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Chemical Engineering

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Next-generation encapsulation technology

| By Gerald Ondrey

Nucleic acid-based medications, such as mRNA vaccines, are opening up new therapeutic approaches. These active ingredients must be enclosed inside nanoparticles to ensure that they get to where they are needed inside the body’s cells. The Fraunhofer Institute for Production Systems and Design Technology IPK ( and FDX Fluid Dynamix GmbH (both Berlin, both Germany; have developed a technology platform — called Fraunhofer Dynamic Mixing Technologies (FDmiX) — for the production of nanoparticles that can achieve particle quality and stability at levels previously out of reach. Lonza AG (Basel, Switzerland; has licensed the patented technology for its own good manufacturing practice (GMP) production activities, and is already using it.

The heart of the FDmiX platform (photo) is an OsciJet nozzle from FDX Fluid Dynamix. Inside the nozzle, a jet of liquid is positioned on one of the sides of the main chamber. Before leaving the nozzle, a small part of the jet is deflected into a side channel. At the end of the side channel, it meets the main jet again and pushes it to the other side. This causes the main jet to oscillate continuously from one side to the other at a high frequency. In this way, the jet of lipid solution oscillating through the nozzle meets the stream of the mRNA active ingredient at a perpendicular angle, creating a homogeneous mixture with nanoparticles of uniform size. In tests of conventional impinging mixers (T- or Y-mixers), by contrast, the lipid solution and mRNA active ingredient collide before flowing together through the same channel. This creates a dynamic vortex, resulting in inhomogeneous particles of lower quality.

The oscillating flow in the FDmiX enables 6–8 times faster and more reliable mixing. This results in improved critical quality attributes (CQAs) and higher yields thanks to consistent nanoparticle size and fewer filtration losses. The system is scalable, because encapsulation can take place with volume streams ranging from 5 mL/min to 1.5 L/min without affecting the particle properties.



Source: B. Bobusch/FDX Dluid Dynamix