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K. dos Reis Vezo

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For tissue barrier monitoring

Dielectric spectroscopy, a non-contact electromagnetic readout technique, offers significant potential in Organ-on-Chip devices for accelerating drug development by enabling non-invasive, multi-layer sensing of tissue barrier integrity. While open-ended coaxial probes are well-established for dielectric spectroscopy in high-loss biological samples, their inherent lack of biocompatibility and impracticality in conventional setups limits their application. This work investigates novel fabrication approaches using printed circuit boards (PCBs) and glass manufacturing techniques to overcome these challenges. A planarized OECP fabricated on a PCB with via-array shielded coplanar waveguides was developed and evaluated. The PCB-based design demonstrated satisfactory electromagnetic performance, biocompatibility potential, and cost-effectiveness, making it a promising candidate for integration into well-plate formats. Additionally, laser-induced deep etching (LIDE) was explored for creating high-precision glass substrates with metalized vias, presenting an alternative route for scalable sensor fabrication. Together, these advancements lay the foundation for adaptable and scalable dielectric spectroscopy platforms suitable for Organ-on-Chip applications, merging performance with practicality in biological settings. ...
Real-time cell culture media monitoring can be conducted by Organ-on-Chip (OoC) ion-sensitive floating-gate field-effect transistor based sensors (ISFGFET). A method of modelling the sensor is described and implemented in the Advanced Design System (ADS) design and simulation software. The model is validated using measurement data of the sensor when exposed to an aqueous solution and in a 'dry' scenario. The model is utilized for an overall sensitivity analysis and the effect of the sensor dimensions on the sensitivity to charge variation that are immobilized on the sensing area surface. In addition to a SPICE compatible floating gate, level 3 MOSFET parameters are extracted, along with a sensing area model that links changes in the floating gate voltage to changes in the pH of the solution. Subsequently, a bias point is determined based on measurement data and limiting factors. Finally, the sensitivity of the ISFGFET is analysed. Our results characterize the effect that the sensing area dimensions, control gate capacitance and bias point have on the sensitivity. ...