Lubricating Micro‐Interface Assisted General Strategy for Preparing dECM‐Microparticle–Based Heterogeneous Granular Inks toward 3D Printing

Abstract Decellularized extracellular matrix (dECM) retains the bioactive components to mimic tissue‐specific microenvironment. Designing dECM‐based inks for 3D printing to prepare scaffolds can enhance the regeneration of corresponding tissues. However, due to the strict requirements for inks, how to efficiently prepare dECM‐based inks is a challenge. Inspired by granular lubrication, the present study proposes an effective and general method for preparing granular ink from dECM microparticles (MP) with high content. Through dopamine polymerization, dECM‐MPs are coated with polydopamine (PDA). Meanwhile, gelatin methacryloyl (GelMA)‐based microspheres (GelMA‐MSs) are prepared with available double bonds. dECM‐MPs (30–40 wt%) and GelMA‐MSs assemble to form a granular ink, exhibiting well‐performed extrudability, plasticity, and fidelity. Further inspired by joint lubrication, hyaluronic acid (HA) is introduced into PDA coating and GelMA‐MSs to reduce the micro‐interface friction, further promoting the printability and broadening the printable window of dECM‐MPs content to 30–60 wt%. Osteochondral scaffold and skin wound dressing are fabricated through 3D printing from the corresponding dECM‐MPs, enhancing the regeneration of the corresponding tissues in vivo. Especially, the realization of printability of highly rigid dECM‐MPs confirms the universality, reliability and efficiency of the present strategy.