Monitoring Storage Stability of 3D Printed Hydrogels

Bioprinting of Advanced Therapy Medicinal Products offers promising new strategies for personalized medicine, but it requires comprehensive, non-destructive characterization and quality monitoring. To support patients with tailor-made constructs composed of hydrogels and cells derived from allogeneic donors or autologous samples, several challenges must be addressed—such as on-demand production, robust manufacturing, appropriate storage and logistics, and destruction-free quality control—before successful translation into clinical applications or pharmacy is possible. Although experience in cryo-preservation, blood banking, and organ donation helps to identify critical process parameters, detecting variations in manufacturing and ensuring product stability remain essential. Quality monitoring of 3D-printed objects before and after storage by magnetic resonance imaging (MRI) is complemented here by measurements of total mass and volume. These established methods provide rapid, non-destructive feedback and have well-characterized statistical limitations. Total mass can be assessed quickly; however, such integral measurements do not reveal information about internal structures. MRI, in contrast, offers detailed, spatially resolved insights. By combining these analytical modalities, we quantitatively analyzed the storage stability of 3D-printed hydrogels—without living cells in this study—in order to demonstrate and validate the analytical approach. We describe a workflow for measuring mass and geometry of 3D-printed hydrogel lattices before and after storage under varying process parameters. Critical quality attributes (cQAs), including overall and internal structural fidelity as well as mass conservation, were monitored. The presented workflow supports the development of cryopreservation protocols and has potential applications in biomaterial development for bioprinting and in quality assessment of tailor-made artificial tissues.