Will robotic assisted in situ bioprinting become the next generation of surgical modality for cartilage repair?

Articular cartilage (AC), a specific form of hyaline cartilage found on synovial joints (e.g., knee and shoulder), endows the joint with a low-friction and load-bearing surface, allowing smooth movement and bearing up to 3.5 times of the body’s weight. Nevertheless, the lack of vascularization, innervation, and a lymphatic system, coupled with the low metabolic activity of resident chondrocyte cells, the inability to obtain circulating progenitor cells, and a limited nutrient supply results in limited innate tissue self-regeneration. How to efficiently treat osteochondral-related diseases caused by traumatic injuries or degenerative pathologies addresses increasing attention.

Paulo Bartolo, Professor at the Singapore Centre for 3D Printing, Nanyang Technological University, recently published a review article entitled “Robotic-assisted in situ bioprinting for cartilage tissue repair” in the International Journal of Extreme Manufacturing (IJEM) and comprehensively introduced robotic assisted in situ bioprinting, a new emerging printing technology for cartilage tissue engineering.

This review, based on in situ bioprinting in cartilage repair as a breakthrough point, gets readers a glimpse of how in situ bioprinting will alter the surgical modality in future. It discusses the new frontier of robotic-assisted in situ bioprinting surgical systems for cartilage regeneration and outlines existing clinical approaches and the utilisation of robotic-assisted surgical systems. It defines and presents handheld and robotic-assisted in situ bioprinting techniques including minimally invasive and non-invasive approaches and highlights alternative approaches in micro- and nanorobotics. Finally, the challenges and potential future perspectives of in situ bioprinting for cartilage applications are systematically discussed and concluded.

“In situ bioprinting is an attractive technique which is able to directly deliver bioinks to the desired anatomical site and has the potential to overcome major shortcomings associated with conventional bioprinting.” said Yaxin Wang, Ph.D. candidate and the first author of this review,” It has many advantages such as real-time wound treatment, perfectly wound shape match, and immediate anastomosis with native tissue.”

To achieve a successful fabrication of biologically functional products, bioinks must fulfil essential criteria including printability, cytocompatibility and ability to instruct desired cell responses. “Bioink should be specifically designed for in situ bioprinting and cartilage repair. Dr. Rúben Pereira, a biomaterial specialist said, “The integration between the bioprinted construct and surrounding tissues must be addressed, especially for cartilage tissue which has an anti-adhesive ECM and low metabolism. In situ bioprinted constructs must allow lateral and vertical biological fixation and restore function.”

How to use in situ bioprinting depends on the complexity of the tissue or organ, the anatomical location, and the required clinical outcome. “The application scenarios of handed or robotic-assisted approach should be carefully evaluated and determined by clinical surgeons for specific clinical indications.” said Dr. Boyang Huang. “For example, the handled approach is more suitable for emergency trauma situations while the robotic-assisted approach can be potentially deployed for complex geometric organ printing. Considering larger full-thickness defects or complete resurfacing or total joint replacements, in vitro bioprinting approach may be better.”

Despite of significant progress, in situ bioprinting currently is mainly used in the “touchable” organ printing such as skin, muscle, and bone. Dr Chris Peach, the specialist orthopedic surgeon from the team pointed out “There is a significant challenge using in situ bioprinting in articular joints. There are no commercial in situ bioprinting systems available and all are still in the laboratory research phase. A key factor is the anatomic positioning required for different AC defect pathologies (e.g., medial and lateral regions of the tibia plateau or femoral condyles) and the limited access to the defect site because of the surrounding ligaments, tendons, meniscus, and bones.”

To overcome this issue, the most attractive and innovative way is the provision of minimally invasive surgery (MIS) or arthroscopic techniques allowing the accurate assessment of the pathology using high-definition arthroscopy cameras and minimal damage to the surrounding tissues. Many technological advancements such as in kinematics (movement), control and feedback systems, surgical tools, and visualisation processes can be adopted and adapted for in situ bioprinting. “Since many of the existing systems have had significant development, there may be a direction of travel that the in situ bioprinting technologies become part of the suite of end-effector tools, thus allowing quicker adoption of the technology.” Said Dr. Cian Vyas. “However, advances in robotic and printing systems are still required such as miniaturization of components, movement and feedback, and surgical planning.”

Although it is still a long way to go from bench side to bedside, the team expresses optimism about the future of in situ bioprinting. “The next regeneration robotic surgical system should be integrated with enhanced imaging, sensing and feedback (i.e., force and haptic feedback; thermal, pressure, and positioning sensors), faster digital communication, and improved bioprinting systems.” said Professor Paulo. “Future in situ bioprinting surgery will not only be the matter of Biomedical Engineering but also a highly interdisciplinary approach involving Artificial Intelligence (AI), Internet of Things (IoT), Virtual Reality (VR), Augmented Reality (AR) and 5G technologies interacting with the clinical team.”

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About SC3DP

The Singapore Centre for 3D Printing (SC3DP) commenced in December 2014. The Centre is funded by National Research Foundation (NRF), and supported by Nanyang Technological University, Singapore (NTU, Singapore), Economic Development Board (EDB) and external industry partners. SC3DP is a world-leading research centre in the field of additive manufacturing and was ranked the top Additive Manufacturing university centre in Asia Pacific and 7th in the world. The vision of centre is to become a world leader in 3D Printing and a wellspring of knowledge by attracting leading researchers to the Centre and nurturing a skilled talent pool, establishing strong linkages with and delivering state-of-the-art and innovative solutions to the industry.

About IJEM:

International Journal of Extreme Manufacturing (IF: 10.036) is a new multidisciplinary, double-anonymous peer-reviewed and diamond open-access without article processing charge journal uniquely covering the areas related to extreme manufacturing. The journal is devoted to publishing original articles and reviews of the highest quality and impact in the areas related to extreme manufacturing, ranging from fundamentals to process, measurement and systems, as well as materials, structures and devices with extreme functionalities.

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