Activities. The main activities performed during the EDISENS project are summarised below:
1) Design, fabrication, and testing of edible passive microfluidics. Edible passive microfluidic platforms were developed to confine liquid samples under test. Fourteen candidate edible material formulations for passive fluidic channels were experimentally evaluated. Their wettability properties were systematically characterised, and their suitability for mould-based microfabrication was assessed. Passive microfluidic structures, including single channels and reaction chambers, were fabricated, tested, and compared. As a result, a novel protocol for the fabrication of fully edible passive microfluidic channels was established.
2) Development of an edible transducer. In collaboration with members of the research group, an extended-gate electrolyte-gated field-effect transistor (EGOFET) was designed, fabricated, and tested using exclusively edible materials. The device employed a toothpaste pigment as the semiconductor. Key electronic performance metrics of the fabricated devices were experimentally quantified.
3) Identification of an edible biorecognition layer for H2O2 biosensing. Candidate edible redox systems for H2O2 detection were experimentally screened. A specific edible redox system was selected and characterised using UV–Vis absorption spectroscopy and electrochemical techniques.
4) Biosensor development. The selected biorecognition layer was integrated into the EGOFET architecture, resulting in a fully edible biosensor. The device was validated for H2O2 quantification, an important reactive oxygen species associated with gastrointestinal inflammation, via a controlled redox reaction.
5) Biosensor testing under physiologically relevant conditions. H2O2 biosensing performance was evaluated under various in vitro physiologically relevant conditions, including different temperatures, pH values, and the presence of potentially interfering agents. Device responsivity was consistently confirmed across all tested conditions.
6) Biosensor functional modification. The biosensor was successfully adapted to detect glucose, cholesterol, and gastric peroxidase through minimal modifications of the biorecognition layer.
7) Collaborative projects and knowledge transfer. Eight additional collaborative research projects were completed, all focused on sustainable and degradable electronic materials, resulting in published outcomes and direct collaboration with peer researcher fostering two-way knowledge transfer.
Main result. The main result of the project is the development and testing of an edible H2O2 biosensor, designed to be safely ingested and metabolized after use. The biosensor is validated for H2O2 quantification, a key reactive oxygen species associated with GI inflammations, via a controlled edible redox reaction. The device is tested in vitro and detects H2O2 in the 0–3 mM range, with a limit of detection of ~143.7 µM and sensitivity of 2.7 µC mM-1. As a proof-of-application, we demonstrate the use of the edible biosensor to detect metabolites (glucose and cholesterol) and enzymes (gastric peroxide activity) by minimal modifications of the biorecognition elements, and we validate the sensing mechanism in simulated physiological environment.
