Optimization of the spray-deposited carbon nanotube semiconducting channel for electrolyte-gated field-effect transistor-based biosensing applications

Electrochemical biosensors are widely investigated as they represent attractive analytical tools for detection of a broad range bio-molecules, thanks to their simplicity, high sensitivity and short response time. Especially, employing an electrolyte-gated field-effect transistors (EG-FETs) electrochemical transduction element have gained increasing interest, due the signal amplification intrinsic low voltage operation. In this work we report fabrication flexible EG-FETs using spray-deposited semiconducting carbon nanotubes (CNTs), with specific focus on optimization CNT channel optimize performance resulting CNT-based EG-FET (EG-CNTFET). The transfer output characteristic different devices varying spraying parameters were tested, finding out that only source-drain resistance about ≤10 kΩ showed proper EG-CNTFET operation: these recorded typical p-type behavior on–off ratio 214 A/A up 469 (depending number layers). fabricated EG-CNTFETs functionalized anti-spermidine antibodies detect polyamine spermidine - well-known chemical indicator food quality. To ensure controlled immobilization at same time preserve electrical properties nanotubes, films modified bifunctional molecule, which attaches via non-covalent π interactions leaves free NHS-ester group amide coupling antibodies. EG-CNTFET-based immunosensors linear from 10-3 102 nM, sensitivities ranging -1.03 -2.45 μA/decade.