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Weisbord I, Segal-Peretz T. Revealing the 3D Structure of Block Copolymers with Electron Microscopy: Current Status and Future Directions. ACS Appl Mater Interfaces 2023; 15:58003-58022. [PMID: 37338172 DOI: 10.1021/acsami.3c02956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Block copolymers (BCPs) are considered model systems for understanding and utilizing self-assembly in soft matter. Their tunable nanometric structure and composition enable comprehensive studies of self-assembly processes as well as make them relevant materials in diverse applications. A key step in developing and controlling BCP nanostructures is a full understanding of their three-dimensional (3D) structure and how this structure is affected by the BCP chemistry, confinement, boundary conditions, and the self-assembly evolution and dynamics. Electron microscopy (EM) is a leading method in BCP 3D characterization owing to its high resolution in imaging nanosized structures. Here we discuss the two main 3D EM methods: namely, transmission EM tomography and slice and view scanning EM tomography. We present each method's principles, examine their strengths and weaknesses, and discuss ways researchers have devised to overcome some of the challenges in BCP 3D characterization with EM- from specimen preparation to imaging radiation-sensitive materials. Importantly, we review current and new cutting-edge EM methods such as direct electron detectors, energy dispersive X-ray spectroscopy of soft matter, high temporal rate imaging, and single-particle analysis that have great potential for expanding the BCP understanding through EM in the future.
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Affiliation(s)
- Inbal Weisbord
- Chemical Engineering Department, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Tamar Segal-Peretz
- Chemical Engineering Department, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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2
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Abstract
Polymersomes are polymeric analogues of liposomes with exceptional physical and chemical properties. Despite being dubbed as next-generation vesicles since their inception nearly three decades ago, polymersomes have yet to experience translation into the clinical or industrial settings. This is due to a lack of reliable methods to upscale production without compromising control over polymersome properties. Herein we report a continuous flow methodology capable of producing near-monodisperse polymersomes at scale (≥3 g/h) with the possibility of performing downstream polymersome manipulation. Unlike conventional polymersomes, our polymersomes exhibit metastability under ambient conditions, persisting for a lifetime of ca. 7 days, during which polymersome growth occurs until a dynamic equilibrium state is reached. We demonstrate how this metastable state is key to the implementation of downstream processes to manipulate polymersome size and/or shape in the same continuous stream. The methodology operates in a plug-and-play fashion and is applicable to various block copolymers.
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Affiliation(s)
- Chin Ken Wong
- School of Chemistry, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia.
| | - Rebecca Y Lai
- School of Chemistry, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia
| | - Martina H Stenzel
- School of Chemistry, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia.
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3
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El Yousfi R, Brahmi M, Dalli M, Achalhi N, Azougagh O, Tahani A, Touzani R, El Idrissi A. Recent Advances in Nanoparticle Development for Drug Delivery: A Comprehensive Review of Polycaprolactone-Based Multi-Arm Architectures. Polymers (Basel) 2023; 15:polym15081835. [PMID: 37111982 PMCID: PMC10142392 DOI: 10.3390/polym15081835] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/28/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Controlled drug delivery is a crucial area of study for improving the targeted availability of drugs; several polymer systems have been applied for the formulation of drug delivery vehicles, including linear amphiphilic block copolymers, but with some limitations manifested in their ability to form only nanoaggregates such as polymersomes or vesicles within a narrow range of hydrophobic/hydrophilic balance, which can be problematic. For this, multi-arm architecture has emerged as an efficient alternative that overcame these challenges, with many interesting advantages such as reducing critical micellar concentrations, producing smaller particles, allowing for various functional compositions, and ensuring prolonged and continuous drug release. This review focuses on examining the key variables that influence the customization of multi-arm architecture assemblies based on polycaprolactone and their impact on drug loading and delivery. Specifically, this study focuses on the investigation of the structure-property relationships in these formulations, including the thermal properties presented by this architecture. Furthermore, this work will emphasize the importance of the type of architecture, chain topology, self-assembly parameters, and comparison between multi-arm structures and linear counterparts in relation to their impact on their performance as nanocarriers. By understanding these relationships, more effective multi-arm polymers can be designed with appropriate characteristics for their intended applications.
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Affiliation(s)
- Ridouan El Yousfi
- Laboratory Applied Chemistry and Environmental (LCAE-URAC18), Faculty of Sciences of Oujda, University Mohamed Premier, Oujda 60000, Morocco
| | - Mohamed Brahmi
- Physical Chemistry of Natural Substances and Process Team, Laboratory of Applied Chemistry and Environment (LCAE-CPSUNAP), Department of Chemistry, Faculty of Sciences, University Mohamed Premier, Oujda 60000, Morocco
| | - Mohammed Dalli
- Laboratory of Microbiology, Faculty of Medicine and Pharmacy, University Mohamed Premier, Oujda 60000, Morocco
| | - Nafea Achalhi
- Laboratory Applied Chemistry and Environmental (LCAE-URAC18), Faculty of Sciences of Oujda, University Mohamed Premier, Oujda 60000, Morocco
| | - Omar Azougagh
- Laboratory of Molecular Chemistry, Materials and Environment (LMCME), Department of Chemistry, Faculty Multidisciplinary Nador, University Mohamed Premier, P. B. 300, Nador 62700, Morocco
| | - Abdesselam Tahani
- Physical Chemistry of Natural Substances and Process Team, Laboratory of Applied Chemistry and Environment (LCAE-CPSUNAP), Department of Chemistry, Faculty of Sciences, University Mohamed Premier, Oujda 60000, Morocco
| | - Rachid Touzani
- Laboratory Applied Chemistry and Environmental (LCAE-URAC18), Faculty of Sciences of Oujda, University Mohamed Premier, Oujda 60000, Morocco
| | - Abderrahmane El Idrissi
- Laboratory Applied Chemistry and Environmental (LCAE-URAC18), Faculty of Sciences of Oujda, University Mohamed Premier, Oujda 60000, Morocco
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4
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Quintieri G, Schlattmann D, Schönhoff M, Gröschel AH. Fabrication of diverse multicompartment micelles by redispersion of triblock terpolymer bulk morphologies. Nanoscale 2022; 14:12658-12667. [PMID: 36018306 DOI: 10.1039/d2nr03874a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Redispersing block copolymer (BCP) bulk films in selective solvents is a simple and efficient method to prepare BCP micelles and polymersomes. While ABC triblock terpolymers are known to form multicompartment micelles (MCMs) with intricate nanoarchitecture, this is typically done by solvent exchange instead of redispersion of bulk films despite obvious advantages of greatly reduced solvent usage. Here, we provide guidelines on how to form MCMs with defined shapes and inner structure through direct redispersion of terpolymer bulk morphologies in selective plasticizing solvents. For this purpose, we redisperse a series of polystyrene-b-polybutadiene-b-poly(tert-butyl methacrylate) (PS-b-PB-b-PT) triblock terpolymers in acetone/isopropanol mixtures, where PT is always soluble, PB always insoluble, and PS will range from soft (high acetone content) to kinetically frozen (high isopropanol content). We investigate the effect of solvent mixtures, block composition, and thermal annealing on MCM shape and core morphology. Additionally, we performed terpolymer blend experiments to open up a simple route to further diversify the range of accessible MCM morphologies.
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Affiliation(s)
- Giada Quintieri
- Physical Chemistry, University of Münster, Corrensstr. 28-30, 48149 Münster, Germany.
- Center for Soft Nanoscience (SoN), University of Münster, Busso-Peus-Str. 10, 48149 Münster, Germany
| | - Daniel Schlattmann
- Physical Chemistry, University of Münster, Corrensstr. 28-30, 48149 Münster, Germany.
- Center for Soft Nanoscience (SoN), University of Münster, Busso-Peus-Str. 10, 48149 Münster, Germany
| | - Monika Schönhoff
- Physical Chemistry, University of Münster, Corrensstr. 28-30, 48149 Münster, Germany.
- Center for Soft Nanoscience (SoN), University of Münster, Busso-Peus-Str. 10, 48149 Münster, Germany
| | - André H Gröschel
- Physical Chemistry, University of Münster, Corrensstr. 28-30, 48149 Münster, Germany.
- Center for Soft Nanoscience (SoN), University of Münster, Busso-Peus-Str. 10, 48149 Münster, Germany
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5
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Putaux JL, Lancelon-Pin C, Choisnard L, Gèze A, Wouessidjewe D. Topological defects in polycrystalline hexosomes from β-cyclodextrin fatty esters. Soft Matter 2022; 18:2028-2038. [PMID: 35191906 DOI: 10.1039/d1sm01831k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Colloidal nanoparticles were prepared by aqueous self-assembly of amphiphilic β-cyclodextrins (βCDs) acylated on their secondary face with C14 chains to a total degree of substitution of 7.0, via a thermolysin-catalyzed transesterification process. The small-angle X-ray scattering pattern of the nanoparticles was consistent with a reverse hexagonal organization. Cryo-transmission electron microscopy images revealed particles with spectacular tortuous shapes and consisting of misoriented domains with a regular columnar hexagonal structure, separated by sharp interfaces. Edge dislocations as well as a variety of stepped tilt grain boundaries (GBs) composed of symmetrical and asymmetrical sections, together with one twist GB, were identified from axial views of the columnar organization. The tilt GB structure was analyzed using the concepts of coincidence site lattice and structural units developed to describe the atomic structure of interfaces in various types of polycrystals. The tilt GBs were described using sequences of βCD-C14 columns that differed by the number of neighboring columns (5, 6 or 7) and exhibiting distinctive contrasts. To our knowledge, this is the first time that these types of topological defects are described at the nanometric scale by direct observation of colloidal polycrystalline hexosomes of self-organized amphiphiles.
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Affiliation(s)
- Jean-Luc Putaux
- Univ. Grenoble Alpes, CNRS, CERMAV, F-38000 Grenoble, France.
| | | | - Luc Choisnard
- Univ. Grenoble Alpes, CNRS, DPM, F-38000 Grenoble, France
| | - Annabelle Gèze
- Univ. Grenoble Alpes, CNRS, DPM, F-38000 Grenoble, France
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Janoszka N, Azhdari S, Hils C, Coban D, Schmalz H, Gröschel AH. Morphology and Degradation of Multicompartment Microparticles Based on Semi-Crystalline Polystyrene- block-Polybutadiene- block-Poly( L-lactide) Triblock Terpolymers. Polymers (Basel) 2021; 13:polym13244358. [PMID: 34960909 PMCID: PMC8706259 DOI: 10.3390/polym13244358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 11/24/2022] Open
Abstract
The confinement assembly of block copolymers shows great potential regarding the formation of functional microparticles with compartmentalized structure. Although a large variety of block chemistries have already been used, less is known about microdomain degradation, which could lead to mesoporous microparticles with particularly complex morphologies for ABC triblock terpolymers. Here, we report on the formation of triblock terpolymer-based, multicompartment microparticles (MMs) and the selective degradation of domains into mesoporous microparticles. A series of polystyrene-block-polybutadiene-block-poly(L-lactide) (PS-b-PB-b-PLLA, SBL) triblock terpolymers was synthesized by a combination of anionic vinyl and ring-opening polymerization, which were transformed into microparticles through evaporation-induced confinement assembly. Despite different block compositions and the presence of a crystallizable PLLA block, we mainly identified hexagonally packed cylinders with a PLLA core and PB shell embedded in a PS matrix. Emulsions were prepared with Shirasu Porous Glass (SPG) membranes leading to a narrow size distribution of the microparticles and control of the average particle diameter, d ≈ 0.4 µm–1.8 µm. The core–shell cylinders lie parallel to the surface for particle diameters d < 0.5 µm and progressively more perpendicular for larger particles d > 0.8 µm as verified with scanning and transmission electron microscopy and particle cross-sections. Finally, the selective degradation of the PLLA cylinders under basic conditions resulted in mesoporous microparticles with a pronounced surface roughness.
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Affiliation(s)
- Nicole Janoszka
- Physical Chemistry, Center for Soft Nanoscience (SoN) and Center for Nanotechnology (CeNTech), University of Münster, Corrensstraße 28-30, 48149 Münster, Germany; (N.J.); (S.A.); (D.C.)
| | - Suna Azhdari
- Physical Chemistry, Center for Soft Nanoscience (SoN) and Center for Nanotechnology (CeNTech), University of Münster, Corrensstraße 28-30, 48149 Münster, Germany; (N.J.); (S.A.); (D.C.)
| | - Christian Hils
- Macromolecular Chemistry II, University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany;
| | - Deniz Coban
- Physical Chemistry, Center for Soft Nanoscience (SoN) and Center for Nanotechnology (CeNTech), University of Münster, Corrensstraße 28-30, 48149 Münster, Germany; (N.J.); (S.A.); (D.C.)
| | - Holger Schmalz
- Macromolecular Chemistry II, University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany;
- Bavarian Polymer Institute (BPI), University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
- Correspondence: (H.S.); (A.H.G.)
| | - André H. Gröschel
- Physical Chemistry, Center for Soft Nanoscience (SoN) and Center for Nanotechnology (CeNTech), University of Münster, Corrensstraße 28-30, 48149 Münster, Germany; (N.J.); (S.A.); (D.C.)
- Correspondence: (H.S.); (A.H.G.)
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7
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Tjaberings S, Heidelmann M, Tjaberings A, Steinhaus A, Franzka S, Walkenfort B, Gröschel AH. Terpolymer Multicompartment Nanofibers as Templates for Hybrid Pt Double Helices. ACS Appl Mater Interfaces 2020; 12:39586-39594. [PMID: 32805896 DOI: 10.1021/acsami.0c10385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hybrid inorganic/block copolymer (BCP) materials have become increasingly relevant for application in heterogeneous catalysis, microelectronics, and nanomedicine. While block copolymer templates are widely used for the formation of inorganic nanostructures, multicompartment templates could give access to more complex shapes and inner structures that are challenging to obtain with traditional processes. Here, we report the formation and characterization of hybrid platinum/polymer helices using multicompartment nanofibers (MCNFs) of polystyrene-block-polybutadiene-block-poly(tert-butyl methacrylate) (PS-b-PB-b-PT) triblock terpolymers as templates. Cross-linking of a PS-b-PB-b-PT helix-on-cylinder morphology resulted in uniform nanofibers with a diameter of 90 nm and a length of several micrometers, as well as an inner PB double helix (diameter 35 nm, pitch 25 nm, core 12 nm). The PB double helix served as template for the sol-gel reaction of H2PtCl6 into hybrid Pt double helices (Pt@MCNFs) as verified by STEM, electron tomography, AFM, and SEM. Carbonization of the Pt hybrids into Pt decorated carbon nanofibers (Pt@C) was followed in situ on a TEM heating state. Gradual heating from 25 to 1000 °C induced fusion of amorphous Pt NPs into larger crystalline Pt NP, which sheds light on the aging of Pt NPs in BCP scaffolds under high temperature conditions. The Pt@MCNFs were further sulfonated and incorporated into a filter to catalyze a model compound in a continuous flow process.
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Affiliation(s)
- Stefanie Tjaberings
- Physical Chemistry and Centre for Soft Nanoscience (SoN) University of Münster, 48149 Münster, Germany
| | - Markus Heidelmann
- Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Alexander Tjaberings
- Physical Chemistry and Centre for Soft Nanoscience (SoN) University of Münster, 48149 Münster, Germany
| | - Andrea Steinhaus
- Physical Chemistry and Centre for Soft Nanoscience (SoN) University of Münster, 48149 Münster, Germany
| | - Steffen Franzka
- Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Bernd Walkenfort
- Institute for Experimental Immunology and Imaging, Imaging Center Essen, Electron Microscopy Unit, University of Duisburg-Essen, 45147 Essen, Germany
| | - André H Gröschel
- Physical Chemistry and Centre for Soft Nanoscience (SoN) University of Münster, 48149 Münster, Germany
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Nghiem TL, Chakroun R, Janoszka N, Chen C, Klein K, Wong CK, Gröschel AH. pH-Controlled Hierarchical Assembly/Disassembly of Multicompartment Micelles in Water. Macromol Rapid Commun 2020; 41:e2000301. [PMID: 32613695 DOI: 10.1002/marc.202000301] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/19/2020] [Indexed: 12/21/2022]
Abstract
Multicompartment micelles (MCMs) have become attractive drug delivery systems as they allow the separate storage of two or more incompatible cargos in their core compartments (e.g., drugs and dyes for imaging). A recent hierarchical self-assembly process for hydrophobic terpolymers in organic solvents showed the ability to form very homogeneous MCM populations, yet the transfer of this process into water requires a better understanding of the formation mechanism and influence of chain mobility during assembly. Here, the synthesis of a linear poly(oligo(ethylene glycol) methacrylate)-block-poly(benzyl acrylate)-block-poly(4-vinylpyridine) (POEGMA-b-PBzA-b-P4VP) triblock terpolymer by reversible addition-fragmentation chain transfer (RAFT) polymerization is reported as well as its step-wise assembly into MCMs in water with POEGMA corona, PBzA patches, and P4VP core. Reversible assembly/disassembly of the MCMs is investigated through protonation/deprotonation of the P4VP core. Interestingly, the low glass transition temperature (Tg ) of the hydrophobic PBzA middle block causes MCMs to directly disassemble into molecularly dissolved chains instead of patchy micelles due to mechanical stress from electrosteric repulsion of the protonated P4VP corona chains. In addition, pH resistant MCMs are created by core-crosslinking and fluorescent properties are added by covalent anchoring of fluorescent dyes via straightforward click chemistry.
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Affiliation(s)
- Tai-Lam Nghiem
- Physical Chemistry and Center for Soft Nanoscience (SoN), University of Münster, Münster, 48149, Germany
| | - Ramzi Chakroun
- Physical Chemistry and Center for Soft Nanoscience (SoN), University of Münster, Münster, 48149, Germany
| | - Nicole Janoszka
- Physical Chemistry and Center for Soft Nanoscience (SoN), University of Münster, Münster, 48149, Germany
| | - Chen Chen
- Physical Chemistry and Center for Soft Nanoscience (SoN), University of Münster, Münster, 48149, Germany
| | - Kai Klein
- Inorganic Chemistry, University of Duisburg-Essen, Essen, 45117, Germany
| | - Chin Ken Wong
- Physical Chemistry and Center for Soft Nanoscience (SoN), University of Münster, Münster, 48149, Germany
| | - André H Gröschel
- Physical Chemistry and Center for Soft Nanoscience (SoN), University of Münster, Münster, 48149, Germany
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