268a Oriented Collagen Films for Wound-Healing Applications

An J. Goffin1, Jaykumar Rajadas1, Heather Lake1, Raymon Grogan2, Shahram Aarabi2, Geoff Gurtner2, and Gerald G. Fuller1. (1) Chemical Engineering, Stanford University, 381 North South Mall, Stanford, CA 94305, (2) Medical School: Children's Surgical Research Lab, Stanford University, 381 North South Mall, Stanford, CA 94305

It is known that a fetus has the ability to heal wounds without much scarring, while in an adult, wound healing is characterized by scar formation. This difference has been thought to occur mainly because of the differences in extra-cellular matrices in fetal versus adult skin. Collagen, the most abundant protein in the ECM, forms ordered structures with a very high degree of orientation in fetal skin, while in adult skin, the orientation of the collagen molecules is decreased. A new method is developed of generating well-oriented collagen films with the purpose of producing artificial to promote wound healing. The method involves a means of spreading solubilized collagen on the surface of a phosphate buffer. The orientation of the collagen molecules is manipulated by inducing a surface flow. Subsequently, the oriented collagen structure is harvested through Langmuir-Blodgett deposition. Direct optical measurements of molecular orientation are accomplished through dichroism and birefringence and monitor the kinetics of this process. The molecular orientation is monitored before and after deposition. After deposition, the films are characterized using spectroscopic techniques. To test the biological performance of the collagen films produced in this manner, human skin fibroblasts are cultured onto them. The survival, proliferation rate and shape of the fibroblasts are monitored over time. To gain a more thorough understanding of the loss of collagen orientation in skin during fetal development, the same optical techniques used to study our artificial films, are used to map out the birefringence and orientation changes in the fetal skin. Applying these techniques to biological samples allows us to make a quantitative assessment of the collagen structure in fetal skin. It is found that the oriented collagen films can be produced by the proposed method. Human skin fibroblasts are able to grow on the produced substrates and their shape suggests that they orient along the collagen fibers.