A dynamical model for the fermentative production of fructooligosaccharides

In this paper a detailed mathematical model is presented for the fermentative production of fructo-oligosaccharides with Aspergillus sp. The model accounts for hydrolysis and transfructolization reactions, as well as biomass formation and it contains 27 parameters that were determined from experimental data using a System Biology toolbox with the Simulated Annealing method for curve fitting. Several additional experiments were performed in bioreactors where the time variation of 7 state variables (Sucrose, Glucose, Fructose, 1-Kestose, Nystose, 1-fructosyl nystose and Biomass) was measured. Experimental data were compared with results from simulations using the estimated parameters and it was verified that the model can predict the FOS production profile. The good agreement between simulated and experimental data was verified by calculating the relative percentage deviation modulus, which was lower than 10% for all cases except one. The derived and validated model can be used for process optimization, for example for indicating which fed-batch strategy could be used to improve the production of FOS while minimizing glucose concentration

Additive manufactured Poly("-caprolactone)-graphene scaffolds: Lamellar crystal orientation, mechanical properties and biological performance

Understanding the mechano–biological coupling mechanisms of biomaterials for tissue engineering is of major importance to assure proper scaffold performance in situ. Therefore, it is of paramount importance to establish correlations between biomaterials, their processing conditions, and their mechanical behaviour, as well as their biological performance. With this work, it was possible to infer a correlation between the addition of graphene nanoparticles (GPN) in a concentration of 0.25, 0.5, and 0.75% (w/w) (GPN0.25, GPN0.5, and GPN0.75, respectively) in three-dimensional poly("-caprolactone) (PCL)-based scaffolds, the extrusion-based processing parameters, and the lamellar crystal orientation through small-angle X-ray scattering experiments of extruded samples of PCL and PCL/GPN. Results revealed a significant impact on the scaffold’s mechanical properties to a maximum of 0.5% of GPN content, with a significant improvement in the compressive modulus of 59 MPa to 93 MPa. In vitro cell culture experiments showed the scaffold’s ability to support the adhesion and proliferation of L929 fibroblasts (fold increase of 28, 22, 23, and 13 at day 13 (in relation to day 1) for PCL, GPN0.25, GPN0.5, and GPN0.75, respectively) and bone marrow mesenchymal stem/stromal cells (seven-fold increase for all sample groups at day 21 in relation to day 1). Moreover, the cells maintained high viability, regular morphology, and migration capacity in all the different experimental groups, assuring the potential of PCL/GPN scaffolds for tissue engineering (TE) applications.info:eu-repo/semantics/publishedVersio

A multimodal stimulation cell culture bioreactor for tissue engineering: A numerical modelling approach

This research was funded by the Fundação para a Ciência e a Tecnologia (FCT) and Centro2020 through the following Projects: UIDP/04044/2020, PAMI—ROTEIRO/0328/2013 (No 022158) and Stimuli2BioScaffold— Stimuli modelling for BioScaffolds: from numerical modelling to in vitro tests co-financed by COMPETE2020 under the PT2020 programme, and supported by FCT (02/SAICT/2017). Ref. POCI-01-0145-FEDER-032554; Bone2Move—Development of “in vivo” experimental techniques and modeling methodologies for the evaluation of 4D scaffolds on bone defect in sheep model: an integrative research approach co-financed by COMPETE2020 under the PT2020 programme, and supported by FCT (02/SAICT/2017), Project nº 31146; MATIS—MATERIALS AND SUSTAINABLE INDUSTRIAL TECHNOLOGIES (CENTRO-01-0145-FEDER-000014-3362); Instituto de Biofísica e Engenharia Biomédica (IBEB) is supported by Fundação para a Ciência e Tecnologia (FCT), Portugal, under Grant n UIDB/00645/2020. Also supported by UID/BIO/04565/2020.The use of digital twins in tissue engineering (TE) applications is of paramount importance to reduce the number of in vitro and in vivo tests. To pursue this aim, a novel multimodal bioreactor is developed, combining 3D design with numerical stimulation. This approach will facilitate the reproducibility between studies and the platforms optimisation (physical and digital) to enhance TE. The new bioreactor was specifically designed to be additive manufactured, which could not be reproduced with conventional techniques. Specifically, the design suggested allows the application of dual stimulation (electrical and mechanical) of a scaffold cell culture. For the selection of the most appropriate material for bioreactor manufacturing several materials were assessed for their cytotoxicity. Numerical modelling methods were then applied to the new bioreactor using one of the most appropriate material (Polyethylene Terephthalate Glycol-modified (PETG)) to find the optimal stimulation input parameters for bone TE based on two reported in vitro studies.info:eu-repo/semantics/publishedVersio

Influence of PDLA nanoparticles size on drug release and interaction with cells

Polymeric nanoparticles (NPs) are strong candidates for the development of systemic and targeted drug delivery applications. Their size is a determinant property since it defines the NP–cell interactions, drug loading capacity, and release kinetics. Herein, poly(D,L-lactic acid) (PDLA) NPs were produced by the nanoprecipitationmethod, in which the influence of type and concentration of surfactant as well as PDLA concentration were assessed. The adjustment of these parameters allowed the successful production of NPs with defined medium sizes, ranging from 80 to 460 nm. The surface charge of the different NPs populations was consistently negative. Prednisolone was effectively entrapped and released from NPs with statistically different medium sizes (i.e., 80 or 120 nm). Release profiles indicate that these systems were able to deliver appropriate amounts of drug with potential applicability in the treatment of inflammatory conditions. Both NPs populations were cytocompatible with human endothelial and fibroblastic cells, in the range of concentrations tested (0.187–0.784 mg/mL). However, confocal microscopy revealed that within the range of sizes tested in our experiments, NPs presenting amedium size of 120 nmwere able to be internalized in endothelial cells. In summary, this study demonstrates the optimization of the processing conditions to obtain PDLA NPs with narrow size ranges, and with promising performance for the treatment of inflammatory diseases.info:eu-repo/semantics/publishedVersio

Photocatalytic ozonation of urban wastewater and surface water using immobilized TiO2 with LEDs: Micropollutants, antibiotic resistance genes and estrogenic activity

Photocatalytic ozonation was employed for the first time in continuous mode with TiO2-coated glass Raschig rings and light emitting diodes (LEDs) to treat urban wastewater as well as surface water collected from the supply area of a drinking water treatment plant (DWTP). Different levels of contamination and types of contaminants were considered in this work, including chemical priority substances (PSs) and contaminants of emerging concern (CECs), as well as potential human opportunistic antibiotic resistant bacteria and their genes (ARB&ARG). Photocatalytic ozonation was more effective than single ozonation (or even than TiO2 catalytic ozonation) in the degradation of typical reaction by-products (such as oxalic acid), and more effective than photocatalysis to remove the parent micropollutants determined in urban wastewater. In fact, only fluoxetine, clarithromycin, erythromycin and 17-alpha-ethinylestradiol (EE2) were detected after photocatalytic ozonation, by using solid-phase extraction (SPE) pre-concentration and LC-MS/MS analysis. In surface water, this treatment allowed the removal of all determined micropollutants to levels below the limit of detection (0.01-0.20 ng L(-1)). The efficiency of this process was then assessed based on the capacity to remove different groups of cultivable microorganisms and housekeeping (16S rRNA) and antibiotic resistance or related genes (intI1, blaTEM, qnrS, sul1). Photocatalytic ozonation was observed to efficiently remove microorganisms and ARGs. Although after storage total heterotrophic and ARB (to ciprofloxacin, gentamicin, meropenem), fungi, and the genes 16S rRNA and intI1, increased to values close to the pre-treatment levels, the ARGs (blaTEM, qnrS and sul1) were reduced to levels below/close to the quantification limit even after 3-days storage of treated surface water or wastewater. Yeast estrogen screen (YES), thiazolyl blue tetrazolium reduction (MTT) and lactate dehydrogenase (LDH) assays were also performed before and after photocatalytic ozonation to evaluate the potential estrogenic activity, the cellular metabolic activity and the cell viability. Compounds with estrogenic effects and significant differences concerning cell viability were not observed in any case. A slight cytotoxicity was only detected for Caco-2 and hCMEC/D3 cell lines after treatment of the urban wastewater, but not for L929 fibroblasts.info:eu-repo/semantics/acceptedVersio

Biofunctional nanofibrous substrate for local TNF-capturing as a strategy to control inflammation in arthritic joints

Rheumatoid arthritis (RA) is an autoimmune disease that affects the synovial cavity of joints, and its pathogenesis is associated with an increased expression of pro-inflammatory cytokines, namely tumour necrosis factor-alpha (TNF-α). It has been clinically shown to have an adequate response to systemic administration of TNF-α inhibitors, although with many shortcomings. To overcome such limitations, the immobilization of a TNF-α antibody on a nanofibrous substrate to promote a localized action is herein proposed. By using this approach, the antibody has its maximum therapeutic efficacy and a prolonged therapeutic benefit, avoiding the systemic side-effects associated with conventional biological agents’ therapies. To technically achieve such a purpose, the surface of electrospun nanofibers is initially activated and functionalized, allowing TNF-α antibody immobilization at a maximum concentration of 6 µg/mL. Experimental results evidence that the biofunctionalized nanofibrous substrate is effective in achieving a sustained capture of soluble TNF-α over time. Moreover, cell biology assays demonstrate that this system has no deleterious effect over human articular chondrocytes metabolism and activity. Therefore, the developed TNF-capturing system may represent a potential therapeutic approach for the local management of severely affected joints.This research was funded by the Portuguese Foundation for Science and Technology (FCT), namely the Post-doc fellowships of Marta Alves da Silva and Cristina Cunha (SFRH/BPD/73322/2010 and SFRH/BPD/96176/2013, respectively) and the Starting Investigator Grant of Agostinho Carvalho and Albino Martins (IF/00735/2014 and IF/00376/2014, respectively). It was also acknowledged the funded projects SPARTAN (PTDC/CTM-BIO/4388/2014) and FROnTHERA (NORTE-01-0145-FEDER-000023).info:eu-repo/semantics/publishedVersio

Induction of human mesenchymal stem cells osteogenesis by bioactive agent-releasing liposomes

Stem cell therapy is a rapidly evolving area of research in regenerative medicine. Mesenchymal stem cells (MSCs) have received considerable attention by the scientific community because of their potential of expansion and the ability to differentiate into various mesodermal tissues. Liposomes are well-established non-viral carrier systems, presenting significant advantages over other nanoparticle-based drug delivery systems, namely a high load carrying capacity, a relative safety and an ease of large-scale production, as well as a versatile nature in terms of possible formulation and functionalization. The objectives of the present study were to evaluate the efficacy of growth differentiation factor-releasing liposomes on the induction of MSCs osteogenesis. For that, dexamethasone (Dex) was encapsulated within the liposome bilayer at different lipid formulations. The obtained liposomes showed a monodisperse distribution of particles size, and an increased ζ- potential for the PEGylated liposomes. Dex encapsulation studies demonstrate that the presence of cholesterol (Chol) decreases the Dex loading capacity of the liposome bilayer. The different stabilizing effect of Chol and Dex on the liposomes is due to differences in their interaction with phospholipid molecules. Highly lipophilic Chol gets incorporated between the acyl chains and reduces chain movement increasing rigidity and stabilization the membrane. Dex, being more hydrophilic, interacts differently with phospholipid acyl chains and head groups and destabilizes the membrane. In vitro release study demonstrated an initial burst release within an initial timeframe of 24 hours. Following the initial release, a slower release was observed until 6 days. Afterwards, Dex continues to be released at a slower but steady rate until day 21. The effect of Dex-loaded liposomes on viability, proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) was assessed. The results of the biological activity showed that the Dex-loaded liposomes do not have any cytotoxic effect and, more importantly, were able to promote an earlier induction of hBMSCs differentiation into the osteogenic lineage, as demonstrated by the expression of osteoblastic markers at the phenotypic and the genotypic levels. Concluding, Dex-loaded liposomes represent a novel biological or nature-inspired nanoparticle strategy for tissue engineering and regenerative medicine applications

Air Travel Is Associated with Intracontinental Spread of Dengue Virus Serotypes 1–3 in Brazil

Dengue virus and its four serotypes (DENV-1 to DENV-4) infect 390 million people and are implicated in at least 25,000 deaths annually, with the largest disease burden in tropical and subtropical regions. We investigated the spatial dynamics of DENV-1, DENV-2 and DENV-3 in Brazil by applying a statistical framework to complete genome sequences. For all three serotypes, we estimated that the introduction of new lineages occurred within 7 to 10-year intervals. New lineages were most likely to be imported from the Caribbean region to the North and Northeast regions of Brazil, and then to disperse at a rate of approximately 0.5 km/day. Joint statistical analysis of evolutionary, epidemiological and ecological data indicates that aerial transportation of humans and/or vector mosquitoes, rather than Aedes aegypti infestation rates or geographical distances, determine dengue virus spread in Brazil