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Zhang Y, Tang C, Span PN, Rowan AE, Aalders TW, Schalken JA, Adema GJ, Kouwer PHJ, Zegers MMP, Ansems M. Polyisocyanide Hydrogels as a Tunable Platform for Mammary Gland Organoid Formation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001797. [PMID: 32999851 PMCID: PMC7509700 DOI: 10.1002/advs.202001797] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Indexed: 05/20/2023]
Abstract
In the last decade, organoid technology has developed as a primary research tool in basic biological and clinical research. The reliance on poorly defined animal-derived extracellular matrix, however, severely limits its application in regenerative and translational medicine. Here, a well-defined, synthetic biomimetic matrix based on polyisocyanide (PIC) hydrogels that support efficient and reproducible formation of mammary gland organoids (MGOs) in vitro is presented. Only decorated with the adhesive peptide RGD for cell binding, PIC hydrogels allow MGO formation from mammary fragments or from purified single mammary epithelial cells. The cystic organoids maintain their capacity to branch for over two months, which is a fundamental and complex feature during mammary gland development. It is found that small variations in the 3D matrix give rise to large changes in the MGO: the ratio of the main cell types in the MGO is controlled by the cell-gel interactions via the cell binding peptide density, whereas gel stiffness controls colony formation efficiency, which is indicative of the progenitor density. Simple hydrogel modifications will allow for future introduction and customization of new biophysical and biochemical parameters, making the PIC platform an ideal matrix for in depth studies into organ development and for application in disease models.
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Vandaele J, Louis B, Liu K, Camacho R, Kouwer PHJ, Rocha S. Structural characterization of fibrous synthetic hydrogels using fluorescence microscopy. SOFT MATTER 2020; 16:4210-4219. [PMID: 32292943 DOI: 10.1039/c9sm01828j] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The structural features of the matrix surrounding the cells play a crucial role in regulating their behavior. Here, we used fluorescence microscopy and customized analysis algorithms to characterize the architecture of fibrous hydrogel networks. As a model system, we investigated a new class of synthetic biomimetic material, hydrogels prepared from polyisocyanides. Our results show that these synthetic gels present a highly heterogeneous fibrous network, with pores reaching a few micrometers in diameter. By encapsulating HeLa cells in different hydrogels, we show that a more porous structure is linked to a higher proliferation rate. The approach described here, for the characterization of the network of fibrous hydrogels, can be easily applied to other polymer-based materials and provide new insights into the influence of structural features in cell behavior. This knowledge is crucial to develop the next generation of biomimetic materials for 3D cell models and tissue engineering applications.
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Yuan H, Zhan Y, Rowan AE, Xing C, Kouwer PHJ. Biomimetic Networks with Enhanced Photodynamic Antimicrobial Activity from Conjugated Polythiophene/Polyisocyanide Hybrid Hydrogels. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201910979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yuan H, Zhan Y, Rowan AE, Xing C, Kouwer PHJ. Biomimetic Networks with Enhanced Photodynamic Antimicrobial Activity from Conjugated Polythiophene/Polyisocyanide Hybrid Hydrogels. Angew Chem Int Ed Engl 2020; 59:2720-2724. [PMID: 31917502 DOI: 10.1002/anie.201910979] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/25/2019] [Indexed: 12/26/2022]
Abstract
Hybrid biomimetic hydrogels with enhanced reactive oxygen species (ROS)-generation efficiency under 600 nm light show high antibacterial activity. The hybrid gels are composed of helical tri(ethylene glycol)-functionalized polyisocyanides (PICs) and a conformation-sensitive conjugated polythiophene, poly(3-(3'-N,N,N-triethylammonium-1'-propyloxy)-4-methyl-2,5-thiophene chloride) (PMNT). The PIC polymer serves as a scaffold to trap and align the PMNT backbone into a highly ordered conformation, resulting in redshifted, new sharp bands in the absorption and fluorescence spectra. Similar to PIC, the hybrid closely mimics the mechanical properties of biological gels, such as collagen and fibrin, including the strain stiffening properties at low stresses. Moreover, the PMNT/PIC hybrids show much higher ROS production efficiency under red light than PMNT only, leading to an efficient photodynamic antimicrobial effect towards various pathogenic bacteria.
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Op 't Veld RC, Eerden M, Wagener FADTG, Kouwer PHJ, Jansen JA, Walboomers XF. Polyisocyanopeptide Hydrogels Are Effectively Sterilized Using Supercritical Carbon Dioxide. Tissue Eng Part C Methods 2019; 26:132-141. [PMID: 31847754 DOI: 10.1089/ten.tec.2019.0305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Adequate sterilization procedures for soft biomaterials such as hydrogels are known to be challenging. These materials are delicate in structure, making them sensitive to harsh conditions and prone to damage. In this study, a suitable sterilization method for hydrogels composed of tri(ethylene glycol)-functionalized polyisocyanopeptides (PIC) was explored. These high biomimetic hydrogels are temperature and strain sensitive and have been presented as novel cell culturing matrices, wound dressings, and drug carriers. The methods that were investigated include autoclaving, γ-irradiation, ultraviolet (UV) light irradiation, and supercritical CO2 (scCO2) treatment. The results show that autoclaving and γ-irradiation have deleterious effects on the gelation behavior and mechanical characteristics of PIC. For γ-irradiation, cooling the gels on dry ice alleviated this negative impact, but not sufficiently enough to make the method viable. In contrast, UV light and scCO2 treatment do not affect the mechanical properties of the PIC gels. Studies with gels inoculated with 107 CFU/mL Gram-positive bacteria Staphylococcus aureus show that only scCO2 is capable of successfully sterilizing PIC hydrogels by achieving a 6-log reduction in bacterial load. It was concluded that, within the range of tested techniques, the sterilization of PIC is limited to scCO2.
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Voerman D, Schluck M, Weiden J, Joosten B, Eggermont LJ, van den Eijnde T, Ignacio B, Cambi A, Figdor CG, Kouwer PHJ, Verdoes M, Hammink R, Rowan AE. Synthetic Semiflexible and Bioactive Brushes. Biomacromolecules 2019; 20:2587-2597. [PMID: 31150222 PMCID: PMC6620732 DOI: 10.1021/acs.biomac.9b00385] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/29/2019] [Indexed: 11/29/2022]
Abstract
Polymer brushes are extensively used for the preparation of bioactive surfaces. They form a platform to attach functional (bio)molecules and control the physicochemical properties of the surface. These brushes are nearly exclusively prepared from flexible polymers, even though much stiffer brushes from semiflexible polymers are frequently found in nature, which exert bioactive functions that are out of reach for flexible brushes. Synthetic semiflexible polymers, however, are very rare. Here, we use polyisocyanopeptides (PICs) to prepare high-density semiflexible brushes on different substrate geometries. For bioconjugation, we developed routes with two orthogonal click reactions, based on the strain-promoted azide-alkyne cycloaddition reaction and the (photoactivated) tetrazole-ene cycloaddition reaction. We found that for high brush densities, multiple bonds between the polymer and the substrate are necessary, which was achieved in a block copolymer strategy. Whether the desired biomolecules are conjugated to the PIC polymer before or after brush formation depends on the dimensions and required densities of the biomolecules and the curvature of the substrate. In either case, we provide mild, aqueous, and highly modular reaction strategies, which make PICs a versatile addition to the toolbox for generating semiflexible bioactive polymer brush surfaces.
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Liu K, Mihaila SM, Rowan A, Oosterwijk E, Kouwer PHJ. Synthetic Extracellular Matrices with Nonlinear Elasticity Regulate Cellular Organization. Biomacromolecules 2019; 20:826-834. [PMID: 30608161 PMCID: PMC6372982 DOI: 10.1021/acs.biomac.8b01445] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
One of the promises
of synthetic materials in cell culturing is
that control over their molecular structures may ultimately be used
to control their biological processes. Synthetic polymer hydrogels
from polyisocyanides (PIC) are a new class of minimal synthetic biomaterials
for three-dimensional cell culturing. The macromolecular lengths and
densities of biofunctional groups that decorate the polymer can be
readily manipulated while preserving the intrinsic nonlinear mechanics,
a feature commonly displayed by fibrous biological networks. In this
work, we propose the use of PIC gels as cell culture platforms with
decoupled mechanical inputs and biological cues. For this purpose,
different types of cells were encapsulated in PIC gels of tailored
compositions that systematically vary in adhesive peptide (GRGDS)
density, polymer length, and concentration; with the last two parameters
controlling the gel mechanics. Both cancer and smooth muscle cells
grew into multicellular spheroids with proliferation rates that depend
on the adhesive GRGDS density, regardless of the polymer length, suggesting
that for these cells, the biological input prevails over the mechanical
cues. In contrast, human adipose-derived stem cells do not form spheroids
but rather spread out. We find that the morphological changes strongly
depend on the adhesive ligand density and the network mechanics; gels
with the highest GRGDS densities and the strongest stiffening response
to stress show the strongest spreading. Our results highlight the
role of the nonlinear mechanics of the extracellular matrix and its
synthetic mimics in the regulation of cell functions.
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Op 't Veld RC, van den Boomen OI, Lundvig DMS, Bronkhorst EM, Kouwer PHJ, Jansen JA, Middelkoop E, Von den Hoff JW, Rowan AE, Wagener FADTG. Thermosensitive biomimetic polyisocyanopeptide hydrogels may facilitate wound repair. Biomaterials 2018; 181:392-401. [PMID: 30103178 DOI: 10.1016/j.biomaterials.2018.07.038] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/20/2018] [Accepted: 07/25/2018] [Indexed: 02/06/2023]
Abstract
Changing wound dressings inflicts pain and may disrupt wound repair. Novel synthetic thermosensitive hydrogels based on polyisocyanopeptide (PIC) offer a solution. These gels are liquid below 16 °C and form gels beyond room temperature. The architecture and mechanical properties of PIC gels closely resemble collagen and fibrin, and include the characteristic stiffening response at high strains. Considering the reversible thermo-responsive behavior, we postulate that PIC gels are easy to apply and remove, and facilitate healing without eliciting foreign body responses or excessive inflammation. Biocompatibility may be higher in RGD-peptide-functionalized PIC gels due to enhanced cell binding capabilities. Full-thickness dorsal skin wounds in mice were compared to wounds treated with PIC gel and PIC-RGD gel for 3 and 7 days. No foreign body reactions and similar wound closure rates were found in all groups. The level of macrophages, myofibroblasts, epithelial migration, collagen expression, and blood vessels did not significantly differ from controls. Surprisingly, granulocyte populations in the wound decreased significantly in the PIC gel-treated groups, likely because foreign bacteria could not penetrate the gel. RGD-peptides did not further improve any effect observed for PIC. The absence of adverse effects, ease of application, and the possibilities for bio-functionalization make the biomimetic PIC hydrogels suitable for development into wound dressings.
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Schoenmakers DC, Schoonen L, Rutten MGTA, Nolte RJM, Rowan AE, van Hest JCM, Kouwer PHJ. Virus-like particles as crosslinkers in fibrous biomimetic hydrogels: approaches towards capsid rupture and gel repair. SOFT MATTER 2018; 14:1442-1448. [PMID: 29392267 DOI: 10.1039/c7sm02320k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Biological hydrogels can become many times stiffer under deformation. This unique ability has only recently been realised in fully synthetic gels. Typically, these networks are composed of semi-flexible polymers and bundles and show such large mechanical responses at very small strains, which makes them particularly suitable for application as strain-responsive materials. In this work, we introduced strain-responsiveness by crosslinking the architecture with a multi-functional virus-like particle. At high stresses, we find that the virus particles disintegrate, which creates an (irreversible) mechanical energy dissipation pathway, analogous to the high stress response of fibrin networks. A cooling-heating cycle allows for re-crosslinking at the damaged site, which gives rise to much stronger hydrogels. Virus particles and capsids are promising drug delivery vehicles and our approach offers an effective strategy to trigger the release mechanically without compromising the mechanical integrity of the host material.
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Yuan H, Xu J, van Dam EP, Giubertoni G, Rezus YLA, Hammink R, Bakker HJ, Zhan Y, Rowan AE, Xing C, Kouwer PHJ. Strategies To Increase the Thermal Stability of Truly Biomimetic Hydrogels: Combining Hydrophobicity and Directed Hydrogen Bonding. Macromolecules 2017; 50:9058-9065. [PMID: 29213150 PMCID: PMC5707627 DOI: 10.1021/acs.macromol.7b01832] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/08/2017] [Indexed: 01/29/2023]
Abstract
Enhancing the thermal stability of proteins is an important task for protein engineering. There are several ways to increase the thermal stability of proteins in biology, such as greater hydrophobic interactions, increased helical content, decreased occurrence of thermolabile residues, or stable hydrogen bonds. Here, we describe a well-defined polymer based on β-helical polyisocyanotripeptides (TriPIC) that uses biological approaches, including hydrogen bonding and hydrophobic interactions for its exceptional thermal stability in aqueous solutions. The multiple hydrogen bonding arrays along the polymer backbone shield the hydrophobic core from water. Variable temperature CD and FTIR studies indicate that, on heating, a better packed polymer conformation further stiffens the backbone. Driven by hydrophobic interactions, TriPIC solutions give fully reversible hydrogels that can withstand high temperatures (80 °C) for extended times. Cryo-scanning electron microscopy (cryo-SEM), small-angle X-ray scattering (SAXS), and thorough rheological analysis show that the hydrogel has a bundled architecture, which gives rise to strain stiffening effects on deformation of the gel, analogous to many biological hydrogels.
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Lopez-Perez PM, da Silva RMP, Strehin I, Kouwer PHJ, Leeuwenburgh SCG, Messersmith PB. Self-healing hydrogels formed by complexation between calcium ions and bisphosphonate-functionalized star-shaped polymers. Macromolecules 2017; 50:8698-8706. [PMID: 29403089 DOI: 10.1021/acs.macromol.7b01417] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Star-shaped poly(ethylene glycol) (PEG) chain termini were functionalized with alendronate to create transient networks with reversible crosslinks upon addition of calcium ions. The gelation ability of alendronate-functionalized PEG was greatly dependent on the number of arms and arm molecular weight. After mixing polymer and calcium solutions, the formed hydrogels could be cut and then brought back together without any visible interface. After 2 minutes of contact, their connection was strong enough to allow for stretching without tearing through the previous fracture surface. Oscillatory rheology showed that the hydrogels recovered between 70 and 100% of the original storage and loss modulus after rupture. Frequency sweep measurements revealed a liquid-like behavior at lower frequencies and solid-like at high frequencies. Shifting frequency curves obtained at different calcium and polymer concentrations, all data collapsed in a single common master curve. This time-concentration superposition reveals a common relaxation mechanism intrinsically connected to the calcium-bisphosphonate complexation equilibrium.
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Jaspers M, Vaessen SL, van Schayik P, Voerman D, Rowan AE, Kouwer PHJ. Nonlinear mechanics of hybrid polymer networks that mimic the complex mechanical environment of cells. Nat Commun 2017; 8:15478. [PMID: 28541273 PMCID: PMC5458517 DOI: 10.1038/ncomms15478] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 04/03/2017] [Indexed: 12/20/2022] Open
Abstract
The mechanical properties of cells and the extracellular environment they reside in are governed by a complex interplay of biopolymers. These biopolymers, which possess a wide range of stiffnesses, self-assemble into fibrous composite networks such as the cytoskeleton and extracellular matrix. They interact with each other both physically and chemically to create a highly responsive and adaptive mechanical environment that stiffens when stressed or strained. Here we show that hybrid networks of a synthetic mimic of biological networks and either stiff, flexible and semi-flexible components, even very low concentrations of these added components, strongly affect the network stiffness and/or its strain-responsive character. The stiffness (persistence length) of the second network, its concentration and the interaction between the components are all parameters that can be used to tune the mechanics of the hybrids. The equivalence of these hybrids with biological composites is striking.
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van der Asdonk P, Kouwer PHJ. Liquid crystal templating as an approach to spatially and temporally organise soft matter. Chem Soc Rev 2017; 46:5935-5949. [DOI: 10.1039/c7cs00029d] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Liquid crystal templating: an emerging technique to organise and control soft matter at multiple length scales.
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Feenstra J, van Eerden M, Lemmens AK, de Poel W, Kouwer PHJ, Rowan AE, Schermer JJ. Muscovite mica as a growth template of PC61BM crystallites for organic photovoltaics. CrystEngComm 2017. [DOI: 10.1039/c6ce02492k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The processing conditions for and (local) performance benefits of epitaxially crystallized PC61BM for organic solar cells are investigated.
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40
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Mirri G, Schoenmakers DC, Kouwer PHJ, Veranič P, Muševič I, Štefane B. Synthesis of Functional Fluorescent BODIPY-based Dyes through Electrophilic Aromatic Substitution: Straightforward Approach towards Customized Fluorescent Probes. ChemistryOpen 2016; 5:450-454. [PMID: 27777837 PMCID: PMC5062010 DOI: 10.1002/open.201600067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Indexed: 02/02/2023] Open
Abstract
Fluorescent materials are widely used in biological and material applications as probes for imaging or sensing; however, their customization is usually complicated without the support of an organic chemistry laboratory. Here, we present a straightforward method for the customization of BODIPY cores, which are among the most commonly used fluorescent probes. The method is based on the formation of a new C-C bond through Friedel-Crafts electrophilic aromatic substitution carried out at room temperature. The method presented can be used to obtain completely customized fluorescent materials in one or two steps from commercially available compounds. Examples of the preparation of fluorescent materials for cell staining and functionalization of silica colloids are also presented.
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41
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Lauko J, Kouwer PHJ, Rowan AE. 1
H
‐1,2,3‐Triazole: From Structure to Function and Catalysis. J Heterocycl Chem 2016. [DOI: 10.1002/jhet.2770] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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42
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van der Asdonk P, Keshavarz M, Christianen PCM, Kouwer PHJ. Directed peptide amphiphile assembly using aqueous liquid crystal templates in magnetic fields. SOFT MATTER 2016; 12:6518-6525. [PMID: 27320385 DOI: 10.1039/c6sm00652c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An alignment technique based on the combination of magnetic fields and a liquid crystal (LC) template uses the advantages of both approaches: the magnetic fields offer non-contact methods that apply to all sample sizes and shapes, whilst the LC templates offer high susceptibilities. The combination introduces a route to control the spatial organization of materials with low intrinsic susceptibilities. We demonstrate that we can unidirectionally align one such material, peptide amphiphiles in water, on a centimeter scale at a tenfold lower magnetic field by using a lyotropic chromonic liquid crystal as a template. We can transform the aligned supramolecular assemblies into optically active π-conjugated polymers after photopolymerization. Lastly, by reducing the magnetic field strength needed for addressing these assemblies, we are able to create more complex structures by initiating self-assembly of our supramolecular materials under competing alignment forces between the magnetically induced alignment of the assemblies (with a positive diamagnetic anisotropy) and the elastic force dominated alignment of the template (with a negative diamagnetic anisotropy), which is directed orthogonally. Although the approach is still in its infancy and many critical parameters need optimization, we believe that it is a very promising technique to create tailor-made complex structures of (aqueous) functional soft matter.
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43
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Dennison M, Jaspers M, Kouwer PHJ, Storm C, Rowan AE, MacKintosh FC. Critical behaviour in the nonlinear elastic response of hydrogels. SOFT MATTER 2016; 12:6995-7004. [PMID: 27464595 DOI: 10.1039/c6sm01033d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper we study the elastic response of synthetic hydrogels to an applied shear stress. The hydrogels studied here have previously been shown to mimic the behaviour of biopolymer networks when they are sufficiently far above the gel point. We show that near the gel point they exhibit an elastic response that is consistent with the predicted critical behaviour of networks near or below the isostatic point of marginal stability. This point separates rigid and floppy states, distinguished by the presence or absence of finite linear elastic moduli. Recent theoretical work has also focused on the response of such networks to finite or large deformations, both near and below the isostatic point. Despite this interest, experimental evidence for the existence of criticality in such networks has been lacking. Using computer simulations, we identify critical signatures in the mechanical response of sub-isostatic networks as a function of applied shear stress. We also present experimental evidence consistent with these predictions. Furthermore, our results show the existence of two distinct critical regimes, one of which arises from the nonlinear stretch response of semi-flexible polymers.
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44
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Jaspers M, Pape ACH, Voets IK, Rowan AE, Portale G, Kouwer PHJ. Bundle Formation in Biomimetic Hydrogels. Biomacromolecules 2016; 17:2642-9. [DOI: 10.1021/acs.biomac.6b00703] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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45
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van der Asdonk P, Kragt S, Kouwer PHJ. Directing Soft Matter in Water Using Electric Fields. ACS APPLIED MATERIALS & INTERFACES 2016; 8:16303-16309. [PMID: 27269124 DOI: 10.1021/acsami.6b03910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Directing the spatial organization of functional supramolecular and polymeric materials at larger length scales is essential for many biological and molecular optoelectronic applications. Although the application of electrical fields is one of the most powerful approaches to induce spatial control, it is rarely applied experimentally in aqueous solutions, since the low susceptibility of soft and biological materials requires the use of high fields, which leads to parasitic heating and electrochemical degradation. In this work, we demonstrate that we can apply electric fields when we use a mineral liquid crystal as a responsive template. Besides aligning and positioning functional soft matter, we show that the concentration of the liquid crystal template controls the morphology of the assembly. As our setup is very easy to operate and our approach lacks specific molecular interactions, we believe it will be applicable for a wide range of (aqueous) materials.
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46
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Alvarez Fernandez A, Kouwer PHJ. Key Developments in Ionic Liquid Crystals. Int J Mol Sci 2016; 17:E731. [PMID: 27196890 PMCID: PMC4881553 DOI: 10.3390/ijms17050731] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 11/25/2022] Open
Abstract
Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?
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Zinkevich T, Venderbosch B, Jaspers M, Kouwer PHJ, Rowan AE, van Eck ERH, Kentgens APM. Solid-state NMR characterization of tri-ethyleneglycol grafted polyisocyanopeptides. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:328-333. [PMID: 26559660 DOI: 10.1002/mrc.4379] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/30/2015] [Accepted: 10/09/2015] [Indexed: 06/05/2023]
Abstract
In aqueous media, ethylene glycol substituted polyisocyanopeptides (PICPs) change their state (undergo a sol-to-gel transition) as a response to temperature. This makes them promising materials for various biomedical applications, for instance, for controlled drug release and non-damaging wound dressing. To utilize PICP in biomedical applications, understanding of the origin of the gelation process is needed, but this is experimentally difficult because of the notoriously low gelator concentration in combination with the slow polymer dynamics in the sample. This paper describes a detailed characterization of the dried state of PICPs by solid-state NMR measurements. Both the (13) C and the (1) H NMR resonances were assigned using a combination of 1D cross-polarization magic angle spinning, 2D (13) C-(1) H heteronuclear correlation spectra and (1) H-(1) H single quantum-double quantum experiments. In addition, the chemical groups involved in dipolar interaction with each other were used to discuss the dynamics and spatial conformation of the polymer. In contrast to other PICP polymers, two resonances for the backbone carbon are observed, which are present in equal amounts. The possible origin of these resonances is discussed in the last section of this work. The data obtained during the current studies will be further used in elucidating mechanisms of the bundling and gelation. A comprehensive picture will make it possible to tailor polymer properties to meet specific needs in different applications. Copyright © 2015 John Wiley & Sons, Ltd.
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48
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Venkata Sai D, Mirri G, Kouwer PHJ, Sahoo R, Musevic I, Dhara S. Unusual temperature dependence of elastic constants of an ambient-temperature discotic nematic liquid crystal. SOFT MATTER 2016; 12:2960-2964. [PMID: 26883494 DOI: 10.1039/c6sm00065g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the first experimental studies on the temperature dependence of viscoelastic properties of a room temperature discotic nematic liquid crystal. The splay elastic constant is greater than the bend elastic constant and both show unusual temperature and order parameter dependence. The rotational viscosity is remarkably larger than conventional calamitic liquid crystals. We provide a simple physical explanation based on the columnar short-range order to account for the the unusual temperature dependence of the elastic constants.
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Bruekers SMC, Jaspers M, Hendriks JMA, Kurniawan NA, Koenderink GH, Kouwer PHJ, Rowan AE, T S Huck W. Fibrin-fiber architecture influences cell spreading and differentiation. Cell Adh Migr 2016; 10:495-504. [PMID: 26910190 DOI: 10.1080/19336918.2016.1151607] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The mechanical and structural properties of the extracellular matrix (ECM) play an important role in regulating cell fate. The natural ECM has a complex fibrillar structure and shows nonlinear mechanical properties, which are both difficult to mimic synthetically. Therefore, systematically testing the influence of ECM properties on cellular behavior is very challenging. In this work we show two different approaches to tune the fibrillar structure and mechanical properties of fibrin hydrogels. Addition of extra thrombin before gelation increases the protein density within the fibrin fibers without significantly altering the mechanical properties of the resulting hydrogel. On the other hand, by forming a composite hydrogel with a synthetic biomimetic polyisocyanide network the protein density within the fibrin fibers decreases, and the mechanics of the composite material can be tuned by the PIC/fibrin mass ratio. The effect of the changes in gel structure and mechanics on cellular behavior are investigated, by studying human mesenchymal stem cell (hMSC) spreading and differentiation on these gels. We find that the trends observed in cell spreading and differentiation cannot be explained by the bulk mechanics of the gels, but correlate to the density of the fibrin fibers the gels are composed of. These findings strongly suggest that the microscopic properties of individual fibers in fibrous networks play an essential role in determining cell behavior.
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Alvarez Fernandez A, Keshavarz M, Christianen PCM, Kouwer PHJ. Maximizing Orientational Order in Polymer-Stabilized Liquid Crystals Using High Magnetic Fields. Macromolecules 2015. [DOI: 10.1021/ma501867f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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