Advances in Organ-on-a-chip Technologies for Biomedical Research and Applications

The schematic diagram of organ-on-chips. Various OOCs for the human body are introduced in the outer circle, three applications of OOC are introduced on the left side of the inner circle, and three ways of OOC fabrication are introduced on the right side. Source: Created with BioRender.com.

This picture introduces four tools for preclinical drug screening and disease modeling: 2D cell culture, 3D cell culture and organ-on-chip models in vitro, and small and large animal models such as mice and pigs in vivo. Source: Created with BioRender.com.

a (i) Schematic diagram of the TOP system's capabilities; (ii) Schematic of the distribution of Matrigel in the TOP; (iii) Schematic illustration of the cytokine concentration gradient in the TOP.^[82] Copyright 2024, Wiley-VCH GmbH. b Schematic of hiPSCs derived multi-organoid-on-chip system in vitro. (i) Illustration of how human liver and pancreatic islet tissues regulate glucose levels in vivo; (ii) The differentiation, formation, and co-culture process of liver and pancreatic islet organoids derived from hiPSCs in the microwell device; (iii) Microfluidic perfusion system device and chip physical diagram.^[84] Copyright 2021, The Authors. Advanced Science published by Wiley-VCH GmbH. c (i) Schematic representation of PSO culture within a microfluidic system; (ii) Analysis of the chemical gradient for molecules of A) high (40 kDa) and B) low (519 Da) molecular weight; (iv) IF images of Krt14 (in red) in PSO cultures under different conditions on day 32 within the device.^[85] Copyright 2024, Wiley-VCH GmbH.

a The formation of the complex biliary tree within prepatterned hydrogel chips. (i) Laser-ablated channel diameter of the branch network is from 150 to 50 μm; (ii) Time-lapse bright field images depicting the epithelium formation following repopulating by organoid-derived cholangiocytes from d0 (left) to d7 (right); (iii) Live-imaging of Rhodamine 123 in the structure at 10 days from delivery; (iv) 3D reconstruction of the entire construct, along with three distinct views on day 8, showing Nuclei and F-actin staining.^[89] Copyright 2024, Wiley-VCH GmbH. b (i) Numerical simulation comparing the O₂ concentration profiles within PSOs grown in 3D ECM as a sphere versus as a spindle shape in the spindle device; (ii) On day 32, IF images of Caspase 3 and DAPI in PSO.^[85] Copyright 2024, Wiley-VCH GmbH. c (i) Schematic representation of the workflow for generating human mini-colons; (ii) Laser ablation creates an open microchannel with specific dimensions; (iii) Bright-field time-course imaging of the formation of epithelium in mini-colons.^[90] Copyright 2024, The Author(s). Published by Elsevier Inc. d (i) The generation process of microfabricated tissues; (ii) A collection of intestinal organoids derived from engineered intestinal tissues with a rod-like shape and specified magnification; (iii) Frequency map of Lgr 5, showing average Lgr 5 expression over around 80 tissues; (iv) Lysozyme staining of Paneth cells in the array of intestinal organoids; v) average Paneth cell distribution; (vi) 3D reconstruction of the immunofluorescence images.^[91] Copyright 2022, The American Association for the Advancement of Science. e (i) Illustration of the in vitro fabrication of liver organoids featuring biomimetic lobular architecture through a multi-cellular 3D bioprinting approach; (ii) Programming of 3D droplet-based bioprinting for the in vitro liver model fabrication; (iii) Multicellular composition of the assembled liver organoid; (iv) Printing process photos; 3D liver organoid and its hydrogel scaffold optical image; confocal microscopy image showing the hexagonal central region within the lobule-like structure following 1 day of culture; (v) Confocal images of the assembled liver organoids following 7 days of culture; (vi) Cell proliferation assay results.^[92] Copyright 2023, The Authors. Cell Proliferation published by Beijing Institute for Stem Cell and Regenerative Medicine and John Wiley & Sons Ltd.

a (i) Cross-sectional design of AoC model; (ii) EC, SMC co-culture membrane schematic diagram; (iii) Schematic diagram of AoC and microfluidic pump; (iv) 3D view of the bottom channel; (v) 2D diagram of wall shear stress distribution along film; (vi) Immunofluorescence staining of EC and SMC on the membrane.^[93] Copyright 2023, The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH. b Spheroid-based microfluidic perfusion culture of pancreatic islets used to simulate the in vivo environment. (i) Clusters of endocrine cells are scattered throughout the exocrine acini in the native pancreas, forming islets of Langerhans; (ii) Engineering of islet spheroids on a microchip with a perfusion system is implemented to simulate in vivo environment; (iii-v) Schematics of the experimental setup; (vi) Pancreatic islet cells cultured in microfluidic chips under three disparate environments.^[94] Copyright 2019, The American Association for the Advancement of Science. c Progression and characterization of human ecto-and endo-cervix chips. (i) Schematic diagram and cross-sectional design of two-channel microfluidic organ chip; (ii) A fluorescent microscopy side view shows the mucous layer in live Cervix Chip cultures, stained with wheat germ agglutinin (WGA) fluorescence (green), after seven days of differentiation. The images compare the effects of continuous flow (top) and periodic flow (bottom) regimens (bar, 1 mm); (iii) Phase-contrast microscopy top view of a Cervix Chip, with cervical epithelium on the apical side and fibroblasts on the basal side of the porous membrane, captured on day 1 (left) and after 12 days of culture under continuous (middle) or periodic (right) flow conditions (bar, 200 μm); (iv) Cervical epithelial cells’ gene expression from three different donors were RNAseq analyzed and differentiated into static Transwell or Cervix chips in either a periodic or continuous flow.^[20] Copyright 2024, The Author(s).

a (i-ii) Schematic illustration of a simulated alveolar device with IOS-PU film; (iii-vi) Characterization of alveolar-mimicking devices; (iii-iv) The relationship between tensile degree and perfusion volume; (v) The relationship between tensile degree and film color; (vi) Changes of reflection spectra of IOS-PU films under different stretching degree.^[99] Copyright 2023, Wiley-VCH GmbH. b (i) Schematic representation of the living anisotropic structural color hydrogels used for screening cardiotoxicity caused by environmental toxins; (ii) Heart-on-a-chip platform; (iii) Optical microscopic images showing structural color variations throughout a beating cycle of hiPSC-derived cardiomyocytes (hiPSC-CMs); (iv-v) The CLSM images of hiPSC-CMs treated with 75 μg/mL PQ (iv) and 25 μM CdCl₂ (v) were sustained for 24 hours when anisotropic structural color hydrogels in vivo were evaluated for environmental toxins.^[100] Copyright 2023, American Chemical Society. c (i-ii) Principle and schematic diagram of bionic human lung chip with microphysiological respiration visualization; (iii-vi) Engineered pulmonary alveolus deform under low and high cycle stretching; Low (iii-iv) and high (v-vi) flow PDMS film deformation diagram and numerical simulation of film deformation at peak cycle; (vii) Schematic of idiopathic pulmonary fibrosis (IPF) model by exposure to TGF-β; (viii-ix) Optical microscope images of structural color changes of low and high airflow during breathing under IPF model; (x) EdU staining (red) of co-cultured HFL1 and HPAEpiC cells, with or without cyclic stretching after TGF-ββ treatment.^[101] Copyright 2022, Wiley-VCH GmbH.

a (i) Pneumatic hybrid microfluidic device; (ii) Schematic diagram of molecular networks interacting in prediabetic hyperglycemia; (iii) Pancreatic islets and liver spheroids are generated and recovered using ultralow attachment (ULA) plates; (iv-v) Immunofluorescent staining of primary human islets for insulin (β-cells), glucagon (α-cells), and somatostatin (δ-cells); (vi) Quantification of insulin secretion following exposure of islets to hypoglycemic or hyperglycemic conditions.^[106] Copyright 2022, The Authors. Advanced Science published by Wiley-VCH GmbH. b (i-iii) Characterization of renal tubule. (i) photographs; (ii) cross-sectional view; (iii) schematic illustration; (iv) Immunofluorescence staining of 2D-culture renal tubuloids in static, dynamic, and dynamic co-culture with DAPI-stained nuclei (blue), the tight junction protein ZO-1 (green), and the Na/K-ATPase (red) showing polarized epithelial cell layers in all conditions; (v) Static, dynamic, and dynamic co-culture conditions of liver organoids; (vi) Experimental timeline. KDM: kidney differentiation medium, LDM: liver differentiation medium.^[107] Copyright 2022, The Authors. Journal of Extracellular Vesicles published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles. c Multi-organ chip of bone marrow-heart-liver-vascular.^[111] Copyright 2024, The Author(s). Advanced Science published by Wiley-VCH GmbH. d (i) A compartmentalized and functional gut-immune-skin OOC device; (ii) Legend for (i).^[112] Copyright 2023, Author(s). Published by Elsevier Ltd.

a (i) Schematic of the absorption process of oral anti-lung cancer drugs and construction of a high-throughput intestine-liver-heart-lung cancer microphysiological system, which can evaluate four different drugs at the same time; (ii) Application of MSCP platform; (iii) The schematic representation of the organ formation mode.^[121] Copyright 2024, The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. b (i) 3D human alveolar-capillary barrier model in vivo; (ii) Configuration of a bionic human alveolus chip that is infected by SARS-CoV-2.^[122] Copyright 2020, The Authors. Advanced Science published by Wiley-VCH GmbH. c (i) Schematic diagram of microfluidic chip architecture; (ii-vi) Application of PT-EVs in homologous tumor therapy.^[129] Copyright 2024, Wiley-VCH GmbH.