Jia-Kuo Yu is the director of the Institute of Orthopedics and Sports Medicine of Tsinghua Medicine, the director of the Orthopaedic Sports Medicine Center of Beijing Tsinghua Changgeng Hospital affiliated to Tsinghua University, the director of the knee surgery Department of the Orthopaedic Sports Medicine Center, and the founding chairman of the Geriatric Sports Medicine Society of Chinese Gerontology and Geriatric Society.

Topic title: In situ bioprinting for cartilage repair using a parallel manipulator

Abstract:

Regeneration of large-sized cartilage injury is a challenging endeavor. In vitro bioprinting for cartilage repair presents various challenges, including the laborious material preparation process, potential contamination risks, and incongruities between the implant and the defect. The primary objective of this investigation was to explore the use of in situ bioprinting for cartilage repair employing a parallel manipulator. The material extrusion rate and printing speed were adjusted to obtain the suitable forming parameters in a custom-made parallel manipulator. Cell experiments were conducted to determine the biocompatibility. Finally, a rabbit cartilage defect model was used to evaluate the feasibility of in situ bioprinting combined with machine vision. The results showed that to achieve optimum printing using the custom-made three-dimensional printer, 400–560 mm/min should be set as the standard printing speed, with an extrusion multiplier of 0.09–0.10. Cartilage defects can be precisely and easily segmented using a bimodal method with a 2% deviation error. In vitro experiments revealed that the utilized materials are highly biocompatible. Based on the findings of in vivo experiments, in situ bioprinting proves beneficial in mending cartilage defects. The comprehensive results affirm the feasibility of employing a parallel manipulator in in situ bioprinting for cartilage repair. Additional optimizations of the proposed approach are warranted prior to translation into clinical applications in the future.