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author:("mares, Mona K")
1.  Nanoporosity Significantly Enhances the Biological Performance of Engineered Glass Tissue Scaffolds 
Tissue Engineering. Part A  2013;19(13-14):1632-1640.
Nanoporosity is known to impact the performance of implants and scaffolds such as bioactive glass (BG) scaffolds, either by providing a higher concentration of bioactive chemical species from enhanced surface area, or due to inherent nanoscale topology, or both. To delineate the role of these two characteristics, BG scaffolds have been fabricated with nearly identical surface area (81 and 83±2 m2/g) but significantly different pore size (av. 3.7 and 17.7 nm) by varying both the sintering temperature and the ammonia concentration during the solvent exchange phase of the sol-gel fabrication process. In vitro tests performed with MC3T3-E1 preosteoblast cells on such scaffolds show that initial cell attachment is increased on samples with the smaller nanopore size, providing the first direct evidence of the influence of nanopore topography on cell response to a bioactive structure. Furthermore, in vivo animal tests in New Zealand rabbits (subcutaneous implantation) indicate that nanopores promote colonization and cell penetration into these scaffolds, further demonstrating the favorable effects of nanopores in tissue-engineering-relevant BG scaffolds.
PMCID: PMC3665319  PMID: 23427819
3.  Mandibular reconstruction using an axially vascularized tissue-engineered construct 
Current reconstructive techniques for continuity defects of the mandible include the use of free flaps, bone grafts, and alloplastic materials. New methods of regenerative medicine designed to restore tissues depend mainly on the so-called extrinsic neovascularization, where the neovascular bed originates from the periphery of the construct. This method is not applicable for large defects in irradiated fields.
We are introducing a new animal model for mandibular reconstruction using intrinsic axial vascularization by the Arterio-Venous (AV) loop. In order to test this model, we made cadaveric, mechanical loading, and surgical pilot studies on adult male goats. The cadaveric study aimed at defining the best vascular axis to be used in creating the AV loop in the mandibular region. Mechanical loading studies (3 points bending test) were done to ensure that the mechanical properties of the mandible were significantly affected by the designed defect, and to put a base line for further mechanical testing after bone regeneration. A pilot surgical study was done to ensure smooth operative and post operative procedures.
The best vascular axis to reconstruct defects in the posterior half of the mandible is the facial artery (average length 32.5 ± 1.9 mm, caliber 2.5 mm), and facial vein (average length 33.3 ± 1.8 mm, caliber 2.6 mm). Defects in the anterior half require an additional venous graft. The defect was shown to be significantly affecting the mechanical properties of the mandible (P value 0.0204). The animal was able to feed on soft diet from the 3rd postoperative day and returned to normal diet within a week. The mandible did not break during the period of follow up (2 months).
Our model introduces the concept of axial vascularization of mandibular constructs. This model can be used to assess bone regeneration for large bony defects in irradiated fields. This is the first study to introduce the concept of axial vascularization using the AV loop for angiogenesis in the mandibular region. Moreover, this is the first study aiming at axial vascularization of synthetic tissue engineering constructs at the site of the defect without any need for tissue transfer (in contrast to what was done previously in prefabricated flaps).
PMCID: PMC3069948  PMID: 21418603

Results 1-3 (3)