High resolution 3D printed biocatalytic reactor core with optimized efficiency for continuous flow synthesis

• 3D printed enzymatically active hydrogels. • High resolution 3D printed hydrogels with channel sizes as small as 10 µm. • Tailored geometry leads to significantly improved effectiveness factor (64%). • Fully 3D printed continuous flow reactor. 3D printing has the potential to transform biocatalytic continuous flow reactor technology, where precise control of topology is essential for maximizing reactor performance. By embedding enzymatic catalysts in polymer hydrogel networks, continuous synthesis has recently been demonstrated. The reactor core, however, inherently suffers from poor substrate accessibility to the biocatalyst, due to limited diffusion through the gel. We 3D print high-resolution (10 μm), high-fidelity, enzymatically-active hydrogel reactor cores, using Projection Micro-Stereolithography (PμSL). At a scale previously inaccessible, channels with optimized dimensions are included to increase reactor efficiency and mass transport. This leads to a 60 % increase in specific activity compared to 3D printed parts without channels. Under flow, high resolution geometric control enabled a 240 % increase in synthesis rate compared to static experiments. This lays the foundation for a new generation of optimized 3D printed flow reactors.