Developing a Robot-assisted in Situ Bioprinter Using Extrusion Technology

In situ bioprinting technology, a novel branch of traditional ex vivo bioprinting, directly deposits bio-ink onto a patient's defective area. This study introduces a UR5-assisted bioprinting system with six degrees of freedom to address issues such as tissue mismatch at the defect site, complex operations, and high costs from conventional bioprinting technologies. The system's end-effector integrates hardware and software on an STM32F103C8T6 microcontroller to control air pressure extrusion and bio-ink temperature. It featured a Peltier module and corresponding water-cooling block for temperature regulation, along with an external air compressor and proportional valve for precise extrusion control. The system's Graphical User Interface (GUI) incorporated a digital-twin model of the UR5 robotic arm, improving human-machine interaction and refining the planning of the printing path. The printing path programming converts G-code into JavaScript, executed by the UR5. Additionally, real-time monitoring of the printing path was displayed directly on the GUI. The overall in situ bioprinting system was validated by bioprinting Pluronic F127 into 2D images and a 3D scaffold on an actual femur model. The fidelity of the in situ bioprinting system was quantified by comparing the area error of printed results with preset images.