Application of membrane-engineering to bioelectric recognition cell sensors for the ultra-sensitive detection of superoxide radical: A novel biosensor principle

Anew, hybrid type of ultra-sensitive electrophysiological superoxide anion (O-2(.-)) sensor is described, which is based on membrane-engineered mammalian cells immobilized in an alginate matrix. The membrane-engineering process involved the electroinsertion of superoxide dismutase (SOD) molecules in the membranes of Vero fibroblast cells, which acted as catalytic units able to convert O-2(.-) to H2O2. Superoxide dismutation triggered changes to the cell membrane potential that were measured by appropriate microelectrodes, according to the principle of the bioelectric recognition assay (BERA). The sensor instantly responded to O-2(.-) with a detection limit (S/N = 3) of 100pM. Combined with a 4-month storage capacity at room temperature, the novel biosensor principle offers new perspectives for monitoring ultra-low concentrations of free radical species and oxidative agents in biological systems. (c) 2006 Elsevier B.V. All rights reserved.