TUDOS - Micro dosage system for μ-exact drug dosage

Press briefing / October 22, 2012

Micropumps capable of exact drug dosage could open whole new possibilities for treatment of illnesses in the future – for instance in the tumor therapy. In the TUDOS project five Fraunhofer institutes work together for creating a totally controlled micro dosage system for very small volumes. The research partners are exhibiting a prototype of the system on the COMPAMED fair in Hall 8a, Booth D26.

© Fraunhofer EMFT
Microfluidic system for tumor therapy. Left (back side) channel system with PEEK foil. Right (front side) micropump for air, micropump for the drug, bubble separator.

The liquid volume of 14 μl – approximately the volume of a quarter of a water droplet – is hardly distinguishable with the naked eye. The TUDOS drug dosage system is capable of dosing such minute volumes of liquid with as high a precision as 4%, thanks to the novel, patented dosage control system. Such a high precision is unique worldwide so far for a system this size: The size of TUDOS is 20x32x19 mm3, which is no bigger than a box of matches – including the drug reservoir and battery.




New dosing principle for the highest possible reliability
TUDOS is based on two miniature silicon pumps – one for the drug and one for air. Unlike in the products available on the market so far, the dosage precision is not dependent on the micropumps themselves. Instead, the precision is controlled by the volume of the dosage channel in meander form: When it is completely filled with liquid – as monitored by a measuring electrode – the second pump injects a bubble of air into the system, working like a piston, pressing the liquid drug forwards. At the end of the channel another capacitive electrode is monitoring the air bubble. As soon as it passes the electrode, the air pump stops. This completes the dosage interval. Before administering the drug, the bubble separator removes the air bubble from the liquid. This novel dosing principle makes TUDOS highly reliable, which is essential for applications in medical technology.

Focusing on the security of the patients
The pumps are capable of creating very high pressures and thus for instance purging clogged catheters. Additional electrodes continuously monitor the system status and reliably and quickly recognize such error conditions as defects in the pumps or air bubbles in the reservoir or catheter. An automatically closing security valve guarantees “free-flow” protection: In case of excess pressure at the inlet – for example since the patient is undeliberately pressing on the reservoir in an unfavorable position – the valve automatically closes and stops the drug from being administered.

The system can be wirelessly programmed using an external user interface, enabling the doctor to adjust the dosing profile to the therapy when necessary. In addition to diabetes or pain treatment the scientists envision great potential in tumor therapy: Highly concentrated cytostatic drugs could be given directly into the tumor using the TUDOS system, when systemic administration of the drug is no longer possible. This could shrink the tumor enough to make it operable.