Transistor-Based Nanoplastics Sensor: Investigation of Sensitivity Toward Polystyrene and Polyethylene Terephthalate

The accumulation of nanoplastics (NPs) in the environment poses serious ecological and health risks, underscoring the urgent need for simple and reliable detection methods. In this study, we explored the use of electrolyte-gated field-effect transistor (EG-FET) based sensors incorporating carbon nanotube (CNT) semiconducting channels (EG-CNTFET) for NPs detection. In particular, we first evaluated the EG-CNTFET’s sensitivity to two NPs models: non-functionalized polystyrene (PS), and polyethylene terephthalate (PET). EG-CNTFETs exhibited distinct responses to the two polymers: PS NPs induced a current increase of up to 35.48% at 0.25 mg/mL, whereas PET NPs caused a pronounced current decrease of up to 87.77% at the same concentration. Further tests with PS NPs types (with or without surface carboxylation) at low concentrations (ranging from 0.025 to 0.5 mg/mL) revealed high sensitivity, quantified as 26.4 μA*mL/mg for non-functionalized PS NPs and 20.5 μA*mL/mg for carboxylated PS NPs. Control experiments with pure electrolyte confirmed that the observed signal changes were not due to volumetric effects. These findings demonstrate the potential of EG-CNTFET-based sensors for sensitive detection of PS NPs, while highlighting the need for further investigation into their applicability for PET NPs detection.