Design and Fabrication of In-House Nozzle System to Extrude Multi-Hydrogels for 3D Bioprinting Process

The field of 3D bioprinting is rapidly expanding as researchers strive to create functional tissues for medical and pharmaceutical purposes. The ability to print multiple materials, each containing various living cells, brings us closer to achieving tissue regeneration. Deliberately transitioning between different material types encapsulating distinct cells and extruding through a single outlet, can lead to the achievement of user-defined material distribution, which is still challenging. In a previous study, we designed a Y-shaped nozzle connector system that allowed for continuous deposition of multiple materials through a single outlet. This system was made of plastic and had a fixed switching angle, rendering it suitable for a single use. In this article, we present the updated version of our nozzle system, which includes a range of angles (30 deg, 45 deg, 60 deg, and 90 deg) between the two materials. Changing the angles helps us figure out how that affects the control of backflow and minimizes the overall material switching time in the nozzle. We used stainless steel as the fabrication material and recorded the overall material switching time, comparing the effects of the various angles. Our previously developed hybrid hydrogel, which comprised 4% alginate and 4% carboxymethyl cellulose (CMC), was used as a test material to flow through the nozzle system. The in-house fabricated nozzle connectors are reusable, sterile, and easy to clean, ensuring a smooth material transition and flow. Our proposition can offer to achieve user-defined material distribution across a given region with appropriate selection of rheology and printing process parameters.