This project involves the design, fabrication, and characterization of inkjet printing technology that enables its integration with common microfluidic modules. We have termed this concept as Lab-on-a-Printer, an extension to the well-known Lab-on-a-Chip concept. Such platform will enable on-chip processing of microfluids followed by their direct printing. Potnetial fields where this platform can be used include, but not limited to, combinatorial chemistry, tissue engineering, and printable electronics.
The dispenser component has many advantages over industrial inkjet dispensers: it is mainly made of PDMS which enables its integration with other PDMS-based components. Furthermore, it has a modular design that allows for the separation of the actuator and the low-cost microfluidic chip – making the latter optionally disposable. The main device microfabrication process are based on soft-lithography with the most of the molds are made using 3D printing.
As part of the concept demonstration, we have successfully integrated our inkjet dispenser with a simple microfluidic mixer. This specific example device enabled printing arbitrary patterns of programmable composition.
Inkjet dispenser working concept
Stroboscopic images of droplet formation
Stroboscopic video of droplet formation
Printed UBC logo showing on-the-fly modification of ink composition using on-chip mixing
Journal: Lab on a Chip, vol. 16, pp. 3351-3361
Date: July 2016
Abstract: In this paper, we present a disposable inkjet dispenser platform technology and demonstrate the Lab-on-a-Printer concept, an extension of the ubiquitous Lab-on-a-Chip concept, whereby microfluidic modules are directly integrated into the printhead. The concept is demonstrated here through the integration of an inkjet dispenser and a microfluidic mixer enabling control over droplet composition from a single nozzle in real-time during printing. The inkjet dispenser is based on a modular design platform that enables the low-cost microfluidic component and the more expensive actuation unit to be easily separated, allowing for the optional disposal of the former and reuse of the latter. To limit satellite droplet formation, a hydrophobic-coated and tapered micronozzle was microfabricated and integrated with the fluidics to realize the dispenser. The microfabricated devices generated droplets with diameters ranging from 150–220 μm, depending mainly on the orifice diameter, with printing rates up to 8000 droplets per second. The inkjet dispenser is capable of dispensing materials with a viscosity up to ∼19 mPa s. As a demonstration of the inkjet dispenser function and application, we have printed type I collagen seeded with human liver carcinoma cells (cell line HepG2), to form patterned biological structures.
Conference Proceedings: The 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2015)
Date: October 2015
Abstract: This work introduces and demonstrates the concept of Lab-on-a-Printer whereby microfluidiccomponents are integrated with inkjet dispensers. This concept allows for multi-functional microfluidic materials processing to be performed on chip and direct post-process printing of those materials enabling printing of programmable gradients and more generally structures with programmable composition. This concept is demonstrated with a disposable PDMS device that integrates an inkjet dispenser technology with a microfluidic mixer.
Conference Proceedings: The 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2013 – Oral 8.7%)
Date: October, 2013
Abstract: This paper reports on the design, fabrication and demonstration of a polydimethylsiloxane (PDMS)/SU-8 inkjet dispenser with the following novel features: (1) the use of low-cost fabrication process and bio-compatible materials, (2) the use of hydrophobic SU-8 micro-nozzles to limit satellite droplet formation, (3) a modular device design that allows for the reuse of the external actuator, (4) the capability of printing hydrogel constructs, (5) a limited cross-contamination risk as the device is disposable, (6) and the potential for integration with other PDMS microfluidic systems. The device
successfully dispenses droplets with diameters ranging from 80-130µm at rates of 2-1000 droplets/second.