Effect of microwave radiation on the permeability of carbonic anhydrase loaded unilamellar liposomes

The influence of 2.45 GHz microwave exposure (6 mW/g) on the diffusion processes in enzyme‐loaded unilamellar liposomes as bioreactors was studied. The enzyme carbonic anhydrase (CA) was entrapped into cationic unilamellar vesicles. Previous kinetic experiments showed a very low self‐diffusion rate of the substrate p‐nitrophenyl acetate (PNPA) across intact liposome bilayer. A twofold increase in the diffusion rate of PNPA through the lipid bilayer was observed after 120 min of microwave radiation compared to temperature control samples. The microwave effect was time dependent. The enzyme activity, as a function of increased diffusion of PNPA, rises over 120 min from 22.3% to 80%. The increase in stearylamine concentration reduces the enzyme activity from 80% to 65% at 120 min. No enzyme leakage was observed. © 1994 Wiley‐Liss, Inc. Copyright © 1994 Wiley‐Liss, Inc., A Wiley Company