3D-printed poly-4-hydroxybutyrate bioabsorbable scaffolds for nipple reconstruction

Nearly all autologous tissue techniques and engineered tissue substitutes utilized for nipple reconstruction are hindered by scar contracture and loss of projection of the reconstructed nipple. The use of unprocessed costal cartilage (CC) as an internal support for the reconstructed nipple has not been widely adopted because of the excessively firm resultant construct. Herein we use a 3D-printed Poly4-Hydroxybutyrate (P4HB) bioabsorbable scaffold filled with mechanically processed patient-derived CC to foster ingrowth of tissue in vivo to protect the regenerated tissue from contractile forces as it matures. After 6 months in vivo , newly formed spongy fibrovascular cartilaginous tissue was noted in processed CC filled 3D-printed scaffolds, which maintained significantly greater projection than reconstructions without scaffolds. Interestingly, 3D-printed P4HB scaffolds designed with an internal 3D lattice of P4HB filaments (without CC) displayed the fastest material absorption and vascularized adipose-fibrous tissue as demonstrated by SEM and histological analysis, respectively. Using 3D-printed P4HB scaffolds filled with either processed CC, a 3D P4HB lattice or no fills, we have engineered neo-nipples that maintain projection over time, while approximating the biomechanical properties of the native human nipple. We believe that this innovative 3D-printed P4HB nipple reconstruction scaffold will be readily translatable to the clinic.