101
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Zhao X, Chen X, Yuk H, Lin S, Liu X, Parada G. Soft Materials by Design: Unconventional Polymer Networks Give Extreme Properties. Chem Rev 2021; 121:4309-4372. [PMID: 33844906 DOI: 10.1021/acs.chemrev.0c01088] [Citation(s) in RCA: 295] [Impact Index Per Article: 98.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hydrogels are polymer networks infiltrated with water. Many biological hydrogels in animal bodies such as muscles, heart valves, cartilages, and tendons possess extreme mechanical properties including being extremely tough, strong, resilient, adhesive, and fatigue-resistant. These mechanical properties are also critical for hydrogels' diverse applications ranging from drug delivery, tissue engineering, medical implants, wound dressings, and contact lenses to sensors, actuators, electronic devices, optical devices, batteries, water harvesters, and soft robots. Whereas numerous hydrogels have been developed over the last few decades, a set of general principles that can rationally guide the design of hydrogels using different materials and fabrication methods for various applications remain a central need in the field of soft materials. This review is aimed at synergistically reporting: (i) general design principles for hydrogels to achieve extreme mechanical and physical properties, (ii) implementation strategies for the design principles using unconventional polymer networks, and (iii) future directions for the orthogonal design of hydrogels to achieve multiple combined mechanical, physical, chemical, and biological properties. Because these design principles and implementation strategies are based on generic polymer networks, they are also applicable to other soft materials including elastomers and organogels. Overall, the review will not only provide comprehensive and systematic guidelines on the rational design of soft materials, but also provoke interdisciplinary discussions on a fundamental question: why does nature select soft materials with unconventional polymer networks to constitute the major parts of animal bodies?
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Affiliation(s)
- Xuanhe Zhao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Xiaoyu Chen
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hyunwoo Yuk
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Shaoting Lin
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Xinyue Liu
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - German Parada
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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102
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Abstract
Hydrogels are polymeric networks highly swollen with water. Because of their versatility and properties mimicking biological tissues, they are very interesting for biomedical applications. In this aim, the control of porosity is of crucial importance since it governs the transport properties and influences the fate of cells cultured onto or into the hydrogels. Among the techniques allowing for the elaboration of hydrogels, photopolymerization or photo-cross-linking are probably the most powerful and versatile synthetic routes. This Review aims at giving an overview of the literature dealing with photopolymerized hydrogels for which the generation or characterization of porosity is studied. First, the materials (polymers and photoinitiating systems) used for synthesizing hydrogels are presented. The different ways for generating porosity in the photopolymerized hydrogels are explained, and the characterization techniques allowing adequate study of the porosity are presented. Finally, some applications in the field of controlled release and tissue engineering are reviewed.
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Affiliation(s)
- Erwan Nicol
- Institut des Molécules et Matériaux du Mans (IMMM), UMR 6283 CNRS Le Mans Université, Avenue Olivier Messiaen, 72085 Cedex 9 Le Mans, France
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103
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Nasimova IR, Rudyak VY, Doroganov AP, Kharitonova EP, Kozhunova EY. Microstructured Macromaterials Based on IPN Microgels. Polymers (Basel) 2021; 13:polym13071078. [PMID: 33805579 PMCID: PMC8036913 DOI: 10.3390/polym13071078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/20/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
This study investigates the formation of microstructured macromaterials from thermo- and pH-sensitive microgels based on interpenetrating networks of poly-N-isopropylacrylamide (PNIPAM) and polyacrylic acid (PAA). Macromaterials are produced as a result of the deposition of microgel particles and subsequent crosslinking of polyacrylic acid subnetworks to each other due to the formation of the anhydride bonds during annealing. Since both PNIPAM and PAA are environment-sensitive polymers, one can expect that their conformational state during material development will affect its resulting properties. Thus, the influence of conditions of preparation for annealing (pH of the solution, the temperature of preliminary drying) on the swelling behavior, pH- and thermosensitivity, and macromaterial inner structure was investigated. In parallel, the study of the effect of the relative conformations of the IPN microgel subnetworks on the formation of macromaterials was carried out by the computer simulations method. It was shown that the properties of the prepared macromaterials strongly depend both on the temperature and pH of the PNIPAM-PAA IPN microgel dispersions. This opens up new opportunities to obtain materials with pre-chosen characteristics and environmental sensitivity.
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Affiliation(s)
- Irina Rashitovna Nasimova
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.Y.R.); (A.P.D.); (E.P.K.); (E.Y.K.)
- Russian Academy of Science, 119991 Moscow, Russia
- Correspondence:
| | - Vladimir Yurievich Rudyak
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.Y.R.); (A.P.D.); (E.P.K.); (E.Y.K.)
| | - Anton Pavlovich Doroganov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.Y.R.); (A.P.D.); (E.P.K.); (E.Y.K.)
| | - Elena Petrovna Kharitonova
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.Y.R.); (A.P.D.); (E.P.K.); (E.Y.K.)
| | - Elena Yurievna Kozhunova
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.Y.R.); (A.P.D.); (E.P.K.); (E.Y.K.)
- Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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104
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Significance of Crosslinking Approaches in the Development of Next Generation Hydrogels for Corneal Tissue Engineering. Pharmaceutics 2021; 13:pharmaceutics13030319. [PMID: 33671011 PMCID: PMC7997321 DOI: 10.3390/pharmaceutics13030319] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 02/07/2023] Open
Abstract
Medical conditions such as trachoma, keratoconus and Fuchs endothelial dystrophy can damage the cornea, leading to visual deterioration and blindness and necessitating a cornea transplant. Due to the shortage of donor corneas, hydrogels have been investigated as potential corneal replacements. A key factor that influences the physical and biochemical properties of these hydrogels is how they are crosslinked. In this paper, an overview is provided of different crosslinking techniques and crosslinking chemical additives that have been applied to hydrogels for the purposes of corneal tissue engineering, drug delivery or corneal repair. Factors that influence the success of a crosslinker are considered that include material composition, dosage, fabrication method, immunogenicity and toxicity. Different crosslinking techniques that have been used to develop injectable hydrogels for corneal regeneration are summarized. The limitations and future prospects of crosslinking strategies for use in corneal tissue engineering are discussed. It is demonstrated that the choice of crosslinking technique has a significant influence on the biocompatibility, mechanical properties and chemical structure of hydrogels that may be suitable for corneal tissue engineering and regenerative applications.
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105
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Richbourg NR, Wancura M, Gilchrist AE, Toubbeh S, Harley BAC, Cosgriff-Hernandez E, Peppas NA. Precise control of synthetic hydrogel network structure via linear, independent synthesis-swelling relationships. SCIENCE ADVANCES 2021; 7:eabe3245. [PMID: 33579714 PMCID: PMC7880590 DOI: 10.1126/sciadv.abe3245] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/23/2020] [Indexed: 05/12/2023]
Abstract
Hydrogel physical properties are tuned by altering synthesis conditions such as initial polymer concentration and polymer-cross-linker stoichiometric ratios. Traditionally, differences in hydrogel synthesis schemes, such as end-linked poly(ethylene glycol) diacrylate hydrogels and cross-linked poly(vinyl alcohol) hydrogels, limit structural comparison between hydrogels. In this study, we use generalized synthesis variables for hydrogels that emphasize how changes in formulation affect the resulting network structure. We identify two independent linear correlations between these synthesis variables and swelling behavior. Analysis through recently updated swollen polymer network models suggests that synthesis-swelling correlations can be used to make a priori predictions of the stiffness and solute diffusivity characteristics of synthetic hydrogels. The same experiments and analyses performed on methacrylamide-modified gelatin hydrogels demonstrate that complex biopolymer structures disrupt the linear synthesis-swelling correlations. These studies provide insight into the control of hydrogel physical properties through structural design and can be used to implement and optimize biomedically relevant hydrogels.
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Affiliation(s)
- N R Richbourg
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, University of Texas, Austin, TX 78712, USA
| | - M Wancura
- Department of Chemistry, University of Texas, Austin, TX 78712, USA
| | - A E Gilchrist
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - S Toubbeh
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
| | - B A C Harley
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - E Cosgriff-Hernandez
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
| | - N A Peppas
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA.
- Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, 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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106
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Varnava CK, Patrickios CS. Polymer networks one hundred years after the macromolecular hypothesis: A tutorial review. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123322] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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107
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Kanduč M, Kim WK, Roa R, Dzubiella J. How the Shape and Chemistry of Molecular Penetrants Control Responsive Hydrogel Permeability. ACS NANO 2021; 15:614-624. [PMID: 33382598 PMCID: PMC7844830 DOI: 10.1021/acsnano.0c06319] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
The permeability of hydrogels for the selective transport of molecular penetrants (drugs, toxins, reactants, etc.) is a central property in the design of soft functional materials, for instance in biomedical, pharmaceutical, and nanocatalysis applications. However, the permeation of dense and hydrated polymer membranes is a complex multifaceted molecular-level phenomenon, and our understanding of the underlying physicochemical principles is still very limited. Here, we uncover the molecular principles of permeability and selectivity in hydrogel permeation. We combine the solution-diffusion model for permeability with comprehensive atomistic simulations of molecules of various shapes and polarities in a responsive hydrogel in different hydration states. We find in particular that dense collapsed states are extremely selective, owing to a delicate balance between the partitioning and diffusivity of the penetrants. These properties are sensitively tuned by the penetrant size, shape, and chemistry, leading to vast cancellation effects, which nontrivially contribute to the permeability. The gained insights enable us to formulate semiempirical rules to quantify and extrapolate the permeability categorized by classes of molecules. They can be used as approximate guiding ("rule-of-thumb") principles to optimize penetrant or membrane physicochemical properties for a desired permeability and membrane functionality.
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Affiliation(s)
- Matej Kanduč
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Won Kyu Kim
- Korea
Institute for Advanced Study, 85 Hoegiro, Seoul 02455, Republic of Korea
| | - Rafael Roa
- Departamento
de Física Aplicada I, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Joachim Dzubiella
- Applied
Theoretical Physics−Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
- Research
Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
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108
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Teimouri S, Dekiwadia C, Kasapis S. Decoupling diffusion and macromolecular relaxation in the release of vitamin B6 from genipin-crosslinked whey protein networks. Food Chem 2021; 346:128886. [PMID: 33422921 DOI: 10.1016/j.foodchem.2020.128886] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/29/2020] [Accepted: 12/16/2020] [Indexed: 11/16/2022]
Abstract
This study examined the release of vitamin B6 from a hydrogel made of whey protein isolate (WPI). Work was carried out at ambient temperature without preheating the whey protein. Native-state macromolecules were crosslinked with a nontoxic compound, genipin. Experimentation included a ninhydrin assay with UV-vis absorbance, FTIR, 13C NMR, compression testing, SEM imaging, WPI matrix swelling and vitamin release protocols. It was confirmed that geninin crosslinked effectively the protein chains whose network strength was reinforced with increasing crosslinker concentrations. The modified Flory-Rehner theory predicted the molecular weight between crosslinks, network mesh size and crosslinking density in the swollen WPI gels as a function of added crosslinker. Transport patterns of vitamin B6 through the polymeric matrix were monitored over prolonged periods of observation. These were examined with the generalised Fick's equation and the Peppas-Sahlin equation to unveil the interplay between diffusion and relaxation dynamics in the anomalous transport of the bioactive compound.
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Affiliation(s)
- Shahla Teimouri
- School of Science, RMIT University, Bundoora West Campus, Melbourne, Vic 3083, Australia
| | - Chaitali Dekiwadia
- School of Science, RMIT University, Bundoora West Campus, Melbourne, Vic 3083, Australia
| | - Stefan Kasapis
- School of Science, RMIT University, Bundoora West Campus, Melbourne, Vic 3083, Australia.
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109
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Zhang H, Yue M, Wang T, Wang J, Wu X, Yang S. Conductive hydrogel-based flexible strain sensors with superior chemical stability and stretchability for mechanical sensing in corrosive solvents. NEW J CHEM 2021. [DOI: 10.1039/d0nj05880g] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Wearable flexible sensors face many harsh environments in practical applications.
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Affiliation(s)
- Hong Zhang
- College of Chemical Engineering, Northwest Minzu University, Key Laboratory for Utility of Environmental-Friendly Composite Materials and Biomass in University of Gansu Province
- Lanzhou 730030
- China
| | - Mingqiang Yue
- College of Chemical Engineering, Northwest Minzu University, Key Laboratory for Utility of Environmental-Friendly Composite Materials and Biomass in University of Gansu Province
- Lanzhou 730030
- China
| | - Tingting Wang
- College of Chemical Engineering, Northwest Minzu University, Key Laboratory for Utility of Environmental-Friendly Composite Materials and Biomass in University of Gansu Province
- Lanzhou 730030
- China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
| | - Jinqing Wang
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou 730000
- China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences
| | - Xianzhang Wu
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou 730000
- China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences
| | - Shengrong Yang
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou 730000
- China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences
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110
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Sung B, Kim M, Abelmann L. Magnetic microgels and nanogels: Physical mechanisms and biomedical applications. Bioeng Transl Med 2021; 6:e10190. [PMID: 33532590 PMCID: PMC7823133 DOI: 10.1002/btm2.10190] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 02/06/2023] Open
Abstract
Soft micro- and nanostructures have been extensively developed for biomedical applications. The main focus has been on multifunctional composite materials that combine the advantages of hydrogels and colloidal particles. Magnetic microgels and nanogels can be realized by hybridizing stimuli-sensitive gels and magnetic nanoparticles. They are of particular interest since they can be controlled in a wide range of biological environments by using magnetic fields. In this review, we elucidate physical principles underlying the design of magnetic microgels and nanogels for biomedical applications. Particularly, this article provides a comprehensive and conceptual overview on the correlative structural design and physical functionality of the magnetic gel systems under the concept of colloidal biodevices. To this end, we begin with an overview of physicochemical mechanisms related to stimuli-responsive hydrogels and transport phenomena and summarize the magnetic properties of inorganic nanoparticles. On the basis of the engineering principles, we categorize and summarize recent advances in magnetic hybrid microgels and nanogels, with emphasis on the biomedical applications of these materials. Potential applications of these hybrid microgels and nanogels in anticancer treatment, protein therapeutics, gene therapy, bioseparation, biocatalysis, and regenerative medicine are highlighted. Finally, current challenges and future opportunities in the design of smart colloidal biodevices are discussed.
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Affiliation(s)
- Baeckkyoung Sung
- KIST Europe Forschungsgesellschaft mbHSaarbrückenGermany
- Department of Biological SciencesKent State UniversityKentOhioUSA
- Division of Energy and Environment TechnologyUniversity of Science and TechnologyDaejeonRepublic of Korea
| | - Min‐Ho Kim
- Department of Biological SciencesKent State UniversityKentOhioUSA
| | - Leon Abelmann
- KIST Europe Forschungsgesellschaft mbHSaarbrückenGermany
- MESA+ Institute for Nanotechnology, University of TwenteEnschedeThe Netherlands
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111
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Silva D, Sousa R, Salgado A. Hydrogels as delivery systems for spinal cord injury regeneration. Mater Today Bio 2021; 9:100093. [PMID: 33665602 PMCID: PMC7905359 DOI: 10.1016/j.mtbio.2021.100093] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 01/04/2023] Open
Abstract
Spinal cord injury is extremely debilitating, both at physiological and psychological levels, changing completely the patient's lifestyle. The introduction of biomaterials has opened a new window to develop a therapeutic approach to induce regeneration after injury due to similarities with extracellular matrix. Particularly, hydrogels have the ability to support axonal growth and endogenous regeneration. Moreover, they can also act as potential matrixes in which to load and deliver therapeutic agents at injury site. In this review, we highlight some important characteristics to be considered when designing hydrogels as delivery systems (DS), such as rheology, mesh size, swelling, degradation, gelation temperature and surface charge. Additionally, affinity-based release systems, incorporation of nanoparticles, or ion-mediated interactions are also pondered. Overall, hydrogel DS aim to promote a sustained, controlled and prolonged release at injury site, allowing a targeted oriented action of the therapeutic agent that will be used.
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Affiliation(s)
- D. Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's—PT Government Associate Laboratory, 4710-057/4805-017, Braga/Guimarães, Portugal
- Stemmatters, Biotecnologia e Medicina Regenerativa SA, 4805-017, Guimarães, Portugal
| | - R.A. Sousa
- Stemmatters, Biotecnologia e Medicina Regenerativa SA, 4805-017, Guimarães, Portugal
| | - A.J. Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's—PT Government Associate Laboratory, 4710-057/4805-017, Braga/Guimarães, Portugal
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112
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Hydrogel Properties and Their Impact on Regenerative Medicine and Tissue Engineering. Molecules 2020; 25:molecules25245795. [PMID: 33302592 PMCID: PMC7764781 DOI: 10.3390/molecules25245795] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/21/2022] Open
Abstract
Hydrogels (HGs), as three-dimensional structures, are widely used in modern medicine, including regenerative medicine. The use of HGs in wound treatment and tissue engineering is a rapidly developing sector of medicine. The unique properties of HGs allow researchers to easily modify them to maximize their potential. Herein, we describe the physicochemical properties of HGs, which determine their subsequent applications in regenerative medicine and tissue engineering. Examples of chemical modifications of HGs and their applications are described based on the latest scientific reports.
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113
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Beckett LE, Lewis JT, Tonge TK, Korley LTJ. Enhancement of the Mechanical Properties of Hydrogels with Continuous Fibrous Reinforcement. ACS Biomater Sci Eng 2020; 6:5453-5473. [PMID: 33320571 DOI: 10.1021/acsbiomaterials.0c00911] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reinforcing mechanically weak hydrogels with fibers is a promising route to obtain strong and tough materials for biomedical applications while retaining a favorable cell environment. The resulting hierarchical structure recreates structural elements of natural tissues such as articular cartilage, with fiber diameters ranging from the nano- to microscale. Through control of properties such as the fiber diameter, orientation, and porosity, it is possible to design materials which display the nonlinear, synergistic mechanical behavior observed in natural tissues. In order to fully exploit these advantages, it is necessary to understand the structure-property relationships in fiber-reinforced hydrogels. However, there are currently limited models which capture their complex mechanical properties. The majority of reported fiber-reinforced hydrogels contain fibers obtained by electrospinning, which allows for limited spatial control over the fiber scaffold and limits the scope for systematic mechanical testing studies. Nevertheless, new manufacturing techniques such as melt electrowriting and bioprinting have emerged, which allow for increased control over fiber deposition and the potential for future investigations on the effect of specific structural features on mechanical properties. In this review, we therefore explore the mechanics of fiber-reinforced hydrogels, and the evolution of their design and manufacture from replicating specific features of biological tissues to more complex structures, by taking advantage of design principles from both tough hydrogels and fiber-reinforced composites. By highlighting the overlap between these fields, it is possible to identify the remaining challenges and opportunities for the development of effective biomedical devices.
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Affiliation(s)
- Laura E Beckett
- University of Delaware, Department of Materials Science and Engineering, 127 The Green, Newark, Delaware 19716, United States
| | - Jackson T Lewis
- W. L. Gore & Associates, Inc., 501 Vieves Way, Elkton, Maryland 21921, United States
| | - Theresa K Tonge
- W. L. Gore & Associates, Inc., 501 Vieves Way, Elkton, Maryland 21921, United States
| | - LaShanda T J Korley
- University of Delaware, Department of Materials Science and Engineering, 127 The Green, Newark, Delaware 19716, United States.,University of Delaware, Department of Chemical and Biomolecular Engineering, 150 Academy Street, Newark, Delaware 19716, United States
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114
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Drozdov AD, deClaville Christiansen J. The effect of saccharides on equilibrium swelling of thermo-responsive gels. RSC Adv 2020; 10:30723-30733. [PMID: 35547557 PMCID: PMC9088206 DOI: 10.1039/d0ra05845a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 08/10/2020] [Indexed: 11/21/2022] Open
Abstract
Mechanical and optical properties of thermo-responsive (TR) gels change drastically at their volume phase transition temperature. As the critical temperature is strongly affected by the presence of small amounts of additives in aqueous solutions, TR gels can be employed as sensors for detection and recognition of multiple analytes (from specific ions to hazardous biochemicals to pathogenic proteins) and actuators for biomedical applications. A simplified mean-field model is developed for equilibrium swelling of TR gels in aqueous solutions of additives. Its advantage is that the model involves a relatively small (compared with the conventional approaches) number of material constants and accounts for changes in the thermo-mechanical response at transition from the swollen to collapsed state. The ability of the model to describe experimental swelling diagrams and to predict the influence of additives on the equilibrium degree of swelling and the volume phase transition temperature of TR gels is confirmed by comparison of observations on poly(N-isopropylacrylamide) gel in aqueous solutions of saccharides (glucose, sucrose and galactose) with results of numerical analysis.
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Affiliation(s)
- A D Drozdov
- Department of Materials and Production, Aalborg University Fibigerstraede 16 Aalborg 9220 Denmark
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