Jun 15, 2024 When you want to create the biomaterials of the future: think thin. Melt electrowriting (MEW) is a technique that is gaining momentum, creating finer fibers than traditional 3D printing. With the ability to control fibers for scaffold production, MEW is poised to push the boundaries of 3D printing. We received the inside scoop from a panel of experts hosted by 3DHEALS: here is what we learned.
MEW’s precursor, called electrospinning, uses a nozzle that applies high voltages to a polymer solution, resulting in fibers ejected onto a print bed. On the other hand, MEW melts the material first and extrudes at low flow rates to create its microscale filaments, using the high voltage to stabilize this flow. MEW shines for its ability to create varying diameter fibers with a single nozzle—a step up from traditional printing.
Paul Dalton, an Associate Professor at the University of Oregon, is pioneering the MEW field and gave the opening presentation to our event. “One of the advantages of very small fibers is you have a lot of design space where you can kind of build up structures,” says Dalton. In recent work, Dalton and colleagues have grown human-like skin by utilizing electrospinning and MEW to create bilayer scaffolds to seed cells. Such scaffolds lay the framework for growing a realistic skin microenvironment and establishing appropriate cell orientations. These skin models open new opportunities for studying wound healing and testing cosmetics.
Dalton is also changing the game on MEW’s accessibility: designing open-sourced printers to make it easier for companies and researchers to get started. “Having hobby printers which you modify,” he says, “… really empowers people to innovate.” Now, a conventional desktop 3D printer can be converted into a MEW device of the future.
Researchers are also shaping MEW’s future by expanding the design options for biomimetic scaffolds. Central to this design is the ability to tune the mechanical properties of scaffolds. “We can now selectively control to what degree the scaffold expands across the length of the scaffold, which is opening up some really exciting avenues for mechanical control,” says Naomi Paxton, Senior Research Fellow and leader of the Bioinspired Additive Manufacturing (BioAM) group at Queensland University of Technology.
Paxton and colleagues are also using MEW scaffolds for personalized medicine, creating patient-specific ear implants based on 2D photos. These ears, made from high-density polyethylene, may one day be used for patients with microtia, a condition where the outer ear has not been properly formed. Their recent work has shown favorable mechanical properties, with higher tensile strength and stiffness compared to conventional MEW polycaprolactone scaffolds.
Beyond the ears, scientists such as Bahram Mirani, a PhD candidate at the University of Toronto, are using MEW to produce life-saving heart valves. Traditional mechanical heart valves have risks for blood coagulation, and current tissue-engineered heart valves can have leakage that occurs due to tissue remodeling. Mirani and colleagues are tackling these limitations by using MEW to control the sinusoidal-shaped fiber architecture of their engineered valve scaffolds, fine-tuning parameters such as sinusoid amplitude to obtain the desired stress-strain behaviors of native tissue.
The researchers delivered human umbilical cord perivascular cells onto their scaffolds, forming sheets that were placed onto a 3D-printed supporting frame in the shape of a pediatric heart valve. Under physiological pressures, they find that their valve exhibits desired mechanical properties to avoid leakage. Such in vitro tests may get us closer to more reliable heart valves that grow with the patient, which is particularly important in pediatric settings.
Advancing MEW commercially, Filippos Tourlomousis, founder and CEO of Biological Lattice Industries Corp., sees the potential of MEW to create scaffold feature sizes on the scale of single cells to influence cellular phenotypes. Tourlomousis’ MEW scaffolds create 3D microenvironments that enable the tunability of cell shapes and functionality.
“After talking with customers, there is a big need and desire for research groups around the world to have a complete system that is as close as possible and takes into account the real-world applications, which means the regulatory pathway,” says Tourlomousis. In response, his company has developed BioLoom, a combined MEW, bioink, and fused deposition modeling printer with software for optimization and machine learning.
As an up-and-coming technology, MEW provides a promising level of control over scaffold architectures. From research in academia to innovations in industry, MEW’s thin fibers may help us to create more effective and reliable structures for a wide range of organ systems and medical applications. To learn more from our speakers, watch the recording of the 3DHEALS event, and subscribe to join our upcoming events live.
About the Author:
Peter Hsu
Peter Hsu is an editorial intern for 3DHEALS. He is currently an undergraduate at the University of Illinois Urbana-Champaign and studies bioengineering with a focus on cell and tissue engineering. He is also minoring in computer science with interests in artificial intelligence and image processing. Peter conducts research on using computer vision methods to analyze human tissue images and improving the robustness of machine learning workflows. He is interested in the use of AI to assist tissue engineering and bioprinting research for medical applications. He is passionate about science communication and leads STEM outreach lessons at schools in the central Illinois area.
Related Links:
Interview with Prof. Paul Dalton: Melt Electrowriting and Biofabrication
Interview with Natan Barros: 3D Bioprinting and Microfluidics
Interview with Dr. Nicole Black: 3D-Printed Biomimetic Eardrum Grafts
Interview with Y. Shrike Zhang: 3D Bioprinting & Organoids
3D Bioprinting Biofabricating Skin Components (On-Demand, 2024)
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