Soft matter systems interfaced to an electronic device are presently one of the most challenging research activity that has relevance not only for fundamental studies but also for the development of highly performing bio-sensors. In this presentation the full integration of hierarchically organized layers phospholipid bilayers and proteins into an electrolyte gated organic field effect transistor (EGOFET) is proposed.
In EGOFETs, the dielectric gating is achieved through the formation of a Debye-Helmholtz double layer (DHDL) at the interface between the electrolyte solution and the OSC layer. Being very thin (few Å) such DHDL has a large capacitance allowing for sub-volt operation.
We have functionalized the OSC by anchoring on it a biotinylated phospholipid bilayer [1]. The supported bilayer can be easily further functionalized with virtually any receptors by using biotin-streptavidin chemistry. Actually, we have functionalized the EGOFET with a antibody against the C-reactive protein (CRP) thus obtaining a transistor device able to sense the CRP concentration. The device performances improve upon increasing the high ionic strength of the electrolyte solution thus allowing the sensing also on blood serum. This result challenges the current believe that electronic detection is unsuited to sense any recognition event taking place at a distance from the semiconductor surface much larger than the Debye’s length. The sensing mechanism that allows to circumvent the screening due to the background electrolytes will be discussed
[1] M. Magliulo, A. Mallardi, M. Yusuf Mulla, S. Cotrone, B.R. Pistillo, P. Favia, I. Vikholm-Lundin, G. Palazzo, L Torsi
Electrolyte-Gated Organic Field-Effect Transistor Sensors Based on Supported Biotinylated Phospholipid Bilayer
Adv. Mater. 2013, 25, 2090–2094
gerardo.palazzo@uniba.it
