GEA homogenizers power bioinks for regenerative medicine

GEA is passionate about driving innovation in industrial processing to truly demonstrate the company’s purpose “Engineering for a better world” across diverse sectors, from breweries to biomedicine.

The company’s engineers also like a challenge. So when, during the early 2020s, GEA was approached by scientists at Graz University of Technology to configure a homogenization process and technology that would allow them to turn eucalyptus pulp into 3D-printed, organic structures mimicking human veins, arteries and other tissues, GEA set up a collaboration with the university team and got straight to work.

The GEA team spent time with the scientists learning about their research, challenges and goals, so they could really understand the critical part that homogenization plays in creating nanostructured cellulose fibers from the pulped eucalyptus starting material. Within just a couple of years, in partnership with academic project lead Prof Dr. Mag. Karin Stana Kleinschek, Ph.D., vice head of the University’s Institute of Chemistry and Technology of Biobased Systems (IBioSys), the team developed a robust homogenization process. It enables the researchers to process eucalyptus-derived nanocellulose as liquid “ink.”

These nanocellulose-based inks can be 3D printed into structures that replicate the anisotropic biomechanics of different human tissues, such as blood vessels and tracheae, explains Rupert Kargl, Ph.D., assistant professor at IBioSys. Following appropriate testing, such plant-derived “tissues,” generated from renewable resources, could be used to prepare organ models that resemble the anatomy and biomechanics of patients´ arteries. “These models can potentially be used by surgeons to plan cardiovascular interventions and adapt implants to the patient’s anatomy,” Kargl says.

These models can potentially be used by surgeons to plan cardiovascular interventions and adapt implants to the patient’s anatomy.

Rupert Kargl, Ph.D.

Assistant Professor at IBioSys

In the long term, biobased 3D-printed tissue might offer a more flexible alternative to conventional autografts. Those are the process by which clinicians take a tissue, such as a vein, from one part of the patient’s’ body and use it as a direct replacement for the damaged tissue elsewhere in the body. The ability to 3D print replacements for transplantation might also allow for a more personalized design of therapies. “For that purpose, 3D-printed scaffolds could be seeded with human cells for in vitro tissue culture, followed by implantation of the mature organ,” Kargl notes. “Clinical applications of such a technology, however, will require several years to decades of development and regulatory approval.”

Prof Dr. Mag. Karin Stana Kleinschek, Ph.D., vice head of the University’s Institute of Chemistry and Technology of Biobased Systems (IBioSys), left, speaks with Dr. Silvia Grasselli, GEA Head of Process Technology, Homogenization.

Custom hardware: a GEA Panther Homogenizer 3006

For their ongoing project, the university team purchased in 2024 a GEA Panther Homogenizer 3006, a compact system that can process up to 50 liters of nanocellulose ink every hour. Nanocellulose emulsions are hard to pump, and standard homogenizers such as those that might be used to process milk products, for example, aren’t suitable. So, for the university’s nanocellulose process, GEA designed and configured a Panther unit optimized to handle the material, and the system includes the filling pump and cooling as well.

Dr. Silvia Grasselli, GEA Head of Process Technology, Homogenization, has spearheaded the nanocellulose homogenization collaboration with Stana Kleinschek and the IBioSys team. She explains that to develop the process and homogenizer system in parallel, GEA started by carrying out very low volume tests at the GEA homogenization center of excellence, demonstrating feasibility of the process itself and fine-tuning the process parameters and homogenizer setup and component configuration.

Engineers then optimized the process and technology at a larger scale, and they addressed potential challenges, particularly relating to pumpability of cellulose-water emulsion. GEA representatives also travelled to the university in 2024 to set up the Panther 3006 system homogenizer on site, carry out and check system configuration and help to train Stana Kleinschek’s team in its operation.

The homogenizer set-up is self-contained and user friendly for the university team to operate, program and maintain on a day-to-day basis. Importantly, the scientists can adjust the homogenization process to help create precisely structured nanocellulose fibers and 3D printing inks, making it possible to design the desired properties into their final products.

A 3D printer loaded with the team's nanocellulose bioink prints a tubular structure.

Enabling materials science from first principles

“In fact, nanocellulose can be purchased already partially processed, but professor Stana Kleinschek was interested in designing the materials from first principles,” Grasselli says. “Using our technology, the scientists can adapt the recipe and carry out further research into the effects of pretreatment and homogenization on the material properties and structure. It gives them more control of the process such as the fiber source and pretreatment and insight into how homogenization impacts the nanocellulose structure and rheology of the material and final 3D printed parts.”

Kargl appreciates in particular how the pressure, fiber concentration, number of cycles and temperature can be changed. “The raw material, pretreatment, number of cycles and pressure have the highest influence on the fiber size and ink rheology,” he says.

Dipl. Ing. Dr. Florian Lackner, University Assistant at IBioSys, shows some dried short-fiber eucalyptus pulp.

The institute’s researchers combine expertise in the chemistry and technology of biobased materials, working to develop methods for deriving, synthesizing and modifying bioactive natural products from renewable sources. Potential applications are manifold, including their use in 3D printing, coating and surface-active substances, in fields ranging from biomedical devices and implants to packaging, textiles, cosmetics and paper coatings.

Fully adaptable and collaborative

“The ongoing collaboration between GEA and the IBioSys Institute team is particularly exciting because the university researchers are at the forefront of biobased material research and development,” Grasselli says. “They are connected with researchers – both within the technology center and externally – in linked or related fields, and we are here to work with them and provide our processing expertise and technologies to help accelerate research and development across a wide range of innovative biobased product and application fields.”

The ongoing collaboration between GEA and the IBioSys Institute team is particularly exciting because the university researchers are at the forefront of biobased systems material research and technology development.

Silvia Grasselli

GEA Head of Process Technology, Homogenization

IBioSys benefits from the collaboration with GEA through access to the expertise of the equipment manufacturer and process engineers, Kargl adds. “This allows testing and adapting the homogenization process for many different biobased materials such as polysaccharides, proteins, oils and emulsions in future collaborations.”