51
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Dupré de Baubigny J, Trégouët C, Salez T, Pantoustier N, Perrin P, Reyssat M, Monteux C. One-Step Fabrication of pH-Responsive Membranes and Microcapsules through Interfacial H-Bond Polymer Complexation. Sci Rep 2017; 7:1265. [PMID: 28455535 PMCID: PMC5430763 DOI: 10.1038/s41598-017-01374-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/27/2017] [Indexed: 11/09/2022] Open
Abstract
Biocompatible microencapsulation is of widespread interest for the targeted delivery of active species in fields such as pharmaceuticals, cosmetics and agro-chemistry. Capsules obtained by the self-assembly of polymers at interfaces enable the combination of responsiveness to stimuli, biocompatibility and scaled up production. Here, we present a one-step method to produce in situ membranes at oil-water interfaces, based on the hydrogen bond complexation of polymers between H-bond acceptor and donor in the oil and aqueous phases, respectively. This robust process is realized through different methods, to obtain capsules of various sizes, from the micrometer scale using microfluidics or rotor-stator emulsification up to the centimeter scale using drop dripping. The polymer layer exhibits unique self-healing and pH-responsive properties. The membrane is viscoelastic at pH = 3, softens as pH is progressively raised, and eventually dissolves above pH = 6 to release the oil phase. This one-step method of preparation paves the way to the production of large quantities of functional capsules.
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Affiliation(s)
- Julien Dupré de Baubigny
- ESPCI Paris, PSL Research University, CNRS UMR 7615, Laboratoire Sciences et Ingénierie de la Matière Molle, 10 rue Vauquelin, 75231, Paris, Cedex 05, France
| | - Corentin Trégouët
- ESPCI Paris, PSL Research University, CNRS UMR 7615, Laboratoire Sciences et Ingénierie de la Matière Molle, 10 rue Vauquelin, 75231, Paris, Cedex 05, France
| | - Thomas Salez
- ESPCI Paris, PSL Research University, CNRS UMR 7083, Laboratoire Gulliver, 10 rue Vauquelin, 75231, Paris, Cedex 05, France
- Global Institution for Collaborative Research and Education, Global Station for Soft Matter, Hokkaido University, Sapporo, Hokkaido, 060-0808, Japan
| | - Nadège Pantoustier
- ESPCI Paris, PSL Research University, CNRS UMR 7615, Laboratoire Sciences et Ingénierie de la Matière Molle, 10 rue Vauquelin, 75231, Paris, Cedex 05, France
| | - Patrick Perrin
- ESPCI Paris, PSL Research University, CNRS UMR 7615, Laboratoire Sciences et Ingénierie de la Matière Molle, 10 rue Vauquelin, 75231, Paris, Cedex 05, France
| | - Mathilde Reyssat
- ESPCI Paris, PSL Research University, CNRS UMR 7083, Laboratoire Gulliver, 10 rue Vauquelin, 75231, Paris, Cedex 05, France.
| | - Cécile Monteux
- ESPCI Paris, PSL Research University, CNRS UMR 7615, Laboratoire Sciences et Ingénierie de la Matière Molle, 10 rue Vauquelin, 75231, Paris, Cedex 05, France.
- Global Institution for Collaborative Research and Education, Global Station for Soft Matter, Hokkaido University, Sapporo, Hokkaido, 060-0808, Japan.
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52
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Kaufman G, Mukhopadhyay S, Rokhlenko Y, Nejati S, Boltyanskiy R, Choo Y, Loewenberg M, Osuji CO. Highly stiff yet elastic microcapsules incorporating cellulose nanofibrils. SOFT MATTER 2017; 13:2733-2737. [PMID: 28358160 DOI: 10.1039/c7sm00092h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Microcapsules with high mechanical stability and elasticity are desirable in a variety of contexts. We report a single-step method to fabricate such microcapsules by microfluidic interfacial complexation between high stiffness cellulose nanofibrils (CNF) and an oil-soluble cationic random copolymer. Single-capsule compression measurements reveal an elastic modulus of 53 MPa for the CNF-based capsule shell with complete recovery of deformation from strains as large as 19%. We demonstrate the ability to manipulate the shell modulus by the use of polyacrylic acid (PAA) as a binder material, and observe a direct relationship between the shell modulus and the PAA concentration, with moduli as large as 0.5 GPa attained. These results demonstrate that CNF incorporation provides a facile route for producing strong yet flexible microcapsule shells.
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Affiliation(s)
- Gilad Kaufman
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA.
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53
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Liu J, Lan Y, Yu Z, Tan CS, Parker RM, Abell C, Scherman OA. Cucurbit[n]uril-Based Microcapsules Self-Assembled within Microfluidic Droplets: A Versatile Approach for Supramolecular Architectures and Materials. Acc Chem Res 2017; 50:208-217. [PMID: 28075551 PMCID: PMC5474693 DOI: 10.1021/acs.accounts.6b00429] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Indexed: 12/13/2022]
Abstract
Microencapsulation is a fundamental concept behind a wide range of daily applications ranging from paints, adhesives, and pesticides to targeted drug delivery, transport of vaccines, and self-healing concretes. The beauty of microfluidics to generate microcapsules arises from the capability of fabricating monodisperse and micrometer-scale droplets, which can lead to microcapsules/particles with fine-tuned control over size, shape, and hierarchical structure, as well as high reproducibility, efficient material usage, and high-throughput manipulation. The introduction of supramolecular chemistry, such as host-guest interactions, endows the resultant microcapsules with stimuli-responsiveness and self-adjusting capabilities, and facilitates hierarchical microstructures with tunable stability and porosity, leading to the maturity of current microencapsulation industry. Supramolecular architectures and materials have attracted immense attention over the past decade, as they open the possibility to obtain a large variety of aesthetically pleasing structures, with myriad applications in biomedicine, energy, sensing, catalysis, and biomimicry, on account of the inherent reversible and adaptive nature of supramolecular interactions. As a subset of supramolecular interactions, host-guest molecular recognition involves the formation of inclusion complexes between two or more moieties, with specific three-dimensional structures and spatial arrangements, in a highly controllable and cooperative manner. Such highly selective, strong yet dynamic interactions could be exploited as an alternative methodology for programmable and controllable engineering of supramolecular architectures and materials, exploiting reversible interactions between complementary components. Through the engineering of molecular structures, assemblies can be readily functionalized based on host-guest interactions, with desirable physicochemical characteristics. In this Account, we summarize the current state of development in the field of monodisperse supramolecular microcapsules, fabricated through the integration of traditional microfluidic techniques and interfacial host-guest chemistry, specifically cucurbit[n]uril (CB[n])-mediated host-guest interactions. Three different strategies, colloidal particle-driven assembly, interfacial condensation-driven assembly and electrostatic interaction-driven assembly, are classified and discussed in detail, presenting the methodology involved in each microcapsule formation process. We highlight the state-of-the-art in design and control over structural complexity with desirable functionality, as well as promising applications, such as cargo delivery stemming from the assembled microcapsules. On account of its dynamic nature, the CB[n]-mediated host-guest complexation has demonstrated efficient response toward various external stimuli such as UV light, pH change, redox chemistry, and competitive guests. Herein, we also demonstrate different microcapsule modalities, which are engineered with CB[n] host-guest chemistry and also can be disrupted with the aid of external stimuli, for triggered release of payloads. In addition to the overview of recent achievements and current limitations of these microcapsules, we finally summarize several perspectives on tunable cargo loading and triggered release, directions, and challenges for this technology, as well as possible strategies for further improvement, which will lead to substainitial progress of host-guest chemistry in supramolecular architectures and materials.
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Affiliation(s)
- Ji Liu
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Yang Lan
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Ziyi Yu
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Cindy S.Y. Tan
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Faculty
of Applied Sciences, Universiti Teknologi
MARA, 94300 Kota Samarahan, Sarawak, Malaysia
| | - Richard M. Parker
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Chris Abell
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Oren A. Scherman
- Melville
Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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54
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Hann SD, Lee D, Stebe KJ. Tuning interfacial complexation in aqueous two phase systems with polyelectrolytes and nanoparticles for compound all water emulsion bodies (AWE-somes). Phys Chem Chem Phys 2017; 19:23825-23831. [DOI: 10.1039/c7cp02809a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Compound AWE-somes with tunable shells generated by aqueous interfacial complexation of a polycation with a polyanion and anionic nanoparticle mixture.
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Affiliation(s)
- Sarah D. Hann
- Department of Chemical and Biomolecular Engineering
- University of Pennsylvania
- Philadelphia
- USA
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering
- University of Pennsylvania
- Philadelphia
- USA
| | - Kathleen J. Stebe
- Department of Chemical and Biomolecular Engineering
- University of Pennsylvania
- Philadelphia
- USA
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55
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Richardson JJ, Cui J, Björnmalm M, Braunger JA, Ejima H, Caruso F. Innovation in Layer-by-Layer Assembly. Chem Rev 2016; 116:14828-14867. [PMID: 27960272 DOI: 10.1021/acs.chemrev.6b00627] [Citation(s) in RCA: 449] [Impact Index Per Article: 56.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Methods for depositing thin films are important in generating functional materials for diverse applications in a wide variety of fields. Over the last half-century, the layer-by-layer assembly of nanoscale films has received intense and growing interest. This has been fueled by innovation in the available materials and assembly technologies, as well as the film-characterization techniques. In this Review, we explore, discuss, and detail innovation in layer-by-layer assembly in terms of past and present developments, and we highlight how these might guide future advances. A particular focus is on conventional and early developments that have only recently regained interest in the layer-by-layer assembly field. We then review unconventional assemblies and approaches that have been gaining popularity, which include inorganic/organic hybrid materials, cells and tissues, and the use of stereocomplexation, patterning, and dip-pen lithography, to name a few. A relatively recent development is the use of layer-by-layer assembly materials and techniques to assemble films in a single continuous step. We name this "quasi"-layer-by-layer assembly and discuss the impacts and innovations surrounding this approach. Finally, the application of characterization methods to monitor and evaluate layer-by-layer assembly is discussed, as innovation in this area is often overlooked but is essential for development of the field. While we intend for this Review to be easily accessible and act as a guide to researchers new to layer-by-layer assembly, we also believe it will provide insight to current researchers in the field and help guide future developments and innovation.
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Affiliation(s)
- Joseph J Richardson
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia.,Manufacturing, CSIRO , Clayton, Victoria 3168, Australia
| | - Jiwei Cui
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia
| | - Mattias Björnmalm
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia
| | - Julia A Braunger
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia
| | - Hirotaka Ejima
- Institute of Industrial Science, The University of Tokyo , Tokyo 153-8505, Japan
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia
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56
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Hann SD, Niepa THR, Stebe KJ, Lee D. One-Step Generation of Cell-Encapsulating Compartments via Polyelectrolyte Complexation in an Aqueous Two Phase System. ACS APPLIED MATERIALS & INTERFACES 2016; 8:25603-11. [PMID: 27580225 DOI: 10.1021/acsami.6b07939] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Diverse fields including drug and gene delivery and live cell encapsulation require biologically compatible encapsulation systems. One widely adopted means of forming capsules exploits cargo-filled microdroplets in an external, immiscible liquid phase that are encapsulated by a membrane that forms by trapping of molecules or particles at the drop surface, facilitated by the interfacial tension. To eliminate the potentially deleterious oil phase often present in such processes, we exploit the aqueous two phase system of poly(ethylene glycol) (PEG) and dextran. We form capsules by placing dextran-rich microdroplets in an external PEG-rich phase. Strong polyelectrolytes present in either phase form complexes at the drop interface, thereby forming a membrane encapsulating the fluid interior. This process requires considerable finesse as both polyelectrolytes are soluble in either the drop or external phase, and the extremely low interfacial tension is too weak to provide a strong adsorption site for these molecules. The key to obtaining microcapsules is to tune the relative fluxes of the two polyelectrolytes so that they meet and complex at the interface. We identify conditions for which complexation can occur inside or outside of the drop phase, resulting in microparticles or poor encapsulation, respectively, or when properly balanced, at the interface, resulting in microcapsules. The resulting microcapsules respond to the stimuli of added salts or changes in osmotic pressure, allowing perturbation of capsule permeability or triggered release of capsule contents. We demonstrate that living cells can be sequestered and interrogated by encapsulating Pseudomonas aeruginosa PAO1 and using a Live/Dead assay to assess their viability. This method paves the way to the formation of a broad variety of versatile functional membranes around all aqueous capsules; by tuning the fluxes of complexing species to interact at the interface, membranes comprising other complexing functional moieties can be formed.
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Affiliation(s)
- Sarah D Hann
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Tagbo H R Niepa
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Kathleen J Stebe
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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57
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Zhang L, Cai LH, Lienemann PS, Rossow T, Polenz I, Vallmajo-Martin Q, Ehrbar M, Na H, Mooney DJ, Weitz DA. One-Step Microfluidic Fabrication of Polyelectrolyte Microcapsules in Aqueous Conditions for Protein Release. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201606960] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Liyuan Zhang
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
| | - Li-Heng Cai
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
| | - Philipp S. Lienemann
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
- Wyss Institute for Biologically Inspired Engineering; Harvard University; Boston MA 02115 USA
| | - Torsten Rossow
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
- Wyss Institute for Biologically Inspired Engineering; Harvard University; Boston MA 02115 USA
| | - Ingmar Polenz
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
| | - Queralt Vallmajo-Martin
- Department of Obstetrics, University Hospital Zurich; University of Zurich; Schmelzbergstr, 12 8091 Zurich Switzerland
| | - Martin Ehrbar
- Department of Obstetrics, University Hospital Zurich; University of Zurich; Schmelzbergstr, 12 8091 Zurich Switzerland
| | - Hui Na
- Alan G MacDiarmid Institute, College of Chemistry; Jilin University; Changchun 130012 (C hina
| | - David J. Mooney
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
- Wyss Institute for Biologically Inspired Engineering; Harvard University; Boston MA 02115 USA
| | - David A. Weitz
- John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
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58
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Zhang L, Cai LH, Lienemann PS, Rossow T, Polenz I, Vallmajo-Martin Q, Ehrbar M, Na H, Mooney DJ, Weitz DA. One-Step Microfluidic Fabrication of Polyelectrolyte Microcapsules in Aqueous Conditions for Protein Release. Angew Chem Int Ed Engl 2016; 55:13470-13474. [PMID: 27717141 DOI: 10.1002/anie.201606960] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/25/2016] [Indexed: 11/06/2022]
Abstract
We report a microfluidic approach for one-step fabrication of polyelectrolyte microcapsules in aqueous conditions. Using two immiscible aqueous polymer solutions, we generate transient water-in-water-in-water double emulsion droplets and use them as templates to fabricate polyelectrolyte microcapsules. The capsule shell is formed by the complexation of oppositely charged polyelectrolytes at the immiscible interface. We find that attractive electrostatic interactions can significantly prolong the release of charged molecules. Moreover, we demonstrate the application of these microcapsules in encapsulation and release of proteins without impairing their biological activities. Our platform should benefit a wide range of applications that require encapsulation and sustained release of molecules in aqueous environments.
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Affiliation(s)
- Liyuan Zhang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Li-Heng Cai
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Philipp S Lienemann
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Torsten Rossow
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - Ingmar Polenz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Queralt Vallmajo-Martin
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Schmelzbergstr, 12, 8091, Zurich, Switzerland
| | - Martin Ehrbar
- Department of Obstetrics, University Hospital Zurich, University of Zurich, Schmelzbergstr, 12, 8091, Zurich, Switzerland
| | - Hui Na
- Alan G MacDiarmid Institute, College of Chemistry, Jilin University, Changchun, 130012 (C, hina
| | - David J Mooney
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA
| | - David A Weitz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.
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59
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Lee TY, Choi TM, Shim TS, Frijns RAM, Kim SH. Microfluidic production of multiple emulsions and functional microcapsules. LAB ON A CHIP 2016; 16:3415-40. [PMID: 27470590 DOI: 10.1039/c6lc00809g] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Recent advances in microfluidics have enabled the controlled production of multiple-emulsion drops with onion-like topology. The multiple-emulsion drops possess an intrinsic core-shell geometry, which makes them useful as templates to create microcapsules with a solid membrane. High flexibility in the selection of materials and hierarchical order, achieved by microfluidic technologies, has provided versatility in the membrane properties and microcapsule functions. The microcapsules are now designed not just for storage and release of encapsulants but for sensing microenvironments, developing structural colours, and many other uses. This article reviews the current state of the art in the microfluidic-based production of multiple-emulsion drops and functional microcapsules. The three main sections of this paper discuss distinct microfluidic techniques developed for the generation of multiple emulsions, four representative methods used for solid membrane formation, and various applications of functional microcapsules. Finally, we outline the current limitations and future perspectives of microfluidics and microcapsules.
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Affiliation(s)
- Tae Yong Lee
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon, South Korea.
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60
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Affiliation(s)
| | - Matthew V. Tirrell
- Institute for Molecular Engineering; The University of Chicago; Chicago IL USA
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61
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Ma Q, Song Y, Kim JW, Choi HS, Shum HC. Affinity Partitioning-Induced Self-Assembly in Aqueous Two-Phase Systems: Templating for Polyelectrolyte Microcapsules. ACS Macro Lett 2016; 5:666-670. [PMID: 35614670 DOI: 10.1021/acsmacrolett.6b00228] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Affinity partitioning refers to the preferential dissolution of solute molecules in a particular liquid phase of an immiscible liquid-liquid mixture, such as an aqueous two-phase system (ATPS). Affinity partitioning in ATPS is widely used to achieve extraction and purification of biomolecules. However, the potential of applying it to direct the self-assembly of solutes into controlled structures has been largely overlooked. Here we introduce the affinity partitioning of polyelectrolytes in ATPS to induce their self-assembly into polyelectrolyte microcapsules. The approach is purely based on the preferential solubility of different polyelectrolytes in different aqueous phases; therefore it has wide applicability and exhibits excellent compatibility with bioactives. The release of encapsulated components can be triggered by changing the pH value or ionic strength of the surrounding environment. The proposed method represents an important advance in fabricating multifunctional materials and inspires new ways to engineer sophisticated structures with hydrophilic macromolecules.
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Affiliation(s)
- Qingming Ma
- Department
of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, China
- HKU-Shenzhen Institute
of Research and Innovation (HKU-SIRI), Shenzhen 518000, China
| | - Yang Song
- Department
of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, China
- HKU-Shenzhen Institute
of Research and Innovation (HKU-SIRI), Shenzhen 518000, China
| | | | - Hong Sung Choi
- Shinsegae International
Co. Ltd., Seoul, 135-954, Republic of Korea
| | - Ho Cheung Shum
- Department
of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, China
- HKU-Shenzhen Institute
of Research and Innovation (HKU-SIRI), Shenzhen 518000, China
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62
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Kim M, Doh J, Lee D. pH-Induced Softening of Polyelectrolyte Microcapsules without Apparent Swelling. ACS Macro Lett 2016; 5:487-492. [PMID: 35607238 DOI: 10.1021/acsmacrolett.6b00124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polyelectrolyte microcapsules represent a versatile platform to encapsulate and release active ingredients. Understanding the effect of environmental conditions on the mechanical properties of microcapsules is critically important for enabling their applications under various settings. In this report, we investigate the effect of solution pH on the mechanical properties of polyelectrolyte microcapsules made of two weak polyelectrolytes (poly(acrylic acid) and branched poly(ethylenimine)), formed via recently introduced nanoscale interfacial complexation in emulsion (NICE). Interestingly, the stiffness of the NICE microcapsule shell is reduced significantly (by 2 orders of magnitude) when the solution pH is raised from 2 to 6 even though there is little change in the size of microcapsules. These seemingly counterintuitive results suggest that the molecular structure of NICE microcapsules may be different from those of conventional polyelectrolyte microcapsules. The possibility of tuning the shell stiffness without inducing significant changes in the microcapsule size could offer unique advantages in practical applications.
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Affiliation(s)
- Miju Kim
- Department
of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department
of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Junsang Doh
- Department
of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
- School
of Interdisciplinary Bioscience and Bioengineering (I-Bio), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Daeyeon Lee
- Department
of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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