Improving 3D bioprinting in liquids

A long-term goal behind 3D printing of biomaterials is to make functional implants and tissues. One problem in using this approach is that the materials must often be shaped in the liquid phase, leading to slumping and spreading of structures. Researchers have addressed this problem by using embedded 3D printing, in which bio-inks are extruded into support media that can hold them in shape as they slowly solidify.

Duraivel et al. explored the interface between investigations of 3D bioprinting and liquid-liquid phase separation (LLPS) to highlight new ways to improve the use of embedded 3D printing. When the interfacial tension between the extruded and support media is high, instabilities can disrupt the interface and interfere with printing quality, so finding ways to reduce the interfacial tension is important.

“LLPS may be leveraged to perform a critical stabilizing role in embedded 3D printing, helping to maintain ultra-low interfacial tension at the interfaces between printed inks and the surrounding support material,” author Thomas E. Angelini said.

The investigators included a review of the discovery of LLPS in living cells, which plays key roles in embryonic development, cell function, and disease progression.

They also report several preliminary experiments that illustrate the feasibility of leveraging LLPS phenomena to improve embedded 3D bioprinting. The experiments used a support medium consisting of microgels mixed with a high molecular weight polymer. Test printing, which used hyaluronic acid and dextran as ink, showed this medium to be a promising approach.

Source: “Leveraging ultra-low interfacial tension and liquid-liquid phase separation in embedded 3D bioprinting,” by Senthilkumar Duraivel, Vignesh Subramaniam, Steven Chisolm, Georg M. Scheutz, Brent S. Sumerlin, Tapomoy Bhattacharjee, and Thomas E. Angelini. Biophysics Reviews (2022) The article can be accessed at https://doi.org/10.1063/5.0087387 .