Dielectric properties of hydrated proteins at 9.9 GHz

The complex dielectric permittivities of bovine serum albumin, cytochrome-c and lysozyme powders have been measured as a function of partial hydration at 9.9 GHz using a microwave cavity perturbation technique. By analysing the results in terms of multilayer sorption it is concluded that only water bound to these proteins in the secondary hydration layers is able to contribute significantly to dielectric loss at this frequency. Such measurements are of relevance regarding the development of microwave techniques for the treatment or detection of cancerous tissue.