TechMENI: ready to use acellular meniscus implant for knee meniscus replacement

Introduction: Knee meniscus lesions are of outmost relevance for their high prevalence and critical impact on individuals' mobility and quality of life. Moreover, over 75% of patients with symptomatic osteoarthritis exhibit a meniscus tear. Although meniscus repair systems are the first-line treatment, 65% of meniscal tears are still deemed unrepairable and there is no current alternative. Unprecedented in its approach, we are introducing the use of supercritical carbon dioxide (scCO2) systems for the development of ALL-in-ONE tissue decellularization/sterilization/drying method to produce xenograft meniscus implants. Method: Ovine meniscus was used as source of biological tissue. The process involved pre-processing, continuous mode decellularization with scCO2 and co-solvents (Hydrogen peroxide and ethanol), followed by sterilization and drying (DSD) under controlled temperature and pressure. Operational parameters were optimized. DSD efficacy was evaluated by histological analysis. Quantification of residual DNA was performed. Spore strips containing one biological indicator—B. stearothermophilus (steam sterilization)- was incubated. The success of sterilization was determined by evaluating the turbidity of trypticase soy broth (TSB) medium. Additionally, histological analyses utilizing Masson’s Trichrome techniques was used to access extracellular matrix (ECM) preservation. Scanning electron microscopy (SEM) was used to evaluate implant integrity and in vitro cytotoxicity assays were performed to access biocompatibility. Lastly, mechanical properties, including standard uniaxial testing, were assessed. Result: The results revealed that the DSD process was efficient and fast setting. The histological analysis and SEM observation showed effective cell removal and ECM preservation. The DNA quantification tests revealed a significant decrease in terms of DNA targeting value DNA<50ng/g of dry sample. Furthermore, the TSB assay showed that the samples were effectively sterilized. Lastly, the xenografts showed in vitro biocompatibility and mechanical properties resembling the native tissue. Conclusion: The sCO2-based DSD method efficiently produced biocompatible, mechanically robust xenograft meniscus implants with preserved ECM and effective sterilization, revealing significant clinical potential.