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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 58078 (06)
- University: Sharif University of Technology
- Department: Chemical and Petroleum Engineering
- Advisor(s): Abdekhodaie, Mohammad Jafar
- Abstract:
- Corneal perforations are one of the most widespread illnesses which are associated with severe pains and vision loss. Eyes with corneal perforations must be treated immediately in order to preserve its morphology and prohibit secondary complications. Opthalmologist usually apply cyanoacrylate and fibrin glues for filling and sealing incisions, but they have several drawbacks besides their advantages. Cyanoacrylates which are unabsorbable remains as a foreign body in the patient’s eyes and will cause annoyment. Fibrin glues that are attained from ibrinogen and thrombin, can transfer blood diseases. Therefore, fabricating a bioadhesive with high biocompatibility, adhesion and mechanical stability is vital. The aim of this study, is designing and fabricating a regenerative in situ forming hydrogel for treating corneal perforations. The main substance of this adhesive is collagen type I which is similar to corneal stromal tissue as it mainly consists of collagen type I. Collagen lose its robustness when it is extracted and would degrade soon. Poly (ethylene glycol) was used for reinforcing and crosslinking of the collagen strands. Its chains were chemically modified in order to bind amine and thiol groups of the tissue surface even in wet circumstances. Since collagen is one of the most abundant proteins in the extra cellular matrix, it can also acts as a scaffold for adhering, developing, and differentiating of corneal cells which leads to tissue regeneration. For this purpose, at first, collagen type I was extracted from rat tails and poly (ethylene glycol) was chemically modified. Then, the materials were composited by the aid of visible light irridation to form the bioadhesive hydrogel. To determine the optimum sample with the maximum adhesion, mechanical strength, and biocompatibility, characterization tests were applied. The optimum sample contained 8 mg/ml collagen type I and 30% (w/v) modified poly (ethylene glycol) as the cross-linker and was exposed to visible light for 5 minutes. The maximum adhesive strength of this sample was 783/6 kPa and its maximum shear strength was measured 53/7 kPa. These values are much higher than the maximum adhesive and shear strength of the commercialized eye adhesives. The average pore size of this hydrogel was 61/11μm and it was completely destroyed by collagenase type I within 30 days. Also, the results of the biocompatibility test showed the survival of the keratocytes seeded on the hydrogel adhesive was noticeably high (more than 100%) after 7 days of incubation. Therefore, it is expected that the designed bioadhesive with high adhesion strength, good mechanical strength and high biocompatibility, will improve the process of spontaneous repair of damaged corneal stromal tissue. Furthermore, due to its injection and rapid formation at the lesion site, it could overcome some technical challenges. The designed product can be commercialized since the synthesis, characterization and animal testing steps are not difficult, and the materials used for their synthesis are available and reasonably priced.
- Keywords:
- Bioadhesive ; In-Situ Forming Hydrogel ; Collagen Type I ; Tissue Spontaneous Regenertion ; Corneal Perforations ; Corneal Tissue Regeneraction
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