Proto Labs reinforces the war on cancer

When it comes to the war on cancer, the body has its own front guard: 'Natural killer cells' are able to destroy their cancer cell rivals and prevent viral infections from spreading. Unfortunately, the immune system in many patients is already weakened to such an extent that it cannot produce enough of these precious cells. Now however, Zellwerk GmbH of Eichstaedt, some 25km northwest of Berlin, has succeeded in cultivating cells outside the human body in greater quantities than ever previously achieved. Zellwerk, a specialist in cell culture and tissue engineering, performs the task using single-use bioreactors manufactured using injection moulded components supplied by Proto Labs. The Zell system is called Z® RP Technology and comprises an incubator, located in the sterile work chamber of the bioreactor, and a special adapter. An external control unit monitors, controls and documents all of the parameters. To ensure the repeatability of the process, the vital element of the challenge was to create a special surface in the reactor offering the optimum amount of friction – not too smooth and not too rough. Construction Manager Rainer Mausolf summarises the requirements for the reactor resin and its surface condition: "The choice of plastic was crucial because we needed to provide constant chemical and physical conditions in the reactor. We tried several common plastics but had difficulty in finding a material that was resistant to sterilisation by gamma-rays. Finally, with the help of Proto Labs, we found the optimum resin for our system," he says. "Proto Labs also helped extensively with the implementation of our surface requirements. In Z® RP Technology systems the cells must not be free to be rinsed around and therefore require a finely grained surface on which they find support. Only this makes it possible to have a standard, repeatable process. To keep the conditions uniform throughout the system we have a probe upstream of the reactor adapter that continuously measures the pH, temperature and oxygen, and relays this data to an external control unit." "At first we could not believe the speed and reliability of the service," says Mr. Mausolf. "We knew of no other suppliers who could deliver finished parts within 10 days of transferring the 3D model. Sometimes we would even receive components within five days, if we had opted for this. The process was so simple: I just uploaded my 3D SolidWorks model to the Protomold website. Almost immediately my quote arrived and shortly after I was contacted with valuable tips on implementation. Within days we had received the first reactors and adapters made using our special plastic." All the bioreactors and probe adapters (in different versions) used in Z RP Technology are manufactured using the Protomold rapid injection-moulded parts service.