Mechanisms of supported bilayer detection using field-effect devices

Abstract

The adsorption of positively charged supported lipid bilayers (SLBs) on field-effect devices was studied using various salt solutions to make it possible to understand the signal generation mechanisms of the devices. The flat-band voltage change that occurred with SLB formation was dependent on the type of monovalent cations contained in the solution. Zeta potential data showed that the intrinsic charge of the bilayers was almost constant in the presence of any of the examined alkali ions. The results suggest that the lipid charge does not solely determine the flat-band voltage. The binding affinity of alkali ions to silicon nitride showed a similar trend to the dependence of the flat-band voltage change on alkali ions. The results indicate that the specific interaction of small inorganic ions with the device surface has a significant influence on the magnitude of the signal response that occurs with SLB formation. It appears that salt ions specifically bound to the device surface and the charge of the bilayers both contribute to the signal generation mechanisms.