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Naik K, du Toit LC, Ally N, Choonara YE. In vivo evaluation of a Nano-enabled therapeutic vitreous substitute for the precise delivery of triamcinolone to the posterior segment of the eye. Drug Deliv Transl Res 2024; 14:2668-2694. [PMID: 38519828 PMCID: PMC11384602 DOI: 10.1007/s13346-024-01566-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2024] [Indexed: 03/25/2024]
Abstract
This study focused on the design of a thermoresponsive, nano-enabled vitreous substitute for the treatment of retinal diseases. Synthesis of a hydrogel composed of hyaluronic acid and a poloxamer blend was undertaken. Poly(D,L-lactide-co-glycolide) acid nanoparticles encapsulating triamcinolone acetonide (TA) were synthesised with a spherical morphology and mean diameter of ~ 153 nm. Hydrogel fabrication and nanoparticle loading within the hydrogel was confirmed via physicochemical analysis. Gelation studies indicated that hydrogels formed in nine minutes and 10 min for the unloaded and nanoparticle-loaded hydrogels, respectively. The hydrogels displayed in situ gel formation properties, and rheometric viscoelastic studies indicated the unloaded and loaded hydrogels to have modulus values similar to those of the natural vitreous at 37 °C. Administration of the hydrogels was possible via 26G needles allowing for clinical application and drug release of triamcinolone acetonide from the nanoparticle-loaded hydrogel, which provided sustained in vitro drug release over nine weeks. The hydrogels displayed minimal swelling, reaching equilibrium swelling within 12 h for the unloaded hydrogel, and eight hours for the nanoparticle-loaded hydrogel. Biodegradation in simulated vitreous humour with lysozyme showed < 20% degradation within nine weeks. Biocompatibility of both unloaded and loaded hydrogels was shown with mouse fibroblast and human retinal pigment epithelium cell lines. Lastly, a pilot in vivo study in a New Zealand White rabbit model displayed minimal toxicity with precise, localised drug release behaviour, and ocular TA levels maintained within the therapeutic window for the 28-day investigation period, which supports the potential applicability of the unloaded and nanoparticle-loaded hydrogels as vitreous substitutes that function as drug delivery systems following vitrectomy surgery.
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Affiliation(s)
- Kruti Naik
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Johannesburg, Parktown, 2193, South Africa
| | - Lisa Claire du Toit
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Johannesburg, Parktown, 2193, South Africa
| | - Naseer Ally
- Division of Ophthalmology, Department of Neurosciences, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Johannesburg, Parktown, 2193, South Africa
| | - Yahya Essop Choonara
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Johannesburg, Parktown, 2193, South Africa.
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2
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Qu S, Tang Y, Ning Z, Zhou Y, Wu H. Desired properties of polymeric hydrogel vitreous substitute. Biomed Pharmacother 2024; 172:116154. [PMID: 38306844 DOI: 10.1016/j.biopha.2024.116154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/06/2024] [Accepted: 01/10/2024] [Indexed: 02/04/2024] Open
Abstract
Vitreous replacement is a commonly employed method for treating a range of ocular diseases, including posterior vitreous detachment, complex retinal detachment, diabetic retinopathy, macular hole, and ocular trauma. Various clinical substitutes for vitreous include air, expandable gas, silicone oil, heavy silicone oil, and balanced salt solution. However, these substitutes have drawbacks such as short retention time, cytotoxicity, high intraocular pressure, and the formation of cataracts, rendering them unsuitable for long-term treatment. Polymeric hydrogels possess the potential to serve as ideal vitreous substitutes due to their structure-mimicking to natural vitreous and adjustable mechanical properties. Replacement with hydrogels as the tamponade can help maintain the shape of the eyeball, apply pressure to the detached retina, and ensure the metabolic transport of substances without impairing vision. This literature review examines the required properties of artificial vitreous, including the optical properties, rheological properties, expansive force action, and physiological and biochemical functions of chemically and physically crosslinked hydrogels. The strategies for enhancing the biocompatibility and injectability of hydrogels are also summarized and discussed. From a clinical ophthalmology perspective, this paper presents the latest developments in vitreous replacement, providing clinicians with a comprehensive understanding of hydrogel clinical applications, which offers guidance for future design directions and methodologies for hydrogel development.
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Affiliation(s)
- Sheng Qu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Yi Tang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Zichao Ning
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Yanjie Zhou
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China
| | - Hong Wu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun 130041, China.
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3
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Zengin S, Mercan S, Tarhan D, Gök A, Ercan AM. Age-related changes on physicochemical properties of the artificial vitreous humor: A practical tool for enhancing ex vivo studies. Exp Eye Res 2024; 239:109762. [PMID: 38147936 DOI: 10.1016/j.exer.2023.109762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/01/2023] [Accepted: 12/20/2023] [Indexed: 12/28/2023]
Abstract
The vitreous humor (VH) is a hydrophilic, jelly-like ocular fluid, which is located in the posterior chamber of the eye. The rheological, structural, and chemical properties of VH change significantly during aging, which further causes eye-associated diseases and could be a potential indicator for various diseases. In this study, artificial VH (A-VH) samples were created by taking into account different age groups to observe age-related changes in the physicochemical properties of these samples. This study aimed to measure the physicochemical properties of age-dependently prepared A-VH samples to determine the changes with aging in the physicochemical properties of A-VH samples. Phosphate-buffered saline (PBS)-based A-VH samples were prepared in three types representing adult, middle-aged, and elder individuals. Age-related changes in physicochemical properties (surface tension, osmolality, pH, relative viscosity, density, and refractive index) were analyzed by related equipment. The A-VH samples, prepared using PBS, showed strong similarity to authentic VH in terms of physicochemical properties. While the age-related changes studies have revealed some discrepancies between age-dependently prepared A-VH samples in terms of surface tension, osmolality, relative viscosity, and pH with high correlation coefficients (r2 > 0,94), density and refractive index values did not show any significant differences and correlation between types of A-VH representing 3 age groups. In conclusion, age-dependent A-VH samples were created successfully to use ex vivo method development studies, and the influence of aging on the physicochemical properties of VH was demonstrated as well.
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Affiliation(s)
- Simge Zengin
- Istanbul University-Cerrahpaşa, Institute of Forensic Sciences and Legal Medicine, Department of Science, Buyukcekmece, Istanbul, Turkey
| | - Selda Mercan
- Istanbul University-Cerrahpaşa, Institute of Forensic Sciences and Legal Medicine, Department of Science, Buyukcekmece, Istanbul, Turkey.
| | - Duygu Tarhan
- Bahcesehir University, School of Medicine, Department of Biophysics, Goztepe, Istanbul, Turkey
| | - Aslı Gök
- Istanbul University-Cerrahpaşa, Faculty of Engineering, Department of Chemical Engineering, Avcılar, Istanbul, Turkey
| | - Alev Meltem Ercan
- Istanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Department of Biophysics, Fatih, Istanbul, Turkey
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4
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Naik K, Du Toit LC, Ally N, Choonara YE. Advances in Polysaccharide- and Synthetic Polymer-Based Vitreous Substitutes. Pharmaceutics 2023; 15:566. [PMID: 36839888 PMCID: PMC9961338 DOI: 10.3390/pharmaceutics15020566] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/01/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023] Open
Abstract
The vitreous humour is a gel-like structure that composes the majority of each eye. It functions to provide passage of light, be a viscoelastic dampener, and hold the retina in place. Vitreous liquefaction causes retinal detachment and retinal tears requiring pars plana vitrectomy for vitreous substitution. An ideal vitreous substitute should display similar mechanical, chemical, and rheological properties to the natural vitreous. Currently used vitreous substitutes such as silicone oil, perfluorocarbon liquids, and gases cannot be used long-term due to adverse effects such as poor retention time, cytotoxicity, and cataract formation. Long-term, experimental vitreous substitutes composed of natural, modified and synthetic polymers are currently being studied. This review discusses current long- and short-term vitreous substitutes and the disadvantages of these that have highlighted the need for an ideal vitreous substitute. The review subsequently focuses specifically on currently used polysaccharide- and synthetic polymer-based vitreous substitutes, which may be modified or functionalised, or employed as the derivative, and discusses experimental vitreous substitutes in these classes. The advantages and challenges associated with the use of polymeric substitutes are discussed. Innovative approaches to vitreous substitution, namely a novel foldable capsular vitreous body, are presented, as well as future perspectives related to the advancement of this field.
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Affiliation(s)
- Kruti Naik
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Lisa C. Du Toit
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Naseer Ally
- Division of Ophthalmology, Department of Neurosciences, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Yahya E. Choonara
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
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5
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Recent Advances in Hydrogels for the Diagnosis and Treatment of Dry Eye Disease. Gels 2022; 8:gels8120816. [PMID: 36547340 PMCID: PMC9778550 DOI: 10.3390/gels8120816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Dry eye disease (DED) is the most common clinical ocular surface disease. Given its multifactorial etiology, no consensus has been reached on the diagnosis criteria for dry eye disease. Topical drug administration remains the mainstay of treatment but is limited to the rapid clearance from the eye surface. To address these problems, hydrogel-based materials were designed to detect biomarkers or act as drug delivery systems by taking advantage of their good biocompatibility, excellent physical and mechanical properties, and long-term implant stability. Biosensors prepared using biocompatible hydrogels can be sensitive in diagnosing DED, and the designed hydrogels can also improve the drug bioavailability and retention time for more effective and long-term treatment. This review summarizes recent advances in the use of hydrogels for diagnosing and treating dry eye, aiming to provide a novel reference for the eventual clinical translation of hydrogels in the context of dry eye disease.
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He B, Yang J, Liu Y, Xie X, Hao H, Xing X, Liu W. An in situ-forming polyzwitterion hydrogel: Towards vitreous substitute application. Bioact Mater 2021; 6:3085-3096. [PMID: 33778190 PMCID: PMC7960944 DOI: 10.1016/j.bioactmat.2021.02.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/06/2021] [Accepted: 02/20/2021] [Indexed: 12/18/2022] Open
Abstract
Development of a biostable and biosafe vitreous substitute is highly desirable, but remains a grand challenge. Herein, we propose a novel strategy for constructing a readily administered vitreous substitute based on a thiol-acrylate clickable polyzwitterion macromonomer. A biocompatible multivinyl polycarboxybetaine (PCB-OAA) macromonomer is designed and synthesized, and mixed with dithiothreitol (DTT) via a Michael addition reaction to form a hydrogel in vitreous cavity. This resultant PCB-OAA hydrogel exhibits controllable gelation time, super anti-fouling ability against proteins and cells, excellent biocompatibility, and approximate key parameters to human vitreous body including equilibrium water content, density, optical properties, modulus. Remarkably, outperforming clinically used silicone oil in biocompatibility, this rapidly formed hydrogel in the vitreous cavity of rabbit eyes remains stable in vitreous cavity, showing an appealing ability to prevent significantly inflammatory response, fibrosis and complications such as raised intraocular pressure (IOP), and cataract formation. This zwitterionic polymer hydrogel holds great potential as a vitreous substitute.
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Affiliation(s)
- Binbin He
- School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300350, China
| | - Jianhai Yang
- School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300350, China
| | - Yang Liu
- School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300350, China
| | - Xianhua Xie
- School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300350, China
| | - Huijie Hao
- Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Xiaoli Xing
- Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, 300384, China
| | - Wenguang Liu
- School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300350, China
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Wang T, Ran R, Ma Y, Zhang M. Polymeric hydrogel as a vitreous substitute: current research, challenges, and future directions. Biomed Mater 2021; 16. [PMID: 34038870 DOI: 10.1088/1748-605x/ac058e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/26/2021] [Indexed: 02/08/2023]
Abstract
Vitreoretinal surgery is an essential approach to treat proliferative diabetic vitreopathy, retinal detachment, retinal tear, ocular trauma, and macular holes. The removal of the natural vitreous and the replacement with substitutes are critical steps for retina reattachment. Vitreous substitutes including silicone oil (SiO), air, sulfur hexafluoride (SF6), and perfluoropropane (C3F8), have been widely applied in clinical practice. However, these substitutes are reported to cause complications such as emulsification, high intraocular pressure, and lens opacification. Polymeric hydrogels are a kind of material with favorable physical, mechanical properties, and adaptable biocompatibility, thus being highly expected to be ideal vitreous substitutes. Despite years of research, very few polymeric hydrogels can be applied practically in the vitreous cavity. In this review, we focus on the development of polymeric natural-based hydrogels and synthetic hydrogels. Particularly, we pay attention to recent advances in the novel stimuli-response and self-assembly supramolecular hydrogels. Characterized by easy injectability and long residence time, this kind of hydrogel becomes the potentially promising candidates for ideal vitreous substitutes. Finally, we evaluate the current challenges and provide the future directions of vitreous substitutes.
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Affiliation(s)
- Ting Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China.,West China School of Medicine, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
| | - Ruijin Ran
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China.,Minda Hospital of Hubei Minzu University, Enshi, People's Republic of China
| | - Yan Ma
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, People's Republic of China
| | - Ming Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, People's Republic of China
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8
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Sheikhi M, Rafiemanzelat F, Moroni L, Setayeshmehr M. Ultrahigh-water-content biocompatible gelatin-based hydrogels: Toughened through micro-sized dissipative morphology as an effective strategy. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 120:111750. [PMID: 33545891 DOI: 10.1016/j.msec.2020.111750] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/10/2020] [Accepted: 11/22/2020] [Indexed: 11/19/2022]
Abstract
Fabrication of simultaneously robust and superabsorbent gelatin-based hydrogels for biomedical applications still remains a challenge due to lack of locally dissipative points in the presence of large water content. Here, we apply a synthesis strategy through which water absorbency and energy dissipative points are separated, and toughening mechanism is active closely at the crack tip. For this, gelatin-based microgels (GeMs) were synthesized in a way that concentrated supramolecular interactions were present to increase the energy necessary to propagate a macroscopic crack. The microgels were interlocked to each other via both temporary hydrophobic associations and permanent covalent crosslinks, in which the sacrificial binds sustained the toughness due to the mobility of the junction zones and particles sliding. However, chemical crosslinking points preserved the integrity and fast recoverability of the hydrogel. Hysteresis increased strongly with increasing supramolecular interactions within the network. The prepared hydrogels showed energy loss and swelling ratio up to 3440 J. m-3 and 830%, respectively, which was not achievable with conventional network fabrication methods. The microgels were also assessed for their in vivo biocompatibility in a rat subcutaneous pocket assay. Results of hematoxylin and eosin (H&E) staining demonstrated regeneration of the tissue around the scaffolds without incorporation of growth factors. Also, vascularization within the scaffolds was observed after 4 weeks implantation. These results indicate that our strategy is a promising method to manipulate those valuable polymers, which lose their toughness and applicability with increasing their water content.
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Affiliation(s)
- M Sheikhi
- Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan 81746-73441, Islamic Republic of Iran
| | - F Rafiemanzelat
- Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan 81746-73441, Islamic Republic of Iran.
| | - L Moroni
- MERLN Institute for Technology Inspired Regenerative Medicine, Complex Tissue Regeneration Department, Maastricht University, Universiteitssingel 40, 6229ER Maastricht, the Netherlands.
| | - M Setayeshmehr
- MERLN Institute for Technology Inspired Regenerative Medicine, Complex Tissue Regeneration Department, Maastricht University, Universiteitssingel 40, 6229ER Maastricht, the Netherlands; Department of Biomaterials, Tissue Engineering and Nanotechnology, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Tissue Engineering & Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
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9
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Karayilan M, Clamen L, Becker ML. Polymeric Materials for Eye Surface and Intraocular Applications. Biomacromolecules 2021; 22:223-261. [PMID: 33405900 DOI: 10.1021/acs.biomac.0c01525] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ocular applications of polymeric materials have been widely investigated for medical diagnostics, treatment, and vision improvement. The human eye is a vital organ that connects us to the outside world so when the eye is injured, infected, or impaired, it needs immediate medical treatment to maintain clear vision and quality of life. Moreover, several essential parts of the eye lose their functions upon aging, causing diminished vision. Modern polymer science and polymeric materials offer various alternatives, such as corneal and scleral implants, artificial ocular lenses, and vitreous substitutes, to replace the damaged parts of the eye. In addition to the use of polymers for medical treatment, polymeric contact lenses can provide not only vision correction, but they can also be used as wearable electronics. In this Review, we highlight the evolution of polymeric materials for specific ocular applications such as intraocular lenses and current state-of-the-art polymeric systems with unique properties for contact lens, corneal, scleral, and vitreous body applications. We organize this Review paper by following the path of light as it travels through the eye. Starting from the outside of the eye (contact lenses), we move onto the eye's surface (cornea and sclera) and conclude with intraocular applications (intraocular lens and vitreous body) of mostly synthetic polymers and several biopolymers. Initially, we briefly describe the anatomy and physiology of the eye as a reminder of the eye parts and their functions. The rest of the Review provides an overview of recent advancements in next-generation contact lenses and contact lens sensors, corneal and scleral implants, solid and injectable intraocular lenses, and artificial vitreous body. Current limitations for future improvements are also briefly discussed.
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Affiliation(s)
- Metin Karayilan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Liane Clamen
- Adaptilens, LLC, Boston, Massachusetts 02467, United States
| | - Matthew L Becker
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Mechanical Engineering and Materials Science, Orthopaedic Surgery, and Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States
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10
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Polymeric hydrogels as a vitreous replacement strategy in the eye. Biomaterials 2020; 268:120547. [PMID: 33307366 DOI: 10.1016/j.biomaterials.2020.120547] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 11/16/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022]
Abstract
Vitreous endo-tamponades are commonly used in the treatment of retinal detachments and tears. They function by providing a tamponading force to support the retina after retina surgery. Current clinical vitreous endo-tamponades include expansile gases (such as sulfur hexafluoride (SF6) and perfluoropropane (C3F8)) and also sislicone oil (SiO). They are effective in promoting recovery but are disadvantaged by their lower refractive indices and lower densities as compared to the native vitreous, resulting in immediate blurred vision after surgery and necessitating patients to assume prolonged face-down positioning respectively. While the gas implants diffuse out over time, the SiO implants are non-biodegradable and require surgical removal. Therefore, there is much demand to develop an ideal vitreous endo-tamponade that can combine therapeutic effectiveness with patient comfort. Polymeric hydrogels have since attracted much attention due to their favourable properties such as high water content, high clarity, suitable refractive indices, suitable density, tuneable rheological properties, injectability, and biocompatibility. Many design strategies have been employed to design polymeric hydrogel-based vitreous endo-tamponades and they can be classified into four main strategies. This review seeks to analyse these various strategies and evaluate their effectiveness and also propose the key criteria to design successful polymeric hydrogel vitreous endo-tamponades.
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11
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Tram NK, Maxwell CJ, Swindle-Reilly KE. Macro- and Microscale Properties of the Vitreous Humor to Inform Substitute Design and Intravitreal Biotransport. Curr Eye Res 2020; 46:429-444. [PMID: 33040616 DOI: 10.1080/02713683.2020.1826977] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested in vitro, has been hypothesized to be different in vivo. Future studies should focus on testing the mechanical properties of the vitreous in situ or in vivo. In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport.
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Affiliation(s)
- Nguyen K Tram
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Courtney J Maxwell
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Katelyn E Swindle-Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA.,Department of Ophthalmology & Visual Science, The Ohio State University, Columbus, OH, USA
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12
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Laradji A, Shui YB, Karakocak BB, Evans L, Hamilton P, Ravi N. Bioinspired Thermosensitive Hydrogel as a Vitreous Substitute: Synthesis, Properties, and Progress of Animal Studies. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E1337. [PMID: 32183465 PMCID: PMC7143394 DOI: 10.3390/ma13061337] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 11/16/2022]
Abstract
In many vitreal diseases, the surgeon removes the natural vitreous and replaces it with silicone oils, gases, or balanced salt solutions to fill the eyeball and hold the retina in position. However, these materials are often associated with complications and have properties that differ from natural vitreous. Herein, we report an extension of our previous work on the synthesis of a biomimetic hydrogel that is composed of thiolated gellan as an analogue of type II collagen and poly(methacrylamide-co-methacrylate-co-bis(methacryloyl)cystamine), a polyelectrolyte, as an analogue of hyaluronic acid. This thermosensitive hydrogel can be injected into the eye as a viscous solution at 45 °C. It then forms a physical gel in situ when it reaches body temperature, and later forms disulfide covalent crosslinks. In this article, we evaluated two different formulations of the biomimetic hydrogels for their physical, mechanical, and optical properties, and we determined their biocompatibility with several cell lines. Finally, we report on the progress of the four-month preclinical evaluation of our bio-inspired vitreous substitute in comparison to silicone oil or a balanced salt solution. We assessed the eyes with a slit-lamp examination, intraocular pressure measurements, electroretinography, and optical coherence tomography. Preliminary results are very encouraging for the continuing evaluation of our bio-inspired hydrogel in clinical trials.
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Affiliation(s)
- Amine Laradji
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; (A.L.); (Y.-B.S.); (B.B.K.); (L.E.); (P.H.)
- Department of Veterans Affairs, St. Louis Medical Center, St. Louis, MO 63106, USA
| | - Ying-Bo Shui
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; (A.L.); (Y.-B.S.); (B.B.K.); (L.E.); (P.H.)
| | - Bedia Begum Karakocak
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; (A.L.); (Y.-B.S.); (B.B.K.); (L.E.); (P.H.)
- Department of Veterans Affairs, St. Louis Medical Center, St. Louis, MO 63106, USA
| | - Lynn Evans
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; (A.L.); (Y.-B.S.); (B.B.K.); (L.E.); (P.H.)
| | - Paul Hamilton
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; (A.L.); (Y.-B.S.); (B.B.K.); (L.E.); (P.H.)
| | - Nathan Ravi
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; (A.L.); (Y.-B.S.); (B.B.K.); (L.E.); (P.H.)
- Department of Veterans Affairs, St. Louis Medical Center, St. Louis, MO 63106, USA
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63110, USA
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13
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Tram NK, Jiang P, Torres‐Flores TC, Jacobs KM, Chandler HL, Swindle‐Reilly KE. A Hydrogel Vitreous Substitute that Releases Antioxidant. Macromol Biosci 2019; 20:e1900305. [DOI: 10.1002/mabi.201900305] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/11/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Nguyen K. Tram
- Department of Biomedical Engineering The Ohio State University 1080 Carmack Rd. Columbus OH 43210 USA
| | - Pengfei Jiang
- William G. Lowrie Department of Chemical and Biomolecular Engineering The Ohio State University 151 W. Woodruff Avenue Columbus OH 43210 USA
| | - Tiara C. Torres‐Flores
- Department of Biomedical Engineering The Ohio State University 1080 Carmack Rd. Columbus OH 43210 USA
| | - Kane M. Jacobs
- William G. Lowrie Department of Chemical and Biomolecular Engineering The Ohio State University 151 W. Woodruff Avenue Columbus OH 43210 USA
| | - Heather L. Chandler
- College of Optometry The Ohio State University 338 West 10th Avenue Columbus OH 43210 USA
| | - Katelyn E. Swindle‐Reilly
- Department of Biomedical Engineering The Ohio State University 1080 Carmack Rd. Columbus OH 43210 USA
- William G. Lowrie Department of Chemical and Biomolecular Engineering The Ohio State University 151 W. Woodruff Avenue Columbus OH 43210 USA
- Department of Ophthalmology and Visual Science The Ohio State University 915 Olentangy River Road, Suite 5000 Columbus OH 43212 USA
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