New approaches to prototype 3D vascular-like structures by additive layer manufacturing.

In this paper preliminary results are summarized on the use of a combined Additive Layer Manufacturing (ALM) and indirect replication methodology to reconstruct reticular-like, three-dimensional (3D) structures mimicking the 3D vascular network of the adult human thyroid gland. In a first step, we developed a fractal-like algorithm capable of modeling the native arterial distribution of the adult thyroid lobe, allowing for vascular growth within its geometrical domain. Although some arbitrary simplifications were adopted, yet the vascular density of the computational simulation showed good consistency with that of a native thyroid lobe. In a second step, single vascular branches were prototyped based on the STL output of the algorithm and ALM techniques, up to the achievement of a model having satisfactory geometrical/morphological accuracy. In a third step, the problem of reproducing the vascular geometry with a biocompatible polymer was ad-dressed, and different protocols of replication technology were evaluated. Limits and possible methodological solutions are discussed.