Oral Presentation ESA-SRB-ANZOS 2025 in conjunction with ENSA

Novel approach using tuneable matrices for 3D bioprinting early-pregnancy placental organoid models (128557)

Ananya Raman 1 , Claire Richards 1 , Louise Cole 2 , Lana McClements 1 3
  1. School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
  2. Australian Institute for Microbiology and Infection (AIMI), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
  3. Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia

Single cell-derived organoids enable the study of organ-like structures that recapitulate native tissue characteristics. However, many early-pregnancy organoid models are limited by their reliance on animal-derived matrices which are highly variable and cannot be tuned to mimic human in vivo tissue. Emerging high-throughput bioprinting technologies can precisely deposit cells within tuneable, biologically-relevant hydrogels, enhancing translational potential. Here, we characterise bioprinted placental organoids, generated using first-trimester trophoblasts (ACH-3Ps) together with human umbilical vein endothelial cells (HUVECs), or trophoblast stem cells (TSCs).

The RASTRUM drop-on-demand bioprinter was used to print the CT29 TSC line or ACH-3P with HUVECs in a polyethylene glycol (PEG)-based matrix. Matrix selection compared a ‘blank’ matrix without adhesion peptides to a ‘rich’ matrix containing fibronectin, laminin, collagen IV and hyaluronic acid. Matrices tested were all ~1.1kPa to mimic the stiffness of the decidua basalis where placental invasion takes place. In parallel, cells were manually Matrigel-embedded for comparison. Organoid growth was quantified over 12 days using an Incucyte imaging system. Organoids were immunolabelled in situ for E-cadherin, SDC1 and HLA-G and imaged using a Leica Stellaris confocal fluorescence microscope. 

Bioprinted TSCs readily formed organoids, though they were significantly smaller than TSC organoids in Matrigel (p<0.001), which is less stiff. Both bioprinted and Matrigel-embedded organoids could differentiate into syncytiotrophoblast organoids (SDC1+ and β-hCG+) and extravillous trophoblast organoids (HLA-G+) under predefined medium. The ‘rich’ matrix significantly increased organoid number (p<0.0001) and size (p<0.05-0.001) compared to either subtype alone in the ‘blank’. Matrix selection for co-cultured ACH-3P and HUVEC organoids also favoured a rich matrix.

This trophoblast organoid model is an innovative, high-throughput approach that is tuneable to reflect the placental microenvironment. ACH-3Ps grew comfortably in 1.1kPa PEG-based matrix whereas TSCs seem to require a “richer” and softer environment, given they arise from the early blastocyst stage and invade the softer endometrium.