Effect of crosslinking in chitosan/aloe vera-based membranes for biomedical applications

The  positive  interaction  between  polysaccharides  with  active  phytochemicals found  in  medicinal  plants  may  represent  a  strategy  to  create  active  wound dressing  materials  useful  for  skin  repair.  In  the  present  work,  blended membranes  composed  of  chitosan  (Cht)  and  Aloe  vera  gel  were  prepared through the solvent casting, and were crosslinked with genipin to improve their properties. Topography, swelling, wettability, mechanical properties and in vitro cellular response of the membranes were investigated. With the incorporation of aloe  vera  gel  into  chitosan  solution,  the  developed  chitosan/aloe-based membranes  displayed  increased  roughness  and  wettability;  while  the  genipin crosslinking  promoted  the  formation  of  stiffer  membranes  in  comparison  to those  of  the  non-modified  membranes.  Moreover, in  vitro cell  culture  studies evidenced that the L929 cells have high cell viability, confirmed by MTS test and calcein-AM staining. The findings suggested that both blend compositions and crosslinking  affected  the  physico-chemical  properties  and  cellular  behavior  of the developed membranes.The authors acknowledge financial support from Portuguese Foundation for Science and Technology - FCT (Grant SFRH/BPD/45307/2008; SFRH/BD/64601/2009), "Fundo Social Europeu" - FSE, and "Programa Diferencial de Potencial Humano - POPH". This work was partially supported by the FEDER through POCTEP 0330_IBEROMARE_1_P

Fucoidan-based hydrogels particles as versatile carriers for diabetes treatment strategies

There is a current lack of fully efficient therapies for diabetes mel-litus, a chronic disease where the metabolism of blood glucose isseverely hindered by a deficit in insulin or cell resistance to thishormone. Therefore, it is crucial to develop new therapeutic strat-egies to treat this disease, including devices for the controlleddelivery of insulin or encapsulation of insulin-producing cells. Inthis work, fucoidan (Fu)â a marine sulfated polysaccharide exhib-iting relevant properties on reducing blood glucose and antioxi-dant and anti-inflammatory effectsâ was used for thedevelopment of versatile carriers envisaging diabetes advancedtherapies. Fu was functionalized by methacrylation (MFu) using8% and 12% (v/v) of methacrylic anhydride and further photo-crosslinked using visible light in the presence of triethanolamineand eosin-y to produce hydrogel particles. Degree of methacryla-tion varied between 2.78 and 6.50, as determined by1HNMR, andthe produced particles have an average diameter ranging from0.63 to 1.3mm (dry state). Insulin (5%) was added to MFu solutionto produce drug-loaded particles and the release profile wasassessed in phosphate buffer solution (PBS) and simulated intes-tinal fluid (SIF) for 24h. Insulin was released in a sustained man-ner during the initial 8 h, reaching then a plateau, higher in PBSthan in SIF, indicating that lower pH favors drug liberation.Moreover, the ability of MFu particles to serve as templates forthe culture of human pancreatic cells was assessed using 1.1B4cell line during up to 7 days. During the culture period studied,pancreatic beta cells were proliferating, with a global viabilityover 80% and tend to form pseudo-islets, thus suggesting thatthe proposed biomaterial could be a good candidate as versatilecarrier for diabetes treatment as they sustain the release of insulinand support pancreatic beta cells viability.We acknowledge ERDF for the financial support through POCTEP Project 0687_NOVOMAR_1_P, under the scope of INTERREG 2007-2013, and project 0302_CVMAR_I_1_P, under the scope of INTERREG Espana-Portugal 2014-2020, and Structured Projects NORTE-01-0145-FEDER-000021, NORTE-01-0145-FEDER-000023 and ATLANTIDA (ref. NORTE-01–0145-FEDER-000040), under the scope of Programa Operacional Regional do Norte (Norte 2020). Funding from the Portuguese Foundation for Science and Technology for doctoral grant (SFRH/BD/112139/2015) and post-doctoral grant (SFRH/BPD/85790/2012) is also acknowledge

Marine-derived polymers in ionic liquids: architectures development and biomedical applications

Marine resources have considerable potential to develop high-value materials for applications in different fields, namely pharmaceutical, environmental, and biomedical. Despite that, the lack of solubility of marine-derived polymers in water and common organic solvents could restrict their applications. In the last years, ionic liquids (ILs) have emerged as platforms able to overcome those drawbacks, opening many routes to enlarge the use of marine-derived polymers as biomaterials, among other applications. From this perspective, ILs can be used as an efficient extraction media for polysaccharides from marine microalgae and wastes (e.g., crab shells, squid, and skeletons) or as solvents to process them in different shapes, such as films, hydrogels, nano/microparticles, and scaffolds. The resulting architectures can be applied in wound repair, bone regeneration, or gene and drug delivery systems. This review is focused on the recent research on the applications of ILs as processing platforms of biomaterials derived from marine polymers.FCT (JMG, PD/BD/135247/2017 and LCR, SFRH/BPD/93697/2013). This work was also financially supported by a PhD programme in Advanced Therapies for Health (PATH) (PD/00169/2013); FCT R&D&I projects with references PTDC/BII‐BIO/31570/2017, PTDC/CTM‐CTM/29813/2017 and PTDC/CTM‐BIO/4706/2014‐(POCI‐01‐0145‐ FEDER‐016716) and R&D&I Structured Projects with reference NORTE‐01‐0145‐FDER‐00002

Using ensembles of artificial neural networks to improve PM10 forecasts

High concentrations of atmospheric pollutants provoke negative effects that range from respiratory problems in humans to altered growth in crops due to the reduction of solar radiation. In this context, the study of suspended particulate matter (PM) in the atmosphere is especially relevant. Several works in the literature are dedicated to evaluate PM impacts and to develop models to forecast PM concentrations. Among these models, artificial neural networks (ANNs) are often employed mainly due to the facts that they are capable of learning from a set of training data samples and that they are known to be universal function approximators. However, most ANN training algorithms are susceptible to initial conditions, so the resulting models of distinct training phases may present different accuracies for the same problem. It is known from the machine learning literature that the ensemble approach, which basically combines a set of slightly different high-accuracy predictors, tends to lead to more accurate forecasts. Therefore, in this paper an ensemble of ANNs is proposed to forecast the daily concentrations of PM10 (phi <= 10 mu m) in the city of Piracicaba, Brazil. The ensemble was trained with daily samples collected from 07.2009 to 06.2013 and evaluated with one-day-ahead forecasts from 07.2013 to 06.2014. Experiments with distinct ANN configurations were made and an average reduction of 8.85 % was obtained in the Mean Squared Error. The ensembles were compared to individual ANNs that led to the best accuracy in the training dataset. It was also verified that, when compared to distinct single ANNs, the ensemble-based approach facilitated the generation of high accuracy models, as it increased the robustness of the development process. It is important to highlight that the proposed approach can be directly applied to other scenarios related to the prediction of PM concentrations, such as different atmospheric pollutants and meteorological data.High concentrations of atmospheric pollutants provoke negative effects that range from respiratory problems in humans to altered growth in crops due to the reduction of solar radiation. In this context, the study of suspended particulate matter (PM) in th4321612166sem informaçãosem informaçã

Improved estimation of inbreeding and kinship in pigs using optimized SNP panels

BACKGROUND: Traditional breeding programs consider an average pairwise kinship between sibs. Based on pedigree information, the relationship matrix is used for genetic evaluations disregarding variation due to Mendelian sampling. Therefore, inbreeding and kinship coefficients are either over or underestimated resulting in reduction of accuracy of genetic evaluations and genetic progress. Single nucleotide polymorphism (SNPs) can be used to estimate pairwise kinship and individual inbreeding more accurately. The aim of this study was to optimize the selection of markers and determine the required number of SNPs for estimation of kinship and inbreeding. RESULTS: A total of 1,565 animals from three commercial pig populations were analyzed for 28,740 SNPs from the PorcineSNP60 Beadchip. Mean genomic inbreeding was higher than pedigree-based estimates in lines 2 and 3, but lower in line 1. As expected, a larger variation of genomic kinship estimates was observed for half and full sibs than for pedigree-based kinship reflecting Mendelian sampling. Genomic kinship between father-offspring pairs was lower (0.23) than the estimate based on pedigree (0.26). Bootstrap analyses using six reduced SNP panels (n = 500, 1000, 1500, 2000, 2500 and 3000) showed that 2,000 SNPs were able to reproduce the results very close to those obtained using the full set of unlinked markers (n = 7,984-10,235) with high correlations (inbreeding r > 0.82 and kinship r > 0.96) and low variation between different sets with the same number of SNPs. CONCLUSIONS: Variation of kinship between sibs due to Mendelian sampling is better captured using genomic information than the pedigree-based method. Therefore, the reduced sets of SNPs could generate more accurate kinship coefficients between sibs than the pedigree-based method. Variation of genomic kinship of father-offspring pairs is recommended as a parameter to determine accuracy of the method rather than correlation with pedigree-based estimates. Inbreeding and kinship coefficients can be estimated with high accuracy using ≥2,000 unlinked SNPs within all three commercial pig lines evaluated. However, a larger number of SNPs might be necessary in other populations or across lines

Hybrid biodegradable membranes of silane-treated chitosan/soy protein for biomedical applications

In recent years, progress in the field of hybrid materials has been accelerated through use of the sol–gel process for creating materials and devices, which benefit from the incorporation of both inorganic and organic components. In this work, organic–inorganic hybrid membranes were prepared from tetraethoxysilane and a blend system composed of chitosan and soy protein. By introducing a small amount of siloxane bond into the chitosan/soy protein system, the chitosan/soy protein hybrid membranes were improved in terms of structure, topography and mechanical properties. It appears that the chitosan/soy protein hybrid membranes were formed by discrete inorganic moieties entrapped in the chitosan/soy protein blend, which improved the stability and mechanical performance assessed by the dynamic mechanical analysis as compared to chitosan/soy protein membrane. Also, in vitro cell culture studies evidenced that the chitosan/soy protein hybrid membranes are non-cytotoxic over a mouse fibroblast-like cell line. The hybrid membranes of silane-treated chitosan/soy protein developed in this work have potential in biomedical applications, including tissue engineering.This work was financially supported by the Portuguese Foundation for Science and Technology - FCT (Grant SFRH/BPD/45307/2008, SFRH/BPD/21786/2009, SFRH/BPD/39331/2007 and SFRH/BD/64601/2009), 'Fundo Social Europeu' - FSE and 'Programa Diferencial de Potencial Humano - POPH' and was partially supported by the FEDER through POCTEP 0330_IBEROMARE_1_P

Cell adhesion and proliferation onto chitosan-based membranes treated by plasma surface modification

Surface properties play a vita role in the functioning of a biomaterial. Cellular adherence and growth onto biomaterials can be enhanced in biomaterial modifications of their surface. In this work, the cell behaviour on chitosan membranes modified by argon and nitron-plasma treatments was investigated. Characterization of the membranes was performed using atomic force microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. Cytotoxicity assessment and direct contact assay were carried out for untreated and treated chitosan membranes using L929 fibroblast-like cells. Cell morphology and cell viability were assessed to evaluate the cell attachment and proliferation. Changes in terms of roughness, surface chemistry, and hydrophilicity/hydrophobic balance of chitosan-modified membranes were observed. Regarding cell studies, the findings revealed that the extracts of all membranes do not induce cytotoxicity effects. Moreover, the in vitro assays evidenced an improvement of the L929 adhesion, and attachment when compared to untreated chitosan membranes. overall, the data obtained clearly demonstrated that plasma treatments constitute an effective way of improving the biocompatibility of chitosan membranes towards to their use in biomedical applications.S. M. Luna acknowledges the support of the Programme Alssan - The European Union Programme of High Level Scholarships for Latin America (scholarship No E04M041362CO) and Silva SS acknowledge the support of the Portuguese Foundation for Science and Technology, (SFRH/BPD/45307/2008). This work was also partially supported by the European Union-funded - STREP project HIPPOCRATES (NMP3-CT-2003-505758) and was carried out under the scope of European NoE EXPERTISSUES (NMP3-CT-2004-500283)

3-(2,4-Dibromo­anilino)-2,2-dimethyl-2,3-dihydro­naphtho[1,2-b]furan-4,5-dione: a new substituted aryl­amino nor-β-lapachone derivative

The title compound, C20H15Br2NO3, shows the furan ring to adopt a half-chair conformation and the two ring systems to be approximately perpendicular [dihedral angle = 71.0 (2)°]. In the crystal structure, inter­molecular C—H⋯O contacts link the mol­ecules

Tailoring natural-based oleogels combining ethylcellulose and virgin coconut oil

Oleogels are becoming an attractive research field, since they have recently been shown to be feasible for the food and pharmaceutical sectors and provided some insights into the biomedical area. In this work, edible oleogels were tailored through the combination of ethylcellulose (EC), a gelling agent, with virgin coconut oil (VCO), vegetable oil derived from coconut. The influence of the different EC and VCO ratios on the structural, physical, and thermal properties of the oleogels was studied. All EC/VCO-based oleogels presented a stable network with a viscoelastic nature, adequate structural stability, modulable stiffness, high oil-binding capability, antioxidant activity, and good thermal stability, evidencing the EC and VCOâ s good compatibility.The authors acknowledge financial support from the Portuguese FCT (SFRH/BPD/93697/2013, and CEECIND/01306/2018). This work is also financially supported by the FCT R&D&I projects with references POCI-01-0145-FEDER-029813 (PTDC/CTM-CTM/29813/2017), POCI-01-0145-FEDER-031570 (PTDC/BII-BIO/31570/2017), and TERM RES Hub, Ref Norte-01-0145-FEDER-02219015