Removable support beams to improve the printing outcome of 2-photon-polymerized structures

Using direct-laser writing, 3D microstructures of almost every shape can be fabricated. However, using liquid photoresists, the fabrication of free-floating structures is still challenging. To give stability to those structures during the printing process, support beams can be implemented which are usually not needed for direct-laser writing. With that, free-floating elements can be fixed and are not distorted due to unwanted movement during fabrication. In this work, the design, realization and characterization of support beams for the printing outcome of 2-photon polymerization processes is examined. The support beams described here connect the static and the rotating part of flap-like structures. Experimental results show that two thin cone-shaped support beams are sufficient to stabilize the flaps (typical size $20\times 50\mu m^2$) so that they are not distorted during printing. After finishing the writing process, the support beams can be broken with a gentle nitrogen stream and the structures move freely. Structures like these can for example be implemented in microfluidic channels to work as flow direction pointers or self-closing cell traps.