Design, Characterization, Control, and Use of Biopolymer Gels

We study the properties of collagen I based gels at equilibrium and during gelation through complementary use of rheology and confocal microscopy. We find that collagen I gels at equilibrium are "well behaved," and a subset of their mechanical properties can be ascertained from optical imaging alone. On the other hand, collagen is less well behaved as it self-assembles, and its gelation can not be easily described with theories previously used to describe chemical and physical gelation.

• We perform confocal reflectance and confocal fluorescence microscopy to understand collagen fiber and network structure.

Schematic for confocal reflectance microscopy (CRM) imaging, 2D CRM slices of a collagen gel, and a 3D reconstruction from 2D CRM slices.






• We are particularly interested in tuning pore size and fiber diameter in collagen gels of identical collagen concentration. Such studies help us understand how structure sets mechanical properties in these gels and also are useful forcell migration studies.

1.0 mg/ml collagen gels formed at 37oC and 22oC. Low temperature induces fibril and fiber bundling, which in turn enhances gel stiffness even as pore size in these gels increases.






• To understand why gels differ structurally and mechanically as a function of gelation temperature, as well as to understand whether traditional measures of "gelation time" are useful for understanding biopolymer gelation, we study collagen during self-assembly from monomers to fibrils, fibers, and a fiber network.

Complementary CRM and rheology reveal structures responsible for setting the loss and storage moduli of collagen gels as they develop.






Would you like to learn more? If so, contact Matt Wilhelm.