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Scherrer S, Ramakrishna SN, Niggel V, Spencer ND, Isa L. Measuring Rolling Friction at the Nanoscale. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:6750-6760. [PMID: 38497776 PMCID: PMC10993404 DOI: 10.1021/acs.langmuir.3c03499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/24/2024] [Accepted: 02/27/2024] [Indexed: 03/19/2024]
Abstract
Colloidal probe microscopy, a technique whereby a microparticle is affixed at the end of an atomic force microscopy (AFM) cantilever, plays a pivotal role in enabling the measurement of friction at the nanoscale and is of high relevance for applications and fundamental studies alike. However, in conventional experiments, the probe particle is immobilized onto the cantilever, thereby restricting its relative motion against a countersurface to pure sliding. Nonetheless, under many conditions of interest, such as during the processing of particle-based materials, particles are free to roll and slide past each other, calling for the development of techniques capable of measuring rolling friction alongside sliding friction. Here, we present a new methodology to measure lateral forces during rolling contacts based on the adaptation of colloidal probe microscopy. Using two-photon polymerization direct laser writing, we microfabricate holders that can capture microparticles, but allow for their free rotation. Once attached to an AFM cantilever, upon lateral scanning, the holders enable both sliding and rolling contacts between the captured particles and the substrate, depending on the interactions, while simultaneously giving access to normal and lateral force signals. Crucially, by producing particles with optically heterogeneous surfaces, we can accurately detect the presence of rotation during scanning. After introducing the workflow for the fabrication and use of the probes, we provide details on their calibration, investigate the effect of the materials used to fabricate them, and report data on rolling friction as a function of the surface roughness of the probe particles. We firmly believe that our methodology opens up new avenues for the characterization of rolling contacts at the nanoscale, aimed, for instance, at engineering particle surface properties and characterizing functional coatings in terms of their rolling friction.
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Affiliation(s)
- Simon Scherrer
- Department of Materials, ETH
Zürich, Zürich 8093, Switzerland
| | | | - Vincent Niggel
- Department of Materials, ETH
Zürich, Zürich 8093, Switzerland
| | | | - Lucio Isa
- Department of Materials, ETH
Zürich, Zürich 8093, Switzerland
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2
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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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3
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Zhu Y, Zhang M, Sun Q, Wang X, Li X, Li Q. Advanced Mechanical Testing Technologies at the Cellular Level: The Mechanisms and Application in Tissue Engineering. Polymers (Basel) 2023; 15:3255. [PMID: 37571149 PMCID: PMC10422338 DOI: 10.3390/polym15153255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/24/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
Mechanics, as a key physical factor which affects cell function and tissue regeneration, is attracting the attention of researchers in the fields of biomaterials, biomechanics, and tissue engineering. The macroscopic mechanical properties of tissue engineering scaffolds have been studied and optimized based on different applications. However, the mechanical properties of the overall scaffold materials are not enough to reveal the mechanical mechanism of the cell-matrix interaction. Hence, the mechanical detection of cell mechanics and cellular-scale microenvironments has become crucial for unraveling the mechanisms which underly cell activities and which are affected by physical factors. This review mainly focuses on the advanced technologies and applications of cell-scale mechanical detection. It summarizes the techniques used in micromechanical performance analysis, including atomic force microscope (AFM), optical tweezer (OT), magnetic tweezer (MT), and traction force microscope (TFM), and analyzes their testing mechanisms. In addition, the application of mechanical testing techniques to cell mechanics and tissue engineering scaffolds, such as hydrogels and porous scaffolds, is summarized and discussed. Finally, it highlights the challenges and prospects of this field. This review is believed to provide valuable insights into micromechanics in tissue engineering.
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Affiliation(s)
- Yingxuan Zhu
- School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Center for International Joint Research of Micro-nano Moulding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Mengqi Zhang
- School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Center for International Joint Research of Micro-nano Moulding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Qingqing Sun
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Xiaofeng Wang
- School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Center for International Joint Research of Micro-nano Moulding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Xiaomeng Li
- School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Center for International Joint Research of Micro-nano Moulding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Qian Li
- School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Center for International Joint Research of Micro-nano Moulding Technology, Zhengzhou University, Zhengzhou 450001, China
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Akbari E, Imani R, Shokrollahi P, Heidari Keshel S. Corneal sustained delivery of hyaluronic acid from nanofiber-containing ring-implanted contact lens. J Biomater Appl 2023; 37:992-1006. [PMID: 36564919 DOI: 10.1177/08853282221146390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Dry eye syndrome, as a persist corneal epithelial defect (PED), is an inconvenient ocular disorder that is generally treated by high-dosage, conventional eye drops. Addressing low efficacy and rather restricted bioavailability of the conventional eye drops, drug-eluting contact lenses (CLs) are widely used as alternatives in ophthalmic drug delivery applications. In the present study, a nanofiber-containing ring implant poly (vinyl alcohol) (PVA) hydrogel is designed as a carrier for hyaluronic acid (HA) delivery. hyaluronic acid is physically encapsulated in a nanofiber-containing ring-shaped hydrogel with a 2 mm width that is implanted in the final CLs hydrogel. The designed CL has 59% porosity, 275% swelling ratio and undergoes no weight loss at physiological conditions in14 days. In-vitro release studies were performed on the CLs with and without nanofibers. The results showed that nanofiber incorporation in the designed CL was highly influential in decreasing burst release and supported sustained release of HA over 14 days. In addition, nanofiber incorporation in the designed system strengthened the lens, and the young modulus of the PVA hydrogel increased from 6 to 10 kPa. Cell viability study also revealed no cell cytotoxicity and cell attachment. Overall, the study demonstrated the effective role of nanofibers in the physical strengthening of the CL. Also, the designed system holds promise as a potential candidate for HA delivery over an extended period for treating dry eye syndrome.
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Affiliation(s)
- Elham Akbari
- Biomedical Engineering Department, 48410Amirkabir University of Technology, Tehran, Iran
| | - Rana Imani
- Biomedical Engineering Department, 48410Amirkabir University of Technology, Tehran, Iran
| | - Parvin Shokrollahi
- Faculty of Science, Department of Biomaterials, Iran Polymer and Petrochemical Institute, Tehran, Iran
| | - Saeed Heidari Keshel
- Department of Tissue Engineering and Applied Cell Science, School of Advanced Technologies InMedicine, 556492Shahid Beheshti University of Medical Sciences, Iran
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Effect of poly(ethylene glycol) methacrylate on the ophthalmic properties of silicone hydrogel contact lenses. Colloids Surf B Biointerfaces 2022. [DOI: 10.1016/j.colsurfb.2022.112713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Maurya MK, Ruscher C, Mukherji D, Singh MK. Computational indentation in highly cross-linked polymer networks. Phys Rev E 2022; 106:014501. [PMID: 35974630 DOI: 10.1103/physreve.106.014501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Indentation is a common experimental technique to study the mechanics of polymeric materials. The main advantage of using indentation is this provides a direct correlation between the microstructure and the small-scale mechanical response, which is otherwise difficult within the standard tensile testing. The majority of studies have investigated hydrogels, microgels, elastomers, and even soft biomaterials. However, a less investigated system is the indentation in highly cross-linked polymer (HCP) networks, where the complex network structure plays a key role in dictating their physical properties. In this work, we investigate the structure-property relationship in HCP networks using the computational indentation of a generic model. We establish a correlation between the local bond breaking, network rearrangement, and small-scale mechanics. The results are compared with the elastic-plastic deformation model. HCPs harden upon indentation.
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Affiliation(s)
- Manoj Kumar Maurya
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur UP 208016, India
| | - Céline Ruscher
- Department of Mechanical Engineering, University of British Columbia, Vancouver, Canada BC V6T 1Z4
| | - Debashish Mukherji
- Quantum Matter Institute, University of British Columbia, Vancouver, Canada BC V6T 1Z4
| | - Manjesh Kumar Singh
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur UP 208016, India
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Finite Element Analysis of Cornea and Lid Wiper during Blink, with and without Contact Lens. J Ophthalmol 2022; 2022:7930334. [PMID: 35620413 PMCID: PMC9129998 DOI: 10.1155/2022/7930334] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/26/2022] [Indexed: 11/18/2022] Open
Abstract
Ocular surface disorders such as Lid Wiper Epitheliopathy (LWE), Superior Epithelial Arcuate Lesion (SEAL), and contact lens-induced Limbal Stem Cell Deficiency (LSCD) as well as Superior Limbic Keratoconjunctivitis (SLK) affect one’s quality of life. Hence, it is imperative to investigate the underlying causes of these ocular surface disorders. During blink, the undersurface of the eyelid tends to interact with the cornea and the conjunctiva. The presence of a contact lens can add to the biomechanical frictional changes on these surfaces. To estimate these changes with and without a contact lens, a finite element model (FEM) of the eyelid wiper, eyeball, and contact lens was developed using COMSOL Multiphysics. Biomechanical properties such as von Mises stress (VMS) and displacement were calculated. Our study concluded that (a) maximum VMS was observed in the lid wiper in the absence of contact lens in the eye and (b) maximum VMS was observed in the superior 1.3 mm of the cornea in the presence of the contact lens in the eye. Thus, the development of friction-induced ocular surface disorders such as LWE, SLK, SEAL, and LSCD could be attributed to increased VMS. FEA is a useful simulation tool that helps us to understand the effect of blink on a normal eye with and without CL.
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Maeda S, Chikami S, Latag GV, Song S, Iwakiri N, Hayashi T. Analysis of Vicinal Water in Soft Contact Lenses Using a Combination of Infrared Absorption Spectroscopy and Multivariate Curve Resolution. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27072130. [PMID: 35408526 PMCID: PMC9000845 DOI: 10.3390/molecules27072130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/17/2022] [Accepted: 03/23/2022] [Indexed: 11/16/2022]
Abstract
In this paper, we propose a new spectroscopic method to explore the behavior of molecules near polymeric molecular networks of water-containing soft materials such as hydrogels. We demonstrate the analysis of hydrogen bonding states of water in the vicinity of hydrogels (soft contact lenses). In this method, we apply force to hydrated contact lenses to deform them and to modulate the ratio between the signals from bulk and vicinal regions. We then collect spectra at different forces. Finally, we extracted the spectra of the vicinal region using the multivariate curve resolution-alternating least square (MCR-ALS) method. We report the hydration states depending on the chemical structures of hydrogels constituting the contact lenses.
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Affiliation(s)
- Shoichi Maeda
- Department of Material Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta-Cho Midori-Ku, Yokohama 226-8502, Japan; (S.M.); (S.C.); (G.V.L.); (S.S.)
| | - Shunta Chikami
- Department of Material Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta-Cho Midori-Ku, Yokohama 226-8502, Japan; (S.M.); (S.C.); (G.V.L.); (S.S.)
| | - Glenn Villena Latag
- Department of Material Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta-Cho Midori-Ku, Yokohama 226-8502, Japan; (S.M.); (S.C.); (G.V.L.); (S.S.)
| | - Subin Song
- Department of Material Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta-Cho Midori-Ku, Yokohama 226-8502, Japan; (S.M.); (S.C.); (G.V.L.); (S.S.)
| | - Norio Iwakiri
- Life Science Products Division, NOF Corporation, Yebisu Garden Place Tower, 20-3 Ebisu 4-Chome, Shibuya-Ku, Tokyo 150-6019, Japan;
| | - Tomohiro Hayashi
- Department of Material Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta-Cho Midori-Ku, Yokohama 226-8502, Japan; (S.M.); (S.C.); (G.V.L.); (S.S.)
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa 277-0882, Japan
- Correspondence: ; Tel.: +81-45-924-5400
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9
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Kawabata K, Totani M, Kawaguchi D, Matsuno H, Tanaka K. Two-Dimensional Cellular Patterning on a Polymer Film Based on Interfacial Stiffness. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14911-14919. [PMID: 34902971 DOI: 10.1021/acs.langmuir.1c02776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The mechanical properties in the outermost region of a polymer film strongly affect various material functions. We here propose a novel and promising strategy for the two-dimensional regulation of the mechanical properties of a polymer film at the water interface based on an inkjet drawing of silica nanoparticles (SNPs) underneath it. A film of poly(2-hydroxyethyl methacrylate) (PHEMA), which exhibits excellent bioinertness properties at the water interface, was well fabricated on a substrate with a pattern of SNPs. X-ray photoelectron spectroscopy and atomic force microscopy confirmed that the surface of the PHEMA film was flat and chemically homogeneous. However, the film surface was in-plane heterogeneous in stiffness due to the presence of the underlying SNP lines. It was also noted that NIH/3T3 fibroblast cells selectively adhered and formed aggregates on the areas under which an SNP line was drawn.
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Affiliation(s)
- Kento Kawabata
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Masayasu Totani
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
| | - Daisuke Kawaguchi
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
- Centre for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Hisao Matsuno
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
- Centre for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Keiji Tanaka
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan
- Centre for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka 819-0395, Japan
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Dorishetty P, Balu R, Gelmi A, Mata JP, Dutta NK, Choudhury NR. 3D Printable Soy/Silk Hybrid Hydrogels for Tissue Engineering Applications. Biomacromolecules 2021; 22:3668-3678. [PMID: 34460237 DOI: 10.1021/acs.biomac.1c00250] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The development of protein-based 3D printable hydrogel systems with tunable structure and properties is a critical challenge in contemporary biomedicine. Particularly, 3D printing of modular hydrogels comprising different types of protein tertiary structure, such as globular and fibrous, has not yet been achieved. Here we report the extrusion-based 3D printing of hybrid hydrogels photochemically co-cross-linked between globular soy protein isolate (SPI) and fibrous silk fibroin (SF) for the first time. The hierarchical structure and organization of pristine SPI and SF, and 1:3 (SPI/SF) hybrid inks under various shear stress were investigated using in situ rheology combined with small-/ultra-small-angle neutron scattering (Rheo-SANS/USANS). The hybrid ink exhibited an isotropic mass fractal structure that was stable between tested shear rates of 0.1 and 100 s-1 (near printing shear). The kinetics of sol-gel transition during the photo-cross-linking reaction and the micromechanical properties of fabricated hydrogels were investigated using photorheology and atomic force microscopy, where the hybrid hydrogels exhibited tunable storage and Young's moduli in the range of 13-29 and 214-811 kPa, respectively. The cross-link density and printing accuracy of hybrid hydrogels and inks were observed to increase with the increase in SF content. The 3D printed hybrid hydrogels exhibited a micropore size larger than that of solution casted hydrogels; where the 3D printed 1:3 (SPI/SF) hybrid hydrogel showed a pore size about 7.6 times higher than that of the casted hydrogel. Moreover, the fabricated hybrid hydrogels exhibit good mouse fibroblast cell attachment, viability, and proliferation, demonstrating their potential for tissue engineering applications.
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Affiliation(s)
- Pramod Dorishetty
- School of Engineering, RMIT University, Melbourne, VIC 3000, Australia
| | - Rajkamal Balu
- School of Engineering, RMIT University, Melbourne, VIC 3000, Australia
| | - Amy Gelmi
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Jitendra P Mata
- Australian Centre for Neutron Scattering (ACNS), Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Sydney, NSW 2232, Australia
| | - Naba K Dutta
- School of Engineering, RMIT University, Melbourne, VIC 3000, Australia
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11
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Xi Y, Sharma PK, Kaper HJ, Choi CH. Tribological Properties of Micropored Poly(2-hydroxyethyl methacrylate) Hydrogels in a Biomimetic Aqueous Environment. ACS APPLIED MATERIALS & INTERFACES 2021; 13:41473-41484. [PMID: 34449208 DOI: 10.1021/acsami.1c13718] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The applications of hydrogels in tissue engineering as implants have rapidly grown in the last decade. However, the tribological properties of hydrogels under physiologically relevant conditions, especially those of textured hydrogels, have remained largely unknown due to the complexity of their mechanical and chemical properties. In this study, we experimentally investigated the tribological properties of micopored poly(2-hydroxyethyl methacrylate) (pHEMA) with the lateral pore dimensions varied compared to untextured pHEMA, the most commonly used hydrogel in ophthalmology, under physiologically relevant conditions. The pHEMA specimens were slid against a smooth glass curve under varying loads (6-60 mN, leading to an average contact pressure of 10-21 kPa) and sliding speeds (1-10 mm/s) in phosphate-buffered saline (pH 7.4) at 33 °C to mimic the physiological conditions in human eyes. At relatively low loads and sliding speeds (e.g., 6 mN and 1 mm/s), the micopored pHEMA did not reduce the dissipated frictional energy significantly. However, at relatively high loads and sliding speeds (e.g., 60 mN and 100 mm/s), the micopored pHEMA resulted in significantly lower frictional energy (reduced by up to 68%) dissipation than the untextured pHEMA. The effect was more pronounced with the micropores with smaller dimensions. These are attributed to the greater amount and retentivity of the interfacial fluid supported by the free water squeezed out of the micropores with the smaller dimensions under the higher load and sliding speed. These results suggest that the use of micropore texturing on hydrogels in practice, such as for ocular applications, can be leveraged to reduce friction and wear under physiological conditions and hence lower the chance of inflammation near eye implants or keratoprosthesis.
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Affiliation(s)
- Yiwen Xi
- Department of Mechanical Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030, United States
- Department of Biomedical Engineering (FB40), University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713AV, The Netherlands
| | - Prashant Kumar Sharma
- Department of Biomedical Engineering (FB40), University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713AV, The Netherlands
| | - Hans Jan Kaper
- Department of Biomedical Engineering (FB40), University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, Groningen 9713AV, The Netherlands
| | - Chang-Hwan Choi
- Department of Mechanical Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030, United States
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Kubota R, Tanaka W, Hamachi I. Microscopic Imaging Techniques for Molecular Assemblies: Electron, Atomic Force, and Confocal Microscopies. Chem Rev 2021; 121:14281-14347. [DOI: 10.1021/acs.chemrev.0c01334] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ryou Kubota
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Wataru Tanaka
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
- JST-ERATO, Hamachi Innovative Molecular Technology for Neuroscience, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8530, Japan
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13
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Maldonado-Codina C, Efron N. Impact of manufacturing technology and material composition on the surface characteristics of hydrogel contact lenses. Clin Exp Optom 2021; 88:396-404. [PMID: 16329748 DOI: 10.1111/j.1444-0938.2005.tb05106.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 05/16/2005] [Accepted: 06/10/2005] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Our aim was to investigate the impact of manufacturing method and material composition on the surface characteristics of hydrogel contact lenses. METHODS Five lens types were examined; three polyhydroxyethyl methacrylate (pHEMA) lenses, each manufactured by a different technique, namely, lathing, spin-casting and cast-moulding, a HEMA/methacrylic acid cast-moulded lens and a HEMA/glycerol methacrylate cast-moulded lens. Six lenses of each type were examined (front and back) using scanning electron microscopy (SEM). Additionally, both surfaces of three lenses from each of the pHEMA lens groups were examined, partially hydrated, using an atomic force microscope (AFM). Qualitative data were gathered for both SEM and AFM studies in addition to root-mean-square (RMS) roughness values for the lenses investigated with AFM. RESULTS The surfaces of the lathed lenses were covered in lathing/polishing marks. RMS roughness values for the anterior surface (10.9 +/- 4.3 nm) were significantly greater (p = 0.02) than those of the posterior surface (9.3 +/- 0.8 nm). The two surfaces of the spun-cast lens appeared similar by SEM but AFM RMS roughness values were greater (p = 0.02) for the anterior (12.3 +/- 1.8 nm) than the posterior (5.8 +/- 1.9 nm) surface. Both SEM and AFM showed similar topographic appearances for the surfaces of the cast-moulded pHEMA lens, although RMS roughness values were greater (p = 0.02) for the anterior (5.8 +/- 0.9 nm) than the posterior (3.9 +/- 0.3 nm) surface. All three cast-moulded lenses had more processing debris than the lathed and spun-cast pHEMA lenses. Overall, the surfaces of the lathed lens were 'rougher' than those of the cast-moulded lens (p = 0.01). CONCLUSION The surface topographies of the hydrogel contact lenses are dependent on the method of manufacture. Cast-moulded lenses are associated with apparently 'stickier' surfaces, which may be indicative of surface degradation during the manufacturing process.
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Affiliation(s)
- Carole Maldonado-Codina
- Eurolens Research, Faculty of Life Sciences, The University of Manchester, Moffat Building, PO Box 88, Manchester, M60 1QD, United Kingdom.
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14
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Di Domenico EG, De Angelis B, Cavallo I, Sivori F, Orlandi F, Fernandes Lopes Morais D’Autilio M, Di Segni C, Gentile P, Scioli MG, Orlandi A, D’Agosto G, Trento E, Kovacs D, Cardinali G, Stefanile A, Koudriavtseva T, Prignano G, Pimpinelli F, Lesnoni La Parola I, Toma L, Cervelli V, Ensoli F. Silver Sulfadiazine Eradicates Antibiotic-Tolerant Staphylococcus aureus and Pseudomonas aeruginosa Biofilms in Patients with Infected Diabetic Foot Ulcers. J Clin Med 2020; 9:jcm9123807. [PMID: 33255545 PMCID: PMC7760944 DOI: 10.3390/jcm9123807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/23/2020] [Accepted: 11/23/2020] [Indexed: 12/19/2022] Open
Abstract
Infections are among the most frequent and challenging events in diabetic foot ulcers (DFUs). Pathogenic bacteria growing in biofilms within host tissue are highly tolerant to environmental and chemical agents, including antibiotics. The present study was aimed at assessing the use of silver sulfadiazine (SSD) for wound healing and infection control in 16 patients with DFUs harboring biofilm-growing Staphylococcus aureus and Pseudomonas aeruginosa. All patients received a treatment based on a dressing protocol including disinfection, cleansing, application of SSD, and application of nonadherent gauze, followed by sterile gauze and tibio-breech bandage, in preparation for toilet surgery after 30 days of treatment. Clinical parameters were analyzed by the T.I.M.E. classification system. In addition, the activity of SSD against biofilm-growing S. aureus and P. aeruginosa isolates was assessed in vitro. A total of 16 patients with S. aureus and P. aeruginosa infected DFUs were included in the study. Clinical data showed a statistically significant (p < 0.002) improvement of patients’ DFUs after 30 days of treatment with SSD with significant amelioration of all the parameters analyzed. Notably, after 30 days of treatment, resolution of infection was observed in all DFUs. In vitro analysis showed that both S. aureus and P. aeruginosa isolates developed complex and highly structured biofilms. Antibiotic susceptibility profiles indicated that biofilm cultures were significantly (p ≤ 0.002) more tolerant to all tested antimicrobials than their planktonic counterparts. However, SSD was found to be effective against fully developed biofilms of both S. aureus and P. aeruginosa at concentrations below those normally used in clinical preparations (10 mg/mL). These results strongly suggest that the topical administration of SSD may represent an effective alternative to conventional antibiotics for the successful treatment of DFUs infected by biofilm-growing S. aureus and P. aeruginosa.
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Affiliation(s)
- Enea Gino Di Domenico
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
- Correspondence: ; Tel.: +39-06-5266-5564
| | - Barbara De Angelis
- Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, 00144 Rome, Italy; (B.D.A.); (F.O.); (M.F.L.M.D.); (C.D.S.); (P.G.); (V.C.)
| | - Ilaria Cavallo
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
| | - Francesca Sivori
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
| | - Fabrizio Orlandi
- Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, 00144 Rome, Italy; (B.D.A.); (F.O.); (M.F.L.M.D.); (C.D.S.); (P.G.); (V.C.)
| | | | - Chiara Di Segni
- Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, 00144 Rome, Italy; (B.D.A.); (F.O.); (M.F.L.M.D.); (C.D.S.); (P.G.); (V.C.)
| | - Pietro Gentile
- Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, 00144 Rome, Italy; (B.D.A.); (F.O.); (M.F.L.M.D.); (C.D.S.); (P.G.); (V.C.)
| | - Maria Giovanna Scioli
- Department of Anatomic Pathology, University of Rome Tor Vergata, 00144 Rome, Italy; (M.G.S.); (A.O.)
| | - Augusto Orlandi
- Department of Anatomic Pathology, University of Rome Tor Vergata, 00144 Rome, Italy; (M.G.S.); (A.O.)
| | - Giovanna D’Agosto
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
| | - Elisabetta Trento
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
| | - Daniela Kovacs
- Cutaneous Physiopathology, San Gallicano Dermatological Institute, IRCCS, 00144 Rome, Italy; (D.K.); (G.C.)
| | - Giorgia Cardinali
- Cutaneous Physiopathology, San Gallicano Dermatological Institute, IRCCS, 00144 Rome, Italy; (D.K.); (G.C.)
| | - Annunziata Stefanile
- Department of Clinical Experimental Oncology, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (A.S.); (T.K.)
| | - Tatiana Koudriavtseva
- Department of Clinical Experimental Oncology, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy; (A.S.); (T.K.)
| | - Grazia Prignano
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
| | - Fulvia Pimpinelli
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
| | - Ilaria Lesnoni La Parola
- Lichen Sclerosus Unit, Department of Dermatology, STI, Environmental Health, Tropical and Immigration, San Gallicano Dermatological Institute, IRCCS, 00144 Rome, Italy;
| | - Luigi Toma
- Department of Research, Advanced Diagnostics, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy;
| | - Valerio Cervelli
- Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, 00144 Rome, Italy; (B.D.A.); (F.O.); (M.F.L.M.D.); (C.D.S.); (P.G.); (V.C.)
| | - Fabrizio Ensoli
- Microbiology and Virology, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (I.C.); (F.S.); (G.D.); (E.T.); (G.P.); (F.P.); (F.E.)
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15
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Cimatu KLA, Premadasa UI, Ambagaspitiya TD, Adhikari NM, Jang JH. Evident phase separation and surface segregation of hydrophobic moieties at the copolymer surface using atomic force microscopy and SFG spectroscopy. J Colloid Interface Sci 2020; 580:645-659. [PMID: 32712471 DOI: 10.1016/j.jcis.2020.07.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 11/18/2022]
Abstract
HYPOTHESIS Copolymers are developed to enhance the overall physical and chemical properties of polymers. The surface nature of a copolymer is relevant to creating efficient materials to improve adhesion and biocompatibility. We hypothesize that the improved adhesion, as a surface property, is due to phase separation, surface segregation, and the overall molecular organization of different polymer components at the copolymer surface. EXPERIMENTS The surface structure of a copolymer composed of 2-hydroxyethyl methacrylate (HEMA) monomer and 2-phenoxyethyl methacrylate (PhEMA) monomer was analyzed in comparison to the polyHEMA and polyPhEMA homopolymers using atomic force microscopy (AFM) and sum frequency generation (SFG) spectroscopy. FINDINGS The contrast in the phase images was due to the variance in the hydrophobic level provided by the hydroxyl and phenoxy modified monomers in the copolymer. The distribution of the adhesion values, supporting the presence of hydrophobic moieties, across the polymer surface defined the surface segregation of these two components. SFG spectra of the copolymer thin film showed combined spectral features of both polyHEMA and polyPhEMA thin films at the polymer surface. The tilt angles of the alpha-methyl group of homopolymers using the polarization intensity ratio analysis and the polarization mapping method were estimated to be in the range from 48° to 66°.
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Affiliation(s)
- Katherine Leslee A Cimatu
- Department of Chemistry and Biochemistry, Ohio University, 100 University Terrace, 136 Clippinger Laboratories, Athens, OH 45701-2979, United States.
| | - Uvinduni I Premadasa
- Department of Chemistry and Biochemistry, Ohio University, 100 University Terrace, 136 Clippinger Laboratories, Athens, OH 45701-2979, United States
| | - Tharushi D Ambagaspitiya
- Department of Chemistry and Biochemistry, Ohio University, 100 University Terrace, 136 Clippinger Laboratories, Athens, OH 45701-2979, United States
| | - Narendra M Adhikari
- Department of Chemistry and Biochemistry, Ohio University, 100 University Terrace, 136 Clippinger Laboratories, Athens, OH 45701-2979, United States
| | - Joon Hee Jang
- Department of Nanomedicine, Houston Methodist Research Institute, 6670 Bertner Avenue, Houston, TX 77030, United States
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16
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Vilariño-Feltrer G, Salgado-Gallegos A, de-la-Concepción-Ausina J, Rodríguez-Hernández JC, Shahrousvand M, Vallés-Lluch A. Amphipathic Substrates Based on Crosslinker-Free Poly(ε-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption. Polymers (Basel) 2020; 12:polym12061256. [PMID: 32486185 PMCID: PMC7361809 DOI: 10.3390/polym12061256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/26/2020] [Accepted: 05/29/2020] [Indexed: 11/19/2022] Open
Abstract
A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl–hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 °C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction).
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Affiliation(s)
- Guillermo Vilariño-Feltrer
- Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain
| | - Alfredo Salgado-Gallegos
- Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain
| | | | | | - Mohsen Shahrousvand
- Caspian Faculty of Engineering, College of Engineering, University of Tehran, P.O. Box 119-43841 Rezvanshahr, Iran
| | - Ana Vallés-Lluch
- Centre for Biomaterials and Tissue Engineering, Universitat Politècnica de València, 46022 Valencia, Spain
- Biomedical Research Networking Centre in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 46022 Valencia, Spain
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17
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Xiao C, Chen C, Yao Y, Liu H, Chen L, Qian L, Kim SH. Nanoasperity Adhesion of the Silicon Surface in Humid Air: The Roles of Surface Chemistry and Oxidized Layer Structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5483-5491. [PMID: 32357012 DOI: 10.1021/acs.langmuir.0c00205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The interfacial adhesion between silicon oxide surfaces is normally believed to be governed by the surface chemistry of the topmost surface affecting the water contact angle and hydrogen bonding interactions. In the case of a silicon wafer, the physical structure of the native oxide at the surface can vary drastically depending on the aging process; thus, not only the surface chemistry but also the history of surface treatment can also have a profound impact on nanoasperity adhesion. This study reports the effect of aging conditions (ambient air, liquid water, and liquid ethanol) on the nanoasperity adhesion behaviors of a silicon surface. When the silicon surface is kept in liquid alcohol, the surface remains hydrophobic, and adhesion in ambient air can be explained with the capillary effect of the liquid meniscus condensed around the annulus of the nanoasperity contact. When the silicon surface is oxidized in ambient air, the surface gradually becomes hydrophilic, and the strongly hydrogen-bonded water network of adsorbed water plays a dominant role in the nanoasperity interfacial adhesion force. When the silicon surface is aged in liquid water, the interfacial adhesion force measured in ambient air is significantly larger than the value predicted from the theoretical model based on the water contact angle and the hydrogen bonding interaction at the topmost surface. This is because the surface layer oxidized in liquid water is gel-like and thus can swell upon uptake of water from the humid air. To fully encompass all these behaviors, a solid-adsorbate-solid model predicting the adhesion force is developed by introducing a fitting parameter β, which can be adjusted depending on the adsorbed water structure and the swelling capacity of the oxidized surface layer.
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Affiliation(s)
- Chen Xiao
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Chao Chen
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Yangyang Yao
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Hongshen Liu
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Lei Chen
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Linmao Qian
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Seong H Kim
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
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18
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Burgener K, Bhamla MS. A polymer-based technique to remove pollutants from soft contact lenses. Cont Lens Anterior Eye 2020; 44:101335. [PMID: 32444249 DOI: 10.1016/j.clae.2020.05.004] [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: 02/19/2020] [Revised: 05/07/2020] [Accepted: 05/10/2020] [Indexed: 11/18/2022]
Abstract
PURPOSE To demonstrate an alternative to the rinse and rub (RR) method for cleaning pollutants from the exterior surface of soft contact lenses. This proposed technique is termed Polymer on Polymer Pollutant Removal (PoPPR), which utilizes the elastic properties of polydimethylsiloxane (PDMS) to physically remove contaminants from contact lens surfaces through non-adhesive unpeeling. METHODS Three different ratios of setting agent to polymer PDMS (1:30, 1:40, and 1:50) were evaluated using the PoPPR method against the control method of RR with a commercial multi-purpose lens cleaning solution. Three simulated pollutants of different sizes: pollen (25-40 μm), microbeads (1-5 μm), and nanoparticles (5-10 nm), were used to test the effectiveness of both cleaning methods. The fraction of pollutants removed from each contact lens was recorded and evaluated for significance. RESULTS PDMS 1:40 was found to be the optimal ratio for lens cleaning using the PoPPR method. For larger particles (>10 μm), no difference was observed between conventional RR and proposed PoPPR method (p > 0.05). However, the new PoPPR technique was significantly better at removing small PM2.5 particles (<2.5 μm) compared to the RR method, specifically for microbeads (p = 0.006) and nanoparticles (p < 0.001). CONCLUSION This proof-of-concept work demonstrates that the PoPPR method of cleaning contact lenses is as effective as the conventional cleaning method for larger particles such as pollen. The PoPPR method is more effective at removing extremely fine particulate pollutants, including microplastics and nanoparticles. This method offers a potentially more efficient cleaning protocol that could enhance the safety, health, and comfort of contact lens users, especially those living in regions with significant air pollution.
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Affiliation(s)
- Katherine Burgener
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - M Saad Bhamla
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, United States.
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19
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Lee JH, Youm JS, Ju HT, Kim JC. Influence of
N
‐vinyl‐2‐pyrrolidone and methacrylic acid on thermal curing process of 2‐hydroxyethyl methacrylate hydrogel. J Appl Polym Sci 2020. [DOI: 10.1002/app.48622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jung Hyun Lee
- Doosan Corporation Electro‐Materials, 10 Suji‐ro 112‐gil, Suji‐gu Yongin‐si Gyeonggi‐do 16858 Republic of Korea
| | - Je Sung Youm
- Korea Institute of Industrial Technology, 6 Cheomdangwagi‐ro 208‐gil, Buk‐gu Gwangju 61012 Republic of Korea
| | - Hyoung Tae Ju
- WINIS Co. Ltd, 19‐5 Cheomdanventureso‐ro 38‐gil, Buk‐gu Gwangju 61007 Republic of Korea
| | - Jeong Cheol Kim
- Korea Institute of Industrial Technology, 6 Cheomdangwagi‐ro 208‐gil, Buk‐gu Gwangju 61012 Republic of Korea
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20
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Ogawa H, Nakaji-Hirabayashi T, Matsumura K, Yoshikawa C, Kitano H, Saruwatari Y. Novel anti-biofouling and drug releasing materials for contact lenses. Colloids Surf B Biointerfaces 2020; 189:110859. [PMID: 32086022 DOI: 10.1016/j.colsurfb.2020.110859] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/23/2020] [Accepted: 02/10/2020] [Indexed: 01/22/2023]
Abstract
Contact lens users very often become patients of allergic conjunctivitis, which is caused by protein and bacteria adsorption to the eye, because contact lenses easily adsorb proteins and bacteria. However, even if contact lens users develop eye diseases such as allergic conjunctivitis, most of them continue to use contact lenses to avoid interference to daily life or a decrease in their quality of life. If novel contact lenses able to prevent and additionally cure eye diseases can be manufactured, they could improve the quality of life of contact lens users worldwide. Thus, we aim to develop a novel material for contact lenses to prevent diseases by incorporating a zwitterionic polymer with the ability to suppress protein and bacteria adsorption. In addition, we also aim to effectively introduce and release a drug against allergic conjunctivitis from the contact lens material. Because the poorly water-soluble drug for allergic conjunctivitis (pranoprofen) forms a rigid crystal structure, we developed the novel "hot-melt press method" to construct a contact lens able to effectively release it. In the present study, polymer sheets containing carboxymethyl betaine (a kind of zwitterionic monomer), 2-hydroxyethyl methacrylate, and 1-vinyl-2-pyrrolidone were prepared using three different procedures. The sheets were hydrophilic and showed a strong resistance against protein and bacteria adsorption. The sheets prepared by the hot-melt press method were transparent and seemed to have potential as a material for contact lenses. In addition, the drug introduced into the sheets during preparation was observed to release at a practically appropriate dose. Therefore, it is expected that the sheets could possibly be used as a material for contact lenses which not only protect against the development of eye trouble due to protein and bacterial adsorption, but also heal allergic conjunctivitis.
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Affiliation(s)
- Hiroaki Ogawa
- Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Tadashi Nakaji-Hirabayashi
- Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan; Department of Advanced Nano-bioscience, Graduate School of Innovative Life Science, University of Toyama, Toyama 930-0194, Japan; International Center for Materials Nanoarchitectonics, National Institute of Material Science, Ibaraki 305-0047, Japan.
| | - Kazuaki Matsumura
- School of Materials Science, Japan Advanced Institute of Science and Technology, Ishikawa 923-1292, Japan
| | - Chiaki Yoshikawa
- International Center for Materials Nanoarchitectonics, National Institute of Material Science, Ibaraki 305-0047, Japan
| | - Hiromi Kitano
- Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan; R and D Head Office, Institute for Polymer-Water Interfaces, Toyama 939-2376, Japan
| | - Yoshiyuki Saruwatari
- Business Operation Division, Osaka Organic Chemical Industry Ltd., Osaka 541-0052, Japan
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21
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Price BL, Morley R, Bowling FL, Lovering AM, Dobson CB. Susceptibility of monomicrobial or polymicrobial biofilms derived from infected diabetic foot ulcers to topical or systemic antibiotics in vitro. PLoS One 2020; 15:e0228704. [PMID: 32069293 PMCID: PMC7028275 DOI: 10.1371/journal.pone.0228704] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 01/22/2020] [Indexed: 12/17/2022] Open
Abstract
Diabetic foot ulcers can become chronic and non-healing despite systemic antibiotic treatment. The penetration of systematically-administered antibiotics to the site of infection is uncertain, as is the effectiveness of such levels against polymicrobial biofilms. We have developed an in vitro model to study the effectiveness of different treatments for infected diabetic foot ulcers in a wound-like environment and compared the activity of systemic levels of antibiotics with that for topically applied antibiotics released from calcium sulfate beads. This is the first study that has harvested bacteria from diabetic foot infections and recreated similar polymicrobial biofilms to those present in vivo for individual subjects. After treatment with levels of gentamicin attained in serum after systemic administration (higher than corresponding tissues concentrations) we measured a 0-2 log reduction in bacterial viability of P. aeruginosa, S. aureus or a polymicrobial biofilm. Conversely, addition of gentamicin loaded calcium sulfate beads resulted in 5-9 log reductions in P. aeruginosa, S aureus and polymicrobial biofilms derived from three subjects. We conclude that systemically administered antibiotics are likely to be inadequate for successfully treating these infections, especially given the vastly increased concentrations required to inhibit cells in a biofilm, and that topical antibiotics provide a more effective alternative.
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Affiliation(s)
- Bianca L. Price
- Division of Pharmacy and Optometry, Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Robert Morley
- Podiatric Surgery Dept, Buxton Hospital, Derbyshire Community Health Services NHS Foundation Trust, Bakewell, United Kingdom
| | - Frank L. Bowling
- Division of Diabetes, Endocrinology & Gastroenterology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Andrew M. Lovering
- Microbiology Department, Antimicrobial Reference Laboratory, Bristol, United Kingdom
| | - Curtis B. Dobson
- Medical Device Biology Group, Division of Pharmacy and Optometry, Faculty of Biology Medicine and Health (FBMH), University of Manchester, Manchester, United Kingdom
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22
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Liamas E, Connell SD, Ramakrishna SN, Sarkar A. Probing the frictional properties of soft materials at the nanoscale. NANOSCALE 2020; 12:2292-2308. [PMID: 31951242 DOI: 10.1039/c9nr07084b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The understanding of friction in soft materials is of increasing importance due to the demands of industries such as healthcare, biomedical, food and personal care, the incorporation of soft materials into technology, and in the study of interacting biological interfaces. Many of these processes occur at the nanoscale, but even at micrometer length scales there are fundamental aspects of tribology that remain poorly understood. With the advent of Friction Force Microscopy (FFM), there have been many fundamental insights into tribological phenomena at the atomic scale, such as 'stick-slip' and 'super-lubricity'. This review examines the growing field of soft tribology, the experimental aspects of FFM and its underlying theory. Moving to the nanoscale changes the contact mechanics which govern adhesive forces, which in turn play a pivotal role in friction, along with the deformation of the soft interface and dissipative phenomena. We examine recent progress and future prospects in soft nanotribology.
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Affiliation(s)
- Evangelos Liamas
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK.
| | - Simon D Connell
- Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, UK
| | | | - Anwesha Sarkar
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK.
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23
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Nishimoto T, Matsukawa K, Nagase K, Kanazawa H, Akimoto AM, Yoshida R. Design of two complementary copolymers that work as a glue for cell-laden collagen gels. Chem Commun (Camb) 2020; 56:10545-10548. [DOI: 10.1039/d0cc03689g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study realised cytocompatible “in situ” surface functionalization of collagen gel for adding the property of gel-to-gel adhesion.
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Affiliation(s)
- Taihei Nishimoto
- Department of Materials Engineering
- School of Engineering
- The University of Tokyo
- Tokyo 113-8656
- Japan
| | - Ko Matsukawa
- Department of Materials Engineering
- School of Engineering
- The University of Tokyo
- Tokyo 113-8656
- Japan
| | | | | | - Aya Mizutani Akimoto
- Department of Materials Engineering
- School of Engineering
- The University of Tokyo
- Tokyo 113-8656
- Japan
| | - Ryo Yoshida
- Department of Materials Engineering
- School of Engineering
- The University of Tokyo
- Tokyo 113-8656
- Japan
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24
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Chen L, Ngo D, Luo J, Gong Y, Xiao C, He X, Yu B, Qian L, Kim SH. Dependence of water adsorption on the surface structure of silicon wafers aged under different environmental conditions. Phys Chem Chem Phys 2019; 21:26041-26048. [PMID: 31746864 DOI: 10.1039/c9cp04776j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Most materials exposed to ambient air can adsorb water molecules and the adsorption capability strongly depends on the surface property. The water contact angle has been widely used as a measure for surface wettability; however, a question can still be asked whether the water contact angle can be used as an adequate sole predictor for water adsorption on the surface in humid air. In this paper, HF-etched silicon wafers were aged (oxidized) under different environmental conditions at room temperature to grow surface layers with varying water contact angles from ∼0° (fully hydrophilic) to ∼83° (highly hydrophobic), and water adsorption as a function of relative humidity (RH) was studied on such surfaces. The thickness and structure of the adsorbed water layer were found to depend on not only the surface wettability on each surface, but also the history of surface oxidation conditions. In particular, the silicon wafer surface oxidized in liquid water uptakes significantly more water from humid air than the fully-hydroxylated native oxide surface (SiOx/OH), even though its water contact angle is higher than that on the SiOx/OH surface. This could be attributed to the formation of a gel-like structure during oxidation in liquid water.
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Affiliation(s)
- Lei Chen
- Tribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Dien Ngo
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA.
| | - Jiawei Luo
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA.
| | - Yunfei Gong
- Tribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Chen Xiao
- Tribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Xin He
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA.
| | - Bingjun Yu
- Tribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Linmao Qian
- Tribology Research Institute, Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Seong H Kim
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA.
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25
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Li G, Dobryden I, Salazar-Sandoval EJ, Johansson M, Claesson PM. Load-dependent surface nanomechanical properties of poly-HEMA hydrogels in aqueous medium. SOFT MATTER 2019; 15:7704-7714. [PMID: 31508653 DOI: 10.1039/c9sm01113g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The mechanical properties of hydrogels are of importance in many applications, including scaffolds and drug delivery vehicles where the release of drugs is controlled by water transport. While the macroscopic mechanical properties of hydrogels have been reported frequently, there are less studies devoted to the equally important nanomechanical response to local load and shear. Scanning probe methods offer the possibility to gain insight on surface nanomechanical properties with high spatial resolution, and thereby provide fundamental insights on local material property variations. In this work, we investigate the local response to load and shear of poly(2-hydroxyethyl methacrylate) hydrogels with two different cross-linking densities submerged in aqueous solution. The response of the hydrogels to purely normal loads, as well as the combined action of load and shear, was found to be complex due to viscoelastic effects. Our results show that the surface stiffness of the hydrogel samples increased with increasing load, while the tip-hydrogel adhesion was strongly affected by the load only when the cross-linking density was low. The combined action of load and shear results in the formation of a temporary sub-micrometer hill in front of the laterally moving tip. As the tip pushes against such hills, a pronounced stick-slip effect is observed for the hydrogel with low cross-linking density. No plastic deformation or permanent wear scar was found under our experimental conditions.
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Affiliation(s)
- Gen Li
- KTH Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE 10044 Stockholm, Sweden.
| | - Illia Dobryden
- KTH Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE 10044 Stockholm, Sweden.
| | | | - Mats Johansson
- KTH Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Fibre & Polymer Technology, Teknikringen 48, SE 10044 Stockholm, Sweden
| | - Per M Claesson
- KTH Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE 10044 Stockholm, Sweden. and RISE Research Institutes of Sweden, Division of Bioscience and Materials, Box 5607, SE 114 86 Stockholm, Sweden
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26
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Abstract
A computationally lean model for the coarse-grained description of contact mechanics of hydrogels is proposed and characterized. It consists of a simple bead-spring model for the interaction within a chain, potentials describing the interaction between monomers and mold or confining walls, and a coarse-grained potential reflecting the solvent-mediated effective repulsion between non-bonded monomers. Moreover, crosslinking only takes place after the polymers have equilibrated in their mold. As such, the model is able to reflect the density, solvent quality, and the mold hydrophobicity that existed during the crosslinking of the polymers. Finally, such produced hydrogels are exposed to sinusoidal indenters. The simulations reveal a wavevector-dependent effective modulus E * ( q ) with the following properties: (i) stiffening under mechanical pressure, and a sensitivity of E * ( q ) on (ii) the degree of crosslinking at large wavelengths, (iii) the solvent quality, and (iv) the hydrophobicity of the mold in which the polymers were crosslinked. Finally, the simulations provide evidence that the elastic heterogeneity inherent to hydrogels can suffice to pin a compressed hydrogel to a microscopically frictionless wall that is undulated at a mesoscopic length scale. Although the model and simulations of this feasibility study are only two-dimensional, its generalization to three dimensions can be achieved in a straightforward fashion.
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27
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Singh M, Kang C, Ilg P, Crockett R, Kröger M, Spencer ND. Combined Experimental and Simulation Studies of Cross-Linked Polymer Brushes under Shear. Macromolecules 2018; 51:10174-10183. [PMID: 32063653 PMCID: PMC7018396 DOI: 10.1021/acs.macromol.8b01363] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/24/2018] [Indexed: 12/11/2022]
Abstract
We have studied the effect of cross-linking on the tribological behavior of polymer brushes using a combined experimental and theoretical approach. Tribological and indentation measurements on poly(glycidyl methacrylate) brushes and gels in the presence of dimethylformamide solvent were obtained by means of atomic force microscopy. To complement experiments, we have performed corresponding molecular dynamics (MD) simulations of a generic bead-spring model in the presence of explicit solvent and cross-linkers. Our study shows that cross-linking leads to an increase in friction between polymer brushes and a counter-surface. The coefficient of friction increases with increasing degree of cross-linking and decreases with increasing length of the cross-linker chains. We find that the brush-forming polymer chains in the outer layer play a significant role in reducing friction at the interface.
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Affiliation(s)
- Manjesh
K. Singh
- Laboratory
for Surface Science and Technology, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Chengjun Kang
- Laboratory
for Surface Science and Technology, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Patrick Ilg
- School
of Mathematical, Physical and Computational Sciences, University of Reading, Reading RG6 6AX, United Kingdom
| | - Rowena Crockett
- Swiss
Federal Laboratories for Materials Science and Technology (EMPA), CH-8600 Dübendorf, Switzerland
| | - Martin Kröger
- Polymer
Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Nicholas D. Spencer
- Laboratory
for Surface Science and Technology, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
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28
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Paltrinieri L, Poltorak L, Chu L, Puts T, van Baak W, Sudhölter EJ, de Smet LC. Hybrid polyelectrolyte-anion exchange membrane and its interaction with phosphate. REACT FUNCT POLYM 2018. [DOI: 10.1016/j.reactfunctpolym.2018.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Macron J, Bresson B, Tran Y, Hourdet D, Creton C. Equilibrium and Out-of-Equilibrium Adherence of Hydrogels against Polymer Brushes. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01063] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Jennifer Macron
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Bruno Bresson
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Yvette Tran
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Dominique Hourdet
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS, F-75005 Paris, France
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Costantino Creton
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, PSL University, Sorbonne Université, CNRS, F-75005 Paris, France
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
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30
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Donnchadha ÉM, Leal C, Esmonde H. Oscillatory squeeze film analysis of soft contact lenses. Cont Lens Anterior Eye 2018; 41:377-388. [PMID: 29656886 DOI: 10.1016/j.clae.2018.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/18/2018] [Indexed: 10/17/2022]
Abstract
The complex modulus of a soft contact lens affects the optical performance, fitting, on-eye movement, wettability, physiological impact and overall comfort of the lens. However, despite acknowledgement that the mechanical behaviour of contact lenses is time-dependent, the rheological characteristics of contact lenses remain under-defined. While existing studies have focussed on elasticity to describe lens behaviour, this paper proposes using oscillatory squeeze film analysis to evaluate the complex modulus. The effects of excitation amplitude, repeatability and surface wetness are examined for four commercially available lenses. Slip at the lens/platen interface is considered along with bias introduced by pre-compressing the lens between platens. Test results when compared to results reported from other test methods indicate that a high degree of slip occurs at the lens platen interface suggesting that deformation is primarily due to biaxial extension.
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Affiliation(s)
- Éanna Mac Donnchadha
- School of Mechanical & Manufacturing Engineering, Dublin City University, Dublin 9, Ireland; Physics Department, University of Coimbra, Portugal
| | | | - Harry Esmonde
- School of Mechanical & Manufacturing Engineering, Dublin City University, Dublin 9, Ireland.
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31
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Brygoła R, Sęk S, Sokołowski M, Kowalczyk-Hernández M, Pniewski J. Limits in measurements of contact lens surface profile using atomic force microscopy. Colloids Surf B Biointerfaces 2018; 165:229-234. [DOI: 10.1016/j.colsurfb.2018.02.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 11/17/2017] [Accepted: 02/10/2018] [Indexed: 11/25/2022]
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32
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Kolewe KW, Zhu J, Mako NR, Nonnenmann SS, Schiffman JD. Bacterial Adhesion Is Affected by the Thickness and Stiffness of Poly(ethylene glycol) Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2018; 10:2275-2281. [PMID: 29283244 PMCID: PMC5785418 DOI: 10.1021/acsami.7b12145] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Despite lacking visual, auditory, and olfactory perception, bacteria sense and attach to surfaces. Many factors, including the chemistry, topography, and mechanical properties of a surface, are known to alter bacterial attachment, and in this study, using a library of nine protein-resistant poly(ethylene glycol) (PEG) hydrogels immobilized on glass slides, we demonstrate that the thickness or amount of polymer concentration also matters. Hydrated atomic force microscopy and rheological measurements corroborated that thin (15 μm), medium (40 μm), and thick (150 μm) PEG hydrogels possessed Young's moduli in three distinct regimes, soft (20 kPa), intermediate (300 kPa), and stiff (1000 kPa). The attachment of two diverse bacteria, flagellated Gram-negative Escherichia coli and nonmotile Gram-positive Staphylococcus aureus was assessed after a 24 h incubation on the nine PEG hydrogels. On the thickest PEG hydrogels (150 μm), E. coli and S. aureus attachment increased with increasing hydrogel stiffness. However, when the hydrogel's thickness was reduced to 15 μm, a substantially greater adhesion of E. coli and S. aureus was observed. Twelve times fewer S. aureus and eight times fewer E. coli adhered to thin-soft hydrogels than to thick-soft hydrogels. Although a full mechanism to explain this behavior is beyond the scope of this article, we suggest that because the Young's moduli of thin-soft and thick-soft hydrogels were statistically equivalent, potentially, the very stiff underlying glass slide was causing the thin-soft hydrogels to feel stiffer to the bacteria. These findings suggest a key takeaway design rule; to optimize fouling-resistance, hydrogel coatings should be thick and soft.
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Affiliation(s)
- Kristopher W. Kolewe
- Department of Chemical Engineering, University of Massachusetts
Amherst, Amherst, Massachusetts 01003-9303
| | - Jiaxin Zhu
- Department of Mechanical and Industrial Engineering, University of
Massachusetts Amherst, Amherst, Massachusetts 01003-9265
| | - Natalie R. Mako
- Department of Chemical Engineering, University of Massachusetts
Amherst, Amherst, Massachusetts 01003-9303
| | - Stephen S. Nonnenmann
- Department of Mechanical and Industrial Engineering, University of
Massachusetts Amherst, Amherst, Massachusetts 01003-9265
| | - Jessica D. Schiffman
- Department of Chemical Engineering, University of Massachusetts
Amherst, Amherst, Massachusetts 01003-9303
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33
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Bradley LC, Bade ND, Mariani LM, Turner KT, Lee D, Stebe KJ. Rough Adhesive Hydrogels (RAd gels) for Underwater Adhesion. ACS APPLIED MATERIALS & INTERFACES 2017; 9:27409-27413. [PMID: 28792730 DOI: 10.1021/acsami.7b08916] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, underwater adhesion is achieved between biocompatible hydrogels and a suite of substrates. Surface roughness, which is typically detrimental for adhesion in air, is shown to be beneficial for underwater adhesion. Contact between the hydrogels with macroscopically flat substrates, and the resulting nonspecific chemical interaction, is facilitated by surface roughness, which enables drainage of the lubricating fluid layer. Hydrogel composition plays an important role in tuning the gel elasticity and interaction with the substrate. Hydrogels that are adhesive on two sides are synthesized for potential use as versatile adhesives in various applications.
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Affiliation(s)
- Laura C Bradley
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Nathan D Bade
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Lisa M Mariani
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Kevin T Turner
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Kathleen J Stebe
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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34
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de Leon AC, Rodier BJ, Luo Q, Hemmingsen CM, Wei P, Abbasi K, Advincula R, Pentzer EB. Distinct Chemical and Physical Properties of Janus Nanosheets. ACS NANO 2017; 11:7485-7493. [PMID: 28696656 DOI: 10.1021/acsnano.7b04020] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Janus particles have recently garnered significant attention for their distinct properties compared to particles that are homogeneously functionalized. Moreover, high aspect ratio Janus particles that are rod-like or planar (i.e., nanosheets) are especially intriguing considering their interfacial properties as well as their ability to assemble into higher order and hybrid structures. To date, major challenges facing the exploration and utilization of 2D Janus particles are scalability of synthesis, characterization of tailored chemical functionalization, and ability to introduce a diverse set of functionalities. Herein, a facile method to access Janus 2D graphene oxide (GO) nanosheets by combining a Pickering-type emulsion and grafting-from polymerization via ATRP is reported. Janus GO nanosheets bearing PMMA on one face as well as the symmetrically functionalized analogue are prepared, and the chemical, thermal, structural, surface, and interfacial properties of these materials are characterized. Time-of-flight secondary ion mass spectrometry coupled with Langmuir-Blodgett films is shown to be an ideal route to conclusively establish asymmetric functionalization of 2D materials. This work not only provides a facile route for the preparation of Janus nanosheets but also demonstrates the direct visualization of polymer grown from the surface of GO.
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Affiliation(s)
- Al C de Leon
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Bradley J Rodier
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Qinmo Luo
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Christina M Hemmingsen
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Peiran Wei
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Kevin Abbasi
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Rigoberto Advincula
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Emily B Pentzer
- Department of Chemistry, ‡Swagelok Center for Surface Analysis of Materials, School of Engineering, and §Department of Macromolecular Science and Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
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35
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Casdorff K, Keplinger T, Bellanger H, Michen B, Schön S, Burgert I. High-Resolution Adhesion Mapping of the Odd-Even Effect on a Layer-by-Layer Coated Biomaterial by Atomic-Force-Microscopy. ACS APPLIED MATERIALS & INTERFACES 2017; 9:13793-13800. [PMID: 28345851 DOI: 10.1021/acsami.7b02564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The adhesion behavior of polyelectrolyte multilayers consisting of poly(diallyldimethylammonium chloride), PDDA, and poly(styrenesulfonate), PSS, toward a silicon AFM tip was studied during their build-up on wood, a chemically heterogeneous, micrometer rough biomaterial and compared with a nanometer rough substrate, namely quartz. The atomic force microscopy-based force mapping approach generated high-resolution topography-, and adhesion maps within the first bilayers, which point toward a homogeneous layer-by-layer build-up on the biomaterial surface, and therefore indicate an even charge distribution. By analyzing the force-distance curves in every pixel of the mapping, new insights into the specific interactions of the polyelectrolyte multilayers at the surface were achieved. The characteristic odd-even effect of polyelectrolyte multilayers cannot only be determined on quartz, but also on the biomaterial wood, however, only after an offset of two bilayers. This is potentially due to the specific roughness and charge of wood in comparison to commonly used quartz.
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Affiliation(s)
- Kirstin Casdorff
- Wood Materials Science, Institute for Building Materials, ETH Zürich , Stefano-Franscini-Platz 3, 8093 Zürich, Switzerland
- Applied Wood Materials, EMPA Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Tobias Keplinger
- Wood Materials Science, Institute for Building Materials, ETH Zürich , Stefano-Franscini-Platz 3, 8093 Zürich, Switzerland
- Applied Wood Materials, EMPA Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Hervé Bellanger
- Wood Materials Science, Institute for Building Materials, ETH Zürich , Stefano-Franscini-Platz 3, 8093 Zürich, Switzerland
- Applied Wood Materials, EMPA Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Benjamin Michen
- Wood Materials Science, Institute for Building Materials, ETH Zürich , Stefano-Franscini-Platz 3, 8093 Zürich, Switzerland
- Applied Wood Materials, EMPA Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Silke Schön
- FIRST Laboratory, ETH Zürich , 8093 Zürich, Switzerland
| | - Ingo Burgert
- Wood Materials Science, Institute for Building Materials, ETH Zürich , Stefano-Franscini-Platz 3, 8093 Zürich, Switzerland
- Applied Wood Materials, EMPA Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, 8600 Dübendorf, Switzerland
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36
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Adhikari NM, Premadasa UI, Cimatu KLA. Sum frequency generation vibrational spectroscopy of methacrylate-based functional monomers at the hydrophilic solid–liquid interface. Phys Chem Chem Phys 2017; 19:21818-21828. [DOI: 10.1039/c7cp03113k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An SFGVS study showed H-bonding interactions between the carbonyl groups of methacrylate liquid monomers and surface silanol groups of amorphous quartz.
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37
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Kim J, Dunn AC. Soft hydrated sliding interfaces as complex fluids. SOFT MATTER 2016; 12:6536-6546. [PMID: 27425448 DOI: 10.1039/c6sm00623j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hydrogel surfaces are biomimics for sensing and mobility systems in the body such as the eyes and large joints due to their important characteristics of flexibility, permeability, and integrated aqueous component. Recent studies have shown polymer concentration gradients resulting in a less dense region in the top micrometers of the surface. Under shear, this gradient is hypothesized to drive lubrication behavior due to its rheological similarity to a semi-dilute polymer solution. In this work we map 3 distinct lubricating regimes between a polyacrylamide surface and an aluminum annulus using stepped-velocity tribo-rheometry over 5 decades of sliding speed in increasing and decreasing steps. These regimes, characterized by weakly or strongly time-dependent response and thixotropy-like hysteresis, provide the skeleton of a lubrication curve for hydrogel-against-hard material interfaces and support hypotheses of polymer mechanics-driven lubrication. Tribo-rheometry is particularly suited to uncover the lubrication mechanisms of complex interfaces such as are formed with hydrated hydrogel surfaces and biological surfaces.
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Affiliation(s)
- Jiho Kim
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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38
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McCracken JM, Badea A, Kandel ME, Gladman AS, Wetzel DJ, Popescu G, Lewis JA, Nuzzo RG. Programming Mechanical and Physicochemical Properties of 3D Hydrogel Cellular Microcultures via Direct Ink Writing. Adv Healthc Mater 2016; 5:1025-39. [PMID: 26924676 DOI: 10.1002/adhm.201500888] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/28/2016] [Indexed: 11/12/2022]
Abstract
3D hydrogel scaffolds are widely used in cellular microcultures and tissue engineering. Using direct ink writing, microperiodic poly(2-hydroxyethyl-methacrylate) (pHEMA) scaffolds are created that are then printed, cured, and modified by absorbing 30 kDa protein poly-l-lysine (PLL) to render them biocompliant in model NIH/3T3 fibroblast and MC3T3-E1 preosteoblast cell cultures. Spatial light interference microscopy (SLIM) live cell imaging studies are carried out to quantify cellular motilities for each cell type, substrate, and surface treatment of interest. 3D scaffold mechanics is investigated using atomic force microscopy (AFM), while their absorption kinetics are determined by confocal fluorescence microscopy (CFM) for a series of hydrated hydrogel films prepared from prepolymers with different homopolymer-to-monomer (Mr ) ratios. The observations reveal that the inks with higher Mr values yield relatively more open-mesh gels due to a lower degree of entanglement. The biocompatibility of printed hydrogel scaffolds can be controlled by both PLL content and hydrogel mesh properties.
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Affiliation(s)
- Joselle M. McCracken
- School of Chemical Sciences; University of Illinois Urbana-Champaign; Urbana IL 61801 USA
| | - Adina Badea
- School of Chemical Sciences; University of Illinois Urbana-Champaign; Urbana IL 61801 USA
| | - Mikhail E. Kandel
- Department of Electrical and Computer Engineering; University of Illinois Urbana-Champaign; Urbana IL 61801 USA
| | - A. Sydney Gladman
- Wyss Institute; School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
| | - David J. Wetzel
- School of Chemical Sciences; University of Illinois Urbana-Champaign; Urbana IL 61801 USA
| | - Gabriel Popescu
- Department of Electrical and Computer Engineering; University of Illinois Urbana-Champaign; Urbana IL 61801 USA
| | - Jennifer A. Lewis
- Wyss Institute; School of Engineering and Applied Sciences; Harvard University; Cambridge MA 02138 USA
| | - Ralph G. Nuzzo
- School of Chemical Sciences; University of Illinois Urbana-Champaign; Urbana IL 61801 USA
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39
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Su G, Zhou T, Zhang Y, Liu X, Zhang A. Microdynamics mechanism of D2O absorption of the poly(2-hydroxyethyl methacrylate)-based contact lens hydrogel studied by two-dimensional correlation ATR-FTIR spectroscopy. SOFT MATTER 2016; 12:1145-1157. [PMID: 26577131 DOI: 10.1039/c5sm02542g] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A good understanding of the microdynamics of the water absorption of poly(2-hydroxyethyl methacrylate) (PHEMA)-based contact lens is significant for scientific investigation and commercial applications. In this study, time-dependent ATR-FTIR spectroscopy combined with the perturbation correlation moving-window two-dimensional (PCMW2D) technique and 2D correlation analysis was used to study the microdynamics mechanism. PCMW2D revealed that D2O took 3.4 min to penetrate into the contact lens. PCMW2D also found the PHEMA-based contact lens underwent two processes (I and II) during D2O absorption, and the time regions of processes I and II are 3.4-12.4 min and 12.4-57.0 min. According to 2D correlation analysis, it was proved that process I has 5 steps, and process II has 3 steps. For process I, the first step is D2O hydrogen-bonding with "free" C[double bond, length as m-dash]O in the side chains. The second step is the hydrogen bond generation of the O-HO-D structure between D2O and "free" O-H groups in the side chain ends. The third step is the hydrogen bond generation of D2O and the "free" C[double bond, length as m-dash]O groups close to the crosslinking points in the contact lens. The fourth and the fifth steps are the hydration of -CH3 and -CH2- groups by D2O, respectively. For process II, the first step is the same as that of process I. The second step is the hydrogen bonds breaking of bonded O-H groups and the deuterium exchange between D2O and O-H groups in the side chain ends. The third step is also related to the deuterium exchange, which is the hydrogen bonds regeneration between the dissociated C[double bond, length as m-dash]O groups and the new O-D.
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Affiliation(s)
- Gehong Su
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
| | - Tao Zhou
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
| | - Yanyan Zhang
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
| | - Xifei Liu
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
| | - Aiming Zhang
- State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
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Zhang C, Jasensky J, Chen Z. Multireflection Sum Frequency Generation Vibrational Spectroscopy. Anal Chem 2015; 87:8157-64. [DOI: 10.1021/acs.analchem.5b00641] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chi Zhang
- Departments of †Chemistry and ‡Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Joshua Jasensky
- Departments of †Chemistry and ‡Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- Departments of †Chemistry and ‡Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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Tribological changes in the articular cartilage of a human femoral head with avascular necrosis. Biointerphases 2015; 10:021004. [DOI: 10.1116/1.4919020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Chyasnavichyus M, Young SL, Tsukruk VV. Mapping micromechanical properties of soft polymer contact lenses. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.09.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Torrent-Burgués J, Sanz F. AFM in mode Peak Force applied to the study of un-worn contact lenses. Colloids Surf B Biointerfaces 2014; 121:388-94. [DOI: 10.1016/j.colsurfb.2014.06.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/26/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
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Facile synthesis of 4-vinylpyridine-based hydrogels via laser-ignited frontal polymerization and their performance on ion removal. Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3279-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Selby A, Maldonado-Codina C, Derby B. Influence of specimen thickness on the nanoindentation of hydrogels: measuring the mechanical properties of soft contact lenses. J Mech Behav Biomed Mater 2013; 35:144-56. [PMID: 24378734 DOI: 10.1016/j.jmbbm.2013.11.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 10/25/2022]
Abstract
Nanoindentation offers a convenient method for the testing of thin hydrogel specimens, such as contact lenses, to directly assess their mechanical properties. Here we investigate the mechanical properties of poly(hydroxyethyl methacrylate) (pHEMA) specimens of a range of uniform thickness values and demonstrate that, with 50 and 100μm radius spherical indenters, a significant increase in apparent elastic modulus is seen when the specimen thickness is smaller than 500μm at indentation depths <1μm. This is a manifestation of the well known indentation thickness effect but occurring at larger critical thicknesses than seen with other materials. A simple empirical relation is determined for the variation in apparent elastic modulus with normalised thickness. The empirical thickness correction function obtained from pHEMA specimens was subsequently used to correct for the thickness variation within a range of contact lenses supplied by a number of different manufacturers fabricated from both pHEMA and silicone polymers, with a range of optical strengths and hence thickness profiles. The correction function is seen to compensate for the variation in apparent elastic modulus with lens thickness for all four contact lens types, irrespective of lens material. The measured Young's modulus of the contact lens material, corrected for thickness, was compared with that quoted by the manufacturers of the contact lenses, obtained by conventional bulk mechanical testing, to find good agreement.
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Affiliation(s)
- Alastair Selby
- School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Carole Maldonado-Codina
- Eurolens Research, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Brian Derby
- School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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Zhao C, Li X, Li L, Cheng G, Gong X, Zheng J. Dual functionality of antimicrobial and antifouling of poly(N-hydroxyethylacrylamide)/salicylate hydrogels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:1517-1524. [PMID: 23317290 DOI: 10.1021/la304511s] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The emergence and reemergence of microbial infection demand an urgent response to develop effective biomaterials that prevent biofilm formation and associated bacterial infection. In this work, we have synthesized and characterized hybrid poly(N-hydroxyethylacrylamide) (polyHEAA)/salicylate (SA) hydrogels with integrated antifouling and antimicrobial capacities. The antifouling efficacy of polyHEAA hydrogels was examined via exposure to proteins, cells, and bacteria, while the antimicrobial activity of SA-treated polyHEAA hydrogels was investigated against both gram-negative Escherichia coli RP437 and gram-positive Staphylococcus epidermidis. The results showed that polyHEAA/SA hydrogels exhibited high surface resistance to protein adsorption, cell adhesion, and bacteria attachment. The polyHEAA hydrogels were also characterized by their water content and state of water, revealing a strong ability to contain and retain high nonfreezable water content. This work demonstrates that the hybrid polyHEAA/SA hydrogels can be engineered to possess both antifouling and antimicrobial properties, which can be used for different in vitro and in vivo applications against bacterial infection.
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Affiliation(s)
- Chao Zhao
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
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Zhang C, Myers J, Chen Z. Elucidation of molecular structures at buried polymer interfaces and biological interfaces using sum frequency generation vibrational spectroscopy. SOFT MATTER 2013; 9:4738-4761. [PMID: 23710244 PMCID: PMC3661304 DOI: 10.1039/c3sm27710k] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy has been developed into an important technique to study surfaces and interfaces. It can probe buried interfaces in situ and provide molecular level structural information such as the presence of various chemical moieties, quantitative molecular functional group orientation, and time dependent kinetics or dynamics at such interfaces. This paper focuses on these three most important advantages of SFG and reviews some of the recent progress in SFG studies on interfaces related to polymer materials and biomolecules. The results discussed here demonstrate that SFG can provide important molecular structural information of buried interfaces in situ and in real time, which is difficult to obtain by other surface sensitive analytical techniques.
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Affiliation(s)
- Chi Zhang
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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