A specialized 3D printing extruder developed by a sophomore and collaborator at the University of Alabama in Huntsville (UAH) could lower the costs of printing cellular structures for use in drug testing. The so-called CarmAl extruder (Carbohydrate Anhydrous Rapid Manufacturing Aluminum extruder) its controlling software and manufacturing processes being developed by biological sciences student Tanner Carden and a collaborator studying mechanical and aerospace engineering. They say that they have produced a sugar grid mimicking blood vessels.

The researchers with their CarmAl extruder.

They are using sugar molecules in a form of reverse 3D printing, by first making the structures wanted and then embedding them into a cellular matrix. After cells held in suspension in an agarose solution are grown around the vascular structure, a solvent can be used to wash the sugar away.

The result, they say, is a cell mass that contains vessels like a human organ would, which is an advantage for drug tests over flat-dish cell cultures currently used because it more accurately represents living tissue and more of the test cells can be kept alive by vessel-supplied nutrients.

The researchers aim to lower production costs of testing cultures to allow drugs to be screened for failure earlier, saving on the cost of drug development.

The printer system uses software to control a solenoid valve that regulates the timing of nitrogen pushing on a sugar solution in the CarmAl extruder. The device uses a modular tip and a heated process at temperatures higher than other extruders to better control the viscosity of the sugar solution for more accurate vascular structures.

The next step is growing cells around the sugar structures created, and Carden plans to travel to Wake Forest University’s Institute for Regenerative Medicine to learn from a program already using cells in the 3D printing of biological structures about the techniques and pitfalls involved.

Further advances to their system could include the addition of 5D printing capabilities, which would allow the current grid-like vascular structures to flow and branch in a more natural fashion and truly be created in three dimensions.

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