Highly accurate rendering of the external and internal geometry of bone tissue engineering scaffolds effects fit at the defect site, loading of internal pore spaces with cells, bioreactor-delivered nutrient and growth factor circulation, and scaffold resorption. It may be necessary to render resorbable polymer scaffolds with 50 μm or less accuracy to achieve these goals. This level of accuracy is available using Continuous Digital Light processing (cDLP) which utilizes a DLP(®) (Texas Instruments, Dallas, TX) chip. One such additive manufacturing device is the envisionTEC (Ferndale, MI) Perfactory(®). To use cDLP we integrate a photo-crosslinkable polymer, a photo-initiator, and a biocompatible dye. The dye attenuates light, thereby limiting the depth of polymerization. In this study we fabricated scaffolds using the well-studied resorbable polymer, poly(propylene fumarate) (PPF), titanium dioxide (TiO(2)) as a dye, Irgacure(®) 819 (BASF [Ciba], Florham Park, NJ) as an initiator, and diethyl fumarate as a solvent to control viscosity.

Alloy design coupled with metal additive manufacturing (AM) opens many opportunities for materials innovation. Investigating the effect of printing parameters for alloy design is essential to achieve good part quality. Among different factors, laser absorptivity, heat diffusivity, and in situ intermetallic phase formations are critical. In this study, the first step employed was a reduction in Al and V contents in Ti6Al4V to design Ti3Al2V alloy, and further 10 wt.% tantalum (Ta) and 3 wt.% copper (Cu) were added to Ti3Al2V. A synergistic effect of Ta and Cu addition in Ti3Al2V negated their effect with higher porosities in Ti3Al2V-Ta-Cu. Ti3Al2V-Ta composition was more sensitive to the laser power, whereas Ti3Al2V-Ta-Cu to the overall energy density. Understanding the effect of energy density on these alloys' microstructural evolution and mechanical properties highlights the need for process-property optimization during alloy design using AM.

In the field of tissue engineering, 3D printed shape memory polymers (SMPs) are drawing increased interest. Understanding how these 3D printed SMPs degrade is critical for their use in the clinic, as small changes in material properties can significantly change how they behave after implantation. Degradation of 3D printed acrylated poly(glycerol-dodecanedioate) (APGD) was examined via hydrolytic, enzymatic, and subcutaneous implantation assays. Three APGD manufacturing modalities were assessed to determine differences in degradation. Material extrusion samples showed significantly larger mass and volume loss at 2 months, compared to lasercut and vat photopolymerization samples, under both enzymatic and degradation. Critically, melt transition temperatures of degraded PGD increased over time , but not . Histology of tissue surrounding APGD implants showed no significant signs of inflammation compared to controls, providing a promising outlook for use of 3D printed APGD devices in the clinic.