Importance of cell-substrate impact during drop-based deposition

The development of new technology for the realisation of biocompatible and bioactive structures is an emerging field in the field of tissue engineering, regenerative medicine and biosensors. These techniques are generally based on the computer-aided design approach. Recently the use of ink-jet printers has been extensively studied both using bio-molecules and cells. Ink-jet systems were noted to cause cell damage in the microfluidic system and in the drop generation system (e.g. heating or piezoelectric), and different thermal inkjet printer heads have been used to address these points. In this work we underline that the impact of the drop on the substrate is more relevant, and show how the properties of the deposition surface can influence cell viability. Firstly the printing process and the drop impact were modelled using fluid-dynamics and fluid-structure interaction equations. To validate the model, the Olivetti BioJet system was used to print cells onto different substrates with different elastic and viscous properties and cell viability was monitored in time.