الفهرس 
Review of literatureOnly 14 pages are availabe for public view
 |  | from | 179 |  |  |
| | | from | 179 | | |
Abstract
Bioengineered cornea is the accepted alternative to keratoplasty while it mimics the extracellular matrix and thus permit host tissue regeneration. Unlike bioengineered matrices of synthetic polymers, natural ones especially of plant sources are readily available and highly cytocompatible while considerably are less potential to be immunogenic on contrary to matrices of animal sources.
Here in, the extracted soy protein and glutenin from the commercially available and cost effective soybean seeds and wheat gluten with protein contents of 66.7% and 33.6%, respectively. The resultant proteins utilized in developing membranes to become substitutes to the human cornea. In which soy proteins were strengthened by enzymatic cross linking using horseradish peroxidase/ H202 system and with tannic acid while glutenins were chemically crosslinked with formaldehyde.
The peroxidase crosslinked soy membranes and the formaldehyde crosslinked glutenin membranes have optical and mechanical properties comparative to that measured for the rabbit corneas and also, to that was reported to the human one. The peroxidase crosslinked-soy membranes and the glutenin membranes have a high percentage of transparency of 88.3% ±0.5 and 88.6% ±0.7, respectively which are comparative to that of the rabbit corneas (91.2% ±1.1) with P=0.06 and 0.09, respectively unlike tannic acid crosslinked-soy membranes of the lower percentage of transparency of 63.0% ±1.2 than the rabbit corneas (P≤0.01). The % lightness for the peroxidase crosslinked-soy membranes and formaldehyde crosslinked glutenin membranes were 83.2 ±0.4, 88.6 ±1.2 which were comparative to that of the rabbit cornea (85.7 ±1.2) with P=0.10 and 0.07, respectively, the values which reveal a more light color closer to the white. The % lightness for the tannic acid crosslinked-soy membranes of 40.3 ±1.4 which reveal a less light color closer to the black more than the white and are not comparative to that of the rabbit corneas (P≤0.01). Only, the formaldehyde crosslinked glutenin membranes have a color saturation (9.0 ±0.9) comparative to that of the rabbit cornea (6.49 ±0.8) with P= 0.20, respectively, that all reveal possessing a low saturated color. peroxidase crosslinked-soy membrane and tannic acid crosslinked-soy membrane possesses a higher color saturation (20.2 ±1.6 and 35.5 ±1.6, respectively) than the rabbit cornea with P≤0.01.
Only the tannic acid crosslinked soy protein-based membranes have equilibrium water content (86.4% ±3.6) comparative to that was reported to the human cornea (80%) with p= 0.12) while the peroxidase crosslinked soy protein-based membranes and the formaldehyde crosslinked glutenin-based membrane have lower equilibrium water contents (45.7% ±3.1 and 38.6% ±2.0, respectively) with P≤0.01.
Only the peroxidase crosslinked-soy membranes have maximum stress and maximum strain of 3.6 MPa ±0.4 and 41.8 % ±5.4, respectively which was comparative to that of the rabbit cornea (3.5 MPa ±0.5 and 55.1% ±4.6, respectively) with P=0.76 and 0.19, respectively. The tannic acid crosslinked soy membranes and formaldehyde crosslinked glutenin-based membranes have a lower maximum stress of 1.2 MPa ±0.2 and 0.3 MPa ±0.04, respectively (P=0.01 and ≤0.01, respectively) but a higher maximum strain of 183.4 % ±7.4 and 69.8% ±8.2, respectively (P ≤0.01 and 0.15 respectively).
Our three membranes permit the normal human epithelial cells attachment and growth over them achieving a monolayer of cells with morphology similar to that grown on the control (the polystyrene wells without membranes). While the MTT cytotoxicity test demonstrates that formaldehyde crosslinked glutenin-based membranes show the highest cell viability (108.8 %) that was higher than the control while the peroxidase crosslinked soy membrane and the tannic acid crosslinked soy membranes show a relative cytotoxicity that affect the cell viability (85.7 % and 71.3 %, respectively) when compared to the control.
Despite of the need for further improvements and further investigations, their biocompatibility, high transparency and good mechanical properties which are comparative to those of the rabbit cornea and also, to that was reported for the human one reveal that membranes derived from glutenin and soy protein, a plant protein source, give a great hope for the future of the bioengineered cornea as an alternative to the donor cornea but it still needs more modifications and more investigations.