Abstract
Plastics accumulating in the environment are nowadays of great concern for aquatic systems and for the livingorganisms populating them. In this context, nanoplastics (NPs) are considered the major and most dangerous contaminants becauseof their small size and active surface, which allow them to interact with a variety of other molecules. Current methods used for thedetection of NPs rely on bulky and expensive techniques such as spectroscopy. Here we propose, for the first time, a novel, fast, andeasy-to-use sensor based on an electrolyte-gated field-effect transistor (EG-FET) with a carbon nanotube (CNT) semiconductor(EG-CNTFET) for the detection of NPs in aquatic environments, using polystyrene NPs (PS-NPs) as a model material. Inparticular, as a working mechanism for the EG-CNTFETs we exploited the ability of CNTs and PS to form noncovalent interactions.Indeed, in our EG-CNTFET devices, the interaction between NPs and CNTs caused a change in the electric double layers. A linearincrease in the corrected on current (*ION) of the EG-CNTFETs, with a sensitivity of 9.68 μA/(1 mg/mL) and a linear range ofdetection from 0.025 to 0.25 mg/mL were observed. A π−π interaction was hypothesized to take place between the two materials, asindicated by an X-ray photoelectron spectroscopy analysis. Using artificial seawater as an electrolyte, to mimic a real-case scenario, alinear increase in *ION was also observed, with a sensitivity of 6.19 μA/(1 mg/mL), proving the possibility to use the developedsensor in more complex solutions, as well as in low concentrations. This study offers a starting point for future exploitation ofelectrochemical sensors for NP detection and identification.