Point-of-Care (POC) diagnostics grows currently in importance. Portable devices with electrochemical detection are very attractive for the rapid and low cost identification of diseases, especially when centralized laboratories with well-equipped, automatized analytical setups are either not available or results need to be obtained rapidly on site. There is a need for portable POC devices in developing and emerging countries, but also in developed countries. Electroanalysis, often in combination with immunoassay-based detection, provides sensing platforms with high sensitivity and reproducibility without suffering from optical interferences as optical detection methods can often do.

For electroanalytical sensors, the selection and costs of the electrode materials and sensor fabrication strategies play major roles. Such considerations need to be made for the complete development chain from designing a sensor, fabricating and optimizing prototypes until reaching the industrial production scale. We found that inkjet printing, which is a digital and mask-less material deposition technique where picoliter droplets of functional inks are jetted with high precision, is the ideal tool for process development of commercial electroanalytical platforms.

Herein, we demonstrate the large-scale fabrication of electrochemical microchips with up to eight parallel 50 µL wells containing each carbon nanotube working and counter electrodes, silver/silver chloride quasi-reference electrodes and a dielectric layer to define accurately the dimensions of the electrodes. The employed carbon nanotubes show a superior electrochemical behaviour and the multi-layer inkjet printing process provides highly reproducible electrode surfaces. We shall demonstrate the application as sensing platforms for antioxidants and hormones in several biological fluids using a portable, in-house made multichannel potentiostat.

References

[1] http://lepa.epfl.ch/SENSaSION

[2] A. Lesch, F. Cortés-Salazar, M. Prudent, J. Delobel, S. Rastgar, N. Lion, J.-D. Tissot, P. Tacchini, H. H. Girault, J. Electroanal. Chem., 2014, 61-68, 717.

[3] M. Jović, Y. Zhu, A. Lesch, A. Bondarenko, F. Cortés-Salazar, F. Gumy, Hubert H. Girault, J. Electroanal. Chem., submitted.

[4] A. Lesch, F. Cortés-Salazar, V. Amstutz. P. Tacchini, H. H. Girault, Anal. Chem., 2015, 87, 1026.

[5] A. Lesch, S. Maye, M. Jović, F. Gumy, P. Tacchini, H. H. Girault, In Biotech, Biomaterials and Biomedical TechConnect Briefs, 2016, 3, Chapter 4: Sensors, Diagnostics & Imaging, 121.