Development of a low-cost quad-extrusion 3D bioprinting system for multi-material tissue constructs

This study presents the development and characterization of a low-cost bioprinting system with a compact low-profile quad-extrusion bioprinting head for producing multi-material tissue constructs. The system, created by modifying an off-the-shelf three-dimensional (3D) printer, enables larger print volumes compared to extant systems. Incorporating gelatin methacrylate (GelMA) as a bioink model, the bioprinting system was systematically tested with two different printing techniques, namely the traditional in-air printing (IAP) mode along with an emerging support bath printing (SBP) paradigm. Structural fidelity was assessed by comparing printed structures under different conditions to the computer-aided design (CAD) model. To evaluate biological functionality, a placental model was created using HTR-8 trophoblasts known for their invasive phenotype. Biological assays of cell viability and invasion revealed that the cells achieved high cell proliferation rates and had over 93% cell viability for a 3-day incubation period. The multi-compartmental 3D-bioprinted in vitro placenta model demonstrates the potential for studying native cell phenotypes and specialized functional outcomes enabled by the multi-material capability of the quad-extrusion bioprinter (QEB). This work represents a significant advancement in bioprinting technology, allowing for the printing of complex and highly organized tissue structures at scale. Moreover, the system’s total build cost is only US$ 297, making it an affordable resource for researchers.