Fig. 2From: Fabrication of a three-dimensional bone marrow niche-like acute myeloid Leukemia disease model by an automated and controlled process using a robotic multicellular bioprinting systemCytocompatibility testing of IIZK peptide hydrogel. (A) Cell viability assessment of AML cell lines after 14 days of 3D culture with IIZK peptide hydrogel. Cells were stained with calcein-AM (green, live cells) and ethidium homodimer-1 (red, dead cells). Upper: Fluorescent images of cell viability (scale bar, 200 µM). Bottom: Flow cytometry analysis of cell viability; x-axis: calcein-AM, y-axis: ethidium homodimer. Representative images of 3 independent experiments (n = 3). (B) Assessment of AML cell proliferation with 3D IIZK peptide hydrogel compared to Matrigel and 2D cultures. (C) SEM images of the HL-60 AML cell line after 1 and 4 days of 3D culture within IIZK peptide scaffold. (D) Clonogenicity potential of HL-60 and MV4-11 in 3D culture with IIZK peptide scaffold or in 2D culture. Left panel: Light microscopy images of the colony formation using methylcellulose media for 2D- and 3D-cultured cells (scale bar, 100 μm). Right panel: Percentage of colonies formed in Methylcellulose (**p < 0.01). (E) In vivo fluorescence imaging of mice after receiving DIR-stained KG1a cells from 2D or 3D models (squared image). NSG mice were randomly assigned to 4 groups and intravenously injected with: (i) HBSS (n = 4), (ii) DiR-labeled KG1a cells harvested from 2D culture (2D group; n = 4), (iii) DiR-labeled KG1a cells harvested from 3D culture (3D group; n = 4), or (iv) DiR-labeled peptides (PEP-DiR; n = 4). Mice were placed at various positions for IVIS imaging to track the distribution of KG1a cells. Mice were imaged 2 h (2 H) and 48 h (48 H) after the injection. After 48 h, the mice were euthanized, and the major organs were collected (bones = spine/femur/tibia, heart, kidney, liver, spleen) for ex vivo imaging using the IVIS Spectrum. Representative images of the organs are shown. The average luminescence signal (n = 4 mice per group) is graphed for each organ. Significant differences are indicated (*p < 0.05 and **p < 0.001). Except for the liver, significant differences were only observed in comparisons with the control groups [(i) and (iv)]Back to article page