Patterning of biomaterials by aerosol jet printing: A parametric study

Bioprinting is an emerging field with ongoing interest in the development of new techniques for structuring and patterning biomaterials in different configurations. Two-dimensional patterning techniques such as micro-contact or inkjet printing enable in vitro studies to investigate the effect of spatial organization on cell physiology. However, micro-contact printing requires relatively lengthy preparation times, while inkjet printing subject materials to significant shear forces and the resolution is limited to approximately 50 ​μm in practice. Aerosol jet printing (AJP) is a versatile, direct-write technique capable of high-resolution deposition of biological materials for cell patterning. However, the resolution and print quality are heavily influenced by a range of different printing parameters. This systematic study investigates the influence of critical printing parameters, using aqueous gelatin as a model biomaterial ink. Our results indicate that the tested parameters influence the line quality by inducing a change in one or more of the following primary processes: material deposition rate, evaporation rate and the aerosol jet focusing. Furthermore, with minimal adjustments to parameter settings, gelatin lines could be printed with a width of 30 ​μm. A systematic approach is outlined for the selection of suitable parameters for stable and accurate printing at a desired resolution. This provides a framework for approaching the optimization of parameters for novel combinations of biomaterial inks and substrates. An improved understanding of the complex interplay between different process parameters is expected to support the development of new applications of aerosol jet printing in biology.