Poster presentation at Eleventh International Workshop on Biosensors

Poster title: Paper-based electrochemical (bio)sensors for a disruptive origami Organ-on-Chip device: Phoenix-OoCIn recent years, organ-on-chip (OoC) technology has emerged as a revolutionary approach in the field of biomedical research, offering significant advancements over traditional in vitro and in vivo models. These microengineered devices replicate human organs' complex physiological and mechanical properties on a micro-scale, providing a more accurate and reliable platform for studying human biology and disease. Generally, OoC devices consist of microfluidic systems that integrate living cells cultured in a 3D environment, mimicking the architecture and function of specific human organs. This biomimetic approach allows for the recreation of dynamic biological processes, including tissue-tissue interfaces, fluid flow, and mechanical forces, which are critical for organ function.1 Sustainability is one of the most important concepts today, as it can drive activities in several areas, namely environmental, social, and economic. In analytical chemistry, the development of sustainable devices has been boosted by the introduction of paper-based microfluidic analytical devices (μPADs), whose benefits are not limited to the concept of sustainability. Indeed, paper as a functional material gives μPADs unprecedented properties. However, paper-based devices are still used only as analytical tools and have not been adopted by the OoC world. In this context, we present a revolutionary OoC paper-based platform that uses paper in origami configuration for i) cell co-cultures with the aim to better simulate different organ tissues, (ii) (bio)sensors integration with the aim of on site/continuous monitoring of cells status/response to stimuli, and (iii) with the ultimate goal of performing accurate pharmacological studies. In detail, the OoC device includes a paper-based scaffold consisting of a cage printed using a 3D technique, containing the cell pads in origami configurations preloaded with the different cell lines, the electrochemical sensors modified for the detection of several analytes, and the adsorbent pad as waste. In the first part of the project, electrochemical sensors for pH, nitrate, and glucose were developed and characterized in standard solutions. The sensors were screen printed onto a filter paper support using wax to create a hydrophilic zone delimited by hydrophobic wax barriers. To create layers sensitive to the different ions, the working electrode surface was modified with nanomaterial and ion-selective membranes for nitrate detection, while for H+ detection the surface was modified with a layer sensitive to pH variations. For glucose monitoring, the sensor was modified by drop casting with nanoparticle dispersion and glucose oxidase enzyme. Calibration curves were obtained by potentiometric measurements in standard solutions with regression equations y= (-0.048±0.002) x + (0.359±0.004); R² =0.981, y= (-0.083±0.001) x + (0.763±0. 007); R²=0.998, for nitrate and pH respectively, and by chronoamperometric technique for glucose detection, a linear regression described by the following equations was obtained: y= (-0.12±0.01) x - (0.7±0.1); R² =0.960. The development and application of OoC systems hold great promise for improving drug discovery, reducing animal testing, and advancing our understanding of human physiology and pathology. As this technology continues to evolve, it is expected to play a critical role in the future of medical research and personalized healthcare. Reference [1] Zhang, B., & Radisic, M. (2017). Organ-on-a-chip devices advance to market. Lab on a Chip, 17(14), 2395-2420. L. F. thanks Phoenix-OoC project, funded under European Union’s Horizon Europe EIC 2023 Pathfinder Open program, grant agreement No 101130395.