Protein denaturation provides a path toward more sustainable 3D printing of photoresins

The vast majority of photoresins for 3D printing (also referred to as additive manufacturing or AM) and related technologies are toxic, non-biodegradable, and sourced from unsustainable feedstocks. Non-traditional approaches to 3D printing offer a way to break free of the traditional confines of unsustainable petroleum-based reagents and chemical methods that require toxic monomers.

A recent collaboration between the University of Wisconsin’s Prof. AJ Boydston (Department of Chemistry) and Prof. Audrey Girard (Department of Food Science) has accomplished the first demonstration of additive manufacturing via protein denaturation (AMPD).

The paper is published in the journal Green Chemistry.

The AMPD concept leverages a recently invented AM method that uses photothermal transduction to convert patterned light into heat, thus enabling the creation of 3D shapes in response to patterned heat (U.S. patent 11,597,145 issued March 7, 2023, assigned to WARF).

The method, invented by Boydston and Lee, is called “Heating at a Patterned Photothermal Interface” (HAPPI 3D) printing. Given the ability to pattern photothermal conversion, Dr. Chang-Uk Lee (Boydston Research Group) reasoned that thermal protein denaturation might be feasible as the curing mechanism for converting a liquid resin (aqueous solution of protein) into a solid part.

Above their denaturation temperature, proteins tend to aggregate and solidify. Together with undergraduate researcher Sung June Kim and postdoctoral researcher Dr. Rachel Dietrich, the team successfully demonstrated the 3D printing of complex parts from non-toxic, sustainably sourced protein solutions.

They found that mechanical properties were comparable to those of some commodity plastics and that they could control the porosity of the printed parts by adjusting the concentration of protein in the resin. Additionally, the printed parts display full biodegradability, since no chemical modifications of the proteins are required to make them 3D printable.

Moving forward, the team aims to expand the scope of applicable protein feedstocks, investigate applications that leverage the sustainable features of these materials, and target applications relevant to human health such as bioresorbable tissue scaffolds with patient-specific geometries that will eventually be absorbed by the body over time. This material has the potential to guide the regeneration and growth of tissues inside the body.