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J. Stampfl, J. Torgersen, A. Ovsianikov, X.H. Qin, L. Zhiquan, V. Mironov, R. Liska:
"Photo-sensitive Biocompatible Hydrogels Structuring Extracellular Environments by Two Photon Polymerisation";
Poster: 2012 MRS Spring Meeting & Exhibit, San Francisco; 04-09-2012 - 04-13-2012.

Two-Photon-Polymerisation (2PP) is a rapidly emerging platform technology for the microfabrication of three-dimensional biocompatible scaffolds for tissue engineering at the nanolevel of resolution. The required near-infrared laser emits light of minimally damaging wavelength for biological tissue. This makes it potentially very attractive to apply 2PP for developing new and advanced functional materials to be structured in direct contact with cells or other living organisms. It is crucial to design a polymerisable formulation to be minimally toxic. Furthermore toxicity assays need to be developed allowing for high throughput screening using life organisms.
This paper reports the biofabrication of three-dimensional scaffolds using two-photon polymerisable hydrogels. Caenorhabditis elegans has been used as a test living organism for toxicity studies. The structuring was performed with a pulsed near-infrared laser with a wavelength of 810 nm and adjustable power up to 400 mW. Using a two-photon active, water soluble initiator (WSPI) it was possible to polymerise 3D structures in resins having M9 buffer medium contents of up to 80%; the highest aqueous content reported for the use with 2PP. High writing speeds of 10 mm/s allowed very short fabrication times. The little damaging wavelength of a near-infrared laser and a novel photo-sensitive material system with a high aqueous content made the rapid biofabrication of 3D scaffold with an embedded organism possible for the first time. These data demonstrate the feasibility and possible potential of 2PP and advanced photo-sensitive biomaterials to biofabricate 3D tissue constructs directly in the context of a living organism.