Researchers in McGill's Department of Mechanical Engineering and at Drexel University have developed an innovative manufacturing technique that makes female mosquito proboscides, or feeding tubes, into high-resolution 3D-printing nozzles. With its unique geometry, structure and mechanics, the proboscis enables printed line widths as fine as 20 microns, or a little smaller than a white blood cell. This is roughly twice as fine as what commercially available printing nozzles can currently produce.
The researchers named the process "3D necroprinting," where a non-living biological microstructure is directly used as an advanced manufacturing tool. Potential applications include producing tiny scaffolds for cell growth or tissue engineering, printing cell-laden gels, as well as the delicate transfer of microscopic objects like semiconductor chips.
"High-resolution 3D printing and microdispensing rely on ultrafine nozzles, typically made from specialized metal or glass," said study co-author Jianyu Li, Associate Professor and Canada Research Chair in Tissue Repair and Regeneration at McGill. "These nozzles are expensive, difficult to manufacture and generate environmental waste and health concerns."
"Mosquito proboscides let us print extremely small, precise structures that are difficult or very expensive to produce with conventional tools. Since biological nozzles are biodegradable, we can repurpose materials that would otherwise be discarded," added Changhong Cao of McGill, Assistant Professor and Canada Research Chair in Small-Scale Materials and Manufacturing and study co-author.
The study was led by McGill graduate student Justin Puma. He was involved in a previous study using a mosquito proboscis for biomimetic purposes that established a foundation for this research.
Biodegradable and reusable
To develop the nozzles, the researchers examined insect-derived micronozzles and identified the mosquito proboscis - a tiny, naturally evolved microneedle about half of the width of a human hair - as the optimal candidate. The proboscides were harvested from euthanized mosquitoes, sourced from ethically approved laboratory colonies used for biological research at partner institution Drexel University.
Under a microscope, the researchers carefully removed the mosquito's feeding tube. They then attached this biological needle to a standard plastic dispenser tip using a small amount of resin. The researchers characterized the tips' geometry and mechanical strength, measured their pressure tolerance and integrated them into a custom 3D-printing setup.
Once connected, the proboscis becomes the final opening through which the 3D printer emits material. The researchers have successfully printed high-resolution complex structures, including a honeycomb, a maple leaf and bioscaffolds that encapsulate cancer cells and red blood cells.
The idea of using biotic materials in advanced manufacturing was inspired by necrobotics research at Rice University. While searching for micronozzles, Cao was also in discussions with Drexel University researchers Megan Creighton and Ali Afify on a separate mosquito-related project. These conversations led the team to explore proboscides for 3D printing.
"Evolutions in bioprinting are helping medical researchers develop unique approaches to treatment. As we look to improve technology, we must also strive to innovate," said Creighton, study co-author and Assistant Professor of Chemical and Biological Engineering at Drexel.
"We found the mosquito proboscis can withstand repeated printing cycles as long as the pressures stay within safe limits. With proper handling and cleaning, a nozzle can be reused many times," Cao said.
"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," Li added.
About the study
"3D Necroprinting: Leveraging biotic material as the nozzle for 3D printing," by Justin Puma, Megan Creighton, Ali Afify, Jianyu Li, Changhong Cao et al, was published in Science Advances.
Funding was received from the New Frontiers in Research Fund Exploration program, the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery program, Fonds de recherche du Québec Nature and Technologies. (FRQNT) New Academics program, the Canada Foundation for Innovation John Evans Leaders Fund, the Canada Research Chair Program and an NSERC-FRQNT Nova grant.
