EFFECT OF GRAVITY AND DIFFUSION INTERFACE PROXIMITY ON THE MORPHOLOGYOF COLLAGEN GELS

Collagen solutions (0.25% w/v) were polymerized in microgravity (STS-7 7, 10 days) along with simultaneous ground controls. Assembly conditio ns were achieved by the passage of buffer ions across a dialysis membr ane into a reaction chamber containing the dissolved collagen. The gel s were analyzed macroscopically and microscopically to assess the infl uence of gravity and the oriented diffusion of buffer ions on the resu lting product. Double-blind rankings based on visual observation of th e gels established that all of the flight gels (n = 8) were more unifo rm in appearance than all of the ground gels (n = 6). Photography usin g side illumination of the gels revealed the more granular appearance of the ground gels relative to the highly uniform appearance of the fl ight gels. Scanning electron microscopy established this difference at the microscopic level. Proximity to the dialysis interface and the pr esence or absence of gravity were both found to control the porosity a nd uniformity of the matrix. (C) 1997 John Wiley & Sons, Inc.