Development of a porcine decellularized extracellular matrix (DECM) bioink for 3D bioprinting of meniscus tissue engineering: formulation, characterisation and biological evaluation

This study aims to present an easily scalable, cost-efficient process of dECM extraction from porcine meniscus, dedicated to bioink preparation and 3D bioprinting. Due to its cartilage like structure and mechanical robustness, the meniscus is an exceptionally demanding tissue for extraction and decellularisation of its ECM. Its processing poses a great difficulty and renders the methods previously developed for soft tissues useless. A process, combining homogenisation, hydrolysis, supercritical CO2 (scCO2) extraction and lyophilisation, was developed to meet this challenge. This protocol allows for retaining its native compounds and biocompatibility while offering good printability and providing a stimulatory environment for cell proliferation and differentiation towards a meniscus-like phenotype. Also, this process is economically and ecologically friendly since it doesn't require the use of high amounts of solvents, detergents or expensive enzymes (DNase). The decellularisation process has been meticulously studied, demonstrating a substantial reduction in DNA content but still exceeding accepted thresholds. The study further explores the biocompatibility of the dECM, demonstrating no detrimental effects of remnant DNA on cell survival during extended in vitro culture, indicating excellent biocompatibility. These findings challenge the current definition of decellularisation effectiveness based solely on DNA content, proposing a broader assessment of biological effects.