A research team at the University of Texas, led by chemists Jodi Connell, Marvin Whiteley, and Jason Shear, has 3D-printed this microscopic chimpanzee skull, which later served as an unsettling proof-of-concept for printing "microscopic houses" to trap bacteria, forming "tiny zoos for the study of infections."
The team made the somewhat sinister skull—like a ghostly death's head emerging from the ether—by firing lasers at a substrate of gelatin. Wherever the laser hits, "a solid matrix forms," allowing the production of three-dimensional shapes.
Better yet, the laser uses a "chip adapted from a digital movie projector," Phys.Org explained, as if images from a film could be brought to unnerving life on a microscopic level, conjuring real, physical objects out of short bursts of light.
Jason Shear explained in a phone call with Gizmodo that they can "build up 3D objects" using the technique, in a way that he compared to a 3D Etch-a-Sketch. His team used sequential CAT scan data of a chimpanzee skull taken from the Digital Morphology lab at the university—in fact, apparently this data set—mostly for the technical challenge, although Shear added that they also got data sets for beetles, lizards, and bats.
Later, they learned how to seal bacteria inside "cages" created using the same microscopic printing method. Trapped in these microscopic jail cells, whether chimpanzee-shaped or not, the bacteria's capacity to cause infections and to resist—or succumb to—antibiotics could thus be tested. The chimpanzee skull seen here—though purely a virtuoso example of what's possible with gelatin-based 3D-printing—is thus a weirdly appropriate image for the experiment, as these "tiny zoos" are more like Thunderdomes: death cages for unlucky bacteria fighting to the bitter end against antibiotics.
As Phys.Org reports, the "resulting structures can be of almost any shape or size"—not just chimp skulls—with nearly infinite variables for design. Team member Jodi Connell explains how these printing technologies are a kind of microscopic architecture, allowing the design and creation of total environments where Connell and her colleagues can control every physical detail.
Shear goes all the way with the architectural metaphor, adding that the team was able "to print or build the houses around the bacteria," without relying on the bacteria themselves to move into the resulting structures; it was print-in-place construction on a microscopic scale.
The actual "microscopic house" created by the team; image courtesy J. Connell et al., University of Texas at Austin.
The design can be controlled to an astonishing degree, down to "what a single bacterium feels and senses," Connell told Phys.Org. "We can also much more precisely simulate the kinds of complex bacterial ecologies that exist in actual infections, where there typically aren't just one but multiple species of bacteria interacting with each other."
We'll keep our eyes out for future simulated infections fighting to the death inside 3D-printed microscopic houses—not to mention tiny chimpanzee skulls, lizard skulls, bat skulls, and human skulls. Microscopic skulls coming to a surface near you. Stay tuned. [Phys.Org]
Images used with permission, J. Connell et al., University of Texas at Austin.