Seaweed Bioink Heralds More Sustainable Future for 3D Printing

As 3D printing becomes more common, there is a growing need for specialized inks that can make the process more sustainable. It must also be suitable for creating products like biocompatible medical devices.

Biologically derived inks, called bioinks, are becoming increasingly popular in the 3D printing industry. Researchers have identified a wide range of these inks that could serve as replacements for conventional feedstocks, like thermoplastics. In some cases, they come with a surprising scope of characteristics that plastic filaments lack.

The Challenges of Plastic Feedstocks in 3D Printing

Traditionally, 3D printing uses polymer feedstocks, cost-effective materials that are not typically sustainable. Most often, they are derived from petrochemicals, rely on fossil fuel byproducts and can be harmful to the environment when not disposed of properly.

Over time, these thermoplastics can begin to degrade, shedding microplastic particles that can cause health problems for wildlife and humans. The materials also require heat or UV light during the printing process, increasing the cost and energy usage of the printers on which they’re used.

Researchers Develop Colorful New Inks from Seaweed and Algae

New bioinks could make 3D and 2D printing applications more sustainable. One research team from the Department of Energy’s Pacific Northwest National Laboratory (PNNL) has found that a compound found in algae can be combined with mica pigment to create bio-derived 3D printing feedstocks that are both sustainable and vibrant. It also has certain characteristics that could make it an excellent tool for artists, designers, and manufacturers.

Image courtesy of ACS Omega.

Unlike thermoplastics, these bioinks don’t require processing with heat before or during the printing process. This could make them even more accessible than the more conventional thermoplastic feedstocks that many 3D printers use.

The bioink isn’t stable over the long term and will biodegrade, but the research team sees this as an advantage. Structures printed with the material can be preserved in a calcium chloride solution. When the object is no longer needed, it can be safely removed from the solution and will degrade quickly without leaving behind harmful chemicals or waste.

“Visual representation of mica powders and mica-alginate inks used for 3D printing.” Image courtesy of ACS Omega.

Temporary exhibitions can display designs that intentionally degrade when they are no longer needed. The inks could also be helpful for manufacturers’ prototyping products — old versions could be safely removed from the solution and discarded without concern for potential environmental impacts.

Artists concerned about digital sustainability could find the material a valuable alternative to conventional 3D printing filaments. According to the research team, the material can also be used as a 2D ink, meaning manufacturers of the new bioink could find a market for 3D and 2D printing users.

“Depiction of the chemical structure, cross-linking, and extrusion 3DP capability of alginate as well as a photo depicting the alginate powder, 8% (w/v) solutions, and the calcium cross-linked gel. Note that the G subunit carboxylates, highlighted in green, in the polysaccharide backbone participate in the ionic cross-linking with calcium ions to form gels.” Image courtesy of ACS Omega.

The presence of color could also be key to adoption. Many artists and designers have specific needs which require careful measurement and management of color, especially in industrial settings. The algae used in the bioink is typically colorless, like many bioinks. With mica pigment, the ink can come in a range of vibrant colors.

New Bioinks May Create More Effective 3D Printed Medical Devices

Some of these novel bioinks have surprising characteristics that could make them a good fit for many industries. One team developed a new seaweed-based ink with wound-healing abilities.

The ink is rich in a species-specific variety of an organic compound called ulvan, a water-soluble chemical that makes up around 8%-29% of algae’s dry weight. Algae uses this compound to activate its plant immune system. It also bears a similarity to specific biomolecules found in humans, and researchers have discovered it can stimulate wound healing by encouraging the body to generate more cells.

Bioprinted dermal-like structures using ulvan. Image courtesy of Biomaterials Science.

The team hopes the ink will find a home in 3D printed biostructures, like skin grafts and wound dressings, where it will help accelerate the healing of injuries. The team also believes the ulvan will support these biostructures, acting at a molecular level to prevent structure contraction during the healing process. This would help prevent the formation of scars.

As 3D printed biostructures become more common in the medical field, bioinks like this could significantly improve many patients’ outcomes. Faster wound healing and reduced scar formation could be beneficial in reducing the length of hospital stays and the long-term impact an injury can have.

Seaweed-Derived Bioinks Could Have a Major Impact on 3D Printing

The growing demand for sustainable 3D printing could make bioinks much more important in the next few years. Researchers have already started developing new bioinks that are suitable replacements for thermoplastics and sometimes have unique properties. As 3D printing becomes more widely used, these bioinks will help expand potential applications of the tech and ensure it will be useful in a range of fields.