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Final Hemosep Shaker
3D printing was used exclusively in the development of the Hemosep shaker, including 12 fully-working evaluation systems for in-theatre evaluation.
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Stratasys 3D printed Saline Probe, produced from ABS Plus material, used to pierce a saline bottle and prime the HemoSep bag prior to use.
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Stratasys Dimension 1200es used extensively in the prototyping stages.
Brightwake is a creative development, engineering, production and research company based in Nottingham in the United Kingdom. The company is deploying 3D printing in the development of novel medical applications. Jim Woodcock spoke to Stephen Cotton, the firms Development Director.
UK-based Brightwake designs, develops and manufactures Class, I, II and III medical devices for sale all over the world. One of the company’s recent introductions used 3D printing extensively in the development phase, but the applications for 3D printing in the medical sphere go much further.
“The HemoSep system was developed at the Department of Biomedical Engineering at the University of Strathclyde,” explained Cotton. “In very basic terms the system concentrates the blood recovered from a patient during major surgery. Whole blood is taken from the body during an operation and the packed cell volume (PCV) is increased. This means taking the plasma out, concentrating the platelets, red- and white-blood cells and giving them back to patient as concentrated blood.”
This process would normally be achieved centrifugation, spinning out the blood until the cells and plasma have separated. However this leads high mechanical stresses in the cells and increases the risk of damage — it also removes the platelets. The HemoSep system was developed to be much ‘kinder’ to the blood, helping to ensure cells remain intact and that all cell species are retained, not just the red and white cells.
“The device has a footprint equivalent to the size of A4 paper,” said Cotton. “The outer made of PVC with a membrane inside. On the other side of membrane is a super absorbent sponge that pulls the plasma trough the membrane, similar to the way a disposable nappy wicks water away. Because of the sizes of the holes in the membrane it leaves the cells on the other side without exposing them to high stresses.
“The bag of cells is then agitated to create a vortex that flushes and washes the membrane; because of their shape platelets tend to get stuck in the membrane and need physically removing. It is in this agitator that we used 3D printing most extensively for development.”
The company currently has a Stratasys system that Cotton admits is running all day everyday. “We used to send prototyping work out of the company to be completed. It could sometimes take as long as 2–3 weeks for the models to be back in the hands of the designers, which is much quicker than pre-3D printing, but not quick enough in a competitive marketplace.
“By bringing the printer in house we can draw up a design in the morning, print overnight, hold the part the next morning and then iterate again and again until it’s properly sorted.”
For the time being then, Brightwake used their in-house 3D printer to prototype every plastic component of the machine, making 12 functional prototypes to take into theatre to trial. “ We usually use the 3D printing before moving into injection moulding,” explained Cotton. “Once we have the trialing right we commissioned the tooling for the injection moulding.”
I asked Stephen if he saw opportunity for 3D printing to leap from the prototyping stage to real production: “Yes, we are working on developing ways to use 3D printed parts in the final product. For example, we’re trialing components that can only be made by 3D printing because of their complex geometries. Stratasys already have a line of biocompatible polymers for printing will allow us to make 3D printed parts out of materials with the same properties and certifications that we can currently mould in. At the moment it seems that every six months there is a revolutionary advance like biocompatible polymers that is making us reconsider the way we approach 3D printing in the future.”
Beyond the world of polymers, metal 3D printed components — that would otherwise be made by expensive and time-consuming lost-wax process — start to become viable. Another future opportunity is for 3D printing with living cells, and ‘infusing’ them with DNA so that they can be implanted into humans as donor organs. “The technology is nearly there but the ethics and acceptance will take some time to come around to the ideas,” said Cotton. These ideas aren’t fiction anymore; certainly within the next 10 years we could see printing organs asa real, viable solution.