The Nanoscribe GmbH has developed a laser lithography system with which one can realize complex three-dimensional structures (3D) fully automatic and reproducible with a previously existing design flexibility to Submikrometerskalen with feature sizes down to 1 mm. Of which today are already benefiting many applications, eg can be “laser-write” micro-structures for small pumps and needles produce or biomimetic surfaces equipped with certain properties. A typical use for the 3D laser lithography is also producing three-dimensional scaffolds for cell biology.
The classical cell culture conditions set in the flat Petri dish limits. For in the natural tissue, cells in the body are usually in an extracellular matrix, thus a three-dimensional environment and at the same time flexible in spatial network. A petri dish can not simulate these real environmental conditions. This means that their possible use is restricted. By means of 3D laser lithography can now be arbitrarily structured and flexible frames also produce three-dimensional reproducible. That is, the cells can settle in a special simulated spatial matrix, that of a scaffold.
“Writing” with the laser pen
By strong focusing ultrashort laser pulses in the photosensitive and biocompatible polymer of this nonlinear optical process is exposed through a focus. Comparable to a pin which is performed in three dimensions describes the laser beam, the material along arbitrary paths. This line widths can be achieved by several micrometers down to 150 nm.
Achieved high precision in the three-dimensional lithography, however, only if it is positioned exactly. For while the writing process and laser focus remain fixed and the workpiece to be moved according to the three-dimensional writing task. A further complication is that it is not enough just to take up certain positions. The road is just as important as the destination, the application therefore requires a precise path control. During the journey, then the laser intensity is varied according to the web speed to achieve the desired result lithography. The sample used for the positioning system is thus a key component for the laser lithography device “Photonic Professional” the Nanoscribe GmbH
Precise positioning of the laser focus
Here, the choice fell on a positioning system from the product of the Karlsruhe-based company Physik Instrumente (PI). The multi-axis Stage P-563 is mounted on a high-precision XY scanner table, a writing and Positioning of Piezo print volume to an area of ??up to 100 x 100 mm? allowed. He works with travel ranges of up to 300 x 300 x 300 microns, and the repeatability is in the nanometer range.