Low-autofluorescence, transparent composite for multiphoton 3D printing

Multiphoton lithography allows the high resolution, free-form 3D printing of structures such as micro-optical elements and 3D scaffolds for Tissue Engineering. A major obstacle in its application in these fields is material and structure autofluorescence. Existing photoresists promise near zero fluorescence at the expense of poor mechanical properties, and low printing efficiency. Sudan Black B is a molecular quencher used as a dye for biological studies and as means of decreasing the autofluorescence of polymers. In our study, we report the use of Sudan Black B both as a photoinitiator and as a post-fabrication treatment step, using the zirconium silicate SZ2080 for the development of a non-fluorescent composite. We use this material for the 3D printing of micro-optical elements, and meso-scale scaffolds for mesenchymal stem cell cultures. Our results show that the Sudan Black B photosensitive hybrid can be used for the fabrication of high resolution, highly transparent, autofluorescence-free microstructures.