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Microcrystalline cellulose (MCC) is proposed in this study as an additive in polycaprolactone (PCL) matrices to obtain three‐dimensional (3D) printed scaffolds with improved mechanical and biological properties. Improving the mechanical behavior and the biological performance of polycaprolactone‐based scaffolds allows to increase the potential of these structures for bone tissue engineering. Different groups of samples were evaluated in order to analyze the effect of the additive in the properties of the PCL matrix. The concentrations of MCC in the groups of samples were 0, 2, 5, and 10% (w/w). These combinations were subjected to a thermogravimetric analysis in order to evaluate the influence of the additive in the thermal properties of the composites. 3D printed scaffolds were manufactured with a commercial 3D printer based on fused deposition modelling. The operation conditions have been established in order to obtain scaffolds with a 0/90° pattern with pore sizes between 450 and 500 µm and porosity values between 50 and 60%. The mechanical properties of these structures were measured in the compression and flexural modes. The scaffolds containing 2 and 5% MCC have higher flexural and compression elastic modulus, although those containing 10% do not show this reinforcement effect. On the other hand, the proliferation of sheep bone marrow cells on the proposed scaffolds was evaluated over 8 days. The results show that the proliferation is significantly better (p < 0.05) on the group of samples containing 2% MCC. Therefore, these scaffolds (PCL:MCC 98:2) have suitable properties to be further evaluated for bone tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 521–528, 2019. [ABSTRACT FROM AUTHOR]

Osteoarthritis is the most common chronic degenerative joint disease, recognized by the World Health Organization as a public health problem that affects millions of people worldwide. The project Biomaterials and Additive Manufacturing: Osteochondral Scaffold (BAMOS) innovation applied to osteoarthritis, funded under the frame of the Horizon 2020 Research and Innovation Staff Exchanges (RISE) program, aims to delay or avoid the use of joint replacements by developing novel cost-effective osteochondral scaffold technology for early intervention of osteoarthritis. The multidisciplinary consortium of BAMOS, formed by international leading research centres, collaborates through research and innovation staff exchanges. The project covers all the stages of the development before the clinical trials: design of scaffolds, biomaterials development, processability under additive manufacturing, in vitro test, and in vivo test. This paper reports the translational practice adopted in the project in in vivo assessment of the osteochondral scaffolds developed.

Polyether-ether-ketone (PEEK) is widely used in producing prosthesis and have gained great attention for repair of large bone defect in recent years with the development of additive manufacturing. This is due to its excellent biocompatibility, good heat and chemical stability and similar mechanical properties which mimics natural bone. In this study, three replicates of rectilinear scaffolds were designed for compression, tension, three-point bending and torsion test with unit cell size of 0.8 mm, a pore size of 0.4 mm, strut thickness of 0.4 mm and nominal porosity of 50%. Stress-strain graphs were developed from experimental and finite element analysis models. Experimental Young's modulus and yield strength of the scaffolds were measured from the slop of the stress-strain graph to be 395 and 19.50 MPa respectively for compression, 427 and 6.96 MPa respectively for tension, 257 and 25.30 MPa respectively for three-point bending and 231 and 12.83 MPa respectively for torsion test. The finite element model was found to be in good agreement with the experimental results. Ductile fracture of the struct subjected to tensile strain was the main failure mode of the PEEK scaffold, which stems from the low crystallinity of additive manufacturing PEEK. The mechanical properties of porous PEEK are close to those of cancellous bone and thus are expected to be used in additive manufacturing PEEK bone implants in the future, but the lower yield strength poses a design challenge.

Osteoarthritis is a degenerative joint disease, typified by the loss in the quality of cartilage and bone at the interface of a synovial joint, resulting in pain, stiffness and reduced mobility. The current surgical treatment for advanced stages of the disease is joint replacement, where the non-surgical therapeutic options or less invasive surgical treatments are no longer effective. These are major surgical procedures which have a substantial impact on patients' quality of life and lifetime risk of requiring revision surgery. Treatments using regenerative methods such as tissue engineering methods have been established and are promising for the early treatment of cartilage degeneration in osteoarthritis joints. In this approach, 3-dimensional scaffolds (with or without cells) are employed to provide support for tissue growth. However, none of the currently available tissue engineering and regenerative medicine products promotes satisfactory durable regeneration of large cartilage defects. Herein, we discuss the current regenerative treatment options for cartilage and osteochondral (cartilage and underlying subchondral bone) defects in the articulating joints. We further identify the main hurdles in osteochondral scaffold development for achieving satisfactory and durable regeneration of osteochondral tissues. The evolution of the osteochondral scaffolds - from monophasic to multiphasic constructs - is overviewed and the osteochondral scaffolds that have progressed to clinical trials are examined with respect to their clinical performances and their potential impact on the clinical practices. Development of an osteochondral scaffold which bridges the gap between small defect treatment and joint replacement is still a grand challenge. Such scaffold could be used for early treatment of cartilage and osteochondral defects at early stage of osteoarthritis and could either negate or delay the need for joint replacements.