The inability to replace human muscle in surgical practice is a significant challenge. An artificial muscle controlled by the nervous system is considered a potential solution for this. We defined it as neuromuscular prosthesis. Muscle loss and dysfunction related to musculoskeletal oncological impairments, neuromuscular diseases, trauma or spinal cord injuries can be treated through artificial muscle implantation. At present, the use of dielectric elastomer actuators working as capacitors appears a promising option. Acrylic or silicone elastomers with carbon nanotubes functioning as the electrode achieve mechanical performances similar to human muscle in vitro. However, mechanical, electrical, and biological issues have prevented clinical application to date. In this study, materials and mechatronic solutions are presented which can tackle current clinical problems associated with implanting an artificial muscle controlled by the nervous system. Progress depends on the improvement of the actuation properties of the elastomer, seamless or wireless integration between the nervous system and the artificial muscle, and on reducing the foreign body response. It is believed that by combining the mechanical, electrical, and biological solutions proposed here, an artificial neuromuscular prosthesis may be a reality in surgical practice in the near future

Background context. Fusion is a fundamental procedure in spine surgery. Although autogenous grafts have ideal bone graft characteristics, their use may remain limited due to various morbidities. Even though ceramic based synthetic bone grafts are used commonly at present, in order to enhance their efficacy, their combined use with other materials has been investigated. The use of carbon nanotubes (CNTs) together with synthetic bone grafts such as hydroxyapatite (HA) has contributed to positive developments in bone tissue engineering. Purpose. The aim of the present study was to investigate the effect of CNTs/ HA- tricalcium phosphate (TCP) composite prepared in posterolateral spinal fusion model. Study Design/Setting. Experimental animal study. Methods. At first, CNTs and CNTs/HA-TCP composites were prepared. Twenty adult male Spraque Dawley rats were randomized into four groups with five rats in each group. Decortication was carried out in standard manner in all animals. Group 1 (only decortication), group 2 (CNTs), group 3 (HA-TCP) and group 4 (CNTs/HA-TCP) were formed. Eight weeks later all animals were sacrificed and obtained fusion segments were evaluated by manual palpation, histomorphometry and micro computed tomography (mCT). Results. In all evaluations, highest fusion values were obtained in Group 4. In mCT investigations, bone volume/ tissue volume (BV/TV) ratio was found to be significantly higher in composite group (group 4) only compared to ceramic group (group 3). Although in Group 2, in which only CNTs were used, the ratio was found to be significantly higher than group 1, the difference was not considered significant in terms of fusion and in addition in group 2, CNTs were completely surrounded by fibrous tissue, i.e. no bone formation was observed. Conclusions. The combined use of carbon nanotubes with ceramic based bone grafts enhances spinal fusion markedly. Although CNTs are inadequate in producing spinal fusion when they are used by themselves, due to especially their high biocompatibillity and unique bicomechanic characteristics compatible with bone tissue, they increase fusion rates significantly, particularly together with ceramic based synthetic grafts. Keywords. Spinal fusion; Rat; Carbon nanotube(s); Ceramic(s); Bone graft subsitutes; Hydroxyapatite

Osteoarthritis (OA) is a degenerative joint disease affecting millions worldwide. Early detection of OA and monitoring its progression is essential for effective treatment and for preventing irreversible damage. Although sensors have emerged as a promising tool for monitoring analytes in patients, their application for monitoring the state of pathology is currently restricted to specific fields (such as diabetes). In this study, we present the development of an optical sensor system for real-time monitoring of inflammation based on the measurement of nitric oxide (NO), a molecule highly produced in tissues during inflammation. Single-walled carbon nanotubes (SWCNT) were functionalized with a single-stranded DNA (ssDNA) wrapping designed using an artificial intelligence approach and tested using S-nitroso-N-acetyl penicillamine (SNAP) as a standard released-NO marker. An optical SWIR reader with LED excitation at 650 nm, 730 nm and detecting emission above 1000 nm was developed to read the fluorescence signal from the SWCNTs. Finally, the SWCNT was embedded in GelMa to prove the feasibility of monitoring the release of NO in bovine chondrocyte and osteochondral inflamed cultures (1–10 ng/ml IL1β) monitored over 48 hours. The stability of the inflammation model and NO release was indirectly validated using the Griess and DAF-FM methods. A microfabricated sensor tag was developed to explore the possibility of using ssDNA-SWCNT in an ex vivo anatomic set-up for surgical feasibility, the limit of detection, and the stability under dynamic flexion. The SWCNT sensor was sensitive to NO in both in silico and in vitro conditions during the inflammatory response from chondrocyte and osteochondral plug cultures. The fluorescence signal decreased in the inflamed group compared to control, indicating increased NO concentration. The micro-tag was suitable and stable in joints showing a readable signal at a depth of up to 6 mm under the skin. The ssDNA-SWCNT technology showed the possibility of monitoring inflammation continuously in an in vitro set-up and good stability inside the joint. However, further studies in vivo are needed to prove the possibility of monitoring disease progression and treatment efficacy in vivo. Acknowledgments: The project was co-financed by Innosuisse (grant nr. 56034.1 IP-LS)