Biofabrication of customized bone grafts by combination of additive manufacturing and bioreactor knowhow

This study reports on an original concept of additive manufacturing for the fabrication of tissue engineered constructs (TEC), offering the possibility of concomitantly manufacturing a customized scaffold and a bioreactor chamber to any size and shape. As a proof of concept towards the development of anatomically relevant TECs, this concept was utilized for the design and fabrication of a highly porous sheep tibia scaffold around which a bioreactor chamber of similar shape was simultaneously built. The morphology of the bioreactor/scaffold device was investigated by micro-computed tomography and scanning electron microscopy confirming the porous architecture of the sheep tibiae as opposed to the non-porous nature of the bioreactor chamber. Additionally, this study demonstrates that both the shape, as well as the inner architecture of the device can significantly impact the perfusion of fluid within the scaffold architecture. Indeed, fluid flow modelling revealed that this was of significant importance for controlling the nutrition flow pattern within the scaffold and the bioreactor chamber, avoiding the formation of stagnant flow regions detrimental for in vitro tissue development. The bioreactor/scaffold device was dynamically seeded with human primary osteoblasts and cultured under bi-directional perfusion for two and six weeks. Primary human osteoblasts were observed homogenously distributed throughout the scaffold, and were viable for the six week culture period. This work demonstrates a novel application for additive manufacturing in the development of scaffolds and bioreactors. Given the intrinsic flexibility of the additive manufacturing technology platform developed, more complex culture systems can be fabricated which would contribute to the advances in customized and patient-specific tissue engineering strategies for a wide range of applications.This work was supported by the NHMRC, the Australian Research Council and Hans Fischer Senior Fellowship, IAS-TUM. Pedro Costa acknowledges the Portuguese Foundation for Science and Technology for his PhD grant (SFRH/BD/62452/2009)

3D‐printed cryomilled poly(ε‐caprolactone)/graphene composite scaffolds for bone tissue regeneration

In this study, composite scaffolds based on poly(caprolactone) (PCL) and non-covalently functionalized few-layer graphene (FLG) were manufactured by an extrusion-based system for the first time. For that, functionalized FLG powder was obtained through the evaporation of a functionalized FLG aqueous suspension prepared from a graphite precursor. Cryomilling was shown to be an efficient mixing method, producing a homogeneous dispersion of FLG particles onto the PCL polymeric matrix. Thereafter, fused deposition modeling (FDM) was used to print 3D scaffolds and their morphology, thermal, biodegradability, mechanical, and cytotoxicity properties were analysed. The presence of functionalized FLG demonstrated to induce slight changes in the microstructure of the scaffold, did not affect the thermal stability and enhanced significantly the compressive modulus. The composite scaffolds presented a porosity of around 40% and a mean pore size in the range of 300 μm. The cell viability and proliferation of SaOs-2 cells were assessed and the results showed good cell viability and long-term proliferation onto produced composite scaffolds. Therefore, these new FLG/PCL scaffolds comprised adequate morphological, thermal, mechanical, and biological properties to be used in bone tissue regeneration.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT), the European program FEDER/COMPETE for the financial support through project LA ICVS/3Bs - 2015-2017 and to IPC (UID/CTM/50025/2013 and UID/CTM/50025/2016), and the scholarship SFRH/BD/87214/2012 granted to Eunice Cunha. Daniela Dias acknowledges the mobility grant from the BEAM project- Biomedical Engineering-EU Australian cooperation at master level, ICIECP Education Cooperation Programme (388414-EM-January 1, 2014-IT-ERA MUNDUS-ICIJMP). We also acknowledge Prof. Dietmar W. Hutmacher that kindly hosts Daniela Dias in the IHBI laboratory

The DAily Home LIfe Activity Dataset: A High Semantic Activity Dataset for Online Recognition

Conference of 12th IEEE International Conference on Automatic Face and Gesture Recognition, FG 2017 ; Conference Date: 30 May 2017 Through 3 June 2017; Conference Code:128713International audienceIn this article, we introduce the DAily Home LIfe Activity (DAHLIA) Dataset, a new dataset adapted to the context of smart-home or video-assistance. Videos were recorded in realistic conditions, with 3 KinectTMv2 sensors located as they would be in a real context. The very long-range activities were performed in an unconstrained way (participants received few instructions), and in a continuous (untrimmed) sequence, resulting in long videos (39 min in average per subject). Contrary to previously published databases, in which labeled actions are very short and with low-semantic level, this new database focuses on high-level semantic activities such as 'Preparing lunch' or 'House Working'. As a baseline, we evaluated several metrics on three different algorithms designed for online action recognition or detection