ME PhD Students’ Research from the Laser Thermal Laboratory Published in Nature Materials

Dr. Hojeong Jeon and doctoral student Sangmo Koo of the Laser Thermal Laboratory LTL reported their work on the functionalization of the surface of biological devices by ablative direct laser writing in the August 20 issue of Nature Materials. Patterned surfaces with nanoscale craters can control the cell ability to stick to surfaces. This in turn results in directing cell migration. It has been known that cell migration is dependent on surface protein density or surface rigidity. The researchers suggested patterned nanocrater arrays of isometric and spatial gradient density distribution as a new, facile and scalable method to control cell attachment and migration that are both related to cell growth and differentiation. They used a femtosecond pulsed laser to etch precisely spaced nanometer scale craters on quartz and polystyrene surfaces. Cultured fibroblast cells on patterned surfaces appear to first attach, but then move toward smoother surfaces, where nanocraters are separated by large spacings. Ultrafast laser ablation using far field optics in a tight focusing configuration offers substantial advantages for the direct, maskless and arbitrary patterning of various materials and curved surfaces, while maintaining high feature resolution.

Although nanopatterned surfaces have been known to be able to control cell fate, conventional nanofabrication processes cannot be applied to biomaterials, such as polystyrene culture dish, titanium alloy, biodegradable polymer implants, etc. By changing the shape and arrangement of the ablated patterns, new possibilities will emerge for applying this simpler and cheaper platform in cellular and medical research. For example, the method is applicable to diverse experiments as an effective tool for mechanotransduction studies in the context of regenerative medicine. Different micro-environmental stimuli can be implemented to alter intracellular structures, and contributed the stem cell differentiation and fate. Furthermore, it can be applied to breast implants, electrode leads on pacemakers and defibrillators and orthopedic implants that incur significant health care cost and risk.

The research was under a collaborative project of ME Professor Costas Grigoropoulos with Professor Kevin Healy of Materials Science and Engineering and Bioengineering. Dr. Jeon LTL PhD ’11 and post-doc till ’13 is currently at the Korea Institute of Science and Technology KIST.