A field effect transistor biosensor with a γ-pyrone derivative engineered lipid-sensing layer for ultrasensitive Fe3+ ion detection with low pH interference.

Field effect transistors have risen as one of the most promising techniques in the development of biomedical diagnosis and monitoring. In such devices, the sensitivity and specificity of the sensor rely on the properties of the active sensing layer (gate dielectric and probe layer). We propose here a new type of transistor developed for the detection of Fe(3+) ions in which this sensing layer is made of a monolayer of lipids, engineered in such a way that it is not sensitive to pH in the acidic range, therefore making the device perfectly suitable for biomedical diagnosis. Probes are γ-pyrone derivatives that have been grafted to the lipid headgroups. Affinity constants derived for the chelator/Fe(3+) complexation as well as for other ions demonstrate very high sensitivity and specificity towards ferric ions with values as high as 5.10(10) M and a detected concentration as low as 50 fM.