Search

Osteochondral (OC) defects are debilitating joint injuries characterized by the loss of full thickness articular cartilage along with the underlying calcified cartilage through to the subchondral bone. While current surgical treatments can provide some relief from pain, none can fully repair all the components of the OC unit and restore its native function. Engineering OC tissue is challenging due to the presence of the three distinct tissue regions. Recent advances in additive manufacturing provide unprecedented control over the internal microstructure of bioscaffolds, the patterning of growth factors and the encapsulation of potentially regenerative cells. These developments are ushering in a new paradigm of ‘multiphasic’ scaffold designs in which the optimal micro-environment for each tissue region is individually crafted. Although the adoption of these techniques provides new opportunities in OC research, it also introduces challenges, such as creating tissue interfaces, integrating multiple fabrication techniques and co-culturing different cells within the same construct. This review captures the considerations and capabilities in developing 3D printed OC scaffolds, including materials, fabrication techniques, mechanical function, biological components and design.

Cells : open access journal 11(11), 1752 (2022). doi:10.3390/cells11111752 special issue: "Special Issue "Tissue Engineered Models of Musculoskeletal Regeneration and Pathologies" / Special Issue Editors: Prof. Dr. Boris Michael Holzapfel, Guest Editor; Prof. Dr. Susanne Mayer, Guest Editor", Published by MDPI, Basel

There is an urgent need in the field of soft tissue engineering (STE) to develop biomaterials exhibiting a high degree of biological and mechanical functionality as well as modularity so that they can be tailored according to patient-specific requirements. Recently, biomimetic soft network composites (SNC) consisting of a water-swollen hydrogel matrix and a reinforcing fibrous network fabricated by melt electrospinning writing technology have demonstrated exceptional mechanical and biological properties, thus becoming strong candidates for STE applications. However, there is a lack of design approaches to tailor and optimize their properties in a non-empirical way. To address this challenge, we propose a numerical model-based approach for the rational design of patient-specific SNC for tissue engineering applications. The approach is rooted in an in silico design library that allows for the selection of biomaterial and architecture combinations for the target application, resulting in reduced time, manpower and costs. To demonstrate the validity of the design strategy, a multiphasic SNC with predefined zone-specific properties that captured the complex zonal mechanical and compositional features of articular cartilage was developed based on the natural design of the native tissue.

International audience; In the frame of Severe Accident studies, the VULCANO-facility at PLINIUS-platform (CEA - Cadarache) is devoted to the understanding of the interaction of corium with a concrete containment pit (Molten Corium Concrete Interaction-MCCI) [1]. The VULCANO VF-U1 experiment was designed to be closer as possible of the MCCI conditions possibly occurring in the Fukushima F1 reactor considering the coexistence of two dispersed phases (metallic liquid droplets and gaseous bubbles) in a continuous phase (oxide melt liquid).A MCCI industrial code was used to perform predictive calculation of the VF-U1 experiment, being closer as possible of Fukushima 1-F1 MCCI conditions. The results shown that the axial ablation is 8 times higher than the radial one. Then, a multiplicative factor of 8 for the axial heat exchange coefficient must be applied to find the final cavity shape. VULCANO VF-U1 Post-Test Analyses have shown that the metallic phase is preferably close to the vertical concrete walls and at the bottom of the test section whereas a stratification due to density difference between the oxide and the metallic phase is expected (as modeling by the MCCI code). Regarding to the real coupling physical effects in the integral the VULCANO-ICB test and the difficulties for the MCCI code to reproduce experimental behaviors, numerical simulations were conducted. For this purpose, a multiphase Volume Of Fluid (VOF) code at AMU (MADIREL) has been developed . In these calculations, the corium has been modelled numerically under isothermal conditions as a two-dimensional dispersed medium with multiple metal drops and gas bubbles. The results showed a possible hydrodynamic re-localization matching to experimental results.