3D-Printed Polycaprolactone Implants Modified with Bioglass and Zn-Doped Bioglass.

In this work, composite filaments in the form of sticks and 3D-printed scaffolds were investigated as a future component of an osteochondral implant. The first part of the work focused on the development of a filament modified with bioglass (BG) and Zn-doped BG obtained by injection molding. The main outcome was the manufacture of bioactive, strong, and flexible filament sticks of the required length, diameter, and properties. Then, sticks were used for scaffold production. We investigated the effect of bioglass addition on the samples mechanical and biological properties. The samples were analyzed by scanning electron microscopy, optical microscopy, infrared spectroscopy, and microtomography. The effect of bioglass addition on changes in the SBF mineralization process and cell morphology was evaluated. The presence of a spatial microstructure within the scaffolds affects their mechanical properties by reducing them. The tensile strength of the scaffolds compared to filaments was lower by 58-61%. In vitro mineralization experiments showed that apatite formed on scaffolds modified with BG after 7 days of immersion in SBF. Scaffold with Zn-doped BG showed a retarded apatite formation. Innovative 3D-printing filaments containing bioglasses have been successfully applied to print bioactive scaffolds with the surface suitable for cell attachment and proliferation.

Injection Molding Process Simulation of Polycaprolactone Sticks for Further 3D Printing of Medical Implants.

The aim of the present study was a simulation of the injection molding process of polycaprolactone filament sticks for further 3D printing of osteochondral implants. Polycaprolactone data are not available in the data banks of popular injection molding simulation programs. Therefore, thermal and rheological data from the literature were imported to the material database of Solidworks Plastics software to simulate the injection molding process of filament sticks. The influence of several injection molding parameters including melt temperature, injection time, and injection pressure on the geometry of filament stick (final part) was investigated. Based on the results of the performed simulation and analyses, it was possible to improve the injection process parameters. The accuracy of simulation predictions, based on the literature data, demonstrates the potential of using simulation as a tool to develop polycaprolactone parts for future implants and to optimize the injection molding process.