Additive Manufacturing of Poly(Methyl Methacrylate) Biomedical Implants with Dual-Scale Porosity

The development of bone permanent implants with a porous structure favoring their integration with the surrounding tissues is emerging as an attractive field of application of additive manufacturing (AM). This article reports on the investigation of the suitability of a hybrid AM technique, that is, computer-aided wet-spinning (CAWS), to fabricate novel poly(methyl meth- acrylate) (PMMA) constructs as porous implant prototypes. The optimization of the processing parameters to fabricate PMMA samples with a predefined internal porous structure and different external shapes is described. The study demonstrates that tailoring post-processing conditions represents a powerful tool to optimize samples macroscopic aspect, micromorphology, and mechanical properties. In particular, the possibility of obtaining a dual-scale porosity through the integration of the macroporous structure determined by the material lay-down pattern with a submicrometric porosity resulting from the phase inversion process governing polymer solidification, together with the possibility of purifying the employed commercial material from residual monomer during coagulation in ethanol, are reported as note- worthy advantages of CAWS over other AM techniques. A natural progression of this work is the development of relevant complex anatomical prototypes with tailored porosity by processing digital data obtained from computer tomography imaging of bone defects.