Advanced Printed Transistor Biosensors for Food Contaminant Detection
Résumé
The increasing incidence of food contaminants such as pesticides, antibiotics, and pathogenic bacteria necessitates the development of rapid, portable, and cost-effective detection technologies. Field-effect transistor (FET) biosensors based on two-dimensional (2D) materials offer a promising platform due to their compatibility with solution processing, which enables stable ink formulations. They also encompass a wide range of electronic types, including metals, semiconductors. Herein, we report the toward the development of printed FET biosensors based on electrochemically exfoliated MoS2 and graphene nanosheets in liquid crystalline (LC) inks. MoS₂ and graphene were prepared by controlled electrochemical exfoliation in aqueous electrolytes with large-sized intercalants, to obtain high yield nanosheets of a large size in lateral (>500 nm), a uniform thickness, a low defect density and avoid undesirable phase transition. The resultant nanosheets were stabilized in aqueous medium with polymeric surfactants to form LC phases, which facilitated 3D ordered assembly through direct ink writing (DIW). Ink phase behavior, rheology, and colloidal stability were extensively investigated to guarantee printability and structural alignment for efficient charge transport. The results establish a robust method for producing environmentally friendly, electronically functional inks, laying the groundwork for the subsequent development of high-performance FET biosensors targeting foodborne pathogens such as Salmonella Infantis.