The PAM2 system: a multilevel approach for fabrication of complex three-dimensional structures

Purpose – The traditional tissue engineering approach employs rapid prototyping systems to realise microstructures (i.e. scaffolds) which recapitulate the function and organization of native tissues. The purpose of this paper is to describe a new rapid prototyping system (PAM-modular micro-fabrication system, PAM2) able to fabricate microstructures using materials with different properties in a controlled environment. Design/methodology/approach – Computer-aided technologies were used to design multi-scale biological models. Scaffolds with specific features were then designed using custom software and manufactured using suitable modules. In particular, several manufacturing modules were realised to enlarge the PAM2 processing material window, controlling physical parameters such as pressure, force, temperature and light. These modules were integrated in PAM2, allowing a precise control of fabrication parameters through a modular approach and hardware configuration. Findings – Synthetic and natural polymeric solutions, thermo-sensitive and photo-sensitive materials can be used to fabricate 3D scaffolds. Both simple and complex architectures with high fidelity and spatial resolution ranging from ^15mm to ^200mm (according to ink properties and extrusion module used) were realised. Originality/value – The PAM2 system is a new rapid prototyping technique which operates in controlled conditions (for example temperature, pressure or light intensity) and integrates several manufacturing modules for the fabrication of complex or multimaterial microstructures. In this paper it is shown how the system can be configured and then used to fabricate scaffolds mimicking the extra-cellular matrix, both in its properties (i.e. physic- chemical and mechanical properties) and architecture.