Point-of-care: lithium monitoring chip

A quick and patient friendly way to monitor lithium blood levels

Patients suffering from a manic-depressive illness, also known as bipolar disorder, experience an alternation of manic and depressive episodes. Manic meaning hyperactive, exuberant and full of energy and depressive meaning down and lethargic. In order to control these episodes they take medication in the form of lithium. After ingestion, the lithium spreads itself through the entire body and reduces mood swings. 

In order to monitor the lithium in their blood, patients need to visit the hospital regularly. Which means travel, testing and waiting for the results about a week later. But the amount of lithium in a person’s blood changes regularly, so it can differ from the moment the test is done to the moment the results come in. Making it hard to determine the right amount of medication to prescribe. 

A lithium monitoring chip

A researcher/scientist of the University of Twente and the Medisch Spectrum Twente (hospital) recognized this issue, which they knew had been researched and resolved for patients suffering from other diseases such as diabetes. Together they developed a lithium monitoring chip which resulted in the spin-off company Medimate BV. Medimate focussed on the read-out unit and contacted Micronit to help with the optimization of the chip. We then lead the process of chip design and cartridge development and together with Medimate we also worked out a way for the chip to interface with the needed equipment.

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Monitoring at home

The chip uses electrophoresis in combination with conductivity detection and can be mass produced at low cost. It allows patients suffering from manic depression to almost instantly monitor their lithium blood levels at home with just one drop of blood. Together with Medimate the chip has been optimized for performance as well as production cost which is very important in the price sensitive point-of-care market.

The chip consists of:

  • A filter for removing blood cells;
  • A reservoir for the buffer solution;
  • A reservoir that functions as an expansion chamber;
  • On-chip electrodes for sample injection and ion separation by electrophoresis;
  • On-chip electrodes for conductivity detection.

Furthermore, the chip has a side connect which reduces its footprint. Making it possible to create more chips per wafer and be very cost-effective.