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Faisal KS, Clulow AJ, Krasowska M, Gillam T, Miklavcic SJ, Williamson NH, Blencowe A. Interrogating the relationship between the microstructure of amphiphilic poly(ethylene glycol-b-caprolactone) copolymers and their colloidal assemblies using non-interfering techniques. J Colloid Interface Sci 2022; 606:1140-1152. [PMID: 34492457 DOI: 10.1016/j.jcis.2021.08.084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/20/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
Understanding the microstructural parameters of amphiphilic copolymers that control the formation and structure of aggregated colloids (e.g., micelles) is essential for the rational design of hierarchically structured systems for applications in nanomedicine, personal care and food formulations. Although many analytical techniques have been employed to study such systems, in this investigation we adopted an integrated approach using non-interfering techniques - diffusion nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS) and synchrotron small-angle X-ray scattering (SAXS) - to probe the relationship between the microstructure of poly(ethylene glycol-b-caprolactone) (PEG-b-PCL) copolymers [e.g., block molecular weight (MW) and the mass fraction of PCL (fPCL)] and the structure of their aggregates. Systematic trends in the self-assembly behaviour were determined using a large family of well-defined block copolymers with variable PEG and PCL block lengths (number-average molecular weights (Mn) between 2 and 10 and 0.5-15 kDa, respectively) and narrow dispersity (Ð < 1.12). For all of the copolymers, a clear transition in the aggregate structure was observed when the hydrophobic fPCL was increased at a constant PEG block Mn, although the nature of this transition is also dependent on the PEG block Mn. Copolymers with low Mn PEG blocks (2 kDa) were observed to transition from unimers and loosely associated unimers to metastable aggregates and finally, to cylindrical micelles as the fPCL was increased. In comparison, copolymers with PEG block Mn of between 5 and 10 kDa transitioned from heterogenous metastable aggregates to cylindrical micelles and finally, well-defined ellipsoidal micelles (of decreasing aspect ratios) as the fPCL was increased. In all cases, the diffusion NMR spectroscopy, DLS and synchrotron SAXS results provided complementary information and the grounds for a phase diagram relating copolymer microstructure to aggregation behaviour and structure. Importantly, the absence of commonly depicted spherical micelles has implications for applications where properties may be governed by shape, such as, cellular uptake of nanomedicine formulations.
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Affiliation(s)
- Khandokar Sadique Faisal
- Applied Chemistry and Translational Biomaterials (ACTB) Group, UniSA CHS, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Andrew J Clulow
- Drug Delivery, Disposition & Dynamics, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Marta Krasowska
- Surface Interactions and Soft Matter (SISM) Group, Future Industries Institute, UniSA STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Todd Gillam
- Applied Chemistry and Translational Biomaterials (ACTB) Group, UniSA CHS, University of South Australia, Adelaide, South Australia 5000, Australia; Surface Interactions and Soft Matter (SISM) Group, Future Industries Institute, UniSA STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Stanley J Miklavcic
- Phenomics and Bioinformatics Research Centre, UniSA STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Nathan H Williamson
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| | - Anton Blencowe
- Applied Chemistry and Translational Biomaterials (ACTB) Group, UniSA CHS, University of South Australia, Adelaide, South Australia 5000, Australia.
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Carrazzone RJ, Li X, Foster JC, Uppala VVS, Wall CE, Esker AR, Madsen LA, Matson JB. Strong Variation of Micelle-Unimer Coexistence as a Function of Core Chain Mobility. Macromolecules 2021; 54:6975-6981. [PMID: 36910585 PMCID: PMC10004150 DOI: 10.1021/acs.macromol.1c00635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polymeric micelles coexist in solution with unassembled chains (unimers). We have investigated the influence of glass transition temperature (T g) (i.e., chain mobility) of the micelle core-forming blocks on micelle-unimer coexistence. We synthesized a series of seven PEG-b-P(nBA-ran-tBA) amphiphilic block copolymers (PEG = poly(ethylene glycol), nBA = n-butyl acrylate, tBA = tert-butyl acrylate) with similar molecular weights (12 kg/mol). Varying the nBA/tBA molar ratio enabled broad modulation of core block T g with no significant change in core hydrophobicity or micelle size. NMR diffusometry revealed increasing unimer populations from 0% to 54% of total polymer concentration upon decreasing core block T g from 25 to -46 °C. Additionally, unimer population at fixed polymer composition (and thus core T g) increased with temperature. This study demonstrates the strong influence of core-forming block mobility on polymer self-assembly, providing information toward designing drug delivery systems and suggesting the need for new dynamical theory.
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Affiliation(s)
- Ryan J Carrazzone
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Xiuli Li
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Jeffrey C Foster
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Veera Venkata Shravan Uppala
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Candace E Wall
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Alan R Esker
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Louis A Madsen
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
| | - John B Matson
- † Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, United States
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Pavlov GM, Gosteva AA, Dommes OA, Okatova OV, Gavrilova II, Panarin EF. Detecting Hydrophobic Interactions in Star-Shaped Amphiphilic Copolymers by the Viscometric Method. POLYMER SCIENCE SERIES A 2021. [DOI: 10.1134/s0965545x21010077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Pavlov GM, Gosteva AA, Okatova OV, Dommes OA, Gavrilova II, Panarin EF. Detection and evaluation of polymer–polymer interactions in dilute solutions of associating polymers. Polym Chem 2021. [DOI: 10.1039/d0py01725f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An experimental tool for the evaluation of intramolecular associative/hydrophobic interactions in polymer/solvent systems was proposed and tested.
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Affiliation(s)
| | - Anna A. Gosteva
- Institute of Macromolecular Compounds
- St. Petersburg 199004
- Russia
| | - Olga V. Okatova
- Institute of Macromolecular Compounds
- St. Petersburg 199004
- Russia
| | - Olga A. Dommes
- Institute of Macromolecular Compounds
- St. Petersburg 199004
- Russia
| | | | - Evgenii F. Panarin
- Institute of Macromolecular Compounds
- St. Petersburg 199004
- Russia
- Department of Medical Physics and Bioengineering
- St. Petersburg State Polytechnical University
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5
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Self-assembled nanostructures from amphiphilic block copolymers prepared via ring-opening metathesis polymerization (ROMP). Prog Polym Sci 2020. [DOI: 10.1016/j.progpolymsci.2020.101278] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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6
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Dahal UR, Prhashanna A, Dormidontova EE. Hydration of diblock copolymer micelles: Effects of hydrophobicity and co-solvent. J Chem Phys 2019; 150:184908. [PMID: 31091932 DOI: 10.1063/1.5089251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Diblock polymer micelles dispersed in an aqueous environment are being actively investigated for various applications, but there is only a qualitative understanding of the effect of the chemical structure on the micelle hydration and water dynamics as these properties are difficult to assess experimentally. Using all-atom molecular dynamics simulations, we investigate aqueous solutions of three comparable in size diblock copolymer micelles with core-forming blocks of different hydrophobicity: polybutadiene (PB), polycaprolactone (PCL), and polytetrahydrofuran (pTHF) with the same hydrophilic block, polyethylene oxide (PEO). We found that core-block hydrophobicity and ability to form hydrogen bonds with water strongly affect the water dynamics near the core: water molecules spend considerably less time in contact with the PB block than with PCL and pTHF blocks. We obtained polymer and solvent volume fraction profiles and determined that the interfacial width systematically increases with a decrease of core block hydrophobicity with water penetration into the core being negligible for PB-PEO and PCL-PEO micelles, while for pTHF-PEO micelles the interface is more diffuse and there is a noticeable penetration of water (17% by volume). For PCL-PEO micelles, which are commonly used in biomedical applications, we also investigated tetrahydrofuran (THF) penetration into the micelles from mixed THF:water solution at early stages of micelle dissolution. We found an inhomogeneous solvent distribution with a maximum of THF volume fraction in the interfacial core-corona region and partial exclusion from the PEO corona, which slows down micelle dissolution. These results can have important implications for micelle stability and use in biomedical applications.
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Affiliation(s)
- Udaya R Dahal
- Polymer Program, Institute of Materials Science and Physics Department, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Ammu Prhashanna
- Polymer Program, Institute of Materials Science and Physics Department, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Elena E Dormidontova
- Polymer Program, Institute of Materials Science and Physics Department, University of Connecticut, Storrs, Connecticut 06269, USA
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Li Z, Van Zee NJ, Bates FS, Lodge TP. Polymer Nanogels as Reservoirs To Inhibit Hydrophobic Drug Crystallization. ACS NANO 2019; 13:1232-1243. [PMID: 30648859 DOI: 10.1021/acsnano.8b06393] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The effects of cross-link density and composition on the loading and in vitro dissolution of the drug phenytoin as amorphous solid dispersions in emulsion polymerized poly( N-isopropylacrylamide) (PNIPAm) and poly( N-isopropylacrylamide- co- N, N-dimethylacrylamide) nanogels were investigated near the lower critical solution temperature (LCST). Nanogel size and particle density in phosphate buffered saline were quantified by dynamic light scattering (DLS) and viscometry experiments, while drug-nanogel interactions were revealed by cross peaks in aqueous-state nuclear Overhauser effect spectroscopy measurements. Spray-dried dispersions (SDDs) of drug-loaded PNIPAm nanogel particles ( R ≈ 43 nm) were directly visualized by cryogenic transmission electron microscopy and further quantified by small-angle X-ray scattering during in vitro dissolution. SDD dissolution profiles were highly dependent on the nanogel cross-link density and directly correlated with the state of dispersion of the drug-loaded nanogel particles. A balance between net particle hydrophobicity and hydrophilicity along with the distance in temperature from the LCST are shown to dictate the in vitro dissolution of the amorphous solid dispersions. Solubility enhancement mechanisms disclosed in this study provide essential guidance for the design of effective nanogels for oral drug delivery applications.
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Luo H, Tang Q, Zhong J, Lei Z, Zhou J, Tong Z. Interplay of Solvation and Size Effects Induced by the Counterions in Ionic Block Copolymers on the Basis of Hofmeister Series. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201800508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Haipeng Luo
- Key Laboratory of Advanced Textile Materials and Manufacturing Technology; Ministry of Education; Department of Polymer Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
- Institute of Smart Fiber Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
| | - Qiuju Tang
- Key Laboratory of Advanced Textile Materials and Manufacturing Technology; Ministry of Education; Department of Polymer Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
| | - Jiaxing Zhong
- Key Laboratory of Advanced Textile Materials and Manufacturing Technology; Ministry of Education; Department of Polymer Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
| | - Zhentao Lei
- Key Laboratory of Advanced Textile Materials and Manufacturing Technology; Ministry of Education; Department of Polymer Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
- Institute of Smart Fiber Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
| | - Junyi Zhou
- Key Laboratory of Advanced Textile Materials and Manufacturing Technology; Ministry of Education; Department of Polymer Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
- Institute of Smart Fiber Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
| | - Zaizai Tong
- Key Laboratory of Advanced Textile Materials and Manufacturing Technology; Ministry of Education; Department of Polymer Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
- Institute of Smart Fiber Materials; Zhejiang Sci-Tech University; Hangzhou 310018 China
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9
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Li X, Cooksey TJ, Kidd BE, Robertson ML, Madsen LA. Mapping Coexistence Phase Diagrams of Block Copolymer Micelles and Free Unimer Chains. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01220] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiuli Li
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Tyler J. Cooksey
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77004, United States
| | - Bryce E. Kidd
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Megan L. Robertson
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77004, United States
| | - Louis A. Madsen
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
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Cooksey TJ, Singh A, Le KM, Wang S, Kelley EG, He L, Vajjala Kesava S, Gomez ED, Kidd BE, Madsen LA, Robertson ML. Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Core/Corona Structure and Solvent Uptake. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02580] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Tyler J. Cooksey
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Avantika Singh
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Kim Mai Le
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Shu Wang
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Elizabeth G. Kelley
- Department
of Chemical Engineering, University of Delaware, Newark, Delaware 19716, United States
- National
Institute
of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899-6100, United States
| | - Lilin He
- Biology
and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Sameer Vajjala Kesava
- Department
of Chemical Engineering and the Materials Research Institute, The Pennsylvania State University, State College, Pennsylvania 16801, United States
| | - Enrique D. Gomez
- Department
of Chemical Engineering and the Materials Research Institute, The Pennsylvania State University, State College, Pennsylvania 16801, United States
| | - Bryce E. Kidd
- Department
of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Louis A. Madsen
- Department
of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Megan L. Robertson
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
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