A MODULAR MICROFLUIDIC PARALLEL DISPENSING SYSTEM
II. Results
Cita�ons
[1] Vollersten, A. R. et. al., 23rd Interna�onal Conference on Miniaturized Systems for Chemistry and Life Sciences, μTAS 2019, pp. 86-87, 2019
[2] Loessberg-Zahl, J. T. Developing Microfluidic Tooling for 3D Cell-Culture. PhD thesis University of Twente (2019). doi: 10.3990/1.9789036549202
The controlled dispensing of liquids is of fundamental importance to microfluidic devices and is typically performed using large tabletop lab equipment or with microfluidics in a single monolithic device. Discrete Microfluidic Building Blocks (MFBBs) serving standalone functions offer a potential alternative to this and could be combined with other MFBBs to create more complex systems. Previously at μTAS we presented four different MFBBs following the ISO Workshop Agree-ment 23:2016 standard for improved compatibility on the same Fluidic Circuit Board (FCB) [1]. Here we present an improved version of the liquid dispensing MFBB with a significantly improved dynamic range and demonstrate it working in connection with the previously reported 64 chamber MFBB on the same FCB.
Acknowledgements
This work was supported by the VESCEL ERC Advanced Grant toA. van den Berg (Grant no. 669768)
A dispensing MFBB is presented, featuring an improved dynamic range of up to 1:128 in a 30 second period. The device was demonstrated working with a second MFBB, both using the same FCB and control script. The combination of multiple standardized, modular, and automatable MFBBs on a common FCB platform show great potential to accelerate research in both industry and academia. More precise control on hydraulic resistor geometry and valve design are required to further improve performance.
III. Conclusion and Outlook
1Mesoscale Chemical Systems Group, 2BIOS Lab on a Chip Group, 3Applied Stem Cell Technologies Group
University of Twente, The Netherlands
Dean de Boer
1, Anke R. Vollertsen
2, Albert van den Berg2, Andries D. van der Meer3 and Mathieu Odijk2
The dispensing MFBB was successfully tested working together with another MFBB featuring 64 individually addressable chambers. The two MFBBs shared a common FCB and share pneumatic control lines, as seen in figure 8.
Figure 7: Metered volume of water in various times
Figure 8: Dispensing and 64 chamber MFBBs
I. Device Architecture
Figure 3: Device architecture
M1-121.b
Figure 2: Exploded render view of the
dispensing MFBB
The dispensing MFBB was tested using de-ionized water pressurized to 300 mbar above atmospheric pressure at the inlets and a flow meter at the outlet. The volume dispensed by each channel in different durations of 1 to 10 seconds can be seen in figure 7. The dynamic range of the system can be seen by the three different volumetric metering regimes (0 μL - 4μL, 4 μL - 40 μL, 40 μL - 140 μL) in which the MFBB can operate. In a 30 second period this full range can be covered, yielding at least a 1:128 dynamic range for resistor array 2 (red). The dynamic range of resistor array 1 (blue) is lower, reaching 1:56 due to an air bubble trapped in the channel.
Watch the 60 second
summary video
Watch a video of the MFBBs working
Please address all correspondence to d.deboer@utwente.nl
Abstract
Figure 1: Photograph of dispensing MFBB 10 mm 10 mmThe dispensing MFBB is made of 4 layers of computer numerical control (CNC) milled Poly (methyl methacrylate) (PMMA) which have been solvent bonded together, see figure 1. An exploded view of the device can be seen in figure 2.
The device architecture is shown in figure 3 and is based on parallel arrays of dispensing units, with each unit consisting of a resistor and valve in series. By actuating the valves using pulse width modulation, an amount of liquid determined by the hydraulic resistance can be dispensed, see figure 4. Difference resistances are selected for each dispensing unit in an array such that a high dynamic range can be achieved.
Figure 4: Flow rate for units in an array
Figure 5: Cross section of the valve
Closed
Open
The MFBB has two parallel arrays and can dispense two different liquids. There is a total of 10 integrated valves in normally closed configuration, which are a modified version of a design by J. Loessberg-Zahl [2]. The valves consist of a top and bottom chamber, separated by a Viton membrane. A schematic cross section can be seen in figure 5, and a close up in figure 6.
Top
Bottom
Figure 6: Render of the top and bottom valve halves
youtu.be/Hx3O4MbOe6M youtu.be/BdTI_SqvEsg
