Rheological properties of magnetic biogels

We report an experimental and theoretical study of the rheological properties of magnetic biogels consisting of fibrin polymer networks with embedded magnetite nanoparticles, swollen by aqueous solutions. We studied two types of magnetic biogels, differenced by the presence or absence of an applied magnetic field during the initial steps of cross-linking. The experiments demonstrated very strong dependence of the elastic modulus of the magnetic biogels on the concentration of the magnetic particles. We finally developed some theoretical models that explain the observed strong concentration effects.This study was supported by projects FIS2013-41821-R (Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica, MINECO, Spain, co-funded by ERDF, European Union) and FIS2017-85954-R (Ministerio de Economía, Industria y Competitividad, MINECO, andAgencia Estatal de Investigación, AEI, Spain, co-funded by Fondo Europeo de Desarrollo Regional, FEDER, European Union). A.Z. is grateful to the program of the Ministry of Education and Science of the Russian Federation, projects 02.A03.21.0006, 3.1438.2017/4.6, and 3.5214.2017/6.7, as well as to the Russian Fund of Basic Researches, project 18-08-00178

3D culture of adult mouse neural stem cells within functionalized self-assembling peptide scaffolds

Carla Cunha1,2, Silvia Panseri3,4, Omar Villa1,2, Diego Silva1,2, Fabrizio Gelain1,21Department of Biotechnology and Biosciences, University of Milano-Bicocca; 2Center for Nanomedicine and Tissue Engineering, CNTE – A.O. Ospedale Niguarda Ca' Granda, Milan; 3Laboratory of Biomechanics and Technology Innovation, Rizzoli Orthopaedic Institute, Bologna; 4Laboratory of Nano-Biomagnetism, Institute of Science and Technology for Ceramics, National Research Council, Faenza, ItalyAbstract: Three-dimensional (3D) in vitro models of cell culture aim to fill the gap between the standard two-dimensional cell studies and the in vivo environment. Especially for neural tissue regeneration approaches where there is little regenerative capacity, these models are important for mimicking the extracellular matrix in providing support, allowing the natural flow of oxygen, nutrients, and growth factors, and possibly favoring neural cell regrowth. We have previously demonstrated that a new self-assembling nanostructured biomaterial, based on matrigel, was able to support adult neural stem cell (NSC) culture. In this study, we developed a new 3D cell culture system that takes advantage of the nano- and microfiber assembling process, under physiologic conditions, of these biomaterials. The assembled scaffold forms an intricate and biologically active matrix that displays specifically designed functional motifs: RGD (Arg-Gly-Asp), BMHP1 (bone marrow homing peptide 1), and BMHP2, for the culture of adult NSCs. These scaffolds were prepared at different concentrations, and microscopic examination of the cell-embedded scaffolds showed that NSCs are viable and they proliferate and differentiate within the nanostructured environment of the scaffold. Such a model has the potential to be tailored to develop ad hoc designed peptides for specific cell lines.Keywords: biomaterials, tissue engineering, 3D in vitro mode

Analyse par bandes de fréquences pour la détection des zones de « déviance » dans la parole dysarthrique

International audienceCe travail s'inscrit dans le projet ANR DesPho-APaDy dont l'un des objectifs vise à décrire les caractéristiques phonético-acoustiques de la parole dysarthrique par le biais d'une approche combinant des procédures analy-tiques manuelles et des procédures issues du traitement automatique de la parole

Intestinal absorption of vitamin E in children with atrophy of the jejunal mucosa

The intestinal absorption of vitamin E is often thought to be closely correlated to that of fatty acids, but the biochemical mechanisms involved in the process are still not clear. For this reason, the present study aimed to assess the absorption of triglycerides and vitamin E, following oral administration, in 11 children with suspected malabsorption syndromes. Intestinal biopsy in 9 children showed the presence of a flat mucosa, whereas no changes were present in 2 patients. The results confirm the inverse correlation between the absorption of triglycerides and vitamin E, as if tocopherols used an independent system of transport. These findings contrast with those reported in the literature perhaps due to the low level of precision of colorimetric techniques previously used to assay vitamin E

Histamine control in raw and processed tuna: A rapid tool based on nir spectroscopy

The present study was designed to investigate whether near infrared (NIR) spectroscopy with minimal sample processing could be a suitable technique to rapidly measure histamine levels in raw and processed tuna fish. Calibration models based on orthogonal partial least square regression (OPLSR) were built to predict histamine in the range 10–1000 mg kg−1 using the 1000–2500 nm NIR spectra of artificially-contaminated fish. The two models were then validated using a new set of naturally contaminated samples in which histamine content was determined by conventional high-performance liquid chromatography (HPLC) analysis. As for calibration results, coefficient of determination (r2 ) > 0.98, root mean square of estimation (RMSEE) ≤ 5 mg kg−1 and root mean square of cross-validation (RMSECV) ≤ 6 mg kg−1 were achieved. Both models were optimal also in the validation stage, showing r2 values > 0.97, root mean square errors of prediction (RMSEP) ≤ 10 mg kg−1 and relative range error (RER) ≥ 25, with better results showed by the model for processed fish. The promising results achieved suggest NIR spectroscopy as an implemental analytical solution in fish industries and markets to effectively determine histamine amounts

The role of Y2O3 in the bioactivity of YSZ/PLLA composites

Yttria stabilized zirconia, one of the most common ceramics in the field of dentistry and in particular dental implantology, for decades has been wrongly considered to be completely bio-inert. In this work, we investigate the role of yttria on the bioactivity of yttria stabilized zirconia formulations, proving that the composite ceramic is actually bioactive, do not affect the cell adhesion and can stimulate cell proliferation, in vitro. To reduce to minimum the number of variables, yttria stabilized zirconia particles with different contents of yttria but similar average size and morphology have been used to reinforce an electrospun poly-l-lactide (PLLA) fibers. Characterization of both the ceramic particulates and the scaffolds confirmed the morphological and structural similarities between the samples, which were then tested in vitro using a human fetal osteoblasts model. The results showed that cell proliferation is enhanced by the presence of the composite ceramic additive, with higher contents of yttria being overall more effective. These results confirm that yttria plays a key role in the biocompatibility and bioactivity of ceramics and can be used to improve the chances for a positive outcome in the osteo-integration of dental implants and/or biomedical scaffolds