Mesostructure of fibrillar bovine serum albumin gels.

The mesostructure of bovine serum albumin (BSA) at low pH was investigated. Rheological measurements were performed to determine the critical percolation concentration (c(p)). A decreasing c(p) with increasing ionic strength was found. Fibrils with a contour length of about 100-300 nm were found using transmission electron microscopy. The measured conversion of monomers into fibrils was independent of ionic strength (0.20-0.30 M). Dilution of BSA samples showed that the aggregation process is reversible and that there exists a critical concentration for the self-assembly of BSA. We explain the decreasing c(p) with increasing ionic strength in terms of an adjusted random contact model.