Silica Hybrid for Corneal Replacement: Optical, Biomechanical, and Ex Vivo Biocompatibility Studies

DiVito, Michael D.; Rudisill, Stephen G.; Stein, Andreas; Patel, Sanjay V.; McLaren, Jay W.; Hubel, Allison

doi:10.1167/iovs.12-10561

Cited by 7 publications

(5 citation statements)

References 27 publications

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“…The amine group can also react with carbodiimide-activated carboxyl end of collagen to form a covalent linkage. DiVito and colleagues had developed a composite hydrogel made of a mixture of 3-APTES and collagen type I, which showed the ability to promote corneal epithelialization in rabbit corneas ex vivo . Therefore, 3-APTES can be a candidate molecule to modify the PMMA surface to improve its adhesion with corneal tissue, which is predominantly constructed by collagen type I…”

Section: Introductionmentioning

confidence: 99%

“…DiVito and colleagues had developed a composite hydrogel made of a mixture of 3-APTES and collagen type I, which showed the ability to promote corneal epithelialization in rabbit corneas ex vivo. 13 Therefore, 3-APTES can be a candidate molecule to modify the PMMA surface to improve its adhesion with corneal tissue, which is predominantly constructed by collagen type I. 14 In the current study, we used collagen type I hydrogel, instead of human corneal tissue, to study its adhesion on various modified PMMA surfaces as a KPro model.…”

Section: ■ Introductionmentioning

confidence: 99%

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Surface Modification of PMMA to Improve Adhesion to Corneal Substitutes in a Synthetic Core–Skirt Keratoprosthesis

Riau

Mondal

Yam

et al. 2015

ACS Appl. Mater. Interfaces

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Patients with advanced corneal disease do poorly with conventional corneal transplantation and require a keratoprosthesis (KPro) for visual rehabilitation. The most widely used KPro is constructed using poly(methyl methacrylate) (PMMA) in the central optical core and a donor cornea as skirt material. In many cases, poor adherence between the PMMA and the soft corneal tissue is responsible for device "extrusion" and bacterial infiltration. The interfacial adhesion between the tissue and the PMMA was therefore critical to successful implantation and device longevity. In our approach, we modified the PMMA surface using oxygen plasma (plasma group); plasma followed by calcium phosphate (CaP) coating (p-CaP); dopamine followed by CaP coating (d-CaP); or plasma followed by coating with (3-aminopropyl)triethoxysilane (3-APTES). To create a synthetic KPro model, we constructed and attached 500 μm thick collagen type I hydrogel on the modified PMMA surfaces. Surface modifications produced significantly improved interfacial adhesion strength compared to untreated PMMA (p < 0.001). The p-CaP group yielded the best interfacial adhesion with the hydrogel (177 ± 27 mN/cm(2)) followed by d-CaP (168 ± 31 mN/cm(2)), 3-APTES (145 ± 12 mN/cm(2)), and plasma (119 ± 10 mN/cm(2)). Longer-term stability of the adhesion was achieved by d-CaP, which, after 14 and 28 days of incubation in phosphate buffered saline, yielded 164 ± 25 mN/cm(2) (p = 0.906 compared to adhesion at day 1) and 131 ± 20 mN/cm(2) (p = 0.053), respectively. In contrast, significant reduction of adhesion strength was observed in p-CaP group over time (p < 0.001). All surface coatings were biocompatible to human corneal stromal fibroblasts, except for the 3-APTES group, which showed no live cells at 72 h of culture. In contrast, cells on d-CaP surface showed good anchorage, evidenced by the expression of focal adhesion complex (paxillin and vinculin), and prominent filopodia protrusions. In conclusion, d-CaP can not only enhance and provide stability to the adhesion of collagen hydrogel on the PMMA surface but also promote biointegration.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Surface Modification of PMMA to Improve Adhesion to Corneal Substitutes in a Synthetic Core–Skirt Keratoprosthesis

Riau

Mondal

Yam

et al. 2015

ACS Appl. Mater. Interfaces

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“…Figure 4 shows the plot of transmittance and compared with DiVito model, which shows that the transmittance increases as the wavelength shifts from ultraviolet to infrared regions [27]. The value of transmittance is between 0.9 to 1.0 in the range of 600 to 800 nm and 0.6 to 0.8 for lower wavelength range within 300 to 600.…”

Section: Optical Propertiesmentioning

confidence: 98%

Development of Silica-Collagen Composite as Corneal Substitute through Sol-Gel Additive Manufacturing

Mandal¹,

Chattopadhyay

Halder

2023

Preprint

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The inherent properties of the healthy cornea, namely its strength, transparency and precise curvature enable it to withstand external injury and provides resistant to intraocular pressure, also allowing 95% transmission of incoming lightand providing 70% of the focusing power of the eye. Corneal transparency is dependent on the specific arrangement of collagen within the stroma. The research thrives for synthesis of a composite comprised of Collagen, the basic protein that can be abundantly found in human body and silica which is biosafe and biocompatible to physiological system and can act as a scaffold for tissue engineering and drug delivery. The starting materials of the synthesis are diluted Silica precursor and two types of collagen-I and III. Collagen type III is predominantly found on the epithelium and endothelium of the cornea which can enhance the mechanical property and optical property of the hybrid. Sol Gel technique has been applied for the synthesis of the composite and finally lyophilized after the pH has been stabilized around 7.2-7.4 to obtain dehydrated silica collagen composite. Optical property of the developed composite closely mimics the collagen hybrids from earlier work in this field. The composite exhibits crystallinity due to the presence of silica as it evidenced from its XRD plot. Other material characterizations, viz. FTIR and SEM have been performed on the sample to identify the microstructural nature of the composite.

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“…Silica-collagen biohybrid materials have shown to be transparent and exhibit better mechanical properties than collagen crosslinked scaffolds. 60 The high level of transparency and robust mechanical properties of native cornea are attributed to the orthogonal arrangement of aligned collagen fibrils within the corneal stroma. Development of bioengineered corneas that mimics such structural organization would greatly enhance their potential to be used in corneal regeneration applications.…”

Section: Collagen Hydrogelsmentioning

confidence: 99%

Application of Hydrogels in Ocular Tissue Engineering

et al. 2016

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Corneal disease is a leading cause of blindness worldwide. Transplantation of donor cornea is the preferred treatment for corneal disease. However, these are limited in supply, especially in developing countries. Therefore, there is a need for alternative treatment methods to meet the rising demand for corneal replacements. Over the past two decades, much work has been done in this realm. In this chapter, we fi rst describe the signifi cance of the problem associated with corneal disease, the current treatment options available and their related limitations. Following this, studies in the literature that focus on the development of alternative treatment methodologies including decellularization of xenogenic corneal tissue, development of hydrogel based polymeric bioscaffolds and microengineering are discussed in detail. Finally,

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Silica Hybrid for Corneal Replacement: Optical, Biomechanical, and Ex Vivo Biocompatibility Studies

Abstract: Silica-collagen hybrid materials can be manufactured to specific dimensions to serve as a possible artificial corneal substitute. In preliminary studies, the materials had favorable optical, biomechanical, and biocompatibility properties necessary for replacing the corneal stroma.

Cited by 7 publications

References 27 publications

Surface Modification of PMMA to Improve Adhesion to Corneal Substitutes in a Synthetic Core–Skirt Keratoprosthesis

Surface Modification of PMMA to Improve Adhesion to Corneal Substitutes in a Synthetic Core–Skirt Keratoprosthesis

Development of Silica-Collagen Composite as Corneal Substitute through Sol-Gel Additive Manufacturing

Application of Hydrogels in Ocular Tissue Engineering

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