Rapid prototyping of polymeric hydrogels for biomedical applications

Rapid prototyping techniques have been investigated for the production of biomedical devices that perfectly fit the patient's tissue defect (e.g. for bone and dental applications) and/or reproduce the microstructure of the tissue or organ of interest. The possibility to create patient-specific devices has been recently exploited for the creation of tissue engineer-ing scaffolds, i.e. porous, resorbable matrices, which stimulate cell functions and induce tissue regenera-tion by providing cells with appropriate physical, mechanical and biochemical cues. Poly(ethylene glycol) (PEG)-based hydrogels, although intrinsically non-biodegradable and non-bioactive, show great promise as tissue engineering scaffolds, due to their ability to be covalently linked to bioactive and/or degradable moieties, that elicit specific cell responses, and to their fast and biocompatible formation under ultra-violet (UV) exposure. In this work, poly(ethylene glycol)-based hydrogels, containing bioactive moieties, were photopolymerized and characterized in terms of mechanical, swelling and degradation properties. The production of hydrogels possessing a complex shape was finally investigated by means of stereolithography, a rapid prototyping technique which is able to build a three-dimensional object, starting from the CAD model, by guiding an ultravio-let laser beam on the surface of a photosensitive solution. The results demonstrated that the developed hydrogel formulations allow the creation of biomimetic constructs with complex shapes, which might be useful as platforms for tissue engineering or as tissue mimicking phantoms.