Printability of Bioinks: A Consolidated Definition for Additive Manufacturing

Printability is a key concept extensively used in the context of bioinks for additive manufacturing. However, the absence of a universally accepted definition has led to inconsistencies in its application across studies. Some researchers use the term interchangeably with shape fidelity or shape accuracy, while others incorporate multiple aspects, including rheological properties and extrudability, into its definition. In some cases, the omission of cell viability further limits the scope of current research. As a result, studies that connect rheological properties to printability or employ physical and mathematical models to predict outcomes often fail to capture the complete manufacturing process due to the lack of definitional consistency. This review examines literature from 2011 to 2024, identifying key thematic clusters that contribute to a more robust understanding of printability. We propose an integrative definition that encompasses not only rheological properties across all stages of production but also geometry, shape fidelity, shape accuracy, and functionalitywith particular emphasis on cell viability. This broader definition aims to foster greater consensus and guide future applications of 3D printing in bioprinting and other additive manufacturing fields.