FET-based biosensors with back-gate coupling towards the electrical pre-amplification of cardiac troponin I detection

The existing FET-based biosensors nowadays only depend on a physical structure size of a device. Due to those limitation, the device can only be read with the presence of high sensitivity electrical readers. To synchronize the device with a low-cost portable electrical reader, the electrical signal need to be amplified with minimal noise output. In this work, a label-free, specific and sensitive back-gated FET based biosensor is presented for the detection of cTnI protein by using SOI type of wafer with TiO
2
act as a transducer material. TiO
2
is deposited by using sol-gel method with surface functionalized for cTnI protein binding. From the XPS result, it shows that each covalent bonding characteristic from APTES deposition until cTnI antibody-antigen interaction. Finally, the electrical (I
d
-V
bg
) result show the ability to detect cTnI protein with concentration of 2.0 µg/µl at −150 µA (V
d
= 0). As V
d
increases, a tremendous increment of electrical conductivity with larger difference of I
d
value between each surface functionalization processes can be achieved. At V
d
= −5, the electrical conductivity jumped up to −1 mA, more than 500% increase compared to V
d
= 0.