Study of patterned. multilayered, collagen-based scaffolds designed toserve as a cornea stroma

Kılıç, Cemile
Cornea is the most exterior, avascular and transparent layer of the eye and is about 500 µm in thick. It protects the eye from external objects and it is the main optical element of the eye refracting 70 % of the incoming light. After cataract, corneal diseases and wounds are the second leading cause of the blindness that affects more than 4 million people worldwide. For the highly damaged corneas where the corrections with spectacles or contact lenses cannot be achieved, tissue replacement is the only choice, and is done by cornea transplantation or keratoprostheses. However, due to limited number of donor corneas and the risk of infections during transplantation, and development of glaucoma, necrosis and other complications caused by the keratoprostheses, prevent them from meeting expectations. Tissue engineering is a promising field which emerged from biomaterials science and aims to replace, restore or improve the function of the diseased or injured tissues. In this method, after the production of an ideal scaffold that mimics the natural human tissue, cells of the host are isolated, increased in number, and seeded on the scaffold developed to serve as the microenvironment of the cells. In the current study a 3D corneal stroma replacement was designed to mimic the native stroma. It consisted of 4 films of patterned collagen or collagen blended with Elastin Like Recombinamer (ELR) stacked on top of each other and then crosslinked by dehydrothermal (DHT) treatment. The characterization of the films showed that the pattern fidelity was good and they did not deteriorate after crosslinking. Enzymatic and in situ degradation studies showed that the DHT treatment at 150 oC for 24 h (DHT150) was the optimum condition. The transparency of all the films was quite high where uncrosslinked (UXL) films and DHT150 Col:ELR films yielded the best results. The individual films and 3D construct of 4 stacked films were seeded with isolated human corneal keratocytes (HK) and cultured for 21 days. Cells attached and proliferated well on the single Col and Col:ELR films. However, the proliferation was higher on Col multilayer constructs than their Col:ELR counterparts. Cells were aligned along the patterns of the films while no significant alignment was observed for the cells on unpatterned films. Ultimate tensile strength (UTS) and Young’s Modulus (E) of Col and Col:ELR films were significantly lower after a 30 day culture than that of unseeded films of Day 1. Transparency of the seeded Col:ELR films was superior to Col films over a 30 days test and quite close to the transmittance of the native human cornea. It was concluded that the Col and Col:ELR patterned films and their 3D constructs have a significant potential for use as a corneal stroma equivalent.


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Acun, Aylin; Hasırcı, Vasıf Nejat; Buğra, Kuyaş; Department of Biotechnology (2013)
Cornea is the transparent outermost layer of the eye. It is a thin (500 µm) multilayer tissue which performes around 75% of the total refraction in the eye. It also protects the inner layers against any type of damage. Since it is avascular, the three cellular layers of cornea always need transport of nutrients and other materials in and out of the tissue via diffusion. Any change in shape, transparency or thickness of cornea, or physical damages and infections, may cause serious defects. The conventional m...
Contact guidance enhances the quality of a tissue engineered corneal stroma
Vrana, E.; Builles, N.; Hindie, M.; Damour, O.; AYDINLI, ATİLLA; Hasırcı, Vasıf Nejat (2008-02-01)
Corneal stroma is a very complex structure, composed of 200 lamellae of oriented collagen fibers. This highly complex nature of cornea is known to be important for its transparency and mechanical integrity. Thus, an artificial cornea design has to take into account this complex structure. In this study, behavior of human corneal keratocytes on collagen films patterned with parallel channels was investigated. Keratocytes proliferated well on films and reached confluency after 7 days in the incubation medium....
Influence of keratocytes and retinal pigment epithelial cells on the mechanical properties of polyester-based tissue engineering micropatterned films
Zorlutuna, Pinar; Builles, Nicolas; Damour, Odile; Elsheikh, Ahmed; Hasırcı, Vasıf Nejat (2007-08-01)
In this paper the mechanical properties of micropatterned polyester films prepared to serve as tissue engineering scaffolds of cornea were examined. Films were prepared by solvent casting of blends of poly(L-lactide-co-D,L-lactide) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid), on a micropatterned silicon template. They were seeded with keratocytes or retinal pigment epithelia] cells and subjected to tensile testing to assess the contribution of cells and the deposited extra-cellular matrix (ECM)...
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Optical scattering provides an intrinsic contrast mechanism for the diagnosis of early precancerous changes in tissues. There have been a multitude of numerical studies targeted at delineating the relationship between cancer-related alterations in morphology and internal structure of cells and the resulting changes in their optical scattering properties. Despite these efforts, we still need to further our understanding of inherent scattering signatures that can be linked to precancer progression. As such, c...
Cornea engineering on biodegradable polyesters
Zorlutuna, Pınar; Hasırcı, Vasıf Nejat; Department of Biotechnology (2005)
Cornea is the outermost layer of the eye and has an important role in vision. Damage of cornea due to injuries or infections could lead to blindness lowering the quality of life of the patient severely. In such cases, transplantation or artificial corneas have been used for treatment but both had drawbacks. The novel approach for corneal replacements is the tissue engineering of the cornea, a promising method which would be free of these drawbacks, if successful. In this study, carriers for tissue engineeri...
Citation Formats
C. Kılıç, “Study of patterned. multilayered, collagen-based scaffolds designed toserve as a cornea stroma,” M.S. - Master of Science, Middle East Technical University, 2013.