salt solutions, and supported a faster penetration rate of invading polyelectrolyte chains. These results can be useful in designing polyelectrolyte nanoassemblies for biomedical applications, such as drug delivery coatings for medical implants or tissue engineering matrices.
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Affiliation(s)
- Victor Selin
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX 77843, USA.
| | - John F Ankner
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Svetlana A Sukhishvili
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX 77843, USA.
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28
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Fares HM, Schlenoff JB. Diffusion of Sites versus Polymers in Polyelectrolyte Complexes and Multilayers. J Am Chem Soc 2017; 139:14656-14667. [PMID: 28981268 DOI: 10.1021/jacs.7b07905] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It has long been assumed that the spontaneous formation of materials such as complexes and multilayers from charged polymers depends on (inter)diffusion of these polyelectrolytes. Here, we separately examine the mass transport of polymer molecules and extrinsic sites-charged polyelectrolyte repeat units balanced by counterions-within thin films of polyelectrolyte complex, PEC, using sensitive isotopic labeling techniques. The apparent diffusion coefficients of these sites within PEC films of poly(diallyldimethylammonium), PDADMA, and poly(styrenesulfonate), PSS, are at least 2 orders of magnitude faster than the diffusion of polyelectrolytes themselves. This is because site diffusion requires only local rearrangements of polyelectrolyte repeat units, placing far fewer kinetic limitations on the assembly of polyelectrolyte complexes in all of their forms. Site diffusion strongly depends on the salt concentration (ionic strength) of the environment, and diffusion of PDADMA sites is faster than that of PSS sites, accounting for the asymmetric nature of multilayer growth. Site diffusion is responsible for multilayer growth in the linear and into the exponential regimes, which explains how PDADMA can mysteriously "pass through" layers of PSS. Using quantitative relationships between site diffusion coefficient and salt concentration, conditions were identified that allowed the diffusion length to always exceed the film thickness, leading to full exponential growth over 3 orders of magnitude thickness. Both site and polymer diffusion were independent of molecular weight, suggesting that ion pairing density is a limiting factor. Polyelectrolyte complexes are examples of a broader class of dynamic bulk polymeric materials that (self-) assemble via the transport of cross-links or defects rather than actual molecules.
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Affiliation(s)
- Hadi M Fares
- Department of Chemistry and Biochemistry, The Florida State University , Tallahassee, Florida 32306-4390, United States
| | - Joseph B Schlenoff
- Department of Chemistry and Biochemistry, The Florida State University , Tallahassee, Florida 32306-4390, United States
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