Dielectric and electrical properties of hydrated bovine serum albumin

Steady state conductivity and dielectric measurements over the range 2 × 10–5 to 105 Hz are reported for compressed samples of bovine serum albumin as a function of hydration. Two dielectric dispersions were observed, with the higher frequency dispersion having a relaxation time given by τ=ε0εr/σ, where σ is the steady state conductivity and εr is the relative permittivity measured at 105 Hz. A model is proposed which directly relates the d.c. and dielectric properties in terms of the activated hopping of a fixed number of charge carriers over potential energy barriers within the bulk of the samples.