Researchers at RMIT University in Australia have developed a new 3D printing technique that allows them to create incredibly small and complex biomedical implants. The approach is to print glue molds that can then be filled with biomaterial filler material. Once the mold is dissolved, the biomaterial structure remains. Excitingly, the technique uses standard 3D printers, such as they are even commonly found in high schools, and PVA glue as printing material.
Tissue replacement printing is a huge area of research, but teams around the world have struggled to create highly complex structures that can help improve the viability of printed implants. Fabrics are naturally complex, but so far 3D printed biomaterials are a bit dirty in their resolution and complexity. These researchers realized that printing a reverse shape could be a better approach when creating more complex structures.
“The shapes you can make with a standard 3D printer are limited by the size of the print nozzle: the aperture should be large enough to let the material through, and this ultimately affects the small size you can print. “, said Cathal O’Connell, a researcher involved in the study, in a RMIT press release. “But the gaps between the printed material can be much smaller and much more complicated. Inverting our thinking, we basically draw the structure we want in the empty space of our 3D printed mold. This allows us to create small and complex microstructures where cells will flourish. ”
Researchers have named their technique of 3D negative embodied sacrifice template printing (NEST3D). The printing ink is PVA glue, which is commonly used in children in craft projects, and the 3D printer used by researchers is relatively low, which they describe as “secondary grade”.
“It’s important to note that our technique is versatile enough to use medical-grade materials for sale,” O’Connell said. It is extraordinary to create such complex shapes with a basic 3D printer of “secondary” grade. This really lowers the bar for entry into the field and brings us a significant step towards turning tissue engineering into a medical reality. ”
Printed PVA structures can be dissolved outside the core of the biomaterial simply by placing them in water. “The advantage of our advanced injection molding technique is its versatility,” said Stephanie Doyle, another researcher involved in the study. “We can produce dozens of bioscaffls of test in diverse materials, from biodegradable polymers to hydrogels, silicones and ceramics, without the need of a rigorous optimization neither of skilled equipment. We are able to produce 3D structures that can be only 200 microns in diameter, the width of 4 human hairs and with a complexity that rivals that which can be achieved through light-based manufacturing techniques. It could be a massive accelerator for research in biofabrication and tissue engineering. ”
Watch a time lapse video of the technique:
Study a Advanced materials technologies: Inter-line printing: intricate biomaterial structures made by printing negative 3D embedded sacrificial template (NEST3D)