Untethered mini‐robots can move single cells or aggregates to build complex constructs in confined spaces and may enable various biomedical applications such as regenerative repair in medicine and biosensing in bioengineering. However, a significant challenge is the ability to control multiple microrobots simultaneously in the same space to operate toward a common goal in a distributed operation. A locomotion strategy that can simultaneously guide the formation and operation of multiple robots in response to a common acoustic stimulus is developed. The scaffold‐free cellu‐robots comprise only highly packed cells and eliminate the influence of supportive materials, making them less cumbersome during locomotion. The ring shape of the cellu‐robot contributes to anisotropic cellular interactions which induce radial cellular orientation. Under a single stimulus, several cellu‐robots form predetermined complex structures such as bracelet‐like ring‐chains which transform into a single new living entity through cell–cell interactions, migration or cellular extensions between cellu‐robots.

Liver organoids represent emerging human-relevant in vitro liver models that have a wide range of biomedical applications in basic medical studies and preclinical drug discovery. However, the generation of liver organoids currently relies on the conventional Matrigel dome method, which lacks precise microenvironmental control over organoid growth and results in significant heterogeneity of the formed liver organoids. Here, we demonstrate a novel high-throughput culture method to generate uniform liver organoids from human pluripotent stem cell-derived foregut stem cells in micropatterned agarose scaffold. By using this approach, more than 8000 uniformly-sized liver organoids containing liver parenchyma cells, non-parenchymal cells, and a unique stem cell niche could be efficiently and reproducibly generated in a 48-well plate with a size coefficient of variation significance smaller than that in the Matrigel dome. Additionally, the liver organoids highly expressed liver-specific markers, including ALB, HNF4α, and AFP, and displayed liver functions, such as lipid accumulation, glycogen synthesis, albumin secretion, and urea synthesis. As a proof of concept, we evaluated the acute hepatotoxicity of acetaminophen (APAP) in these organoids and observed APAP-induced liver fibrosis. Overall, we expect that the liver organoids will facilitate wide biomedical applications in hepatotoxicity analysis and liver disease modeling.

Emerging acoustic bioassembly represents an attractive strategy to build cellular closely-packed organotypic constructs in a tunable manner for biofabrication. However, simultaneously assemble heterogenous cell types into heterocellular functional units with spatially-defined cell arrangements, such as complementary and sandwich cytoarchitectures, remains a long-lasting challenge. To overcome this challenge, herein we present an acoustic differential bioassembly technique to assemble different cell types at the distinct positions of the acoustic field based on their inherent physical characteristics including cellular size and buoyant density. Specifically, different cell types can be differentially assembled beneath the nodal or the antinode regions of the Faraday wave to form complementary cytoarchitectures, or be selectively positioned at the center or edge area beneath either the nodal or the antinode regions to form sandwich cytoarchitectures. Using this technique, we assemble hiPSC-derived liver spheroids and endothelial cells into hexagonal cytoarchitectures in vitro to mimic the cord and sinusoid structures in the hepatic lobules. This hepatic lobule model reconstitutes liver metabolic and synthetic functions, such as albumin secretion and urea production. Overall, the acoustic differential bioassembly technique facilitates the construction of human relevant in vitro organotypic models with spatially-defined heterocellular architectures, and can potentially find wide applications in tissue engineering and regenerative medicine.

Human pluripotent stem cell-derived liver organoids are emerging as more human-relevant in vitro models for studying liver diseases and hepatotoxicity than traditional hepatocyte cultures and animal models. The generation of liver organoids is based on the Matrigel dome method. However, the organoids constructed by this method display significant heterogeneity in their morphology, size, and maturity. Additionally, the formed organoid is randomly encapsulated in the Matrigel dome, which is not convenient for in situ staining and imaging. Here, we demonstrate an approach to generate a novel type of liver organoids via micropatterning technique. This approach enables the reproducible and high-throughput formation of bioengineered fetal liver organoids with uniform morphology and deterministic size and location in a multiwell plate. The liver organoids constructed by this technique closely recapitulate some critical features of human liver development at the fetal stage, including fetal liver-specific gene and protein expression, glycogen storage, lipid accumulation, and protein secretion. Additionally, the organoids allow whole-mount in-situ staining and imaging. Overall, this new type of liver organoids is compatible with the pharmaceutical industry’s widely-used preclinical drug discovery tools and will facilitate liver drug screening and hepatotoxic assessment.

In article number 1905713, Utkan Demirci and co‐workers report a locomotion strategy to guide the formation and operation of multiple nueronal mini‐robots by way of a common acoustic stimulus. These scaffold‐free, ring‐shaped cellu‐robots comprise only highly packed cells, making them less cumbersome during locomotion, and they can react together in response to a single uniform external acoustic signal to form complex structures in seconds, giving them potential applications in regenerative medicine, disease modeling, and pharmacokinetic studies.