Volumetric building blocks: A simple and modular approach to create perfusable models via assembly of volumetrically printed subunits

Tomographic volumetric additive manufacturing (tVAM) enables rapid 3D printing of constructs with intricate, freestanding geometries. Besides demonstrating very promising applications in tissue engineering and biofabrication, a limitation of the technology has been the relatively high material consumption and limited maximal model size due to optical and technical constraints. Here we demonstrate the fabrication and use of highly modular hollow structures created with tVAM to produce large scale tubular systems that allow the formation of complex, hollow networks beyond the build space of commercial tVAM devices. In many cases, it can reduce the overall dead volume used for printing by more than 50% compared to printing the whole structure at once. As proof of concept, we made a channel system recapitulating the physiological complexity of human vasculature in vitro. The system was tested with liquid flow dynamic and stent placement into stenosed segments to show that leaktight models could be created. Further, by using gelatin methacryloyl, a large-scale system out of seven single units could be created and effectively endothelialized, showing the potential of the approach for fabrication of physiological stent placement phantoms or vascular tissue models.