Background: The rapid increase in the use of open-source enables the development of new inexpensive, highly configurable, high-performance haematological tests. We have described a low cost (< £300), open-source, and customizable robotic microfluidic device for use in microfluidic blood analysis. Teflon® FEP microcapillary film (MCF) contains 10 parallel capillaries of 200μm diameter, which can be coated with platelet agonists or pro-coagulant factors.

Aims: When dipped into whole blood (WB), the WB is drawn into the MCF capillaries. Changes in capillary rise can be used to measure platelet activation or coagulation.

Methods: We have automated the MCF dipping into WB and image capture to perform time-resolved image analysis. The open-source hardware used a servo motor, a camera, and a lightbox, controlled by the Raspberry Pi, as well as 3D printed parts held in a frame, that allows simultaneous measurement of capillary rise in 12 MCF strips totalling 120 individual capillaries and 180 images per capillary in 30 seconds.

Results: We obtained kinetic data of platelet activation and blood coagulation. Preliminary results show that WB rose rapidly up the capillaries in the first 8 seconds, but slowed and almost stopped at 30 seconds. The rate of rise was reduced in thrombin coated capillaries in a concentration dependant manner. The mean velocity of WB in the first 8 seconds was 0.25, 0.30, 0.37 and 0.40 cm/s for coating concentrations of 500, 158, 50 and 0 U/mL thrombin, respectively (P < 0.001).

Conclusion(s): Capturing high quality and time-lapse images of capillary rise of blood in the capillaries enabled us to quantify haemostatic changes in WB. The simplicity of the design makes it suitable for adapting to different experimental needs and its open-source-based allows it to be easily accessed by other researchers. This low-cost, high throughput imaging rig is a proof-of-concept demonstrating the potential for using open-source hardware in platelet research.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/open-source-robotic-microfluidic-blood-analysis-using-raspberry-pi/