Research Description

My research focuses on the use of biomaterials to deliver cells such as fibroblasts, keratinocytes and stem cells. The biomaterials include fibrin and collagen. The research also focuses on generating synthetic materials coated with fibrin and collagen. The cell – biomaterial interaction is examined by studying the protein expression by cells incorporated in the constructs. The research also examines the biomechanical characteristic of the cell – biomaterials constructs over a period of time. The research so far shows that changing the concentration of fibrinogen, thrombin or collagen in the final constructs influences the protein expression by the cells as well as the biomechanical characteristics of the constructs. The research also indicates that the environment within the constructs affects the mesenchymal stem cell differentiation into osteoblasts.

Future questions under examination:
1. What is the optimal environment to deliver various types of cells?
2. What is the protein profile expression for various cells in different environments?
3. How do these cell – biomaterial constructs behave in In Vivo model?

Publications

2. Ignatius M. J., Large T.H., Houde M., Tawil N.J., Barton A., Esch F., Carbonetto S. and Reichardt L.F. 1990. Molecular cloning of the rat integrin a1 subunit: a receptor for laminin and collagen. J. Cell Biology 111:709-720

3. Tawil N.J., Wilson P., and Carbonetto S. 1993. Integrins in point contacts mediate cell spreading: factors that regulate integrin accumulation in point contacts and focal contacts. J. Cell Biol. 120 (1): 261-271

4. Tawil N.J., Wilson P., and Carbonetto S. 1994. Characterization and distribution of functional integrins in rat CNS. J. Neuros. Research 39: 436-447

5. Tawil N.J., Gowri V., Djoneid M., Nip J., Carbonetto S., and Brodt P. 1996. Integrin A can promote adhesion and spreading of metastatic carcinoma cells on the lymph node stroma. Int. J. Cancer 66: 703-710

6. Burgess E, Hollinger J, Gruskin E, Bennett S, Scmitt J, Buck D, Shannon R,
Joh S-P, Choi J, Mustoe TA, Lin H, Skalia W, Christoforou, C, Tawil N.J., Connors D. 1998. Charged beads promote cutaneous wound healing in Rhesus non-human primates. Plastic and Reconstructive Surgery. 102:2395-2403

7. Tawil N.J., Connors D., Gies D., Lin H., Mustoe T. and Gruskin E. 1999. Stimulation of wound healing by positively charged dextran beads depends upon clustering of beads and cells in close proximity to the wound. Wound Reapir and Regeneration. 7:389-399.

8. Tawil N.J. 1999. Integrins. Wound Repair and Regeneration Newsletter. 9:1.

9. Connors D., Gies D., Cristoforou C., Lin H., Mustoe T., Gruskin E., Tawil N.J. 2000. Increase in wound braking strength in rats in the presence of positively charged dextran beads correlates with an increase in endogenous TGFb1 and its receptor TGFbR1 in close proximity to the wound. Wound Repair and Regeneration. 8:292-303

10. Mogford J, Tawil N.J., Chen A., Xia Y, Gruskin E., Mustoe T., 2002. Effect of age and hypoxia on TGFbeta1 receptor expression and signal transduction in human dermal fibroblasts: impact on cell migration. J Cell Physiol. 190(2):259-65.

11. Tawil N.J. 2003. Fibrin and its Characteristics. Wound Repair and Regeneration Newsletter. 11.2

12. Cox S., Cole M., Mankarious S., Tawil N.J. 2003. The Effect of Tranexamic Acid Incorporated in Fibrin Sealant Clots on Cell Behavior of Neuronal and Non-Neuronal Cells. J. Neuronal Research. 72: 734-746

13. Nien Y.-D., Han Y.-P. , Tawil N.J., Chan L.S., Tuan T.-L. and Garner W. 2003. Fibrinogen Inhibits Fibroblast Mediated Contraction of Collagen. Wound Repair and Regeneration. Wound Repair and Regeneration 11:380-385

14. Helgerson S., Seelich T., Di Orio J., Tawil N.J., Bittner K., and Spaethe R. 2004. Fibrin. Review. Encyclopedia of Biomaterials and Biomedical Engineering. Book Chapter

15. Cox S., Cole M., and Tawil N. 2004. The Behavior of Human Dermal Fibroblasts In 3 Dimensional Fibrin Clots: Dependence on the Fibrinogen and Thrombin Concentration. Tissue Engineering. Vol 10 (5/6): 942

16. Deiters U., Barsig J., Tawil N., and Mühlradt P. 2004. The Macrophage Activating Lipopeptide MALP-2 Accelerates Wound Healing in Diabetic Mice. Exp Dermatol. Dec;13(12):731-9.

17. Mooney R.G., Costales C.A., Curtin J.M., Tawil B., C. Shaw. 2005. Indentation Micromechanics of Fibroblast-Populated Fibrin Constructs. Materials Research Society 874: 205 - 210

18. Tawil B.. 2005. Fibrin and Its Applications. Review. An Introduction to Biomaterials. Chapter 7: 105 – 120. Editors: S.A. Guelcher & J.O. Hollinger. Publisher: CRC Taylor & Francis

19. Mana M, Cole M., Cox S. and Tawil B. 2006. Human U937 monocyte behavior and protein expression on various formulations of three-dimensional fibrin clots Wound Repair and Regeneration. 14 Issue 1 Page 72

20. Ho W., Tawil B., Dunn J. C.Y., B. M. Wu. 2006. The Behavior of Human Mesenchymal Stem Cells In 3D Fibrin Clots: Dependence on Fibrinogen Concentration and Clot Structure. Tissue Engineering. Vol 12(6): 1-9

21. Catelas I., Sese N., Wu B., Dunn J., Helgerson S., Tawil B... 2006. Human Mesenchymal Stem Cells Proliferation and Osteogenic Differentiation in Fibrin Gels in vitro. Tissue Engineering. Vol 12(8): 1-9

22. Mogford J., Tawil B., and. Mustoe T. 2007. Fibrin Sealant Combined with Fibroblasts and PDGF Enhance Wound Healing in Excisional Wounds. Submitted

23. Cole M., Cox S., Inman E., Chan C., Mana M., Helgerson S. and Tawil B. 2007. Fibrin Sealant TisseelR as a Delivery Vehicle for Active Macrophage Activator LipoProtein - 2 Peptide: In Vitro Studies. Submitted.

24. Sese N., Cole M. and and Tawil B. 2007. The Behavior of Human Dermal Fibroblasts and Keratinocytes in 3 Dimensional Fibrin Clots: Cross – Talk Effect Manuscript in Preparation.