From eliminating multi-hour furnace cycles in glass manufacturing to reengineering how poorly soluble drugs dissolve in the body, Leonard Siebert is applying materials science to two of engineering’s most stubborn bottlenecks.
A materials scientist at Kiel University (CAU) and currently a visiting researcher and technical project lead at KU Leuven, Siebert works on process-level innovations to accelerate, improve energy efficiency, and make advanced manufacturing clinically relevant.
He developed Laser-Assisted Melt Printing (LAMP), a method that enables direct 3D printing of glass without prolonged sintering. As a Marie Curie Postdoctoral Fellow, he now leads the DRUG-SPIN project, applying melt-spinning techniques to improve drug solubility and reduce pharmaceutical waste.
Currently a visiting researcher and technical project lead at Belgium’s KU Leuven, Siebert boasts more than a decade of experience in materials science. He’s now applying that expertise to rethink how advanced manufacturing, particularly 3D printing, can reshape the pharmaceutical industry and medicine.
In this interview with Interesting Engineering (IE), Siebert discusses how materials processing, from lasers to rapid quenching, can reshape both manufacturing and medicine.
Interesting Engineering: Walk us through your journey into research.
Leonard Siebert: I’m a materials scientist by training. What drew me to the field is how it combines physics, chemistry and engineering, into real world applications.
After my postgraduate studies, I pursued a Ph.D. because I’ve always been interested in building things. That’s why my PhD focused on additive manufacturing, which is 3D printing. I also began working directly with doctors to solve clinical problems with 3D-printed materials. That showed me how research can translate into genuine help for patients.
IE: Why materials science?
I didn’t start out aiming for materials science. In school I was more interested in food chemistry. As a child, I even wanted to be a cook because I loved the idea of combining aromas and creating things.
Then my dad mentioned he had a colleague who did nanotechnology at Kiel University, so we visited the department. I liked the atmosphere. I immediately felt at home and decided to study materials science.
Leonard Siebert, PhD, a materials scientist at Kiel University. Credit: Julia Siekmann, CAU
IE: Your work links additive manufacturing, advanced materials and medicine. How did your career evolve toward such a highly interdisciplinary space?
It really started early in my studies. By my second semester, I was already working as a research assistant, synthesizing functional materials like zinc oxide. Thenour group began exploring 3D printing, and I was the first PhD student to dive in. I was immediately fascinated.
When 3D-printing took off in Germany around 2015–2016, we bought our first large printer. Then, medical projects naturally started coming in. Biomedicine and materials science fit together very well, so the combination of materials, devices, and clinical collaboration came from all directions.
IE: During your PhD, you spent about three months at Harvard. How did that experience shape the way you approach research?
Harvard was an intense period. The workload and expectations were extremely high, and when you’re part of a team like that, you naturally match that pace. I learned what it means to push a project forward with real focus and energy.
The environment was very interdisciplinary. I worked closely with biomedical and bioengineering students who taught me cell culture, protein work and techniques outside my original training. It gave me a broader perspective on the biomedical side of materials science.
IE: This research and experience ultimately led you to create laser-assisted melt printing (LAMP), a new glass 3D printing method.
The idea began during my early postdoc work, when we worked together with the dental department on 3D-printed ceramic restorations. Ceramics are very difficult to produce because they’re brittle and have high melting temperatures.
Meanwhile, traditional milling and long furnace cycles (five to seven hours at around 1700 degrees Celsius [3,092 degrees Fahrenheit]), were inefficient and frustrating. I’m impatient by nature, so I kept wondering whether we could heat and solidify the printed structures instantly.
At the time, our lab had bought a CO2 laser cutter, and I started experimenting with whether light could bake the ceramic inks directly. That quickly became an obsession. We later switched from zirconium dioxide to glass because its lower melting point and transparency made it easier to see if it was working.
There were many hurdles. That’s why it’s so rewarding to see how far we’ve come. The method now works reliably. It has drawn interest from major glass producers and others in industry.
IE: Why is LAMP important? What are its most promising uses?
It’s most valuable when you need to create something unique. And this is exactly the case in biomedical applications. Bone grafts, dental restorations, and implants are patient-specific so 3D printing makes perfect sense. You can produce the part directly from the patient’s data without molds, milling or cutting.
High-melting-point materials including ceramics have always been a challenge. They need long furnace cycles to reach the properties needed for implantation. That’s where LAMP comes in. It lets you print and fully densify the material in a single step, without an overnight sintering process. In theory, you could produce something that’s ready for implantation immediately.
The energy savings are also significant. With furnaces, you need to heat the entire chamber. LAMP heats only the material and the exact spot touched by the laser. So, you gain both time and energy efficiency, which are major advantages.
IE: How close is LAMP to real-world use?
It’s still in the realm of fundamental research. We do have potential applications in mind, however, in the biomedical sector the stakes are very high. Any implant for the human body requires strict regulatory approval, rigorous quality control, and full certification.
Right now, LAMP is at about Technology Readiness Level 4 – a lab demonstrator. The next step would be to focus on a specific use case, such as dental restorations, refine the process, and work with clinical partners to test it in a study. Realistically, that’s a timeline of at least five years. But the foundation is strong.
IE: Apart from LAMP, you secured a Marie Curie Fellowship for your DRUG-SPIN project.
This project grew out of a spontaneous scientific discussion. Most drugs are tiny crystals, and around 90 percent of the compounds currently in development are poorly water-soluble. That’s a massive problem because our bodies are mostly water, so only a small fraction of the drug is absorbed. Patients often take what is essentially an overdose, with up to 95 percent passing through the body unused and ending up in wastewater.
But you can’t simply modify the chemistry to make these drugs dissolve better, as changing the molecule would break its therapeutic effect. Instead, the solution is to disrupt the crystal structure and make the drug amorphous. In this form, it will dissolve far more readily, up to 100 times faster.
My contribution came from a materials science perspective. In our field, you melt a material and cool it extremely quickly to control its structure. We then realized nobody had applied this technique, melt spinning, to pharmaceuticals, although it has been a standard in materials science since the 1960s.
IE: How does melt-spinning work in drug development?
The method is simple: you melt the drug and jet it onto a rapidly spinning copper wheel. Copper’s high thermal conductivity cools the material almost instantly. The rotation spreads it thin, and ultimately produces amorphous ribbons.
My task in the project will be to establish the process, vary the cooling rates, and characterize how each condition changes during the drug’s properties. The aim is to create drugs that dissolve better, work more efficiently, and require far smaller doses, thus reduce production, shipping, and waste.
IE: Why is drug solubility such a major challenge in pharmaceuticals?
Because it determines how much of a drug the body can actually absorb. When a compound doesn’t dissolve well, patients need to take much higher doses, often multiple times a day. Most of the drug simply passes through the body unused.
The residue ends up in wastewater and in the environment. For instance scientists found cocaine in the blood of sharks off Rio de Janeiro, as these substances travel through waterways and accumulate in marine life.
Right now, about 40 percent of marketed drugs are poorly water-soluble. And 90 percent of the drugs in development have the same problem. If we don’t address this now, treatments will become less effective, patient outcomes will decline, and environmental contamination will rise.
IE: You’ve also worked on hydrogels that mimic human tissue. What gap were you trying to close with that material system?
This work stemmed from our collaboration with the radiology clinic. We were part of a big project aimed at establishing AI processes for medical image evaluation. One challenge our partners faced was the lack of suitable training data, so they needed realistic, customizable models.
To support that, we developed phantoms with CT and ultrasound properties that closely mimic human tissue. We scanned these phantoms with both modalities so the AI systems could be trained on reliable, consistent data.
IE: Much of your work bridges engineering and medicine. What are the greatest challenges in connecting these two fields?
One challenge is the language barrier between engineers and clinicians. We come from completely different backgrounds. I’m not a medical doctor, so I don’t quite understand the practical constraints of the human body. Simultaneously clinicians don’t necessarily know the limitations or possibilities of materials science.
The first step is always establishing a common ground. That’s why we spend a lot of time talking before we start developing anything. Once everyone understands each other, the project moves smoothly.
IE: Sustainability appears in several of your projects. How important is reducing energy use in your research?
I think energy will be the defining research challenge of the next 50 to 100 years. It’s clear that we will eventually run out of fossil fuels, and our current renewable energy production and storage methods are still not sufficient. So, across every part of society, we need to think about how to use energy more efficiently.
I try to contribute by designing processes that inherently use fewer resources and less energy. It’s something I find highly motivating because it aligns with my core belief that we must handle our resources, especially energy, much more carefully. Its importance will only grow in the future.
IE: What big scientific question are you most excited to tackle next?
I’m excited by the idea of using LAMP to combine materials that have never been combined before. I’m also interested in materials that are reconfigurable through the manufacturing process. I’m driven by projects aimed at improving people’s quality of life. Ideally, advanced materials research and real clinical impact, will ultimately come together in the future.
IE: What advice would you give to young scientists?
Stay curious and open-minded. Pay attention to the things no one has tried yet or even imagined. Those unexpected ideas could actually be the ones that shape the technologies of the future.
There’s always far more to discover than you expect. An experiment that seems to have failed can often contain the seed of something new. Many major discoveries happened this way: X-rays, penicillin, rubber. None of them would have emerged if researchers had stayed strictly within their original plans.