Bioink Standards for Bioprinting Published by ASTM International

Unveiling a blueprint for the future of bioprinting, a new 20-page guide outlines essential practices for bioink use, covering everything from preparation to post-printing. Developed over six years, this document sets a new foundational standard to guide the process of bioprinting tissue-engineered medical products (TEMPs), such as implants, grafts, and tissue constructs. These solutions range from skin grafts for burn recovery to multi-layered constructs to replace damaged tissues in critical areas like the heart or liver.

Officially titled “F3659 − Standard Guide for Bioinks Used in Bioprinting,” this document emerges as a vital toolkit for the next frontier in healthcare—printing human tissue. Developed through a collective effort among 35 leading experts, it describes essential practices for creating bioinks.

Key participants included bioink manufacturers, bioprinter manufacturers, organoid manufacturing companies, and businesses specializing in tissue-engineered medical products. Regulatory bodies such as the U.S. Food and Drug Administration (FDA) and research institutions like the National Institute of Standards and Technology (NIST), represented by Biologist Carl Simon and Physicist Greta Babakhanova, played crucial roles.

The project was spearheaded by NIST, the Standards Coordinating Body for Regenerative Medicine (SCB), and the Advanced Regenerative Manufacturing Institute (armi)|BioFabUSA, with significant contributions from Biomedical Engineer Liisa Kuhn of the University of Connecticut and Lexi Garcia, formerly of armi|BioFabUSA. More than just a technical document, their combined efforts are a resource for bioink and bioprinter manufacturers and regulatory bodies like the FDA. Given the extensive collaboration across these varied sectors, the document’s publication by ASTM International highlights its importance and credibility as a new benchmark in global standards development.

3D bioprinted tissue rendering. Image courtesy of 3DPrint.com

While there are existing standards that address biomaterials and scaffolds more generally, such as ASTM’s guides F2150 and F2027 for testing biomaterials and the ISO 10993 series for biological evaluation of medical devices, this new standard zeroes in on extrusion bioprinting. It describes the use of bioinks and biomaterial inks with unique fluidic properties, essential for constructing TEMPs with or without encapsulated cells.

Although extrusion-based bioprinting is the primary focus of the guide due to its widespread application and strong understanding within the field, it also acknowledges a variety of other bioprinting techniques. These include electrospinning, electrospray, droplet-based, inkjet-based, and laser-assisted bioprinting. Each of these methods is explored to some extent to provide a comprehensive overview of the current landscape of bioprinting technologies. It also ensures that the guide is a valuable resource for those employing these techniques to develop and fabricate tissue-engineered medical products.

Moreover, this guide explores the science of ensuring these bioinks are safe, effective, and can integrate seamlessly into the human body. Each parameter has been outlined meticulously, from ensuring that the bioinks have just the right flow to keeping the cells alive during the print process.

The document also emphasizes the importance of bioink compatibility with both the bioprinting equipment and the eventual biological environment, ensuring that printed tissues can actually survive and function within the human body. It tackles complex issues like sterility, bioink shelf life, and optimal cell viability and proliferation conditions.

Beyond the technical specifications and guidelines, the implications of the guide are crucial for future medical practices. By standardizing the use of bioinks in bioprinting, this guide not only paves the way for more reliable and effective medical treatments but also encourages innovation in the creation of synthetic tissues and, eventually, organs. As bioprinting technology advances, the potential to provide patients with custom-tailored tissues on demand could dramatically transform medicine and how chronic diseases and injuries are treated. While the ideal regeneration of human tissues remains a goal for the future, this standard marks a foundational step to advancing bioprinting. It lays out a clear path for further developments, helping to ensure that these technologies can evolve in a way that could one day change medical science.

The complete guide can be found here. However, ASTM has shared the first ten pages of this document.