Description du projet :
The two-photon polymerisation (2PP) technique has proved its potential in the micro-fabrication of three'dimensional (3D)-structures with high resolution (100 nm) starting from either inorganic or organic resins (acrylic, epoxy). It was successfully used to produce various photonic crystals, support scaffolds, microelectronic and optical data storage devices. However, not much was reported about its use in the fabrication of 3D-hydrogels. These are water swellable, biocompatible materials, very important for a broad range of biomedical applications from tissue engineering to drug delivery. As in the 2PP setup the excitation is usually provided by a femtosecond laser in the 'biological window' (700-1050 nm) where tissues have higher transparency, one of its great advantages is the in vivo fabrication of 3D structures. The main reason the 2PP is not yet used for microfabrication of 3D-hydrogels is the lack of efficient photoinitiators soluble in aqueous media, most of the reported ones being obtained in organic solvents.
The goal of our project is to provide the 2PP initiators and the technology needed for the fabrication of micro 3D-hydrogels with high structural reproducibility and specific mechanical and biochemical properties (nontoxicity, inertness, biodegradability) for biomedical applications.
An integrated approach is proposed to synthesize suitable hydrogel precursors either functionalised with 2PP-photosensistive groups or mixed with appropriate 2PP-photoinitiators in order to obtain a material photopolymerisable in aqueous media. The starting materials will be optimized in terms of two-photon absorption cross-section and fluorescence quantum yield in order to avoid the use of high laser power, which would decrease the spatial resolution and the integrity of the 3D structures. As the 2PP microfabrication is time-consuming requiring layer-by-layer processing of the scanning data, a new setup will be developed providing higher writing speed without affecting the quality of the final 3D-microstructures.
The cross-disciplinary collaboration between the chemists from HEIA specialised in the synthesis and the scale-up of chemical processes and the engineers from ARC team using a femtosecond (Yb:KGW) laser with 250µJ at 1030 nm and 300 kHz repetition frequency provides the ideal configuration to develop this technology and make it available to the manufacturers with maximum efficiency and minimum investment.
Research team within HES-SO:
Aellen Thierry, Varisco Massimo, Solea Atena-Bianca, Hochstrasser Eric, Laux Edith, Mamula Steiner Olimpia
Partenaires académiques: FR - EIA - Institut ChemTech
Durée du projet:
15.12.2015 - 07.11.2018