3D‐Bioprinting The novel Photopolymerization of Orderly Extruded Multi‐materials (POEM) technique enables rapid, high‐resolution, and precise biofabrication of multi‐layered, multi‐material 3D live constructs, as presented in article number 2201926 by Rahim Esfandyarpour and co‐workers. With the ultimate goal of mimicking the in‐vivo configuration of human organs and tissues, POEM represents a cutting‐edge approach to 3D biomanufacturing of complex, organ‐like structures in‐vitro.

As a 3D bioprinting technique, digital light processing (DLP) has become popular due to its capability to provide high-throughput and high-resolution constructs with precise chemical and biological factor distributions. However, despite the advancements in DLP technology, several hurdles remain, including phototoxicity, extensive printing time, and the limited portfolio of biocompatible/photo-cross-linkable materials. Recently, few works have attended to resolve some of these issues. However, state-of-the-art techniques bear on complex imaging processing, require highly skilled personnel, and operate with non-biocompatible/photo-cross-linkable materials. Additionally, they are not yet capable of multi-layer and multi-material printing of biocompatible/photo-cross-linkable materials to fabricate physiologically relevant cell-laden structures. Herein, a novel DLP-based 3D-bioprinting technology called photopolymerization of orderly extruded multi-materials (POEM), is proposed, developed, and fully characterized. The utility of the POEM technique for rapid and high-resolution 3D-printing of multi-material, multi-layer, and cell-laden structures is demonstrated. The printed configurations show high cell viability (≈80%) and metabolic activity for more than 5 days. As a study model, a 3D-structure representing the esophagus is also successfully printed and characterized. It is envisioned that the reported light-based POEM technique here enables the fabrication of 3D-cell-laden structures in a multi-material and multi-layer printing manner in biocompatible/photo-cross-linkable materials essential to construct complex heterogeneous tissues/organs.