Our client needed a very cheap single-use cartridge for point-of-care diagnostics – to perform accurate sample preparation prior to on-board detection. The cartridge had to incorporate microfluidics management of the sample and liquid reagents, combining blisters, pumps and fluidic management on a printed circuit board (PCB) layout.
This represented a challenging combination of electronics and microfluidics, all contained within a cartridge with a very low bill-of-materials cost.
After initial requirement analysis and concept generation, the first design architecture was able to combine fluidics, electronics, heating, a low-cost micro-pump, adhesive layers and plastic mouldings.
Five areas were identified as high risk and, to mitigate them, we prepared a proof-of-principle bread board for each of the high-risk modules. Prototyped polydimethylsiloxane seals were tested, as well as pumping, sealing and reagent storage, while PCBs were prototyped at our in-house PCB manufacturing facilities, and included novel thermal management using low-cost electronic components.
In less than five months from the start of the project we had a de-risked system architecture, with the high-risk modules identified and tested in our laboratory.
The design incorporated multiple reagents and was able to provide ‘swab to result’ within the handheld cartridge.
A very low-cost solution was fundamental to guarantee commercial success. From our design, the bill-of-materials cost was less than $3 per cartridge.