In order to 3D-print really intricate items, you need a really fine print nozzle. Scientists have discovered that instead of going to the time and trouble of building one, you can simply repurpose a mosquito's existing blood-sucking proboscis.
Because they need to squeeze between skin cells in order to access the underlying blood vessels, mosquito proboscides (plural of proboscis) are very skinny. They're also conveniently hollow, plus they're stiff and straight. What's more, their source – female mosquitoes – is cheap and plentiful.
With these selling points in mind, scientists from Montreal's McGill University and Philadelphia's Drexel University set about converting the appendages into 3D printing nozzles. Although ultra-fine print nozzles do already exist, they're typically made from costly specialized metal or glass, and are difficult to manufacture.
For their study, the researchers obtained euthanized laboratory-reared female Aedes Aegypti mosquitoes, stored them in a freezer, then dipped them in a solution of 80% ethanol to sterilize them.
Next, the soft protective outer sheath of each insect's proboscis was detached and discarded. An ultraviolet-curable resin was then applied to the now-exposed rigid section of the proboscis, and hardened by exposure to UV light. The resin-coated proboscis was then cut off of the mosquito's body with a razor blade, forming a nice little rigid tube.
That tube/nozzle was subsequently adhered to a standard plastic dispenser tip, which was used to extrude the print media in a DIW (direct ink writing) 3D printer.
The setup was able to print layers as thin as 20 microns, which is about half the width of what commercial 3D printers can currently manage. Some of the tiny complex structures printed so far have included a honeycomb, a maple leaf, and bioscaffolds that encapsulate cancer cells and red blood cells.
Importantly, each nozzle can be reused many times before needing to be replaced. Plus when they are discarded, they biodegrade.
The scientists have rather creepily named the process "3D necroprinting," bringing to mind other studies in which spider carcasses and lobster tails were used as mechanical graspers. In fact, the mosquito proboscis has even been put to use before, as the inspiration for pain-free hypodermic needles.
“By introducing biotic materials as viable substitutes to complex engineered components, this work paves the way for sustainable and innovative solutions in advanced manufacturing and microengineering,” says McGill's Assoc. Prof. Jianyu Li.
A paper on the study, which was led by McGill graduate student Justin Puma, was recently published in the journal Science Advances.
Source: McGill University
