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Schematic for the preparation of Am/HEMA/Me?CMC composite hydrogels.AbstractThe development of light?based three?dimensional (3D) printing has changed the manufacturing processes from various materials. The advantages of printing using customized materials are gradually highlighted due to excellent and reliable precision, high repeatability, and wide range of build materials, which enable customized materials to be use in aerospace, biomedical, engineering, and other fields. Due to the existence of acrylate group or epoxy group, most of the commonly used photoactive macromolecules have the main limitations of poor water solubility and/or high biological stimulation, severely constraining the widespread application of these materials in biomanufacturing. To overcome these challenges, a natural hydrogel was modified in this study to achieve a new photocurable material with good biocompatibility and photocrosslinking activity. In particular, methacrylate?carboxymethyl cellulose (Me?CMC) was esterified by hydroxyl groups on the long chains of CMC, and hydroxyethyl methacrylate (HEMA)/acrylamide (Am) was added as the crosslinking reaction point between the long molecular chains. Thus, networked structures of this biocompatible material can be formed by photo crosslinking in digital light processing (DLP). The developed composite hydrogel can facilitate the rapid prototyping and high precision manufacturing. The mechanical toughness, swelling property, and microstructures of the composite hydrogel were tunable by changing HEMA/Am content. In addition, it was found that cell survival rate of this photocurable composite hydrogel was good by culturing bone marrow stromal cells (BMSCs) with the material and, cells proliferated significantly in a short time (7?days), which proved the biocompatibility of the proposed material.