Researchers have found a way to produce 3D media for bacterial cultures using 3D printing. 

I missed this paper from a few months ago, but it is still worth looking at as they seem to have devised an interesting process for creating biological sandboxes for cancer and other experiments. 

2D Bacterial Environments

The problem is that typical culture media are essentially a Petri dish in which the subject organisms are existing in what is a 2D world. Petri dishes do not have complex geometries in any way.

That’s quite different from real life, where an organism will grow and interact with a three-dimensional environment. It’s this type of scenario that is of most interest to researchers, as a 3D test platform could enable much more sophisticated scenarios. Ultimately, this could assist in curing cancer, for example.

Hydrogel 3D Printing

The process used is quite interesting. The researchers prepared a mix of hydrogel and cellulose particles. Hydrogel is an unusual material that is composed of 90% water, yet remains solid. Cellulose is a natural substance that is one of the main components of paper. 

The hydrogel-cellulose mix was arranged in solid form, ready for 3D printing directly into it. This is a bit different from normal extrusion processes that deposit material on a surface in open air. In this configuration, the extrusion is done by a thin needle-like extruder directly into the interior of the hydrogel. 

The extruder moves in 3D space within the hydrogel to deposit the print material, which was a “petroleum-jelly/liquid paraffin-based fugitive ink”. As the needle extruder passes through the hydrogel, this magic material automatically “heals” and is ready for subsequent printing movements. After printing, the hydrogel block is selectively infused with the jelly material. 

Once complete, the hydrogel is dried in open air. As the water evaporates, this leaves a structure of cellulose containing the jelly extrusions. When dry, the block is paper-like, and reminiscent of a wasp’s nest. 

Cellulose Prints

The “paper” block is then heated, and the jelly mix liquefies and is easily removed. This leaves a cellulose block with open channels that can simulate body vessels. All that’s needed is to hydrate the cellulose block to “bring it back to life” before use. The researchers can then place whatever testing materials they wish within the structure and see how the experiment evolves in 3D. 

What’s really interesting about this approach is that the cellulose blocks can be stored for considerable times in dried state. When needed for use they can be hydrated and put into an experiment. This means a research organization could potentially order a box full of them and store them for future use as experiments are undertaken.

I’m hoping this development will spur medical research in many different areas. 

Via ACS