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Lee W, Eriten M. Poroviscoelastic relaxations and rate-dependent adhesion in gelatin. SOFT MATTER 2024; 20:4583-4590. [PMID: 38742525 DOI: 10.1039/d4sm00318g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Hydrogels, polymeric networks swollen with water, exhibit time/rate-dependent adhesion due to their poroviscoleastic constitution. In this study, we conducted probe-tack experiments on gelatin and investigated the influence of dwelling times and unloading rates on pull-off forces and work of adhesion. We utilized in situ contact imaging to monitor separation kinematics and interfacial crack velocities. We found that the crack velocities scaled nonlinearly with the unloading rate, in a power law with an exponent of 0.8 and were independent of dwelling time. At maximum unloading rates corresponding to subsonic interfacial crack speeds, we observed an order of magnitude enhancement in the apparent work of adhesion. The enhancement of adhesion and the crack velocities were related by a power law with an exponent of 0.39. The maximum vertical extension during unloading, a measure of crack opening, exhibited linear correlation with the enhancement of adhesion. Both correlations were in line with the rate-dependent work of fracture modeled for viscoelastic solids (e.g., Persson and Brener model). We explored the links between dwelling times corresponding to varying degrees of poroelastic diffusion and the adhesion. We found 40% additional enhancement in adhesion at the highest unloading rate. This enhancement is due to the unbalanced osmotic pressure, also known as the suction effect. The influence of dwelling times on adhesion was negligible for the interfacial cracks propagating slower than the diffusive time scales. These results identify viscoelastic relaxations as the dominant mechanism governing the rate-dependent enhancement of adhesion, and hence pave the way for tuning rate-dependent adhesion in soft multiphasic materials.
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Affiliation(s)
- Wonhyeok Lee
- Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
| | - Melih Eriten
- Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
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Stankovits G, Ábrahám Á, Kiss É, Varga Z, Misra A, Szilágyi A, Gyarmati B. The interaction between mucin and poly(amino acid)s with controlled cationic group content in bulk phase and in thin layers. Int J Biol Macromol 2023; 253:126826. [PMID: 37699458 DOI: 10.1016/j.ijbiomac.2023.126826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/18/2023] [Accepted: 09/08/2023] [Indexed: 09/14/2023]
Abstract
The type and concentration of charged groups in polymers have a key role in mucoadhesive interactions. A series of cationic poly(amino acid)s with different charge densities was designed to unravel the correlation between chemical structure and mucin-polymer interactions. Colloidal interactions between the mucin protein and synthetic polyaspartamides were tested by dynamic light scattering, zeta potential measurements and turbidimetric titration as a function of polymer-to-mucin mass ratio. The mucoadhesive interactions displayed a strongly non-linear change with polymer composition. The attractive interactions between mucin and the polyaspartamides with at least 50 % cationic groups caused increased light scattering of dispersions due to the aggregation of mucin particles upon their charge reversal. Interactions were further analysed in a thin mucin layer to model life-like situations using a quartz crystal microbalance (QCM) in flow mode. Results pointed out that the fully cationic polyaspartamide is not necessarily superior to derivatives with lower cationic group content. The maximum of adsorbed mass of polymers on mucin was experienced at medium cationic group contents. This emphasizes the relevance of cationic polyaspartamides as mucoadhesive excipients due to their multiple functionalities and the possibility of fine-tuning their interactions with mucin via straightforward chemical steps.
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Affiliation(s)
- Gergely Stankovits
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Ágnes Ábrahám
- Laboratory of Interfaces and Nanostructures, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter Sétány 1/A, H-1117 Budapest, Hungary; MTA-TTK Lendület "Momentum" Peptide-Based Vaccines Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Krt. 2., H-1117 Budapest, Hungary
| | - Éva Kiss
- Laboratory of Interfaces and Nanostructures, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter Sétány 1/A, H-1117 Budapest, Hungary
| | - Zoltán Varga
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary; Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar tudósok körútja 2., H-1117 Budapest, Hungary
| | - Anil Misra
- Pharmidex Pharmaceutical Services, Office 3.05, 1 King Street, London EC2V 8AU, United Kingdom
| | - András Szilágyi
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary.
| | - Benjámin Gyarmati
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary.
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Hasan MM, Dunn AC. Fewer polymer chains but higher adhesion: How gradient-stiffness hydrogel layers mediate adhesion through network stretch. J Chem Phys 2023; 159:184706. [PMID: 37947516 DOI: 10.1063/5.0174530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/10/2023] [Indexed: 11/12/2023] Open
Abstract
The presence of gradient softer outer layers, commonly observed in biological systems (such as cartilage and ocular tissues), as well as synthetic crosslinked hydrogels, profoundly influences their interactions with opposing surfaces. Our prior research demonstrated that gradient-stiffness hydrogel layers, characterized by increasing elasticity with depth, control contact mechanics, particularly in proximity to the layer thickness. We postulate that the distribution of polymers within these gradient layers imparts extraordinary stretch and adhesion characteristics due to network adaptability and stress-induced reorganization. To investigate this phenomenon, we utilized Atomic Force Microscopy nanoindentation to assess the depth-dependent adhesion behavior of polyacrylamide hydrogels with varying gradient layer thicknesses. Two gradient layer thicknesses were achieved by employing different molding materials: glass and polyoxymethylene (POM). Glass-molded hydrogels exhibited a thinner gradient layer alongside a stiffer bulk layer compared to their POM-molded counterparts. In indentation experiments, the POM-molded hydrogel had larger adhesion compared to glass-molded hydrogel. We find that indenting within the gradient layer engenders increased load-unload hysteresis due to heightened fluid transport in the sparse outer polymer network. Consequently, this led to augmented adhesion and work of separation at shallow depths. We suggest that the prominent stretching capability of the sparse outer polymer network during probe retraction contributes to enhanced adhesion. The Maugis-Dugdale adhesive model only fits well to indentations on the thin layer or indentations which engage significantly with the bulk. These results facilitate a comprehensive characterization of adhesion mechanics in gradient-stiffness hydrogels, which could foster their application across emerging contexts in health science and environmental domains.
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Affiliation(s)
- Md Mahmudul Hasan
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, 1206 W Green St., Urbana, Illinois 61801, USA
| | - Alison C Dunn
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, 1206 W Green St., Urbana, Illinois 61801, USA
- Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, 506 S Mathews Ave., Urbana, Illinois 61801, USA
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Coral stone-inspired superwetting membranes with anti-fouling and self-cleaning properties for highly efficient oil-water separation. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Jha A, Karnal P, Frechette J. Adhesion of fluid infused silicone elastomer to glass. SOFT MATTER 2022; 18:7579-7592. [PMID: 36165082 DOI: 10.1039/d2sm00875k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Elastomers swollen with non-polar fluids show potential as anti-adhesive materials. We study the effect of oil fraction and contact time on the adhesion between swollen spherical probes of PDMS (polydimethylsiloxane) and flat glass surfaces. The PDMS probes are swollen with pre-determined amount of 10 cSt silicone oil to span the range where the PDMS is fluid free (via solvent extraction) up to the limit where it is oil saturated. Probe tack measurements show that adhesion decreases rapidly with an increase in oil fraction. The decrease in adhesion is attributed to excess oil present at the PDMS-air interface. Contact angle measurements and optical microscopy images support this observation. Adhesion also increases with contact time for a given oil fraction. The increase in adhesion with contact time can be interpreted through different competing mechanisms that depend on the oil fraction where the dominant mechanism changes from extracted to fully swollen PDMS. For partially swollen PDMS, we observe that adhesion initially increases because of viscoelastic relaxation and at long times increases because of contact aging. In contrast, adhesion between fully swollen PDMS and glass barely increases over time and is mainly due to capillary forces. While the relaxation of PDMS in contact is well-described by a visco-poroelastic model, we do not see evidence that poroelastic relaxation of the PDMS contributes to an increase of adhesion with glass whether it is partially or fully swollen.
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Affiliation(s)
- Anushka Jha
- Chemical and Biomolecular Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Preetika Karnal
- Chemical and Biomolecular Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemical and Biomolecular Engineering, Lehigh University, 124 E Morton St, Building 205, Bethlehem, Pennsylvania 18015, USA
| | - Joelle Frechette
- Chemical and Biomolecular Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94760, USA.
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Bowen LK, Johannes K, Zuetell E, Calahan KN, Edmundowicz SA, Long R, Rentschler ME. Patterned enteroscopy balloon design factors influence tissue anchoring. J Mech Behav Biomed Mater 2020; 111:103966. [PMID: 32810654 DOI: 10.1016/j.jmbbm.2020.103966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/27/2020] [Accepted: 06/30/2020] [Indexed: 12/22/2022]
Abstract
Balloon-assisted enteroscopy procedures allow visualization and intervention in the small intestine. These balloons anchor an endoscope and/or overtube to the small intestine, allowing endoscopists to plicate the small intestine over the overtube. This procedure can extend examination deeper into the small intestine than the length of the endoscope would allow with direct examination. However, procedures are often prolonged or incomplete due to balloon slippage. Enteroscopy balloons are pressure-limited to ensure patient safety and thus, improving anchoring without increasing pressure is essential. Patterning balloon exteriors with discrete features may enhance anchoring at the tissue-balloon interface. Here, the pattern design space is explored to determine factors that influence tissue anchoring. The anchoring ability of smooth versus balloons with patterned features is investigated by experimentally measuring a peak force required to induce slippage of an inflated balloon inside ex-vivo porcine small intestine. Stiffer materials, low aspect-ratio features, and pattern area/location on the balloons significantly increase peak force compared to smooth silicone balloons. Smooth latex balloons, used for standard enteroscopy, have the lowest peak force. This work demonstrates both a method to pattern curved surfaces and that a balloon with patterned features improves anchoring against a deformable, lubricated tissue interface.
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Affiliation(s)
- Leah K Bowen
- Department of Mechanical Engineering, ECME 114, 1111 Engineering Drive, University of Colorado Boulder, Boulder, CO, 80309, USA; Medical Scientist Training Program, 12631 E. 17th Avenue, AO1 Room 2601, Mail Stop B176, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - Karl Johannes
- Department of Mechanical Engineering, ECME 114, 1111 Engineering Drive, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - Emily Zuetell
- Department of Mechanical Engineering, ECME 114, 1111 Engineering Drive, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - Kristin N Calahan
- Department of Mechanical Engineering, ECME 114, 1111 Engineering Drive, University of Colorado Boulder, Boulder, CO, 80309, USA; BioFrontiers Institute, University of Colorado Boulder, UCB 596, Boulder, CO, 80309, USA.
| | - Steven A Edmundowicz
- Department of Medicine, Gastroenterology, University of Colorado, Anschutz Medical Campus, 12631 E. 17th Ave. B158, Aurora, CO, 80045, USA.
| | - Rong Long
- Department of Mechanical Engineering, ECME 114, 1111 Engineering Drive, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - Mark E Rentschler
- Department of Mechanical Engineering, ECME 114, 1111 Engineering Drive, University of Colorado Boulder, Boulder, CO, 80309, USA; Department of Surgery, University of Colorado Anschutz Medical Campus, 12631 E 17th Ave #6117, Aurora, CO, 80045, USA.
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