Rapid Volumetric Bioprinting of Decellularized Extracellular Matrix Bioinks.

Decellularized extracellular matrix (dECM)-based hydrogels are widely applied to additive biomanufacturing strategies for relevant applications. The extracellular matrix components and growth factors of dECM play crucial roles in cell adhesion, growth, and differentiation. However, the generally poor mechanical properties and printability have remained as major limitations for dECM-based materials. In this study, heart-derived dECM (h-dECM) and meniscus-derived dECM (Ms-dECM) bioinks in their pristine, unmodified state supplemented with the photoinitiator system of tris(2,2-bipyridyl) dichlororuthenium(II) hexahydrate and sodium persulfate, demonstrate cytocompatibility with volumetric bioprinting processes. This recently developed bioprinting modality illuminates a dynamically evolving light pattern into a rotating volume of the bioink, and thus decouples the requirement of mechanical strengths of bioprinted hydrogel constructs with printability, allowing for the fabrication of sophisticated shapes and architectures with low-concentration dECM materials that set within tens of seconds. As exemplary applications, cardiac tissues are volumetrically bioprinted using the cardiomyocyte-laden h-dECM bioink showing favorable cell proliferation, expansion, spreading, biomarker expressions, and synchronized contractions; whereas the volumetrically bioprinted Ms-dECM meniscus structures embedded with human mesenchymal stem cells present appropriate chondrogenic differentiation outcomes. This study supplies expanded bioink libraries for volumetric bioprinting and broadens utilities of dECM toward tissue engineering and regenerative medicine.

Volumetric additive manufacturing of pristine silk-based (bio)inks.

Volumetric additive manufacturing (VAM) enables fast photopolymerization of three-dimensional constructs by illuminating dynamically evolving light patterns in the entire build volume. However, the lack of bioinks suitable for VAM is a critical limitation. This study reports rapid volumetric (bio)printing of pristine, unmodified silk-based (silk sericin (SS) and silk fibroin (SF)) (bio)inks to form sophisticated shapes and architectures. Of interest, combined with post-fabrication processing, the (bio)printed SS constructs reveal properties including reversible as well as repeated shrinkage and expansion, or shape-memory; whereas the (bio)printed SF constructs exhibit tunable mechanical performances ranging from a few hundred Pa to hundreds of MPa. Both types of silk-based (bio)inks are cytocompatible. This work supplies expanded bioink libraries for VAM and provides a path forward for rapid volumetric manufacturing of silk constructs, towards broadened biomedical applications.