In a state of flux.

The safe transport and distribution of media in IVD devices requires stable serialproduced fluidics components which meet the highest cleanliness requirements.

One of the essential functions of IVD devices consists in safely mixing tiny amounts of liquid samples with media and transporting these to measuring cells. The trend towards more affordable and compact point-of-care devices is forcing developers to design these without complicated tubing. This is the only way to reduce installation space and assembly times. Special distributor blocks are the key to achieving this.

Both these distributor blocks and micro valves and measurement cells constitute the classical bottlenecks in IVD devices. Channels in micro valves, for instance, measure only around 1mm across and the flow-through cell for blood cell measurement is a mere 50 – 100 μm. Swarf in the system may lead to severe errors. When it breaks loose from distributor blocks, it may result in a system failure or distort the results. One the one hand by clogging valves that regulate the further transport of media. On the other by distorting the measurements in the measurement cells”, explains Business Developer Stephan Payer.

Safe production of IVD devices therefore requires Special know-how in manufacturing and in the handling of fluidics components. “During the production of parts, it must be ensured that no swarf remains in the parts since it is not possible to fully check the branching channels visually for such residues”, says Payer. Controls using transmitted light are often not feasible. At WILD, these key parts are therefore manufactured using specially developed, swarf-free IVD manufacturing processes, are thermally deburred if necessary, cleaned using ultrasound and ultra-pure water, and then individually packaged.

WILD tests additive manufacturing of distributor blocks

“In addition, we are currently examining the manufacturability of IVD distributor blocks using additive techniques”, says WILD mechanical designer Christian Wuster. The connection nozzles would then be integrated in the part itself and rounded bends and branches would help reduce pressure loss. Moreover, additive manufacturing would allow for varying channel diameters of up to approx. 50 μm, the integration of functions such as mixing and vortices, and the use of transparent materials.