Inkjet Printing for Applications in Microfluidic Lab-on-Chip Systems

Inkjet printing is a digital printing technique that is capable of depositing various functional materials onto different substrates in an additive way. In this contribution, applications of inkjet printed structures for smart microfluidic lab-on-chip systems are discussed. Such systems can be used e.g. for different chemical or biochemical analysis tasks and are often fabricated from polymers. Inkjet-printed electrodes and electroactive polymer (EAP) actuators for use in microfluidic lab-on-chip systems are shown. Silver and gold electrodes are presented that are fabricated by printing metal nanoparticle inks onto polymer substrates. After printing the structures are sintered using low-pressure argon plasma sintering, a low-temperature sintering process that is compatible with polymer substrates with a low glass transition temperature TG. The structures consist of several electrodes and contact pads and feature minimum structure sizes of approximately 70 μm. These structures are in principle suitable for requirements in lab-on-chip systems. The use of all inkjet-printed EAP actuators in a polymer-based micropump is discussed. Cantilever-type bending actuators generate deflections of more than 190 μm when a voltage of 600 V is applied. Based on these results, performance characteristics of a micropump with printed actuators are estimated.