Preliminary study of resistive sensors in inkjet technology for force measurements in biomedical applications

The research aims to the development of sensors for strain measurements using inkjet technology for biomedical applications. The process of inkjet printing is based on the emission of a fixed quantity of material in liquid phase, usually called ink, in the form of small drops, contained in a chamber through a nozzle. The emitted drop falls on a substrate, forming a pattern. The solidification of the liquid can occur through the evaporation of the solvent, chemical modifications (eg by cross-linking of polymers) or crystallization. Often post-processing treatments are required, such as thermal annealing or sintering. For the realization of the sensors, the nanocrystalline silver ink, which is a biocompatible ink, was chosen. The substrate is Kapton and several studies demonstrate its biocompatibility. A preliminary analysis of the material and its compatibility with the chosen printer, the description of the developed devices and finally the experimental results with the calculation of the relative Gauge Factor are reported. The research allowed to study, in a preliminary way, light, thin, flexible, inexpensive, and biocompatible sensors for applications inside the human body.