Researchers at Rice University have developed a 3D-printing method that yields solid plastic implants incorporating different types of living cells. The hard, biodegradable implants produced can be surgically inserted to heal bone, cartilage or muscle.

A fiber engraving technique creates a groove on the surface of a thermoplastic printed fiber using a commercial The 3D-printed scaffold engraved with grooves for the deposition of live cells facilitates growth of new tissues as it degrades. Source: Jeff Fitlow/Rice University3D printer, and a low viscosity bioink is deposited into this structure. Unlike traditional extrusion bioinks that rely on increased viscosity to prevent lateral spreading, this groove creates a defined space for bioink deposition. A broader range of viscosities can be applied by physically restraining bioink spreading.

Production of the 800 micron wide grooved threads and insertion of cellular materials occur in a single process, forming 3D shapes supporting layers of cells that become different kinds of tissue.

The researchers fabricated a multimaterial scaffold containing a thermoplastic polymer and a gelatin-based bioink loaded with either microparticles containing fluorescent albumin or mouse fibroblasts at 24​° C. The structure of the scaffolds showed no significant decrease in porosity or mechanical properties as compared to control scaffolds. Encapsulated microparticles remained in the scaffolds after incubation for 24 hours at 37° C, and the viability of fibroblasts incorporated into the bioink and printed grooves was also confirmed.

The engraving technique offers a new route to the preparation of 3D-printed scaffolds containing a robust thermoplastic structure in combination with low viscosity bioinks.