Printability of PLLA based hybrid scaffolds and evaluation of their physical, surface and degradation behavior

Various 3D printing techniques currently use degradable polymers such as aliphatic polyesters to create well defined scaffolds. Even though degradable polymers are influenced by the printing process, and this subsequently affects the physical properties and degradation profile, degradation of the polymer during the process is not often considered. Our methodology herein was to vary the printing parameters such as temperature, and speed to define the relationship between printability, polymer microstructure, composition, degradation profile during the process, and hydrophilicity. We used Poly(L-lactide) (PLLA) for printing in an extrusion-based printer (Dr.Invivo 4D) in order to shed light on the fact that lactide-based copolymers degrade when used in extrusion based 3D printing. Optical microscopy confirmed that the polymers were printable at high resolution and good speed, until a certain degree of degradation. The results show also that printability cannot be claimed just by optimizing printing parameters and highlight the importance of a careful analysis of how the polymer’s structure and properties vary during printing. This study provides novel insight into designing synthetic piezoelectric scaffolds with significantly improved possibilities for interactions with cells and tissues, which are particularly important for their application in biomedicine.