Sensing flow rates in structured microenvironments like lab-on-chip (LOC) and organ-on-chip (OoC) is crucial to assess important parameters such as transport of media and molecules of interest. So far, these micro-electromechanical systems for biology (bio-MEMS) mostly rely on flow sensing systems based on thermal sensors. However, thermal flow sensing has limitations, since the measurement principle, which is based on generation of heat, can negatively affect the biological system by increasing the fluid temperature above physiological conditions. To overcome this issue, we propose a novel electro-mechanical flow sensor centered around the deformation of a cantilever made of a thin and biocompatible ionic electroactive polymer. The polymer, called ionic polymer metal composite (IPMC), is doped with ions naturally present in most cell media for LOC and OoC devices. Unlike already existing cantilever-based systems which rely on piezo sensitive materials, our IPMC-based flow sensor shows durability in wet environment. We were able to successfully measure pulsatile flow induced by pipetting with flowrate gradually increasing from 10μL/s to 40μL/s. The proposed flow sensor shows good sensing capabilities (4.78 mV/(μL/s)) with a linear behavior in the studied range. This work sets a milestone for using flexible, electroactive materials for sensing applications in delicate biological microenvironments.@en

Stemming from the convergence of tissue engineering and microfluidics, organ-on-chip (OoC) technology can reproduce in vivo-like dynamic microphysiological environments for tissues in vitro. The possibility afforded by OoC devices of realistic recapitulation of tissue and organ (patho)physiology may hold the key to bridge the current translational gap in drug development, and possibly foster personalized medicine. Here we underline the biotechnological convergence at the root of OoC technology, and outline research tracks under development in our group at TU Delft along two main directions: fabrication of innovative microelectromechanical OoC devices, integrating stimulation and sensing of tissue activity, and their embedding within advanced platforms for pre-clinical research. We conclude with remarks on the role of open technology platforms for the broader establishment of OoC technology in pre-clinical research and drug development.@en

We present preliminary recordings on chip of three-dimensional (3D) electric neuronal activity from cultures of cortical neurons derived from human-induced pluripotent stem cells (hiPSCs). The recordings were obtained through 3D microelectrode arrays (MEAs) composed of truncated, 90 μm-high Si micropyramids endowed with multiple, electrically distinct, and vertically arranged TiN microelectrodes. The unique design and implementation of the 3D microelectrodes, complemented by a 60-electrode readout interface, allow for 3D spatial recording of neuronal activity, as well as single-unit recordings in high throughput, which are currently not possible with commercial MEA platforms. Future work will aim at optimizing extended 3D MEAs over optically transparent substrates for electro-physiological investigation of 3D neuronal tissues and organoids.@en