In-situ Printability Maps (IPM): A new approach for in-situ printability assessment with application to extrusion-based bioprinting

3D Bioprinting is an emerging field with many highly valuable applications. The most common and versatile technology is extrusion-based bioprinting, which requires extensive experimental campaigns to achieve appropriate quality of the bioprinted constructs when new bioinks or complex geometrical constructs need to be considered. This paper presents a new approach to easily guide operators and scientists to evaluate the probability of successful bioprinting in a defined window of the process parameters, starting from a small experimental campaign and relying on in-situ quality data. The proposed method consists of defining printability maps based on a probabilistic approach. These maps assess the printing outcome considering a specified acceptable deviation from the nominal geometry, which is predefined by the end-user depending on the application at hand. Even if shown with reference to extrusion-based bioprinting, the proposed method can be used with any other bioprinting process and any quality index, including categorical assessment classification. Eventually, the paper shows how the map can be combined with different quality criteria (e.g., productivity, cell viability) to define the appropriate setting, depending on the application at hand. Furthermore, the map provides a practical tool for rapid material printability assessment and robust process optimization. It offers an enhanced visual representation of the process domain, acceptable region boundaries, and their resilience to variation and uncertainties. Eventually, in-situ printability maps represent a further leap for the advancement of bioprinting toward the digital transformation, aiming at increasing the controllability and scalability of the bioprinting process.