[ effects of epithelial and spongy layers on transparency of amniotic membrane as a substitute for corneal tissue engineering]

Background and Aim: The light transmittance through amniotic membrane [AM] has a major effect on the visual acuity after transplantation of this biomaterial for reconstruction of the cornea. In this study, we evaluated role of placental region of extracted AM and histological layers of the amnion on the light transmission ability [transparency]

Material and Method: The AMs were obtained from disk and peripheral [2 cm away from disk edge] regions of the placenta. The light transmission rates of the prepared intact tissues and also of the tissues after removal of the epithelial and spongy layers were measured. We determined the thicknesses of AMs by evaluating the photos of histological sections using software analyses

Results: Peripheral region of the AM was more transparent than the disk region. Histological studies revealed structural differences between epithelial cells of disk and peripheral regions. Removal of the epithelial cells increased the transparency of AMs and omitted the transparency difference between disk and peripheral regions, while, the thickness of the AMs samples of the two regions had significant differences after removal of the epithelial layer

Conclusion: The epithelial cells of the AM, which have stem cell characteristics, play a major role in the light transmission ability of the AM, and thickness of the membrane had no significant impact on its light transmission rate

[Determination of antibacterial effect of the epithelial and mesenchymal surfaces of amniotic membrane on Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa]

Human amniotic membrane due to its unique characteristics, has many applications various fields of medicine and tissue engineering. One of these characteristics is antibacterial property, which can be important in protection against infections after burn and surgery. This study was designed aiming at investigating the antibacterial effect of amnion on the growth of different bacterial strains and comparing this effect in epithelial and mesenchymal sides of the amnion. In this study, the antibacterial effect of amniotic membrane was evaluated on three standard bacterial strains Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 and two clinical isolated strain of E. coli [E. coli T3 and E. coli T4], and their susceptibility was measured. A modified disk diffusion test was used to assess the antibacterial effect. In this method, amnion was placed on the cultured agar surface as an antibiotic releasing disk. Statistical analysis was performed using analysis of variance and Tukey's tests. The vicinity of amnion membrane caused inhibition zone against Pseudomonas aeruginosa ATCC 27853 and two clinical isolated strains of E. coli. Formation of Inhibition zone in Pseudomonas aeruginosa ATCC 27853 and two clinical isolated strains of E. coli had no relationship with the epithelial or mesenchymal side of amniotic membrane. According to the results of this study, it seems that the type of bacterial strain has a role in the antibacterial effect of amnion membrane. In addition, both sides of amnion [epithelial and mesenchymal] may have similar antibacterial effect

Synthesis and characterization of fiber reinforced polymer scaffolds based on natural fibers and polymer for bone tissue engineering application

A wide range of materials and scaffolding fabrication methods for bone tissue engineering have been explored recently. Fiber reinforced polymers [FRP] system appears to be a suitable system. By the exclusive use of biocompatible or bio-absorbable polymers and fibers, novel generation of scaffolds for applications in tissue engineering can be prepared. Mulberry Silk as highlighted natural fiber with its specific economic, mechanical and biological properties has been used for fabrication FRP scaffolds. In this study FRP scaffolds prepared by a combination of silk fibroin polymer, which is another configuration of silk fibers as a porous matrix and silk fibers as the reinforcement element. FRP scaffolds have been fabricated by the freeze-drying method. Microstructure has been analyzed by scanning electron microscopy and the results show an integrative structure. Mechanical properties have been evaluated by universal testing machine. Compressive mechanical modules as well as strength of FRP scaffolds increased about three times in magnitude in comparison with pure fibroin scaffolds. FRP scaffolds had a compressive module of -3.6 MPa. Osteoblast viability and attachment on FRP scaffolds were investigated in vitro by MTT assay, which showed no cytotoxic response. Additionally, based on SEM results it is concluded that FRP scaffolds provide a good environment for osteoblast attachment