Multiphoton Direct Laser Writing and 3D Imaging of Polymeric Freestanding Architectures for Cell Colonization

International audience; The realization of 3D architectures for the study of cell growth, proliferation and differentiation is a task of fundamental importance for both technological and biological communities involved in the development of biomimetic cell culture environments. Here we report the combination of 3D freestanding scaffolds realized by multi-photon direct laser writing (DLW), seeded with neuroblastoma cells, and their multi-technique characterization using advanced 3D fluorescence imaging techniques. The high accuracy of the fabrication process (≈ 200 nm) provides a much finer control of the meso-, micro-and nano-scale features compared to other 3D printing technologies based on fused deposition modeling, inkjet printing, selective laser sintering or polyjet technology. Scanning electron microscopy (SEM) provided detailed insights about the morphology of both cells and cellular Complete Manuscript interconnections around the 3D architecture. On the other hand, the nature of the seeding in the inner core of the 3D scaffold, inaccessible by conventional SEM imaging, was unveiled by light sheet fluorescence microscopy and multi-photon confocal imaging which highlighted an optimal cell colonization both around and within the 3D scaffold as well as the formation of long neuritic extensions. The results open appealing scenarios for the use of the developed 3D fabrication/3D imaging protocols in several neuroscientific contexts.