3DICE coding matrix multidirectional macro-architecture modulates cell organization, shape, and co-cultures endothelization network

Natural extracellular matrix governs cells providing biomechanical and biofunctional outstanding properties, despite being porous and mostly made of soft materials. Among organs, specific tissues present specialized macro-architectures. For instance, hepatic lobules present radial organization, while vascular sinusoids are branched from vertical veins, providing specific biofunctional features. Therefore, it is imperative to mimic such structures while modeling tissues. So far, there is limited capability of coupling oriented macro-structures with interconnected micro-channels in programmable long-range vertical and radial sequential orientations. Herein, a three-directional ice crystal elongation (3DICE) system is presented to code geometries in cryogels. Using 3DICE, guided ice crystals growth templates vertical and radial pores through bulky cryogels. Translucent isotropic and anisotropic architectures of radial or vertical pores are fabricated with tunable mechanical response. Furthermore, 3D combinations of vertical and radial pore orientations are coded at the centimeter scale. Cell morphological response to macro-architectures is demonstrated. The formation of endothelial segments, CYP450 activity, and osteopontin expression, as liver fibrosis biomarkers, present direct response and specific cellular organization within radial, linear, and random architectures. These results unlock the potential of ice-templating demonstrating the relevance of macro-architectures to model tissues, and broad possibilities for drug testing, tissue engineering, and regenerative medicine.The authors are grateful for the Portuguese Foundation for Science and Technology (FCT) distinction attributed to R. F. Canadas (SFRH/ BD/92565/2013), and to J. M. Oliveira (IF/00423/2012, IF/01285/ 2015). R. F. Canadas is also thankful to FCT, Fundo Europeu de Desenvolvimento Regional (FEDER), and Programa Operacional Competitividade e Internacionalizaç˜ao (POCI) for funding the B-Liver Project (PTDC/EMD-EMD/29139/2017). The authors are also thankful to FCT for supporting the project Hierarchitech (M-ERA-NET/0001/2014) and for the funds provided under the 3 BioMeD project (JICAM/0001/2017). The authors acknowledge that this material and collaboration is based in part upon work supported by Luso-American Development Foundation (FLAD), 2016/CON15/CAN6). U. Demirci is also grateful for the Canary Center at Stanford for Cancer Early Detection Seed Award. The authors are also grateful for the support provided by Diana Bicho and Nicolas Cristini on scaffold characterization and cell culture, respectively

Synthesis and characterization of thermotropic liquid crystalline copolyester/multi-walled carbon nanotubes composites via in situ polymerization

We present a novel approach for the preparation of thermotropic liquid crystalline copolyester (TLCP)/multi-walled carbon nanotubes (MWCNTs) composites via in situ polymerization. A two-stage polycondensation procedure was employed in our process, where carboxylic acid modified MWCNTs were dispersed in acetic anhydride via ultrasonication prior to being charged to a prepolymerization reactor together with monomers and catalysts for esterification reaction at 130 degrees C-200 degrees C. The esterified mixture was then fed into a polycondensation reactor at 280 degrees C-320 degrees C. In this way, fully exfoliated MWCNTs were dispersed in the TLCP matrix at concentrations up to 0.3 wt%. Systematic studies show that well dispersed MWCNTs acted as "pseudo nucleation sites" for the nematic ordering in the adjacent TLCP melt. Thus the extrudates show a smaller core region and higher overall orientational order. Consequently, the addition of MWCNTs is not only effective in improving the mechanical stiffness but also toughness of the composites. For example, the 0.3 wt% TLCP/MWCNT composite shows a 62%, 135% and 145% increase in Young's modulus, tensile strength and toughness, respectively, in comparison with the pure TLCP. (C) 2012 Elsevier Ltd. All rights reserved