Speaker
Description
Despite significant advances in 3D bioprinting, achieving high printing speed, efficiency, and homogeneity in biological samples remains challenging. These limitations restrict its practical application in tissue engineering, particularly in fabricating complex tissues such as skeletal muscle. Microfluidics offers promising strategies to overcome several of these issues.
This project introduces a high-throughput, combinatorial microfluidic-assisted 3D bioprinter designed to address these gaps. The device is compatible with standard multiwell plates and can print up to 96 distinct material sequences in about two hours, enabling rapid screening of cells and biomaterials.
While initially intended for skeletal muscle bioink screening, the system’s capabilities extend further. Printing different materials side-by-side enables heterogeneous constructs, whereas printing the same material simultaneously with all nozzles provides high-throughput homogeneous fabrication. The ability to handle a wide range of viscosities, diverse biomaterials, customizable parameters, and full automation gives the system advantages beyond those of current bioprinters.
The bioprinter uses open cartridges that store diverse bioinks and connect to a pressure controller that applies periodic positive and negative pressure. This gentle mixing prevents cell sedimentation and maintains bioink homogeneity, addressing a major limitation of conventional approaches.
The printer head contains up to 12 microfluidic chips (pens) acting as nozzles, each with a mixing compartment for passive homogenization. These nozzles move independently in the vertical direction via servomotors, while a robotic arm handles horizontal positioning. Each chip is connected to a syringe pump regulating bioink flow, and a low-density oil minimizes residue to ensure consistent operation. The process is fully automated through custom Python code coordinating pumps, motors, and the robotic arm. The microfluidic chips are fabricated with biocompatible transparent resin using SLA 3D printing, allowing seamless geometries and high control over microchannel architecture.
Printing begins with the head aspirating defined volumes of bioink from the cartridges. It then deposits the materials into the well plate filled with printing bath in a programmed pattern. After each printing step, the head moves to a washing station where the oil flushes out residual bioink. This cycle continues until all wells contain distinct combinatorial sequences. For skeletal muscle applications, printed samples are cultured for 14 days and analyzed with image-processing techniques to identify optimal formulations.
The modular design supports additional accessories such as active mixing or photocrosslinking. For high-viscosity inks, the printer head performs pipetting cycles in a separate plate to ensure proper mixing. When photoinitiators are present, a UV-lamp mask aligned with the wells enables selective photocrosslinking, reducing unnecessary UV exposure and preventing cellular or biomaterial damage.
Overall, this bioprinter provides significant advantages in speed, simplicity, affordability, and homogeneity. Its high-throughput capabilities and precision make it a powerful tool for tissue engineering and biomaterial screening, accelerating the development of functional artificial tissues.