Inkjet printing as a tool for function integration in microfluidic lab-on-a-chip systems

Microfluidic lab-on-a-chip systems integrate chemical or biological micro-reactions on compact chips. They are often designed as single-use, disposable devices. In order to ensure low manufacturing costs, they can be processed by polymer replications techniques. When further on-chip functionalities are integrated, low-cost manufacturing is essential. In this contribution, drop-on-demand inkjet printing is suggested as a promising approach for function integration in LOC systems. With this digital printing technology, different functional materials can be deposited in a non-contact, mask-less and additive way. Fully printed piezoelectric polymer actuators are manufactured and configured as membrane pumps. The actuators are based on a piezoelectric polymer film sandwiched between two silver electrodes and are fabricated at temperatures that are compatible with common polymer substrates. As a proof-of-concept, the application of the actuators in a membrane pump with pump rates of up to 130 μL min-1 is demonstrated. Furthermore, the operational stability of the actuators is investigated with respect to cyclic stability, heat generation due to hysteresis losses and operation at elevated temperatures. The suggested manufacturing approach allows the integration of further on-chip functionalities. As an example, printed actuators are combined with resistive heating elements.