Increased thermal stability of a glucose oxidase biosensor under high hydrostatic pressure.

We report the effects of high hydrostatic pressure (HHP), immobilization in electrochemically generated poly-o-phenylenediamine nano-films, and reticulation with glutaraldehyde on the thermal stability of glucose oxidase (GOx). The pseudo-first-order rate constant of inactivation of immobilized GOx inactivated at 70 °C and atmospheric pressure was 20.6 times smaller than that of GOx in solution under the same conditions. Immobilized GOx inactivated at 70 °C and 180 MPa was 87.6 times more stable than GOx in solution inactivated at 70 °C and atmospheric pressure. However, applying high pressure during electropolymerization or cross-linking with glutaraldehyde only had minor influences on GOx thermal stability. The stabilizing effect of HHP was not retained upon depressurization.