An interview with Alessandro Barraco, Additive Manufacturing Process Engineer at BI-REX, on the potential of PolyJet technology
Additive manufacturing, commonly known as 3D printing, is a family of technologies that create physical objects by adding material layer by layer, based on a digital three-dimensional model. Unlike traditional manufacturing methods, which typically involve cutting or molding materials into shape, additive manufacturing builds up structures from scratch. This process allows for greater design freedom, minimal waste, and highly customized results. Today, it is becoming increasingly relevant in fields that demand high levels of customization, structural complexity, and functional fidelity.
In the biomedical and life sciences sectors, 3D printing is revolutionizing the creation of anatomical models with unprecedented possibilities. It excels particularly in its ability to replicate both the geometry and the physical behaviour of human tissues. This capability extends to mechanical response, such as how a material reacts to being cut, compressed, or sutured, which is essential for realistic surgical training and simulation.
PolyJet technology and BI-REX’s strategic integration
Among the most advanced technologies enabling this level of detail is PolyJet. Unlike traditional 3D printing systems that rely on a single material, PolyJet can deposit multiple photopolymers simultaneously, each with distinct mechanical properties. This makes it possible to fabricate complex, heterogeneous models that closely resemble the layered nature of biological tissues. The result is a powerful tool for developing more accurate training devices and better surgical planning models. But also clearer communication aids for patients and clinical teams.
BI-REX is one of the eight national Competence Centers established by the Italian Ministry for Economic Development to promote the adoption of Industry 4.0 technologies. Based in Bologna, it provides companies and public institutions with access to advanced digital tools. These include artificial intelligence, big data, cybersecurity, and additive manufacturing. Through its fully equipped pilot line, the center supports the development and testing of innovative solutions across multiple sectors. Within this broader framework, BI-REX dedicates specific efforts to biomedical use cases. In this sector, the demand for personalization, simulation, and process digitization is particularly strong.
The Stratasys Digital Anatomy system
As part of this strategy, the acquisition of the Stratasys Digital Anatomy system marks a significant step toward exploring the clinical potential of high-resolution, multi-material 3D printing. Based on PolyJet technology, the system has been integrated into BI-REX’s pilot line and is now being used to develop advanced biomedical applications.
To understand how this is being implemented in practice, we spoke with Alessandro Barraco. He is Additive Manufacturing Process Engineer at BI-REX, who is directly involved in the deployment and experimentation of PolyJet technology in medical settings.
How does PolyJet technology work, and what are its potential applications in the biomedical field? What are its main strengths compared to other additive manufacturing technologies?
At BI-REX, we’ve already worked on several biomedical projects, which are among the key drivers of additive manufacturing. PolyJet can print with up to seven different materials at the same time, compared to just two in other similar technologies. This makes it particularly unique. It enables the production of highly complex components, especially with our machine version, which was designed specifically for biomedical applications.
Stratasys, the manufacturer, has put a lot of effort into this technology, not only in the machine itself but also in the development of advanced materials. The printer we use is called the Digital Anatomy, and it’s designed to replicate not only the shape of body parts but also the texture and mechanical behavior of human tissue.
We’re collaborating with institutions like the Rizzoli Orthopedic Institute, where we’ve already produced several patient-specific models based on CT scans. They are not standard models but are custom-made for each patient. We use materials like BoneMatrix, which simulates both the shape and the texture of bone, as well as other materials for soft tissues, veins, arteries, and organs. The results are incredibly realistic.
The main application areas
There are three main application areas. The first is surgical planning. Surgeons can rehearse procedures with much greater precision and get mechanical feedback that feels very close to the real thing, whether they’re drilling, cutting, or handling the model in other ways. The second is communication with patients. Thanks to the use of transparent or color-coded materials, it becomes easier to explain what the surgery involves. The third is medical training. We’re currently developing artery models for resident doctors, designed to offer realistic tactile feedback during practice.
| The three main application areas Surgical planning Communication with patients Medical training |
Another major strength is the software. It allows us to use pre-set material profiles provided by the manufacturer. Furthermore, we can create fully customized materials, tailoring both their morphology and chemical composition. We can replicate complex lattice structures like the spongy interior of bone or simulate different tissue densities in tumors based on their location.Â
We decided to focus on clinical applications through direct collaboration with hospitals. In fact, we believe that’s where this technology can make the most impact. The Digital Anatomy printer was acquired as part of the DEAR project for digital prevention, specifically aimed at biomedical innovation.
Of course, it can also be used for other applications, for example, to create multicolor prototypes that closely resemble the final product, but our strategic decision was to focus on healthcare. Just a few days ago, for example, we provided a Rizzoli Institute surgeon with a patient-specific spinal model to help plan a complex operation in the least invasive way possible. Being able to make a tangible difference in a real case like that is extremely rewarding.
So, would you say that additive manufacturing is now a well-established tool in research and development, particularly in the medical and life sciences sectors?
Yes, it already is. Some applications have become standard, for example, hip prostheses. The ability to create highly complex geometries allows us to overcome the limitations of traditional manufacturing. Using dense lattice structures, for instance, improves bone integration and reduces the risk of rejection. The goal is to develop permanent implants that don’t need to be replaced after a few years.
In the biomedical field, these technologies are already well-established, and as materials and hardware continue to evolve, so do the applications. That said, it’s a sector with a lot of inertia, which makes sense, given the strict certification processes required before any material can be used in contact with the human body or implanted.
What are the main barriers to adopting these technologies in the medical or life sciences sectors?
Whether a prosthesis is made with additive manufacturing or traditional techniques, it has to pass the same safety tests. So even though additive technology is highly advanced, it still has to prove that it matches the reliability of traditional technologies that have been established for decades. Additive manufacturing is still a relatively young technology, the first applications go back to the ’80s and ’90s. It’s growing fast, but there are no shortcuts: every part has to be safe and meet the same standards. The same applies in aerospace: certifications are required for the material and the manufacturing process, and it must be proven that the final part meets all minimum standards. So it’s not enough for the material to be suitable, the entire process must be validated, and the final component has to meet the standards required for critical applications, whether it’s an implant or a flight part.
