Curriculum vitae
Prof. Dr. Reinhart Poprawe holds a M. A. in Physics degree from the California State University in Fresno which he received in 1977. After completion of his diploma and PhD in physics (Darmstadt 1984) he joined the Fraunhofer Institute for Laser Technology in Aachen where he began working as head of the department „Laser oriented process development“ in 1985. From 1989 to 1/1996 he has been managing director of Thyssen Laser Technik GmbH in Aachen. Since February 1996 he is managing director of the Fraunhofer Institute for Laser Technology and holds the University Chair for Laser Technology at the RWTH Aachen. Currently he is a member of the board in the AKL Arbeitskreis Lasertechnik e. V. Aachen. Prof. Poprawe has been elected to the grade of Fellow in the Society of Manufacturing Engineers in USA (SME) since 1998. In 2006 he became Fellow of the Laser Institute of America LIA and in 2012 Fellow of SPIE. Since 2001 he is a member of the board of the Laser Institute of America (LIA) and serves in many national and international boards as advisor, referee or consultant, for instance at the National Laser Centre of South Africa NLC. During the period of 09/2005 until 09/2008 he was Vice-Rector for Structure, Research and Junior Academic Staff. He still is chairing the RWTH-International Board, is the Rectors delegate for China, received an Honorary Professorship at Tsinghua University and the Schawlow Award of the Laser Institute of America in 2014.
Abstract
Biomedical applications of Lasers offer a wide area of research and benefits such as high precision for structuring of implant materials or for non-invasive visualization. Within the Fraunhofer ILT applications from the development of 3D bioprinting technology for soft and stiff implants by Selective Laser Melting SLM to laser based analytical tools, cell printing and tools for the operation theater are under investigation.
A prominent topic in the field of tissue engineering is the printing of artificial organs. Therefore, we investigate cell printing with a contact free process laser induced forward transfer. Artificial organs need vascularization for cell nutrition. Therefore, stereolithography is under investigation to build up branched, porous vessel structures, which provide nutrition supply. Those vessels have an inner diameter down to 200 µm with resolutions of approx. 10 µm. Laser sources with different wavelengths (355 nm or 266 nm) as well as new classes of polymers which allow photocuring of those have been investigated to meet the needs of a biocompatible scaffold. The benefit of 266 nm irradiation is that crosslinking of materials containing thiol- and alkene groups is possible without using toxic photoinitiators.
In addition to stereolithography for soft tissue scaffolds, laser powder bed fusion (L-PBF) is already commercially used with many metallic biomaterials (e.g. titanium alloys, cobalt-chromium alloys or stainless steels). Typical products are individualized dental caps and bridges, orthopedic joint replacements and spinal cages, bone replacements in maxillo-facial surgery, and highly specialized surgical instruments. Perspectives for innovative applications include the extending of processible materials to biodegradable materials such as magnesium alloys or polylactic acid based composites for manufacturing individualized implants with designed interconnected porosity, which will be replaced by endogenous bone tissue while fully degrading within the body.
Another application of laser lies in the fields of surgery because of its high precision and the possibility to combine laser-tissue interaction with laser measurement technology. That is why ILT develops novel processes and devices to perform neurosurgery on the spine and the head with ultrashort pulse lasers. The research and development activities focus on plasma induced hard tissue cutting and on highly integrated hand-pieces with miniaturized scanner technology. The hand-pieces allow the combination of the laser ablation process with inline monitoring by optical coherence tomography to guarantee safety for the patients.
Future developments will focus on new classes of photo polymers for stereo lithography and on materials for L-PBF as well as the increase of process resolution. This will allow the fabrication of highly functional implants or surgical instruments.
