3D printing at microscale by pyro-EHD effect

A challenging request in the fabrication of microfluidics, biomedical microsystems and wearable technology would be a flexible ink-jet printing method for breaking the rigidity of classical lithography. Electrohydrodynamic (EHD) has reached in latest years exciting performances becoming the elite nano-tool for direct printing of lab-on-chip devices, from biomolecules to nano-electronics. However, it suffers of practical but severe limitations due to its intrinsic geometrical configuration. Recently, a pyroelectric-EHD system has been presented and has proved challenging spatial resolution down to nanoscale, printing of high ordered geometrical patterns, capability of dispensing composite polymers, biological ink as DNA and protein array for biosensing fabrication, single cells printing and direct printing of nanoparticles. The method proposed appears as one of the most interesting polymer fabrication process in term of flexibility and viscosity of the material processed. In fact, high viscous polymer could be easily printed at high resolution in 2D or, even more, in 3D configuration. The pyro-EHD process has been also proved for the fabrication of biodegradable microneedles for smart drug delivery while other 3D polymer microstructures have been fabricated for collecting or distributing light signals in lab-on-a-chip optofluidic devices as potential 3D optical waveguides, guiding light for generating or transporting optical/electronic signals from and to cells. The simplicity of the method proposed, associated with the flexibility of the process for fabricating 3D polymer microstructures, demonstrates its great potentiality exploitable in many fields of additive manufacturing, from optics to biomedical applications for improving the quality of life.