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Lanier OL, D’Andrea AP, Shodeinde A, Peppas NA. siRNA Delivery from Cationic Nanocarriers Prepared by Diffusion-assisted Loading in the Presence and Absence of Electrostatic Interactions. J Appl Polym Sci 2024; 141:e55029. [PMID: 38962028 PMCID: PMC11219015 DOI: 10.1002/app.55029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 11/25/2023] [Indexed: 07/05/2024]
Abstract
In this study, we use modified cationic nanocarriers as vehicles for the intracellular delivery of therapeutic siRNA. After developing nanocarrier formulations with appropriate pKa, size, swellability, and cytocompatibility, we investigated the importance of siRNA loading methods by studying the impact of the pH and time over which siRNA is loaded into the nanocarriers. We concentrate on diffusion-based loading in the presence and absence of electrostatic interactions. siRNA release kinetics were studied using samples prepared from nanocarriers loaded by both mechanisms. In addition, siRNA delivery was evaluated for two formulations. While previous studies were conducted with samples prepared by siRNA loading at low pH values, this research provides evidence that loading conditions of siRNA affect the release behavior. This study concludes that this concept could prove advantageous for eliciting prolonged intracellular release of nucleic acids and negatively charged molecules, effectively decreasing dose frequency and contributing to more effective therapies and improved patient outcomes. In addition, our findings could be leveraged for enhanced control over siRNA release kinetics, providing novel methods for the continued optimization of cationic nanoparticles in a wide array of RNA interference-based applications.
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Affiliation(s)
- Olivia L. Lanier
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine
| | - Abielle P. D’Andrea
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine
| | - Aaliyah Shodeinde
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine
| | - Nicholas A. Peppas
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine
- Department of Surgery and Perioperative Care, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
- Department of Pediatrics, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
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2
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Ishihara K, Shi X, Fukazawa K, Yamaoka T, Yao G, Wu JY. Biomimetic-Engineered Silicone Hydrogel Contact Lens Materials. ACS APPLIED BIO MATERIALS 2023; 6:3600-3616. [PMID: 37616500 PMCID: PMC10521029 DOI: 10.1021/acsabm.3c00296] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
Contact lenses are one of the most successful applications of biomaterials. The chemical structure of the polymers used in contact lenses plays an important role in determining the function of contact lenses. Different types of contact lenses have been developed based on the chemical structure of polymers. When designing contact lenses, materials scientists consider factors such as mechanical properties, processing properties, optical properties, histocompatibility, and antifouling properties, to ensure long-term wear with minimal discomfort. Advances in contact lens materials have addressed traditional issues such as oxygen permeability and biocompatibility, improving overall comfort, and duration of use. For example, silicone hydrogel contact lenses with high oxygen permeability were developed to extend the duration of use. In addition, controlling the surface properties of contact lenses in direct contact with the cornea tissue through surface polymer modification mimics the surface morphology of corneal tissue while maintaining the essential properties of the contact lens, a significant improvement for long-term use and reuse of contact lenses. This review presents the material science elements required for advanced contact lenses of the future and summarizes the chemical methods for achieving these goals.
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Affiliation(s)
- Kazuhiko Ishihara
- Division
of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Xinfeng Shi
- Alcon
Research, LLC, Fort Worth, Texas 76134, United States
| | - Kyoko Fukazawa
- National
Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 564-8565, Japan
| | - Tetsuji Yamaoka
- National
Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 564-8565, Japan
| | - George Yao
- Alcon
Research, LLC, Duluth, Georgia 30097, United States
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3
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Richbourg NR, Peppas NA. Solute diffusion and partitioning in multi-arm poly(ethylene glycol) hydrogels. J Mater Chem B 2023; 11:377-388. [PMID: 36511476 DOI: 10.1039/d2tb02004a] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Controlling solute transport in hydrogels is critical for numerous chemical separation applications, tissue engineering, and drug delivery systems. In previous review work, we have pointed out that proposed theoretical models and associated experiments tend to oversimplify the influence of the hydrogel structure on solute transport by addressing only the effects of the polymer volume fraction and mesh size of the networks on solute transport. Here, we reexamine these models by experimenting with a library of multi-arm poly(ethylene glycol) (PEG) hydrogels with simultaneous variations in four independent structural parameters. Standardized, high-throughput fluorescence recovery after photobleaching (FRAP) experiments in hydrogels characterize size-dependent solute diffusion and partitioning in each hydrogel formulation. Solute diffusivity dependence on junction functionality shows an influence from network geometry that is not addressed by mesh size-based models, experimentally validating the use of the geometry-responsive mesh radius in solute diffusivity modeling. Furthermore, the Richbourg-Peppas swollen polymer network (SPN) model accurately predicts how three of the four structural parameters affect solute diffusivity in hydrogels. Comparison with the large pore effective medium (LPEM) model showed that the SPN model better predicts solute size and hydrogel structure effects on diffusivity. This study provides a framework for investigating solute transport in hydrogels that will continue to improve hydrogel design for tissue engineering and drug delivery.
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Affiliation(s)
- Nathan R Richbourg
- Department of Biomedical Engineering, University of Texas, Austin, TX, 78712, USA.
| | - Nicholas A Peppas
- Department of Biomedical Engineering, University of Texas, Austin, TX, 78712, USA. .,McKetta Department of Chemical Engineering, University of Texas, Austin, TX, 78712, USA.,Division of Molecular Therapeutics and Drug Delivery, College of Pharmacy, University of Texas, Austin, TX, 78712, USA.,Departments of Surgery and Pediatrics, Dell Medical School, University of Texas, Austin, TX, 78712, USA
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4
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Cross-evaluation of stiffness measurement methods for hydrogels. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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5
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Berlinger SA, Chen X, Yutkin M, Radke CJ. A Two-Phase Model for Adsorption from Solution Using Quartz Crystal Microbalance with Dissipation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10114-10127. [PMID: 35952658 DOI: 10.1021/acs.langmuir.2c00998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Quartz crystal microbalance with dissipation (QCM-D) conveniently monitors mass and mechanical property changes of thin films on solid substrates with exquisite resolution. QCM-D is frequently used to measure dissolved solute/sol adsorption isotherms and kinetics. Unfortunately, currently available methodologies to interpret QCM-D data treat the adlayer as a homogeneous medium, which does not adequately describe solution-adsorption physics. Tethering of the adsorbate to the solid surface is not explicitly recognized, and the liquid solvent is included in the adsorbate mass, which is especially in error for low coverages. Consequently, the areal mass of adsorbate (i.e., solute adsorption) is overestimated. Further, friction is not considered between the bound adsorbate and the free solvent flowing in the adlayer. To overcome these deficiencies, we develop a two-phase (2P) continuum model that self-consistently determines adsorbate and liquid-solvent contributions and includes friction between the attached adsorbate and flowing liquid solvent. We then compare the proposed 2P model to those of Sauerbrey for a rigid adlayer and Voinova et al. for a viscoelastic-liquid adlayer. Effects of 2P-adlayer properties are examined on QCM-D-measured frequency and dissipation shifts, including adsorbate volume fraction and elasticity, adlayer thickness, and overtone number, thereby guiding data interpretation. We demonstrate that distinguishing between adsorbate adsorption and homogeneous-film adsorption is critical; failing to do so leads to incorrect adlayer mass and physical properties.
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Affiliation(s)
- Sarah A Berlinger
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States
| | - Xunkai Chen
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States
| | - Maxim Yutkin
- Energy Resources and Petroleum Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900 Saudi Arabia
| | - Clayton J Radke
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720 United States
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6
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Zheng Y, Dou J, Wang Y, Zhu L, Yao G, Kim YH, Radke CJ, Wu JY. Sustained Release of a Polymeric Wetting Agent from a Silicone-Hydrogel Contact Lens Material. ACS OMEGA 2022; 7:29223-29230. [PMID: 36033690 PMCID: PMC9404521 DOI: 10.1021/acsomega.2c03310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Uptake and release kinetics are investigated of a dilute aqueous polymeric-surfactant wetting agent, (ethylene oxide)45-(butylene oxide)10 copolymer, also referred to as poly(oxyethylene)-co-poly(oxybutylene), impregnated into a newly designed silicone-hydrogel lens material. Transient scanning concentration profiles of the fluorescently tagged polymeric surfactant follow Fick's second law with a diffusion coefficient near 10-11 cm2/s, a value 3-4 orders smaller than that of the free surfactant in bulk water. The Nernst partition coefficient of the tagged polymeric wetting agent, determined by fluorescence microscopy and by methanol extraction, is near 350, a very large value. Back-extraction of the polymeric-surfactant wetting agent releases only ∼20% of the loaded amount after soaking the fully loaded lens for over 7 days. The remaining ∼80% is irreversibly bound in the lens matrix. Reverse-phase liquid chromatography of the lens-loaded and lens-extracted surfactant demonstrates that the released wetting agent is more hydrophilic with a higher polarity. Aqueous poly(oxyethylene)-co-poly(oxybutylene) is hypothesized to attach strongly to the lens matrix, most likely to the lens silicone domains. Strong binding leads to slow transient diffusion, to large uptake, and to significant irreversible retention. These characteristics indicate the suitability of using a poly(oxyethylene)-co-poly(oxybutylene) nonionic polymeric surfactant to maintain enhanced lens wettability over time. Methodology and findings from this study provide useful insights for designing sustained-release contact-lens wetting agents and materials.
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Affiliation(s)
- Ying Zheng
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
| | - Jinbo Dou
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
| | - Yan Wang
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
| | - Lu Zhu
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
| | - George Yao
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
- Alcon
Research LLC, 6201 South
Freeway, Fort Worth, Texas 76134, United States
| | - Young Hyun Kim
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
- Chemical
and Biomolecular Engineering Department, University of California, Berkeley, California 94720, United States
- Herbert
Wertheim School of Optometry & Vision Science, University of California, Berkeley, California 94720, United States
| | - Clayton J. Radke
- Chemical
and Biomolecular Engineering Department, University of California, Berkeley, California 94720, United States
- Herbert
Wertheim School of Optometry & Vision Science, University of California, Berkeley, California 94720, United States
| | - James Yuliang Wu
- Alcon
Research LLC, 11460 Johns
Creek Parkway, Duluth, Georgia 30097, United States
- Alcon
Research LLC, 6201 South
Freeway, Fort Worth, Texas 76134, United States
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7
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Chan D, Chien JC, Axpe E, Blankemeier L, Baker SW, Swaminathan S, Piunova VA, Zubarev DY, Maikawa CL, Grosskopf AK, Mann JL, Soh HT, Appel EA. Combinatorial Polyacrylamide Hydrogels for Preventing Biofouling on Implantable Biosensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022. [PMID: 35390209 DOI: 10.1101/2020.05.25.115675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered "gold-standard" device coatings to reduce biofouling. To discover novel anti-biofouling materials, a combinatorial library of polyacrylamide-based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet-rich plasma in a high-throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti-biofouling properties over current gold-standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti-biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small-molecule drug in vivo better than gold-standard coatings. The novel methodology described enables the discovery of anti-biofouling materials that can extend the lifetime of real-time in vivo sensing devices.
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Affiliation(s)
- Doreen Chan
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Jun-Chau Chien
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Eneko Axpe
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Louis Blankemeier
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Samuel W Baker
- Department of Comparative Medicine, Stanford University, Stanford, CA, 94305, USA
| | | | | | | | - Caitlin L Maikawa
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Abigail K Grosskopf
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Joseph L Mann
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - H Tom Soh
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Eric A Appel
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Department of Pediatrics - Endocrinology, Stanford University School of Medicine, Stanford, CA, 94305, USA
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8
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Chan D, Chien JC, Axpe E, Blankemeier L, Baker SW, Swaminathan S, Piunova VA, Zubarev DY, Maikawa CL, Grosskopf AK, Mann JL, Soh HT, Appel EA. Combinatorial Polyacrylamide Hydrogels for Preventing Biofouling on Implantable Biosensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109764. [PMID: 35390209 PMCID: PMC9793805 DOI: 10.1002/adma.202109764] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/04/2022] [Indexed: 05/29/2023]
Abstract
Biofouling on the surface of implanted medical devices and biosensors severely hinders device functionality and drastically shortens device lifetime. Poly(ethylene glycol) and zwitterionic polymers are currently considered "gold-standard" device coatings to reduce biofouling. To discover novel anti-biofouling materials, a combinatorial library of polyacrylamide-based copolymer hydrogels is created, and their ability is screened to prevent fouling from serum and platelet-rich plasma in a high-throughput parallel assay. It is found that certain nonintuitive copolymer compositions exhibit superior anti-biofouling properties over current gold-standard materials, and machine learning is used to identify key molecular features underpinning their performance. For validation, the surfaces of electrochemical biosensors are coated with hydrogels and their anti-biofouling performance in vitro and in vivo in rodent models is evaluated. The copolymer hydrogels preserve device function and enable continuous measurements of a small-molecule drug in vivo better than gold-standard coatings. The novel methodology described enables the discovery of anti-biofouling materials that can extend the lifetime of real-time in vivo sensing devices.
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Affiliation(s)
- Doreen Chan
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Jun-Chau Chien
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Eneko Axpe
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Louis Blankemeier
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Samuel W Baker
- Department of Comparative Medicine, Stanford University, Stanford, CA, 94305, USA
| | | | | | | | - Caitlin L Maikawa
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Abigail K Grosskopf
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Joseph L Mann
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - H Tom Soh
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Eric A Appel
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- ChEM-H Institute, Stanford University, Stanford, CA, 94304, USA
- Department of Pediatrics - Endocrinology, Stanford University School of Medicine, Stanford, CA, 94305, USA
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9
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Zhao C, Pan B, Wang M, Si Y, Taha AY, Liu G, Pan T, Sun G. Improving the Sensitivity of Nanofibrous Membrane-Based ELISA for On-Site Antibiotics Detection. ACS Sens 2022; 7:1458-1466. [PMID: 35426310 DOI: 10.1021/acssensors.2c00208] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An ultrasensitive and portable colorimetric enzyme-linked immunosorbent assay (ELISA) sensor for antibiotics was fabricated by immobilizing antibodies inside the largely porous and highly hydrophilic nanofibrous membranes. Different from regular electrospun nanofibrous membranes where antibodies may frequently be blocked by the heterogeneous porous structure and sterically crowded loaded on the surface, the controlled microporous structure and increased hydrophilicity of nanofibrous membranes could improve the diffusion properties of antibodies, reduce the sterically crowding effect, and dramatically improve the sensitivity of the membrane-based ELISA. The limitation of detection (LOD) for chloramphenicol (CAP) reached 0.005 ng/mL, around 200 times lower than the conventional paper-based ELISA, making quantitative analysis and portable on-site detection achievable via the use of smartphones. The successful design and fabrication of the nanofibrous membrane-based ELISA with novel features overcome the structural drawbacks of regular electrospun nanofibrous membranes and provide new paths to develop highly sensitive on-site detection of hazardous chemical agents.
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Affiliation(s)
- Cunyi Zhao
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
| | - Bofeng Pan
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
| | - Minyuan Wang
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616, United States
| | - Yang Si
- Innovation Center for Textile Science and Technology, College of Textiles, Donghua University, Shanghai 201620, China
| | - Ameer Y Taha
- Department of Food Science and Technology, University of California, Davis, California 95616, United States
| | - Gangyu Liu
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616, United States
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Tingrui Pan
- Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
| | - Gang Sun
- Department of Biological and Agricultural Engineering, University of California, Davis, California 95616, United States
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10
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Richbourg NR, Peppas NA. High-Throughput FRAP Analysis of Solute Diffusion in Hydrogels. Macromolecules 2021; 54:10477-10486. [DOI: 10.1021/acs.macromol.1c01752] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nathan R. Richbourg
- Department of Biomedical Engineering, University of Texas, Austin, Texas 78712, United States
| | - Nicholas A. Peppas
- Department of Biomedical Engineering, University of Texas, Austin, Texas 78712, United States
- McKetta Department of Chemical Engineering, University of Texas, Austin, Texas 78712, United States
- Division of Molecular Therapeutics and Drug Delivery, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
- Departments of Surgery and Pediatrics, Dell Medical School, University of Texas, Austin, Texas 78712, United States
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11
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Protection against corneal hyperosmolarity with soft-contact-lens wear. Prog Retin Eye Res 2021; 87:101012. [PMID: 34597771 DOI: 10.1016/j.preteyeres.2021.101012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 01/03/2023]
Abstract
Hyperosmotic tear stimulates human corneal nerve endings, activates ocular immune response, and elicits dry-eye symptoms. A soft contact lens (SCL) covers the cornea preventing it from experiencing direct tear evaporation and the resulting blink-periodic salinity increases. For the cornea to experience hyperosmolarity due to tear evaporation, salt must transport across the SCL to the post-lens tear film (PoLTF) bathing the cornea. Consequently, limited salt transport across a SCL potentially protects the ocular surface from hyperosmotic tear. In addition, despite lens-wear discomfort sharing common sensations to dry eye, no correlation is available between measured tear hyperosmolarity and SCL-wear discomfort. Lack of documentation is likely because clinical measurements of tear osmolarity during lens wear do not interrogate the tear osmolarity of the PoLTF that actually overlays the cornea. Rather, tear osmolarity is clinically measured in the tear meniscus. For the first time, we mathematically quantify tear osmolarity in the PoLTF and show that it differs significantly from the clinically measured tear-meniscus osmolarity. We show further that aqueous-deficient dry eye and evaporative dry eye both exacerbate the hyperosmolarity of the PoLTF. Nevertheless, depending on lens salt-transport properties (i.e., diffusivity, partition coefficient, and thickness), a SCL can indeed protect against corneal hyperosmolarity by reducing PoLTF salinity to below that of the ocular surface during no-lens wear. Importantly, PoLTF osmolarity for dry-eye patients can be reduced to that of normal eyes with no-lens wear provided that the lens exhibits a low lens-salt diffusivity. Infrequent blinking increases PoLTF osmolarity consistent with lens-wear discomfort. Judicious design of SCL material salt-transport properties can ameliorate corneal hyperosmolarity. Our results confirm the importance of PoLTF osmolarity during SCL wear and indicate a possible relation between PoLTF osmolarity and contact-lens discomfort.
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12
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Wang X, Jia P, Sun S, He X, Lu TJ, Xu F, Feng S. Evaporation-Induced Diffusion Acceleration in Liquid-Filled Porous Materials. ACS OMEGA 2021; 6:21646-21654. [PMID: 34471768 PMCID: PMC8388088 DOI: 10.1021/acsomega.1c03052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Liquid-filled porous materials exist widely in nature and engineering fields, with the diffusion of substances in them playing an important role in system functions. Although surface evaporation is often inevitable in practical scenarios, the evaporation effects on diffusion behavior in liquid-filled porous materials have not been well explored yet. In this work, we performed noninvasive diffusion imaging experiments to observe the diffusion process of erioglaucine disodium salt dye in a liquid-filled nitrocellulose membrane under a wide range of relative humidities (RHs). We found that evaporation can significantly accelerate the diffusion rate and alter concentration distribution compared with the case without evaporation. We explained the accelerated diffusion phenomenon by the mechanism that evaporation would induce a weak flow in liquid-filled porous materials, which leads to convective diffusion, i.e., evaporation-induced flow and diffusion (EIFD). Based on the EIFD mechanism, we proposed a convective diffusion model to quantitatively predict the diffusion process in liquid-filled porous materials under evaporation and experimentally validated the model. Introducing the dimensionless Peclet (P e) number to measure the relative contribution of the evaporation effect to pure molecular diffusion, we demonstrated that even at a high RH of 95%, where the evaporation effect is usually assumed negligible in common sense, the evaporation-induced diffusion still overwhelms the molecular diffusion. The flow velocity induced by evaporation in liquid-filled porous materials was found to be 0.4-5 μm/s, comparable to flow in many biological and biomedical systems. The present analysis may help to explain the driving mechanism of tissue perfusion and provide quantitative analysis or inspire new control methods of flow and material exchange in numerous cutting-edge technologies, such as paper-based diagnostics, hydrogel-based flexible electronics, evaporation-induced electricity generation, and seawater purification.
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Affiliation(s)
- Xuefeng Wang
- The
Key Laboratory of Biomedical Information Engineering of Ministry of
Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, P. R. China
- Bioinspired
Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an 710049, P.
R. China
| | - Pengpeng Jia
- The
Key Laboratory of Biomedical Information Engineering of Ministry of
Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, P. R. China
- Bioinspired
Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an 710049, P.
R. China
| | - Shanyouming Sun
- Bioinspired
Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an 710049, P.
R. China
| | - Xiaocong He
- The
Key Laboratory of Biomedical Information Engineering of Ministry of
Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, P. R. China
- Bioinspired
Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an 710049, P.
R. China
| | - Tian Jian Lu
- State
Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P. R. China
- Nanjing
Center for Multifunctional Lightweight Materials and Structures (MLMS), Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P. R. China
| | - Feng Xu
- The
Key Laboratory of Biomedical Information Engineering of Ministry of
Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, P. R. China
- Bioinspired
Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an 710049, P.
R. China
| | - Shangsheng Feng
- The
Key Laboratory of Biomedical Information Engineering of Ministry of
Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, P. R. China
- Bioinspired
Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an 710049, P.
R. China
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13
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Richbourg NR, Ravikumar A, Peppas NA. Solute Transport Dependence on 3D Geometry of Hydrogel Networks. MACROMOL CHEM PHYS 2021; 222:2100138. [PMID: 34456531 PMCID: PMC8389770 DOI: 10.1002/macp.202100138] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Indexed: 11/11/2022]
Abstract
Hydrogels are used in drug delivery applications, chromatography, and tissue engineering to control the rate of solute transport based on solute size and hydrogel-solute affinity. Ongoing modeling efforts to quantify the relationship between hydrogel properties, solute properties, and solute transport contribute toward an increasingly efficient hydrogel design process and provide fundamental insight into the mechanisms relating hydrogel structure and function. However, here we clarify previous conclusions regarding the use of mesh size in hydrogel transport models. We use 3D geometry and hydrogel network visualizations to show that mesh size and junction functionality both contribute to the mesh radius, which determines whether a solute can diffuse within a hydrogel. Using mesh radius instead of mesh size to model solute transport in hydrogels will correct junction functionality-dependent modeling errors, improving hydrogel design predictions and clarifying mechanisms of solute transport in hydrogels.
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Affiliation(s)
- Nathan R. Richbourg
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
| | - Akhila Ravikumar
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
| | - Nicholas A. Peppas
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX 78712, USA
- Division of Molecular Therapeutics and Drug Delivery, College of Pharmacy, University of Texas, Austin, TX 78712, USA
- Departments of Surgery and Pediatrics, Dell Medical School, University of Texas, Austin, TX 78712, USA
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14
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Mazzarotta A, Caputo TM, Raiola L, Battista E, Netti PA, Causa F. Small Oligonucleotides Detection in Three-Dimensional Polymer Network of DNA-PEG Hydrogels. Gels 2021; 7:90. [PMID: 34287281 PMCID: PMC8293047 DOI: 10.3390/gels7030090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 11/23/2022] Open
Abstract
The control of the three-dimensional (3D) polymer network structure is important for permselective materials when specific biomolecule detection is needed. Here we investigate conditions to obtain a tailored hydrogel network that combines both molecular filtering and molecular capture capabilities for biosensing applications. Along this line, short oligonucleotide detection in a displacement assay is set within PEGDA hydrogels synthetized by UV radical photopolymerization. To provide insights on the molecular filter capability, diffusion studies of several probes (sulforhodamine G and dextrans) with different hydrodynamic radii were carried out using NMR technique. Moreover, fluorometric analyses of hybridization of DNA oligonucleotides inside PEGDA hydrogels shed light on the mechanisms of recognition in 3D, highlighting that mesh size and crowding effect greatly impact the hybridization mechanism on a polymer network. Finally, we found the best probe density and diffusion transport conditions to allow the specific oligonucleotide capture and detection inside PEGDA hydrogels for oligonucleotide detection and the filtering out of higher molecular weight molecules.
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Affiliation(s)
- Alessia Mazzarotta
- Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano di Tecnologia (IIT), Largo Barsanti e Matteucci 53, 80125 Naples, Italy; (A.M.); (T.M.C.); (L.R.); (P.A.N.)
| | - Tania Mariastella Caputo
- Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano di Tecnologia (IIT), Largo Barsanti e Matteucci 53, 80125 Naples, Italy; (A.M.); (T.M.C.); (L.R.); (P.A.N.)
| | - Luca Raiola
- Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano di Tecnologia (IIT), Largo Barsanti e Matteucci 53, 80125 Naples, Italy; (A.M.); (T.M.C.); (L.R.); (P.A.N.)
| | - Edmondo Battista
- Interdisciplinary Research Centre on Biomaterials (CRIB), Università degli Studi di Napoli “Federico II”, Piazzale Tecchio 80, 80125 Naples, Italy;
| | - Paolo Antonio Netti
- Center for Advanced Biomaterials for Healthcare@CRIB, Istituto Italiano di Tecnologia (IIT), Largo Barsanti e Matteucci 53, 80125 Naples, Italy; (A.M.); (T.M.C.); (L.R.); (P.A.N.)
- Interdisciplinary Research Centre on Biomaterials (CRIB), Università degli Studi di Napoli “Federico II”, Piazzale Tecchio 80, 80125 Naples, Italy;
- Dipartimento di Ingegneria Chimica del Materiali e della Produzione Industriale (DICMAPI), University “Federico II”, Piazzale Tecchio 80, 80125 Naples, Italy
| | - Filippo Causa
- Interdisciplinary Research Centre on Biomaterials (CRIB), Università degli Studi di Napoli “Federico II”, Piazzale Tecchio 80, 80125 Naples, Italy;
- Dipartimento di Ingegneria Chimica del Materiali e della Produzione Industriale (DICMAPI), University “Federico II”, Piazzale Tecchio 80, 80125 Naples, Italy
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15
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Badugu R, Szmacinski H, Reece EA, Jeng BH, Lakowicz JR. Sodium-Sensitive Contact Lens for Diagnostics of Ocular Pathologies. SENSORS AND ACTUATORS. B, CHEMICAL 2021; 331:129434. [PMID: 33551571 PMCID: PMC7861470 DOI: 10.1016/j.snb.2021.129434] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The ability to measure all the electrolyte concentrations in tears would be valuable in ophthalmology for research and diagnosis of dry eye disease (DED) and other ocular pathologies. However, tear samples are difficult to collect and analyze because the total volume is small and the chemical composition changes rapidly. Measurements of electrolytes in tears is challenging because typical clinical assays for proteins and other biomarkers cannot be used to detect ion concentrations tears. Here, we report the contact lens which is sensitive to sodium ion (Na+), one of the dominant electrolytes in tears. The Na ions in tears is diagnostic for DED. Three sodium-sensitive fluorophores (SG-C16, SG-LPE and SG-PL) were synthesized by derivatizing the sodium green with 1-hexadecyl amine, 1-oleoyl-2-hydroxy-sn-glycero-3-phosphoethanolamine or poly-L-lysine, respectively. These probes were bound to modern silicone hydrogel (SiHG) contact lens, Biofinity from Cooper Vision. Doped lenses were tested for sodium ion dependent spectral properties of probes within the contact lens. The probes displayed changes in intensity and lifetime in response to Na+ concentration, were completely reversible, no significant probe wash-out from the lenses, were not affected by proteins in tears and were not removed after repeated washing. These results are the first step to our long-term goal, which is a lens sensitive to all the electrolytes in tears. We presented design, synthesis and implementation of three new sodium sensitive probes within a silicon hydrogel lens. Contact lenses to measure the other electrolytes in tears can be developed using the same approach by synthesis and testing of new ion-sensitive fluorophores.
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Affiliation(s)
- Ramachandram Badugu
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology University of Maryland School of Medicine, 725 West Lombard St., Baltimore, MD 21201, USA
| | - Henryk Szmacinski
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology University of Maryland School of Medicine, 725 West Lombard St., Baltimore, MD 21201, USA
| | - E Albert Reece
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, Md 21201, USA
| | - Bennie H Jeng
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, 419 W. Redwood Street, Baltimore, Md 21201, USA
| | - Joseph R Lakowicz
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology University of Maryland School of Medicine, 725 West Lombard St., Baltimore, MD 21201, USA
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16
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Zhao C, Si Y, Zhu S, Bradley K, Taha AY, Pan T, Sun G. Diffusion of Protein Molecules through Microporous Nanofibrous Polyacrylonitrile Membranes. ACS APPLIED POLYMER MATERIALS 2021; 3:1618-1627. [PMID: 34541542 PMCID: PMC8445001 DOI: 10.1021/acsapm.0c01394] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Porous nanofibrous membranes have ultrahigh specific surface areas and could be broadly employed in protein purification, enzyme immobilization, and biosensors with enhanced selectivity, sensitivity, and efficiency. However, large biomolecules, such as proteins, have hindered diffusion behavior in the micro-porous media, significantly reducing the benefits provided by the nanofibrous membranes. The study of protein diffusion in polyacrylonitrile (PAN) nanofibrous membranes produced under varied humidity and polymer concentration of electrospinning revealed that heterogeneous structures of the nanofibrous membranes possess much smaller effective pore sizes than the measured pore sizes, which significantly affects the diffusion of large molecules through the system though sizes of proteins and pH conditions also have great impacts. Only when the measured membrane pore size is at least 1000 times higher than the protein size, the diffusion behavior of the protein is predictable in the system. The results provide insights into the design and applications of proper nanofibrous materials for improved applications in protein purification and immobilizations.
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Affiliation(s)
- Cunyi Zhao
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
| | - Yang Si
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
| | - Shenghan Zhu
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
| | - Kevin Bradley
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
| | - Ameer Y Taha
- Department of Food Science and Technology, University of California, Davis, CA 95616, USA
| | - Tingrui Pan
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Gang Sun
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
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17
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Quesada-Pérez M, Martín-Molina A. Solute diffusion in gels: Thirty years of simulations. Adv Colloid Interface Sci 2021; 287:102320. [PMID: 33296722 DOI: 10.1016/j.cis.2020.102320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/20/2020] [Accepted: 11/16/2020] [Indexed: 12/17/2022]
Abstract
In this review, we present a summary of computer simulation studies on solute diffusion in gels carried out in the last three decades. Special attention is paid to coarse-grained simulations in which the role of steric and electrostatic interactions on the particle diffusion can be evaluated. In addition, other important characteristics of particle diffusion in gels, such as the stiffness of the gel structure and hydrodynamic interactions, can be taken into account through coarse-grained simulations. Emphasis is placed on how simulation results help to test phenomenological models and to improve the interpretation interof experimental results. Finally, coarse-grained simulations have also been employed to study the diffusion controlled release of drugs from gels. We believe that scientific advances in this line will be useful to better understand the mechanisms that control the diffusive transport of molecules in a wide variety of biological systems.
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Affiliation(s)
- Manuel Quesada-Pérez
- Departamento de Física, Escuela Politécnica Superior de Linares, Universidad de Jaén, Linares, 23700 Jaén, Spain
| | - Alberto Martín-Molina
- Departamento de Física Aplicada, Universidad de Granada, Campus de Fuentenueva sn, 18071 Granada, Spain; Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, Campus de Fuentenueva sn, 18071 Granada, Spain.
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18
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Multi-region finite element modelling of drug release from hydrogel based ophthalmic lenses. Math Biosci 2020; 331:108497. [PMID: 33098846 DOI: 10.1016/j.mbs.2020.108497] [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: 06/27/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/28/2022]
Abstract
Understanding the way in which drug is released from drug carrying hydrogel based ophthalmic lenses aids in the development of efficient ophthalmic drug delivery. Various solute-polymer interactions affect solute diffusion within hydrogels as well as hydrogel-bulk partitioning. Additionally, surface modifications or coatings may add to resistance of mass transfer across the hydrogel interface. It is necessary to consider both interfacial resistances as well as the appropriate driving force when characterizing interface flux. Such a driving force is induced by a difference in concentration which deviates from equilibrium conditions. We present a Galerkin finite element approach for solute transport in hydrogels which accounts for diffusion within the gel, storage effects due to polymer-solute interaction, as well as partitioning and mass transfer resistance effects at the interface. The approach is formulated using a rotational symmetric model to account for realistic geometry. We show that although the resulting global system is not symmetric in the case of partitioning, it is similar to a symmetric negative semidefinite system. Thus, it has non-positive real eigenvalues and is coercive, ensuring the validity of the finite element formulation as well as the numerical stability of the implicit backward Euler time integration method employed. Two models demonstrating this approach are presented and verified with release experimental data. The first is the release of moxifloxacin from intraocular lenses (IOLs) plasma grafted with different polyacrylates. The second accounts for both loading as well as the release of diclofenac from disc shaped IOL material loaded for varied time periods and temperature.
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19
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Mineart KP, Walker WW, Mogollon‐Santiana J, Lee B. A Fourier transform infrared spectroscopy‐
based
method for tracking diffusion in organogels. JOURNAL OF POLYMER SCIENCE 2020. [DOI: 10.1002/pol.20200144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Kenneth P. Mineart
- Department of Chemical Engineering Bucknell University Lewisburg Pennsylvania USA
| | - William W. Walker
- Department of Chemical Engineering Bucknell University Lewisburg Pennsylvania USA
| | | | - Byeongdu Lee
- X‐ray Science Division, Argonne National Laboratory Lemont Illinois USA
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20
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Li S, Chen Z, Wang J, Yan L, Chen T, Zeng Q. Fabrication and characterization of a novel semi-interpenetrating network hydrogel based on sodium carboxymethyl cellulose and poly(methacrylic acid) for oral insulin delivery. J Biomater Appl 2020; 35:3-14. [PMID: 32216507 DOI: 10.1177/0885328220912843] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this research, pH-sensitive semi-interpenetrating polymer network hydrogels based on sodium carboxymethyl cellulose and poly(methacrylic acid) were synthesized using free radical polymerization and semi-interpenetrating polymer network approach for oral administration of insulin. The chemical structure and thermal stability of the hydrogels were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis measurements. The interior morphology was observed by scanning electron microscopy and the inner structure exhibited a porous honeycomb-like shape. The investigations on the swelling properties of hydrogels revealed their ability to response to pH value change. The in vitro release behavior of insulin was pH dependent and the release of insulin was much lower at pH 1.2 compared to pH 6.8. In vitro cytotoxicity assay indicated that the hydrogels were noncytotoxic to HeLa cells. A sustained reduction in blood glucose level was observed after oral administration of insulin-loaded hydrogel to diabetic rats at 75 IU/kg. These results indicated that the hydrogel would be a promising vehicle for oral insulin delivery systems.
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Affiliation(s)
- Shunying Li
- Biomaterial Research Center, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Zhiru Chen
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Jun Wang
- Biomaterial Research Center, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Libiao Yan
- Biomaterial Research Center, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Tingting Chen
- Biomaterial Research Center, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Qingbing Zeng
- Biomaterial Research Center, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
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21
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Axpe E, Chan D, Offeddu GS, Chang Y, Merida D, Hernandez HL, Appel EA. A Multiscale Model for Solute Diffusion in Hydrogels. Macromolecules 2019; 52:6889-6897. [PMID: 31579160 PMCID: PMC6764024 DOI: 10.1021/acs.macromol.9b00753] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 08/13/2019] [Indexed: 12/27/2022]
Abstract
The number of biomedical applications of hydrogels is increasing rapidly on account of their unique physical, structural, and mechanical properties. The utility of hydrogels as drug delivery systems or tissue engineering scaffolds critically depends on the control of diffusion of solutes through the hydrogel matrix. Predicting or even modeling this diffusion is challenging due to the complex structure of hydrogels. Currently, the diffusivity of solutes in hydrogels is typically modeled by one of three main theories proceeding from distinct diffusion mechanisms: (i) hydrodynamic, (ii) free volume, and (iii) obstruction theory. Yet, a comprehensive predictive model is lacking. Thus, time and capital-intensive trial-and-error procedures are used to test the viability of hydrogel applications. In this work, we have developed a model for the diffusivity of solutes in hydrogels combining the three main theoretical frameworks, which we call the multiscale diffusion model (MSDM). We verified the MSDM by analyzing the diffusivity of dextran of different sizes in a series of poly(ethylene glycol) (PEG) hydrogels with distinct mesh sizes. We measured the subnanoscopic free volume by positron annihilation lifetime spectroscopy (PALS) to characterize the physical hierarchy of these materials. In addition, we performed a meta-analysis of literature data from previous studies on the diffusion of solutes in hydrogels. The model presented outperforms traditional models in predicting solute diffusivity in hydrogels and provides a practical approach to predicting the transport properties of solutes such as drugs through hydrogels used in many biomedical applications.
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Affiliation(s)
- Eneko Axpe
- Department
of Materials Science & Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, United States
- Space
Biosciences Division, NASA-Ames Research Center, Moffett Field, California 94035, United States
| | - Doreen Chan
- Department
of Materials Science & Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, United States
| | - Giovanni S. Offeddu
- Department
of Biological Engineering, Massachusetts
Institute of Technology, 500 Technology Square, Cambridge, Massachusetts 02138, United States
| | - Yin Chang
- Department
of Engineering, Cambridge University, 11 JJ Thomson Ave., Cambridge CB3 0FF, U.K.
| | - David Merida
- Department
of Electricity and Electronics, University
of the Basque Country UPV/EHU, Sarriena s/n, Bilbao 48940, Spain
| | - Hector Lopez Hernandez
- Department
of Materials Science & Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, United States
| | - Eric A. Appel
- Department
of Materials Science & Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, United States
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22
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Taylor NO, Wei MT, Stone HA, Brangwynne CP. Quantifying Dynamics in Phase-Separated Condensates Using Fluorescence Recovery after Photobleaching. Biophys J 2019; 117:1285-1300. [PMID: 31540706 DOI: 10.1016/j.bpj.2019.08.030] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/20/2019] [Accepted: 08/22/2019] [Indexed: 12/22/2022] Open
Abstract
Cells contain numerous membraneless organelles that assemble by intracellular liquid-liquid phase separation. The viscous properties and associated biomolecular mobility within these condensed phase droplets, or condensates, are increasingly recognized as important for cellular function and also dysfunction, for example, in protein aggregation pathologies. Fluorescence recovery after photobleaching (FRAP) is widely used to assess condensate fluidity and to estimate protein diffusion coefficients. However, the models and assumptions utilized in FRAP analysis of protein condensates are often not carefully considered. Here, we combine FRAP experiments on both in vitro reconstituted droplets and intracellular condensates with systematic examination of different models that can be used to fit the data and evaluate the impact of model choice on measured values. A key finding is that model boundary conditions can give rise to widely divergent measured values. This has important implications, for example, in experiments that bleach subregions versus the entire condensate, two commonly employed experimental approaches. We suggest guidelines for determining the appropriate modeling framework and highlight emerging questions about the molecular dynamics at the droplet interface. The ability to accurately determine biomolecular mobility both in the condensate interior and at the interface is important for obtaining quantitative insights into condensate function, a key area for future research.
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Affiliation(s)
| | - Ming-Tzo Wei
- Department of Chemical and Biological Engineering
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering; Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey.
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23
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Network structure and enzymatic degradation of chitosan hydrogels determined by crosslinking methods. Carbohydr Polym 2019; 217:160-167. [DOI: 10.1016/j.carbpol.2019.04.055] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 04/04/2019] [Accepted: 04/15/2019] [Indexed: 01/29/2023]
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24
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Optimization of intraocular lens hydrogels for dual drug release: Experimentation and modelling. Eur J Pharm Biopharm 2019; 141:51-57. [DOI: 10.1016/j.ejpb.2019.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 02/06/2023]
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25
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Sen-Britain S, Hicks WL, Hard R, Gardella JA. Differential orientation and conformation of surface-bound keratinocyte growth factor on (hydroxyethyl)methacrylate, (hydroxyethyl)methacrylate/methyl methacrylate, and (hydroxyethyl)methacrylate/methacrylic acid hydrogel copolymers. Biointerphases 2018; 13:06E406. [PMID: 30360629 PMCID: PMC6905655 DOI: 10.1116/1.5051655] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/27/2018] [Accepted: 10/03/2018] [Indexed: 01/12/2023] Open
Abstract
The development of hydrogels for protein delivery requires protein-hydrogel interactions that cause minimal disruption of the protein's biological activity. Biological activity can be influenced by factors such as orientational accessibility for receptor binding and conformational changes, and these factors can be influenced by the hydrogel surface chemistry. (Hydroxyethyl)methacrylate (HEMA) hydrogels are of interest as drug delivery vehicles for keratinocyte growth factor (KGF) which is known to promote re-epithelialization in wound healing. The authors report here the surface characterization of three different HEMA hydrogel copolymers and their effects on the orientation and conformation of surface-bound KGF. In this work, they characterize two copolymers in addition to HEMA alone and report how protein orientation and conformation is affected. The first copolymer incorporates methyl methacrylate (MMA), which is known to promote the adsorption of protein to its surface due to its hydrophobicity. The second copolymer incorporates methacrylic acid (MAA), which is known to promote the diffusion of protein into its surface due to its hydrophilicity. They find that KGF at the surface of the HEMA/MMA copolymer appears to be more orientationally accessible and conformationally active than KGF at the surface of the HEMA/MAA copolymer. They also report that KGF at the surface of the HEMA/MAA copolymer becomes conformationally unfolded, likely due to hydrogen bonding. KGF at the surface of these copolymers can be differentiated by Fourier-transform infrared-attenuated total reflectance spectroscopy and time-of-flight secondary ion mass spectrometry in conjunction with principal component analysis. The differences in KGF orientation and conformation between these copolymers may result in different biological responses in future cell-based experiments.
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Affiliation(s)
- Shohini Sen-Britain
- Department of Chemistry, State University of New York at Buffalo, 475 Natural Sciences Complex, Buffalo, New York 14221
| | - Wesley L Hicks
- Department of Head and Neck/Plastic and Reconstructive Surgery, Roswell Comprehensive Cancer Center, 665 Elm Street, Buffalo, New York 14203
| | - Robert Hard
- Department of Pathological and Anatomical Sciences, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, 955 Main St, Buffalo, New York 14203
| | - Joseph A Gardella
- Department of Chemistry, State University of New York at Buffalo, 475 Natural Sciences Complex, Buffalo, New York 14221
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26
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Yang YJ, Mai DJ, Dursch TJ, Olsen BD. Nucleopore-Inspired Polymer Hydrogels for Selective Biomolecular Transport. Biomacromolecules 2018; 19:3905-3916. [DOI: 10.1021/acs.biomac.8b00556] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Yun Jung Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Danielle J. Mai
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Thomas J. Dursch
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Bradley D. Olsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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27
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Parrish E, Caporizzo MA, Composto RJ. Network confinement and heterogeneity slows nanoparticle diffusion in polymer gels. J Chem Phys 2017; 146:203318. [DOI: 10.1063/1.4978054] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Emmabeth Parrish
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, USA
| | - Matthew A. Caporizzo
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, USA
| | - Russell J. Composto
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, USA
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28
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Zhou Y, Li J, Zhang Y, Dong D, Zhang E, Ji F, Qin Z, Yang J, Yao F. Establishment of a Physical Model for Solute Diffusion in Hydrogel: Understanding the Diffusion of Proteins in Poly(sulfobetaine methacrylate) Hydrogel. J Phys Chem B 2017; 121:800-814. [DOI: 10.1021/acs.jpcb.6b10355] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
| | - Junjie Li
- Department
of Advanced Interdisciplinary Studies, Institute of Basic Medical
Sciences and Tissue Engineering Research Center, Academy of Military Medical Sciences, Beijing 100850, China
| | | | | | | | | | | | - Jun Yang
- The
Key Laboratory of Bioactive Materials, Ministry of Education, College
of Life Science, Nankai University, Tianjin 300071, China
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Controlled drug release from hydrogels for contact lenses: Drug partitioning and diffusion. Int J Pharm 2016; 515:467-475. [PMID: 27789366 DOI: 10.1016/j.ijpharm.2016.10.047] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 10/21/2016] [Accepted: 10/22/2016] [Indexed: 11/21/2022]
Abstract
Optimization of drug delivery from drug loaded contact lenses assumes understanding the drug transport mechanisms through hydrogels which relies on the knowledge of drug partition and diffusion coefficients. We chose, as model systems, two materials used in contact lens, a poly-hydroxyethylmethacrylate (pHEMA) based hydrogel and a silicone based hydrogel, and three drugs with different sizes and charges: chlorhexidine, levofloxacin and diclofenac. Equilibrium partition coefficients were determined at different ionic strength and pH, using water (pH 5.6) and PBS (pH 7.4). The measured partition coefficients were related with the polymer volume fraction in the hydrogel, through the introduction of an enhancement factor following the approach developed by the group of C. J. Radke (Kotsmar et al., 2012; Liu et al., 2013). This factor may be decomposed in the product of three other factors EHS, Eel and Ead which account for, respectively, hard-sphere size exclusion, electrostatic interactions, and specific solute adsorption. While EHS and Eel are close to 1, Ead>>1 in all cases suggesting strong specific interactions between the drugs and the hydrogels. Adsorption was maximal for chlorhexidine on the silicone based hydrogel, in water, due to strong hydrogen bonding. The effective diffusion coefficients, De, were determined from the drug release profiles. Estimations of diffusion coefficients of the non-adsorbed solutes D=De×Ead allowed comparison with theories for solute diffusion in the absence of specific interaction with the polymeric membrane.
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Liu DE, Dursch TJ, Taylor NO, Chan SY, Bregante DT, Radke CJ. Diffusion of water-soluble sorptive drugs in HEMA/MAA hydrogels. J Control Release 2016; 239:242-8. [PMID: 27565214 DOI: 10.1016/j.jconrel.2016.08.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/21/2016] [Accepted: 08/22/2016] [Indexed: 11/19/2022]
Abstract
We measure and, for the first time, theoretically predict four prototypical aqueous-drug diffusion coefficients in five soft-contact-lens material hydrogels where solute-specific adsorption is pronounced. Two-photon fluorescence confocal microscopy and UV/Vis-absorption spectrophotometry assess transient solute concentration profiles and concentration histories, respectively. Diffusion coefficients are obtained for acetazolamide, riboflavin, sodium fluorescein, and theophylline in 2-hydroxyethyl methacrylate/methacrylic acid (HEMA/MAA) copolymer hydrogels as functions of composition, equilibrium water content (30-90%), and aqueous pH (2 and 7.4). At pH2, MAA chains are nonionic, whereas at pH7.4, MAA chains are anionic (pKa≈5.2). All studied prototypical drugs specifically interact with HEMA and nonionic MAA (at pH2) moieties. Conversely, none of the prototypical drugs adsorb specifically to anionic MAA (at pH7.4) chains. As expected, diffusivities of adsorbing solutes are significantly diminished by specific interactions with hydrogel strands. Despite similar solute size, relative diffusion coefficients in the hydrogels span several orders of magnitude because of varying degrees of solute interactions with hydrogel-polymer chains. To provide a theoretical framework for the new diffusion data, we apply an effective-medium model extended for solute-specific interactions with hydrogel copolymer strands. Sorptive-diffusion kinetics is successfully described by local equilibrium and Henry's law. All necessary parameters are determined independently. Predicted diffusivities are in good agreement with experiment.
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Affiliation(s)
- D E Liu
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States
| | - T J Dursch
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States
| | - N O Taylor
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States
| | - S Y Chan
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States
| | - D T Bregante
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States
| | - C J Radke
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, CA 94720, United States; Vision Science Group, University of California, Berkeley, CA 94720, United States.
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Affiliation(s)
- Chia-Chun Lin
- Department of Materials Science
and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, United States
| | - Emmabeth Parrish
- Department of Materials Science
and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, United States
| | - Russell J. Composto
- Department of Materials Science
and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6272, United States
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Wagner D, Burbach J, Grünzweig C, Hartmann S, Lehmann E, Egelhaaf SU, Hermes HE. Solvent and solute ingress into hydrogels resolved by a combination of imaging techniques. J Chem Phys 2016; 144:204903. [DOI: 10.1063/1.4950954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Liu H, Hu J, Yang X, Chen S, Cui H. Preparation and characterization of dual-responsive spiropyran-based random copolymer brushes via surface-initiated atom transfer radical polymerization. Des Monomers Polym 2016. [DOI: 10.1080/15685551.2015.1136536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Hui Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha, P.R. China
| | - Jin Hu
- College of Chemistry and Chemical Engineering, Central South University, Changsha, P.R. China
| | - Xinwei Yang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, P.R. China
| | - Si Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha, P.R. China
| | - Huanqing Cui
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, P.R. China
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Rossi F, Castiglione F, Ferro M, Marchini P, Mauri E, Moioli M, Mele A, Masi M. Drug-Polymer Interactions in Hydrogel-based Drug-Delivery Systems: An Experimental and Theoretical Study. Chemphyschem 2015; 16:2818-2825. [DOI: 10.1002/cphc.201500526] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 12/19/2022]
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Abstract
PURPOSE We developed an in vitro model-blink cell that reproduces the mechanism of in vivo fouling of soft contact lenses. In the model-blink cell, model tear lipid directly contacts the lens surface after forced aqueous rupture, mirroring the pre-lens tear-film breakup during interblink. METHODS Soft contact lenses are attached to a Teflon holder and immersed in artificial tear solution with protein, salts, and mucins. Artificial tear-lipid solution is spread over the air/tear interface as a duplex lipid layer. The aqueous tear film is periodically ruptured and reformed by withdrawing and reinjecting tear solution into the cell, mimicking the blink-rupture process. Fouled deposits appear on the lenses after cycling, and their compositions and spatial distributions are subsequently analyzed by optical microscopy, laser ablation electrospray ionization mass spectrometry, and two-photon fluorescence confocal scanning laser microscopy. RESULTS Discrete deposit (white) spots with an average size of 20 to 300 μm are observed on the studied lenses, confirming what is seen in vivo and validating the in vitro model-blink cell. Targeted lipids (cholesterol) and proteins (albumin from bovine serum) are identified in the discrete surface deposits. Both lipid and protein occur simultaneously in the surface deposits and overlap with the white spots observed by optical microscopy. Additionally, lipid and protein penetrate into the bulk of tested silicone-hydrogel lenses, likely attributed to the bicontinuous microstructure of oleophilic silicone and hydrophilic polymer phases of the lens. CONCLUSIONS In vitro spoilation of soft contact lenses is successfully achieved by the model-blink cell confirming the tear rupture/deposition mechanism of lens fouling. The model-blink cell provides a reliable laboratory tool for screening new antifouling lens materials, surface coatings, and care solutions.
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Equilibrium water and solute uptake in silicone hydrogels. Acta Biomater 2015; 18:112-7. [PMID: 25725471 DOI: 10.1016/j.actbio.2015.02.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/05/2015] [Accepted: 02/19/2015] [Indexed: 11/21/2022]
Abstract
Equilibrium water content of and solute partitioning in silicone hydrogels (SiHys) are investigated using gravimetric analysis, fluorescence confocal laser-scanning microscopy (FCLSM), and back extraction with UV/Vis-absorption spectrophotometry. Synthesized silicone hydrogels consist of silicone monomer, hydrophilic monomer, cross-linking agent, and triblock-copolymer macromer used as an amphiphilic compatibilizer to prevent macrophase separation. In all cases, immiscibility of the silicone and hydrophilic polymers results in microphase-separated morphologies. To investigate solute uptake in each of the SiHy microphases, equilibrium partition coefficients are obtained for two hydrophilic solutes (i.e., theophylline and caffeine dissolved in aqueous phosphate-buffered saline) and two oleophilic solutes (i.e., Nile Red and Bodipy Green dissolved in silicone oil), respectively. Measured water contents and aqueous-solute partition coefficients increase linearly with increasing solvent-free hydrophilic-polymer volume fraction. Conversely, oleophilic-solute partition coefficients decrease linearly with rising solvent-free hydrophilic-polymer volume fraction (i.e., decreasing hydrophobic silicone-polymer fraction). We quantitatively predict equilibrium SiHy water and solute uptake assuming that water and aqueous solutes reside only in hydrophilic microdomains, whereas oleophilic solutes partition predominately into silicone microdomains. Predicted water contents and solute partition coefficients are in excellent agreement with experiment. Our new procedure permits a priori estimation of SiHy water contents and solute partition coefficients based solely on properties of silicone and hydrophilic homopolymer hydrogels, eliminating the need for further mixed-polymer-hydrogel experiments.
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Dursch TJ, Liu DE, Oh Y, Radke CJ. Fluorescent solute-partitioning characterization of layered soft contact lenses. Acta Biomater 2015; 15:48-54. [PMID: 25484335 DOI: 10.1016/j.actbio.2014.11.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/04/2014] [Accepted: 11/25/2014] [Indexed: 11/28/2022]
Abstract
Partitioning of aqueous packaging, wetting, and care-solution agents into and out of soft contact lenses (SCLs) is important for improving wear comfort and also for characterizing lens physico-chemical properties. We illustrate both features of partitioning by application of fluorescent-solute partitioning into DAILIES TOTAL1® (delefilcon A) water-gradient SCLs, which exhibit a layered structure of a silicone-hydrogel (SiHy) core sandwiched between thin surface-gel layers. Two-photon fluorescence confocal laser-scanning microscopy and attenuated total-reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) characterize the lens and assess uptake profiles of six prototypical fluorescent solutes. Comparison of solute uptake in a SiHy-core prototype lens (i.e., O2OPTIX(TM)) validates the core SiHy structure of DAILIESTOTAL1®. To establish surface-layer charge, partition coefficients and water contents are obtained for aqueous pH values of 4 and 7.4. Solute fluorescence-intensity profiles clearly confirm a layered structure for the DAILIES TOTAL1® lenses. In all cases, aqueous solute partition coefficients are greater in the surface layers than in the SiHy core, signifying higher water in the surface gels. ATR-FTIR confirms surface-layer mass water contents of 82±3%. Water uptake and hydrophilic-solute uptake at pH 4 compared with that at pH 7.4 reveal that the surface-gel layers are anionic at physiologic pH 7.4, whereas both the SiHy core and O2OPTIX™ (lotrafilcon B) are nonionic. We successfully confirm the layered structure of DAILIES TOTAL1®, consisting of an 80-μm-thick SiHy core surrounded by 10-μm-thick polyelectrolyte surface-gel layers of significantly greater water content and aqueous solute uptake compared with the core. Accordingly, fluorescent-solute partitioning in SCLs provides information on gel structure and composition, in addition to quantifying uptake and release amounts and rates.
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Affiliation(s)
- T J Dursch
- Chemical and Biomolecular Engineering Department, University of California, 101E Gilman, Berkeley, CA 94720-1462, USA
| | - D E Liu
- Chemical and Biomolecular Engineering Department, University of California, 101E Gilman, Berkeley, CA 94720-1462, USA
| | - Y Oh
- Chemical and Biomolecular Engineering Department, University of California, 101E Gilman, Berkeley, CA 94720-1462, USA
| | - C J Radke
- Chemical and Biomolecular Engineering Department, University of California, 101E Gilman, Berkeley, CA 94720-1462, USA; Vision Science Group, University of California, Berkeley, CA 94720, USA.
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Perullini M, Jobbágy M, Japas ML, Bilmes SA. New method for the simultaneous determination of diffusion and adsorption of dyes in silica hydrogels. J Colloid Interface Sci 2014; 425:91-5. [DOI: 10.1016/j.jcis.2014.03.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 03/13/2014] [Indexed: 10/25/2022]
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Water-soluble drug partitioning and adsorption in HEMA/MAA hydrogels. Biomaterials 2014; 35:620-9. [DOI: 10.1016/j.biomaterials.2013.09.109] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 09/26/2013] [Indexed: 11/20/2022]
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