1
|
Kim S, Park S, Fesenmeier DJ, Jun T, Sarkar K, Won YY. Surface Pressure-Area Mechanics of Water-Spread Poly(ethylene glycol)-Based Block Copolymer Micelle Monolayers at the Air-Water Interface: Effect of Hydrophobic Block Chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:13546-13559. [PMID: 37706471 DOI: 10.1021/acs.langmuir.3c01574] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Amphiphilic block copolymer micelles can mimic the ability of natural lung surfactant to reduce the air-water interfacial tension close to zero and prevent the Laplace pressure-induced alveolar collapse. In this work, we investigated the air-water interfacial behaviors of polymer micelles derived from eight different poly(ethylene glycol) (PEG)-based block copolymers having different hydrophobic block chemistries to elucidate the effect of the core block chemistry on the surface mechanics of the block copolymer micelles. Aqueous micelles of about 30 nm in hydrodynamic diameter were prepared from the PEG-based block copolymers via equilibration-nanoprecipitation (ENP) and spread on the water surface using water as the spreading medium. Surface pressure-area isotherm and quantitative Brewster angle microscopy (QBAM) measurements were performed to investigate how the micelle/monolayer structures change during lateral compression of the monolayer; widely varying structural behaviors were observed, including the wrinkling/collapse of micelle monolayers and deformation and/or the desorption of individual micelles. By bivariate correlation regression analysis of surface pressure-area isotherm data, it was found that the rigidity and hydrophobicity of the hydrophobic core domain, which are quantified by glass-transition temperature (Tg) and water contact angle (θ) measurements, respectively, are coupled factors that need to be taken into account concurrently in order to control the surface mechanical properties of polymer micelle monolayers; micelles having rigid and strongly hydrophobic cores exhibited high surface pressure and a high compressibility modulus under high compression. High surface pressure and a high compressibility modulus were also found to be correlated with the formation of wrinkles in the micelle monolayer (visualized by Brewster angle microscopy (BAM)). From this study, we conclude that polymer micelles based on hydrophobic block materials having higher Tg and θ are more suitable for surfactant replacement therapy applications that require the therapeutic surfactant to produce a high surface pressure and modulus at the alveolar air-water interface.
Collapse
Affiliation(s)
- Seyoung Kim
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Polymer Science and Engineering, Dankook University, Yongin, Gyeonggi 16890, Republic of Korea
| | - Sungwan Park
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Daniel J Fesenmeier
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Taesuk Jun
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kaustabh Sarkar
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - You-Yeon Won
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue University Institute for Cancer Research, Purdue University, West Lafayette, Indiana 47907, United States
| |
Collapse
|
2
|
Olszewski M, Hu X, Lin TC, Matyjaszewski K, Lebedeva N, Taylor P. Oscillatory and Relaxation Study of the Interfacial Rheology of Star Polymers with Low-Grafting-Density PEO Arms and Hydrophobic Poly(divinylbenzene) Cores. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37216597 DOI: 10.1021/acs.langmuir.3c00557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Star polymers have been gaining interest due to their tunable properties. They have been used as effective stabilizers for Pickering emulsions. Herein, star polymers were synthesized via activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP). Poly(ethylene oxide) (PEO) with terminal α-bromoisobutyrate ATRP functionality was used as a macroinitiator and divinylbenzene as a crosslinker for the arm-first star synthesis. Stars with PEO arms with a molar mass of either 2 or 5 kDa had a relatively low density of grafted chains, i.e., ca. 0.25 chain/nm2. The properties of PEO stars adsorbed at oil-water interfaces were investigated using interfacial tension and interfacial rheology. The magnitude of interfacial tensions at oil-water interfaces depends on the nature of the oil phase, being lower at the m-xylene/water interface than at the n-dodecane/water interface. Small differences were observed for stars with different molecular weights of PEO arms. The overall behavior of PEO stars adsorbed at an interface can be considered as an intermediate between a particle and a linear/branched polymer. Obtained results offer an important insight into the interfacial rheology of PEO star polymers in the context of their application as stabilizers for Pickering emulsions.
Collapse
Affiliation(s)
- Mateusz Olszewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Xiaolei Hu
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Ting-Chih Lin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Natalia Lebedeva
- Syngenta Crop Protection, LLC, Greensboro, North Carolina 27409, United States
| | - Philip Taylor
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, U.K
| |
Collapse
|
3
|
Appel C, Kraska M, Rüttiger C, Gallei M, Stühn B. Crossover from semi-dilute to densely packed thin polymer films at the air-water interface and structure formation at thin film breakup. SOFT MATTER 2018; 14:4750-4761. [PMID: 29796572 DOI: 10.1039/c8sm00629f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A series of poly(n-butyl acrylate) (PnBA, 5 to 32 kg mol-1) homopolymers and diblock copolymers with poly(ethylene glycol) (PEG, constant molecular weight of 0.3 kg mol-1) is synthesized for the purpose of the investigation of quasi-2D polymer films at the air-water interface. The presented compression isotherms show a transition from θ solvent behavior for PnBA homopolymers to good solvent conditions when the volume fraction of the PEG in the block copolymers is increased by decreasing the molecular weight of PnBA. A transition from a semi-dilute regime to a densely packed layer is observed in the pressure isotherms for all the polymers. In the densely packed films we found first evidence for thin film breakup of a thin polymer film directly at the air-water interface. Combination of results from Brewster-Angle-Microscopy and Surface X-ray scattering provide a consistent picture of the film breakup. Our results suggest a preferred length scale of 2.5 μm. This scenario is analogous to a spinodal mechanism driven by thermal fluctuations of the film height.
Collapse
Affiliation(s)
- Christian Appel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 8, D-64289 Darmstadt, Germany.
| | | | | | | | | |
Collapse
|
4
|
Schoch RL, Emilsson G, Dahlin AB, Lim RY. Protein exclusion is preserved by temperature sensitive PEG brushes. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.10.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
5
|
Enhanced capture of bacteria and endotoxin by antimicrobial WLBU2 peptide tethered on polyethylene oxide spacers. Biointerphases 2017; 12:05G603. [DOI: 10.1116/1.4997049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
6
|
Sprouse D, Jiang Y, Laaser JE, Lodge TP, Reineke TM. Tuning Cationic Block Copolymer Micelle Size by pH and Ionic Strength. Biomacromolecules 2016; 17:2849-59. [DOI: 10.1021/acs.biomac.6b00654] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dustin Sprouse
- Department of Chemistry, and ‡Department of Chemical Engineering & Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Yaming Jiang
- Department of Chemistry, and ‡Department of Chemical Engineering & Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Jennifer E. Laaser
- Department of Chemistry, and ‡Department of Chemical Engineering & Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Timothy P. Lodge
- Department of Chemistry, and ‡Department of Chemical Engineering & Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Theresa M. Reineke
- Department of Chemistry, and ‡Department of Chemical Engineering & Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
7
|
Liu F, Lv Y, Liu J, Yan ZC, Zhang B, Zhang J, He J, Liu CY. Crystallization and Rheology of Poly(ethylene oxide) in Imidazolium Ionic Liquids. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01171] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fuyong Liu
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
- Institute
of Environmental Science, Shanxi University, Taiyuan 030006, China
| | - Yuxia Lv
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
| | - Jiajian Liu
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi-Chao Yan
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
| | - Baoqing Zhang
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Zhang
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
| | - Jiasong He
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chen-Yang Liu
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of
Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
8
|
Lee J, Rancilio NJ, Poulson JM, Won YY. Block Copolymer-Encapsulated CaWO4 Nanoparticles: Synthesis, Formulation, and Characterization. ACS APPLIED MATERIALS & INTERFACES 2016; 8:8608-8619. [PMID: 26998964 PMCID: PMC5362163 DOI: 10.1021/acsami.6b00727] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We envision that CaWO4 (CWO) nanocrystals have the potential for use in biomedical imaging and therapy because of the unique ways this material interacts with high-energy radiation. These applications, however, require development of nanoparticle (NP) formulations that are suitable for in vivo applications; primarily, the formulated nanoparticles should be sufficiently small, chemically and biologically inert, and stable against aggregation under physiological conditions. The present study demonstrates one such method of formulation, in which CWO nanoparticles are encapsulated in bioinert block copolymer (BCP) micelles. For this demonstration, we prepared three different CWO nanocrystal samples having different sizes (3, 10, and 70 nm in diameter) and shapes (elongated vs truncated rhombic). Depending on the specific synthesis method used, the as-synthesized CWO NPs contain different surfactant materials (citric acid or cetyltrimethylammonium bromide or a mixture of oleic acid and oleylamine) in the coating layers. Regardless of the type of surfactant, the original surfactant coating can be replaced with a new enclosure formed by BCP materials using a solvent-exchange method. Two types of BCPs have been tested: poly(ethylene glycol-block-n-butyl acrylate) (PEG-PnBA) and poly(ethylene glycol-block-D,L-lactic acid) (PEG-PLA). Both BCPs are able to produce fully PEGylated CWO NPs that are stable against aggregation under physiological salt conditions for very long periods of time (at least three months). The optical and radio luminescence properties of both BCP-encapsulated and surfactant-coated CWO NPs were extensively characterized. The study confirms that the BCP coating structure does not influence the luminescence properties of CWO NPs.
Collapse
Affiliation(s)
- Jaewon Lee
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Nicholas J. Rancilio
- Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jean M. Poulson
- Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - You-Yeon Won
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Purdue University Center for Cancer Research, West Lafayette, IN 47907, USA
| |
Collapse
|
9
|
Lorenzo AT, Ponnapati R, Chatterjee T, Krishnamoorti R. Structural characterization of aqueous solution poly(oligo(ethylene oxide) monomethyl methacrylate)-grafted silica nanoparticles. Faraday Discuss 2016; 186:311-24. [DOI: 10.1039/c5fd00137d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structure of aqueous dispersions of poly(oligo(ethylene oxide) monomethyl methacrylate)-grafted silica nanoparticles was characterized using contrast variation small-angle neutron scattering studies. Modeling the low hybrid concentration dispersion scattering data using a fuzzy sphere and a polydisperse core–shell model, demonstrated that the polymer chains are highly swollen in the dispersions as compared to the dimensions of the free polymer chains in dilute solution. At higher hybrid concentrations, the dispersions were well described using a Percus–Yevick approximation to describe the structure factor. These structural characterization tools are excellent starting points for effective molecular level descriptors of dewetting and macroscopic phase transitions for polymer tethered hybrid nanoparticle systems.
Collapse
Affiliation(s)
- Arnaldo T. Lorenzo
- Department of Chemical and Biomolecular Engineering
- University of Houston
- Houston
- USA
| | | | - Tirtha Chatterjee
- Department of Chemical and Biomolecular Engineering
- University of Houston
- Houston
- USA
| | | |
Collapse
|
10
|
Kim HC, Lee H, Khetan J, Won YY. Surface Mechanical and Rheological Behaviors of Biocompatible Poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) and Poly((D,L-lactic acid-ran-glycolic acid-ran-ε-caprolactone)-block-ethylene glycol) (PLGACL-PEG) Block Copolymers at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13821-13833. [PMID: 26633595 DOI: 10.1021/acs.langmuir.5b03622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Air-water interfacial monolayers of poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) exhibit an exponential increase in surface pressure under high monolayer compression. In order to understand the molecular origin of this behavior, a combined experimental and theoretical investigation (including surface pressure-area isotherm, X-ray reflectivity (XR) and interfacial rheological measurements, and a self-consistent field (SCF) theoretical analysis) was performed on air-water monolayers formed by a PLGA-PEG diblock copolymer and also by a nonglassy analogue of this diblock copolymer, poly((D,L-lactic acid-ran-glycolic acid-ran-caprolactone)-block-ethylene glycol) (PLGACL-PEG). The combined results of this study show that the two mechanisms, i.e., the glass transition of the collapsed PLGA film and the lateral repulsion of the PEG brush chains that occur simultaneously under lateral compression of the monolayer, are both responsible for the observed PLGA-PEG isotherm behavior. Upon cessation of compression, the high surface pressure of the PLGA-PEG monolayer typically relaxes over time with a stretched exponential decay, suggesting that in this diblock copolymer situation, the hydrophobic domain formed by the PLGA blocks undergoes glass transition in the high lateral compression state, analogously to the PLGA homopolymer monolayer. In the high PEG grafting density regime, the contribution of the PEG brush chains to the high monolayer surface pressure is significantly lower than what is predicted by the SCF model because of the many-body attraction among PEG segments (referred to in the literature as the "n-cluster" effects). The end-grafted PEG chains were found to be protein resistant even under the influence of the "n-cluster" effects.
Collapse
Affiliation(s)
- Hyun Chang Kim
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Hoyoung Lee
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Jawahar Khetan
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - You-Yeon Won
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| |
Collapse
|
11
|
Wu X, Ryder MP, McGuire J, Snider JL, Schilke KF. Sequential and competitive adsorption of peptides at pendant PEO layers. Colloids Surf B Biointerfaces 2015; 130:69-76. [PMID: 25909181 DOI: 10.1016/j.colsurfb.2015.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 04/05/2015] [Accepted: 04/06/2015] [Indexed: 11/24/2022]
Abstract
Earlier work provided direction for development of responsive drug delivery systems based on modulation of the structure, amphiphilicity, and surface density of bioactive peptides entrapped within pendant polyethylene oxide (PEO) brush layers. In this work, we describe the sequential and competitive adsorption behavior of such peptides at pendant PEO layers. Three cationic peptides were used for this purpose: the arginine-rich, amphiphilic peptide WLBU2, a peptide chemically identical to WLBU2 but of scrambled sequence (S-WLBU2), and the non-amphiphilic peptide poly-L-arginine (PLR). Optical waveguide lightmode spectroscopy (OWLS) was used to quantify the rate and extent of peptide adsorption and elution at surfaces coated with PEO. UV spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to quantify the extent of peptide exchange during the course of sequential and competitive adsorption. Circular dichroism (CD) was used to evaluate conformational changes after adsorption of peptide mixtures at PEO-coated silica nanoparticles. Results indicated that amphiphilic peptides are able to displace adsorbed, non-amphiphilic peptides in PEO layers, while non-amphiphilic peptides were not able to displace more amphiphilic peptides. In addition, peptides of greater amphiphilicity dominated the adsorption at the PEO layer from mixtures with less amphiphilic or non-amphiphilic peptides.
Collapse
Affiliation(s)
| | - Matthew P Ryder
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Joseph McGuire
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | | | - Karl F Schilke
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
| |
Collapse
|
12
|
Abbott SB, de Vos WM, Mears LLE, Cattoz B, Skoda MWA, Barker R, Richardson RM, Prescott SW. Is Osmotic Pressure Relevant in the Mechanical Confinement of a Polymer Brush? Macromolecules 2015. [DOI: 10.1021/ma502246r] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Stephen B. Abbott
- H H Wills
Physics Laboratory, University of Bristol, Bristol BS8 1TL, U.K
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Wiebe M. de Vos
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
- Membrane
Science and Technology, Mesa+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands
| | - Laura L. E. Mears
- H H Wills
Physics Laboratory, University of Bristol, Bristol BS8 1TL, U.K
| | - Beatrice Cattoz
- H H Wills
Physics Laboratory, University of Bristol, Bristol BS8 1TL, U.K
| | | | - Robert Barker
- Institut Laue Langevin, 71 avenue des Martyrs, F-38042 Grenoble, France
| | | | - Stuart W. Prescott
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
- School of Chemical Engineering, UNSW Australia, UNSW, Sydney, NSW 2052, Australia
| |
Collapse
|
13
|
Lee H, Tsouris V, Lim Y, Mustafa R, Choi J, Choi YH, Park HW, Meron M, Lin B, Won YY. Macroscopic lateral heterogeneity observed in a laterally mobile immiscible mixed polyelectrolyte-neutral polymer brush. SOFT MATTER 2014; 10:3771-82. [PMID: 24695635 PMCID: PMC4397986 DOI: 10.1039/c4sm00022f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We studied mixed poly(ethylene oxide) (PEO) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes. The question we attempted to answer was: when the chain grafting points are laterally mobile, how will this lateral mobility influence the structure and phase behavior of the mixed brush? Three different model mixed PEO/PDMAEMA brush systems were prepared: (1) a laterally mobile mixed brush by spreading onto the air-water interface a mixture of poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) and poly(2-(dimethylamino)ethyl methacrylate)-poly(n-butyl acrylate) (PDMAEMA-PnBA) diblock copolymers (the specific diblock copolymers used will be denoted as PEO113-PnBA100 and PDMAEMA118-PnBA100, where the subscripts refer to the number-average degrees of polymerization of the individual blocks), (2) a mobility-restricted (inseparable) version of the above mixed brush prepared using a PEO-PnBA-PDMAEMA triblock copolymer (denoted as PEO113-PnBA89-PDMAEMA120) having respective brush molecular weights matched with those of the diblock copolymers, and (3) a different laterally mobile mixed PEO and PDMAEMA brush prepared from a PEO113-PnBA100 and PDMAEMA200-PnBA103 diblock copolymer combination, which represents a further more height-mismatched mixed brush situation than described in (1). These three mixed brush systems were investigated by surface pressure-area isotherm and X-ray (XR) reflectivity measurements. These experimental data were analyzed within the theoretical framework of a continuum self-consistent field (SCF) polymer brush model. The combined experimental and theoretical results suggest that the mobile mixed brush derived using the PEO113-PnBA100 and PDMAEMA118-PnBA100 combination (i.e., mixed brush System #1) undergoes a lateral macroscopic phase separation at high chain grafting densities, whereas the more height-mismatched system (System #3) is only microscopically phase separated under comparable brush density conditions even though the lateral mobility of the grafted chains is unrestricted. The macroscopic phase separation observed in the laterally mobile mixed brush system is in contrast with the microphase separation behavior commonly observed in two-dimensional laterally mobile charged small molecule mixtures. Further study is needed to determine the detailed morphologies of the macro- and microphase-separated mixed PEO/PDMAEMA brushes.
Collapse
Affiliation(s)
- Hoyoung Lee
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Wu X, Ryder MP, McGuire J, Schilke KF. Concentration effects on peptide elution from pendant PEO layers. Colloids Surf B Biointerfaces 2014; 118:210-7. [PMID: 24780434 DOI: 10.1016/j.colsurfb.2014.03.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 03/28/2014] [Accepted: 03/30/2014] [Indexed: 11/29/2022]
Abstract
In earlier work, we have provided direction for development of responsive drug delivery systems based on modulation of structure and amphiphilicity of bioactive peptides entrapped within pendant polyethylene oxide (PEO) brush layers. Amphiphilicity promotes retention of the peptides within the hydrophobic inner region of the PEO brush layer. In this work, we describe the effects of peptide surface density on the conformational changes caused by peptide-peptide interactions, and show that this phenomenon substantially affects the rate and extent of peptide elution from PEO brush layers. Three cationic peptides were used in this study: the arginine-rich amphiphilic peptide WLBU2, the chemically identical but scrambled peptide S-WLBU2, and the non-amphiphilic homopolymer poly-l-arginine (PLR). Circular dichroism (CD) was used to evaluate surface density effects on the structure of these peptides at uncoated (hydrophobic) and PEO-coated silica nanoparticles. UV spectroscopy and a quartz crystal microbalance with dissipation monitoring (QCM-D) were used to quantify changes in the extent of peptide elution caused by those conformational changes. For amphiphilic peptides at sufficiently high surface density, peptide-peptide interactions result in conformational changes which compromise their resistance to elution. In contrast, elution of a non-amphiphilic peptide is substantially independent of its surface density, presumably due to the absence of peptide-peptide interactions. The results presented here provide a strategy to control the rate and extent of release of bioactive peptides from PEO layers, based on modulation of their amphiphilicity and surface density.
Collapse
Affiliation(s)
- Xiangming Wu
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Matthew P Ryder
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Joseph McGuire
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Karl F Schilke
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
| |
Collapse
|
15
|
Auxier JA, Dill JK, Schilke KF, McGuire J. Blood protein repulsion after peptide entrapment in pendant polyethylene oxide layers. Biotechnol Appl Biochem 2014; 61:371-5. [DOI: 10.1002/bab.1201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 12/22/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Julie A. Auxier
- School of Chemical, Biological and Environmental Engineering; Oregon State University; Corvallis OR USA
| | - Justen K. Dill
- School of Chemical, Biological and Environmental Engineering; Oregon State University; Corvallis OR USA
| | - Karl F. Schilke
- School of Chemical, Biological and Environmental Engineering; Oregon State University; Corvallis OR USA
| | - Joseph McGuire
- School of Chemical, Biological and Environmental Engineering; Oregon State University; Corvallis OR USA
| |
Collapse
|
16
|
Wu X, Ryder MP, McGuire J, Schilke KF. Adsorption, structural alteration and elution of peptides at pendant PEO layers. Colloids Surf B Biointerfaces 2013; 112:23-9. [PMID: 23939421 PMCID: PMC3818488 DOI: 10.1016/j.colsurfb.2013.07.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/12/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
Abstract
An experimentally based, quantitative understanding of the entrapment and function of small peptides within PEO brush layers does not currently exist. Earlier work provided a rationale for expecting that an ordered, compact peptide will enter the PEO phase more readily than a peptide of similar size that adopts a less ordered, less compact form, and that amphiphilicity will promote peptide retention within the hydrophobic region of the PEO brush. Here we more deliberately describe criteria for peptide integration and structural change within the PEO brush, and discuss the reversibility of peptide entrapment with changing solvent conditions. For this purpose, circular dichroism (CD) was used to record the adsorption and conformational changes of (amphiphilic) WLBU2 and (non-amphiphilic) polyarginine peptides at uncoated (hydrophobic) and PEO-coated silica nanoparticles. Peptide conformation was controlled between disordered and α-helical forms by varying the concentration of perchlorate ion. We show an initially more ordered (α-helical) structure promotes peptide adsorption into the PEO layer. Further, a partially helical peptide undergoes an increase in helicity after entry, likely due to concomitant loss of capacity for peptide-solvent hydrogen bonding. Peptide interaction with the PEO chains resulted in entrapment and conformational change that was irreversible to elution with changing solution conditions in the case of the amphiphilic peptide. In contrast, the adsorption and conformational change of the non-amphiphilic peptide was reversible. These results indicate that responsive drug delivery systems based on peptide-loaded PEO layers can be controlled by modulation of solution conditions and peptide amphiphilicity.
Collapse
Affiliation(s)
- Xiangming Wu
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331
| | - Matthew P. Ryder
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331
| | - Joseph McGuire
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331
| | - Karl F. Schilke
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331
| |
Collapse
|
17
|
Saigal T, Yoshikawa A, Kloss D, Kato M, Golas PL, Matyjaszewski K, Tilton RD. Stable emulsions with thermally responsive microstructure and rheology using poly(ethylene oxide) star polymers as emulsifiers. J Colloid Interface Sci 2013; 394:284-92. [DOI: 10.1016/j.jcis.2012.11.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 11/13/2012] [Accepted: 11/15/2012] [Indexed: 11/29/2022]
|
18
|
Lampi MC, Wu X, Schilke KF, McGuire J. Structural attributes affecting peptide entrapment in PEO brush layers. Colloids Surf B Biointerfaces 2013; 106:79-85. [PMID: 23434695 DOI: 10.1016/j.colsurfb.2013.01.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 11/28/2022]
Abstract
A more quantitative understanding of peptide loading and release from polyethylene oxide (PEO) brush layers will provide direction for development of new strategies for drug storage and delivery. In this work we recorded selected effects of peptide structure and amphiphilicity on adsorption into PEO brush layers based on covalently stabilized Pluronic(®)F 108. Optical waveguide lightmode spectroscopy and circular dichroism measurements were used to characterize the adsorption of poly-l-glutamic acid, poly-l-lysine, and the cationic amphiphilic peptide WLBU2, to the brush layers. The structure of WLBU2 as well as that of the similarly-sized homopolymers was controlled between disordered and more ordered (helical) forms by varying solution conditions. Adsorption kinetic patterns were interpreted with reference to a simple model for protein adsorption, in order to evaluate rate constants for peptide adsorption and desorption from loosely and tightly bound states. While more ordered peptide structure apparently promoted faster adsorption and elution rates, resistance to elution while in the PEO layer was dependent on peptide amphiphilicity. The results presented here are compelling evidence of the potential to create anti-fouling surface coatings capable of storing and delivering therapeutics.
Collapse
Affiliation(s)
- Marsha C Lampi
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | | | | | | |
Collapse
|
19
|
Dill JK, Auxier JA, Schilke KF, McGuire J. Quantifying nisin adsorption behavior at pendant PEO layers. J Colloid Interface Sci 2013; 395:300-5. [PMID: 23445762 DOI: 10.1016/j.jcis.2013.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/31/2012] [Accepted: 01/02/2013] [Indexed: 11/16/2022]
Abstract
The antimicrobial peptide nisin shows potent activity against Gram-positive bacteria including the most prevalent implant-associated pathogens. Its mechanism of action minimizes the opportunity for the rise of resistant bacteria and it does not appear to be toxic to humans, suggesting good potential for its use in antibacterial coatings for selected medical devices. A more quantitative understanding of nisin loading and release from polyethylene oxide (PEO) brush layers will inform new strategies for drug storage and delivery, and in this work optical waveguide lightmode spectroscopy was used to record changes in adsorbed mass during cyclic adsorption-elution experiments with nisin, at uncoated and PEO-coated surfaces. PEO layers were prepared by radiolytic grafting of Pluronic® surfactant F108 or F68 to silanized silica surfaces, producing long- or short-chain PEO layers, respectively. Kinetic patterns were interpreted with reference to a model accounting for history-dependent adsorption, in order to evaluate rate constants for nisin adsorption and desorption, as well as the effect of pendant PEO on the lateral clustering behavior of nisin. Nisin adsorption was observed at the uncoated and F108-coated surfaces, but not at the F68-coated surfaces. Nisin showed greater resistance to elution by peptide-free buffer at the uncoated surface, and lateral rearrangement and clustering of adsorbed nisin was apparent only at the uncoated surface. We conclude peptide entrapment at the F108-coated surface is governed by a hydrophobic inner region of the PEO brush layer that is not sufficient for nisin entrapment in the case of the shorter PEO chains of the F68-coated surface.
Collapse
Affiliation(s)
- Justen K Dill
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331-2702, United States
| | | | | | | |
Collapse
|
20
|
Park HW, Choi J, Ohn K, Lee H, Kim JW, Won YY. Study of the air-water interfacial properties of biodegradable polyesters and their block copolymers with poly(ethylene glycol). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:11555-11566. [PMID: 22830444 DOI: 10.1021/la300810q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
It has been reported that the surface pressure-area isotherm of poly(D,L-lactic acid-ran-glycolic acid) (PLGA) at the air-water interface exhibits several interesting features: (1) a plateau at intermediate compression levels, (2) a sharp rise in surface pressure upon further compression, and (3) marked surface pressure-area hysteresis during compression-expansion cycles. To investigate the molecular origin of this behavior, we conducted an extensive set of surface pressure and AFM imaging measurements with PLGA materials having several different molecular weights and also a poly(D,L-lactic acid-ran-glycolic acid-ran-caprolactone) (PLGACL) material in which the caprolactone monomers were incorporated as a plasticizing component. The results suggest that (i) the plateau in the surface pressure-area isotherm of PLGA (or PLGACL) occurs because of the formation (and collapse) of a continuous monolayer of the polymer under continuous compression; (ii) the PLGA monolayer becomes significantly resistant to compression at high compression because under that condition the collapsed domains become large enough to become glassy (such behavior was not observed in the nonglassy PLGACL sample); and (iii) the isotherm hysteresis is due to a coarsening of the collapsed domains that occurs under high-compression conditions. We also investigated the monolayer properties of PEG-PLGA and PEG-PLGACL diblock copolymers. The results demonstrate that the tendency of PLGA (or PLGACL) to spread on water allows the polymer to be used as an anchoring block to form a smooth biodegradable monolayer of block copolymers at the air-water interface. These diblock copolymer monolayers exhibit protein resistance.
Collapse
Affiliation(s)
- Hae-Woong Park
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | | | | | | | | | | |
Collapse
|