In this work, our attention was drawn towards developing
affinity-based electrical biosensors, using a MESFET (Metal
Semiconductor Field Effect Transistor). Semiconductor (SC) surfaces must be prepared before the incubations with
biomolecules. The peptides route was adapted to exceed and bypass the limits revealed by other types of surface
modification due to the unwanted unspecific interactions. As these peptides reveal specific recognition of materials, then
controlled functionalization can be achieved.
Peptides were produced by phage display technology using a library of M13 bacteriophage. After several
rounds of bio-panning, the phages presenting affinities for GaAs SC were isolated; the DNA of these specific phages
were sequenced, and the peptide with the highest affinity was synthesized and biotinylated. To explore the possibility of
electrical detection, the MESFET fabricated with the GaAs SC were used to detect the streptavidin via the biotinylated
peptide in the presence of the bovine Serum Albumin. After each surface modification step, the IDS (current between the
drain and the source) of the transistor was measured and a decrease in the intensity was detected. Furthermore,
fluorescent microscopy was used in order to prove the specificity of this peptide and the specific localisation of
In conclusion, the feasibility of producing an electrical biosensor using a MESFET has been demonstrated.
Controlled placement, specific localization and detection of biomolecules on a MESFET transistor were achieved
without covering the drain and the source. This method of functionalization and detection can be of great utility for
biosensing application opening a new way for developing bioFETs (Biomolecular Field-Effect Transistor).