| AVS 55th International Symposium & Exhibition | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuP |
| Session: | Biomaterials Interfaces Poster Session with Focus on Cells and Proteins at Interfaces |
| Presenter: | J.A. Appawu, University at Buffalo: The State University of New York |
| Authors: | J.A. Appawu, University at Buffalo: The State University of New York J.A. Gardella, University at Buffalo: The State University of New York |
| Correspondent: | Click to Email |
XPS and TOF-SIMS are techniques that can be used to quantify the uptake and release of proteins from polymers. Hydrogels are cross-linked hydrophilic polymers used in localized delivery of growth factors through pores defined by type and density of cross-links. Therefore uptake and release are diffusion controlled. Keratinocyte growth factor 1(KGF-1) is known to promote re-epithelialization after skin injury and stimulate the proliferation of skin cells. Inadequate amounts of growth factors can result in inefficient healing. In this study, (hydroxyethyl methacrylate ) (HEMA) hydrogels 3% and 6% were prepared with varying cross-link densities to answer three key questions:1) What is the optimal concentration of KGF-1 for cell adhesion, 2) Are HEMA hydrogels with specific structural properties viable for cell proliferation, and 3) What is the amount and time course of released KGF-1 present on the surface? Hydrogels were cut into equal areas to determine the amount of KGF-1 protein taken into and released from the hydrogels by fluorescence spectroscopy. XPS was used to confirm the quantity of KGF-1 on the surface and bulk by varying the take-off angle (TOA). The nitrogen atomic concentration was used to track the protein since nitrogen is present only in KGF-1. The amount of KGF-1 was higher in the 3% hydrogel due to a swelling ratio of 58.5% compared to 40.5% for the 6% hydrogel. Cell adhesion experiments have shown that 80-90% of HaCaT cells successfully adhere to the surface of the KGF-1 imbibed hydrogels and fluorescence microscopy proved that the cells were alive. TOF-SIMS has been used in depth profiling to confirm the XPS results.
Mahoney C. M., Yu J., Fahey A., and Gardella J. A. Jr. SIMS Depth Profiling of polymer blends with protein based drugs. Applied Surface Science (2006) 6690-6614. Pierce G.F. et. al. Stimulation of All Epithelial Elements during Skin Regeneration by Keratinocyte Growth Factor. J. Exp. Med. (1994) 179, 831-840. Tsuboi R. et al. Keratinocyte Growth Factor (FGF-7) Stimulates Migration and Plasminogen Activator Activity of Normal Human Keratinocytes. J. Invest. Dermatol. (1993) 101, 49-53. Greenhalgh D. G. The role of growth factors in wound healing. J. Trauma. (1996) 41, 159. Mahoney C. M., Yu J., and Gardella J. A. Jr. Depth Profiling of Poly(L-lactic Acid)/TriBlock Copolymer Blends with Time-of-Flight Secondary Ion Mass Spectrometry. Anal. Chem. 2005 77, 3570-3578.