62,592 research outputs found

    Study for the development of 3D In vitro cell culture model for ovarian cancer

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    The discovery and development of new drugs is a very lengthy and costly process that can take up to 15 years and more than 2 billons dollars, where almost a third of the promising compounds fail during phase II and phase III clinical stages, due to poor efficacy and safety issues. The main reasons for drug failure are inappropriate preclinical testing methods and in vitro models, which do not sufficiently provide a correct prediction of drug efficacy and toxicity. Cell culture is the most influent process in drug discovery and cancer research but, since the majority of preliminary studies are carried on two-dimensional (2D) cultures, the discovery of new effective active principles and their approval is arduous. Indeed, these 2D models often yield misleading information for several reasons, chief among them being the lack of complexity due to the lack of intercellular interactions and physiologically relevant three-dimensional (3D) extracellular matrix. Novel and improved methods that implement the preclinical studies are therefore indispensably needed. 3D cell culturing techniques suggest compelling evidence that much more advanced experiments can be performed yielding valuable and more reliable insights. These cell culture systems allow reproducing more faithfully cells environment mimicking that in vivo and providing more accurate data about cell-to-cell interactions, cell-extracellular matrix (ECM) interactions, tumour morphology and protein expression, and a more realistic nutrients and drugs up-take, in which outer cell-layers are more exposed to them whereas internal layers are protected and in an almost quiescent state. To date, many 3D approaches exist, each providing different advantages and applications. Scaffold-based techniques, such as hydrogel-based support, are some of the 3D culture practices employed and display an array of benefits, such as mimicking the ECM and allowing soluble factors (e.g., nutrients, cytokines and growth factors) to travel through the tissue-like gel. This work aims to develop a 3D culture model for ovarian cancer, the 5th leading cause of cancer-related death among women. Research on this topic will allow to obtain reliable results in preclinical trials during the drug discovery process, in toxicity evaluations and many other fields of medicine and chemistry. Chitosan and alginate, two naturally-derived polymers with proven biocompatibility, have been used to fabricate 3D microstructured polyelectrolyte complex (mPEC) hydrogels using Computer-Aided Wet-Spinning (CAWS). This additive manufacturing technique allows precise control of the external geometry and macroporosity, determined by the deposition path of the polymeric fibre. 3D microstructured hydrogels based only on chitosan ionically crosslinked with tripolyphosphate (TPP) were also produced and investigated as reference samples to determine the influence of chemical composition on the scaffolds’ chemical-physical, mechanical, and biological properties. The degree of chitosan deacetylation was determined by means of Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). All scaffolds were morphologically assessed by means of scanning electron microscopy (SEM), whereas their chemical-physical properties were characterized by means of FT-IR analysis. The thermal properties were evaluated by means of thermogravimetric analysis (TGA) and DSC, thus determining the degradation temperature and the glass transition temperature (Tg). Hydrogels mechanical properties were also studied by means of tension and compression tests. Scaffold stability upon incubation in cell culture medium as also investigated. The obtained results suggested that they preserve their integrity up to 90 days of incubation at 37 °C, a feature that makes them suitable for long-term cell culture applications. The biological evaluation experiment has been set up to assess the proliferation and viability of human ovarian cancer cell lines A2780 in a period of 9 weeks long with WST-1 assay. The results showed a significantly higher viability of cells onto PEC scaffolds in comparison with chitosan-only structures, thus suggesting an important role of the chemical composition in guiding cell response

    Preparació de Vectors No Virals Ternaris per als Transtorns del Sistema Nerviós Central

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    Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2022, Tutors: Jordi Ignés-Mullol, Carlos Rodríguez-Abreu, Santiago Grijalvo TorrijoThe use of nanosystems for the treatment of brain disorders, like cancer, has emerged in recent years. In this project, a ternary system based on poly(lactic-co-glycolic acid) (PLGA), chitosan and 2’-deoxy-5-fluorouridine (FdU) has been engineered as a promising non-viral vehicle in which all the components interact via electrostatic forces. The goal is to find a strategy to transport FdU, which acts as a therapeutic molecule. We hypothesised that our system, owing to its nanometric properties, might go through the blood-brain barrier (BBB). A formulation composition in which the nanosystem is stable has been found, exhibiting a small diameter, low polydispersity index values and a positive ζ-potential. We demonstrated that tumour cells were able to take up our nanosystem, according to flow cytometry analyses. In addition, MTT assays indicate that the nanosystem displays certain degree of toxicity in cancer cells. Trans-Ferulic acid (FA) was encapsulated in PLGA NPs and 50% of the drug was released gradually after 9 hour

    Influence of surface active organic substances on electrochemical determination of copper complexing capacity in seawater

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    Kapacitet kompleksiranja bakra (KKCu) predstavlja sposobnost organskih molekula u prirodnim vodama da “vežu” određenu koncentraciju Cu2+ -iona u stabilne komplekse čime se regulira njihova biodostupnost. Metodom diferencijalo pulsne voltametrije anodnog otapanja uz viseću živinu kap kao radnu elektrodu definirani su uvjeti mjerenja (desorpcijski potencijal, Ed = −1,4 V i dodatak 1 mg dm−3 T-X-100) pri kojima je minimalan utjecaj adsorpcije organskih površinsko aktivnih tvari (BSA, kitozan, karagenan, alginat, dekstran, fulvična kiselina) na detekciju Cu2+ -iona. Optimalni uvjeti primijenjeni su za određivanje parametara KKCu u uzorcima postaje SJ101 (0 m i dno) uzorkovani u proljeće-ljeto 2017. godine u sjevernom Jadranu: određena su dva razreda liganada (12,0 − 71,5)x10−9 mol dm−3 i pripadajuće uvjetne konstanta stabilnosti (log K´ = 8,42 − 11,17). Koncentracije liganada su bile više u površinskom sloju tijekom ljetnih mjeseci kada je izraženija fitoplanktonska aktivnost.Copper complexing capacity (KKCu) represents the ability of organic molecules in natural waters to „bind“ a certain concentration of Cu2+ -ions in stable complexes, regulating their bioavailability. Using the differential pulse voltammetry method the measurement conditions were defined (desorption potential, Ed = −1.4 V, addition of 1 mg dm−3 T-X-100) under which the adsorption interference of organic surface-active substances (BSA, chitosan, carrageenan, alginate, dextran, fulvic acid) on the working electrode (mercury drop) is minimal for the detection of Cu2+ -ions. The optimal conditions were applied to determine the KKCu parameters in the samples from station SJ101 (0 m and bottom) sampled in the northern Adriatic Sea in spring/summer 2017: two classes of ligands were determined (12.0 − 71.5)x10−9 mol dm−3 and the corresponding conditional stability constants (log K´ = 8.42 − 11.17). The concentrations of ligands were higher in the surface layer during the summer months due to more pronounced phytoplankton activity

    Adhesive and biodegradable membranes made of sustainable catechol-functionalized marine collagen and chitosan

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    We describe bioadhesive membranes developed from marine renewable biomaterials, namely chitosan and collagen extracted from fish skins. Collagen was functionalized with catechol groups (Coll-Cat) to provide the membranes with superior adhesive properties in a wet environment and blended with chitosan to improve the mechanical properties. The blended membranes were compared to chitosan and chitosan blended with unmodified collagen in terms of surface morphology, wettability, weight loss, water uptake, mechanical and adhesive properties. The metabolic activity, the viability and the morphology of L929 fibroblastic cells seeded on these membranes were also assessed. Our results show that the functionalization with catechol groups improves the adhesive and mechanical properties of the membranes and enhances cell attachment and proliferation. These data suggest that the developed marine origin-raw membranes present a potential towards the restoration of the structural and functional properties of damaged soft tissues.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) and the European program FEDER/FEEI for the financial support through projects PTDC/BTM-MAT/28123/2017 and PTDC/NAN-MAT/31036/2017. FCT is also acknowledged for the Ph.D. scholarship SFRH/BD/143209/2019 granted to Catia ´ Correia. This article has been prepared with the support of REMIX Project, funded by the European Union’s Horizon 2020 Research and Innovation pro gramme under the Maria Sklodowska-Curie grant agreement n. 7

    Development of highly selective composite polymeric membranes for Li+/Mg2+ separation

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    Associate Laboratory for Green Chemistry-LAQV, which is financed by Portuguese national funds from FCT/MCTES (UID/QUI/50006/2019). This work was also supported by "Programa Operacional Regional de Lisboa, na componente FEDER" and "Fundacao para a Ciencia e Tecnologia, I.P." through research project PTDC/EQU-EPQ/29579/2017. S. Pawlowski acknowledges Fundacao para a Ciencia e Tecnologia, I.P. for his contracts CEECIND/01617/2017 and CEECIND/00340/2018. iNOVA4Health UIDB/Multi/04462/2020, a program financially supported by Fundacao para a Ciencia e Tecnologia is acknowledged. Funding from INTERFACE Programme, through the Innovation, Technology and Circular Economy Fund (FITEC), is also gratefully acknowledged. The authors acknowledge Professor Vitor D. Alves, from Instituto Superior de Agronomia, Universidade de Lisboa, for the support to analysing mechanical properties.To meet the exponentially rising demand for lithium, it becomes vital to develop environmentally friendly processes for its recovery from brines, salt lakes and/or seawater. In this work, novel composite lithium transport selective polymeric membranes were developed to separate lithium and magnesium ions. Hydrogen manganese oxide (HMO) (at weight percentage from 0 to 25%), polystyrene sulfonate sodium salt (PSS–Na) and lithium triflate (LiCF3SO3) were added into the sulfonated polyethersulfone (SPES) matrix to prepare composite membranes. The developed membranes showed high mechanical stability and a homogeneous distribution of HMO. The most promising membrane, containing 20% (w/w) of HMO, showed an almost 13 times higher Li+ ionic conductivity (8.28 mS/cm) compared to the control composite membrane (without HMO) and an average ideal selectivity of 11.75 for the Li+/Mg2+ pair. The composite-20% membrane had the lowest intermolecular distance between the polymer chains (according to X-ray diffraction (XRD) analysis), the most flexible structure (lowest Tg) and showed the homogeneous dispersion of HMO (SEM images), which explains its highest Li+/Mg2+ selectivity among the tested membranes. The lithium ion transport performance and separation efficiency were investigated through diffusion dialysis experiments, under different operating conditions. A binary separation factor of 9.10 for Li+/Mg2+ and Li+ molar flux of 0.026 mol/(m2.h) was achieved without applying any external potential difference. When an external potential difference of 0.2 V was applied, the binary separation factor of Li+/Mg2+ pair was 5, while the Li+ molar flux increased almost 5 times. The obtained results provide the basis to design and develop composite lithium transport selective polymeric membranes, thus representing a promising step for future implementation of such membranes to recover lithium from saline streams.preprintauthorsversionpublishe

    Study of scaffold based 3D in vitro cell culture model for ovarian cancer

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    The discovery and development of new drugs is a very lengthy and costly process that ranges between 800millionand800 million and 2 billion and can take up to 15 years, where almost a third of the promising compounds fail during phase II and phase III clinical stages, due to poor efficacy and safety issues. One of the main reasons for drug failure is inappropriate preclinical testing methods and in vitro models, which do not sufficiently produce information for prediction of drug efficacy and toxicity. Cell culture is an important and necessary, if not the most influent, process in drug discovery and cancer research but, since most research studies are still carried on two-dimensional (2D) cultures, the disclosure of new effective molecules and their approval is arduous. Novel and improved methods that implement this process are therefore indispensably needful. Three-dimensional (3D) cell culturing techniques suggest compelling evidence that much more advanced experiments can be performed yielding valuable and more reliable insights. This cell culture system allows reproducing more faithfully the cell environment mimicking that of a cell in vivo and providing more accurate data about cell-to-cell interactions, tumour characteristics, drug discovery and other types of diseases. To date many three-dimensional approaches exist, each providing their own advantages and applications. Scaffold based techniques, such as hydrogel-based support, are some of the 3D culture practice employed and present an array of benefits. 3D hydrogel scaffolds are unique because of their ability to mimic the extracellular matrix (ECM) while allowing soluble factors such as cytokines and growth factors to travel through the tissue-like gel. The present research activity has been performed under a multidisciplinary approach that combines polymer chemistry, additive manufacturing and biology with the purpose of developing a 3D cell culture model for ovarian cancer that will allow, with further studies, to enhance and obtain more reliable results in drug discovery, toxicity evaluations and many other fields of medicine and chemistry. Two natural polymers, namely Chitosan and Alginate, were chosen for their proven biocompatibility, opposite charge at physiological pH and ready availability from renewable and sustainable sources, as matrices for the development of 3D Microstructured Polyelectrolyte Complex (mPECs) Hydrogels. The samples were fabricated employing additive manufacturing techniques that compared to conventional techniques, allow for a fine control of the external geometry and macro and microporosity of the polymeric structure, leading to the obtainment of customizable shapes and above all reproducible samples. Chitosan and Alginate were used in a mixture, to create hydrogels for the manufacture of microstructured scaffolds by means of Computer-Aided Wet-Spinning (CAWS). The CAWS technique is an additive manufacturing technique which, starting from polymer solutions or suspensions, allows to obtain structures with a multiscale porosity characterized by a macro-porous network, determined by the path of deposition of the polymeric fibre, and by a micro or nano- porosity, determined by the phase separation process induced by non-solvent which is at the basis of the solidification of the material. With this technique, scaffolds were manufactured with different compositions of the polymer blend of the two natural polysaccharides and the manufacturing parameters were optimized for each composition. 3D microstructure hydrogel based only on Chitosan ionically crosslinked with tripolyphophate (TPP) was also prepared by CAWS, in order to compare the influence of hydrogel composition on the physical-chemical, mechanical and biological features of the systems. The swelling degree of the manufactured scaffolds was evaluated in physiological conditions, and the results suggested the presence of a diffuse and interconnected porous structure that further studies, to be preformed by scanning electron microscopy, will have to confirm. Furthermore, all fabricated the scaffolds preserved their physical integrity after a long period of incubation up to 21 days, a feature that can possibly make them suitable for the employment for long-term cell culture applications. The biological evaluation of the developed 3D Hydrogels was started by analysing the cell adhesion response of the human ovarian cancer cell line A2780. The obtained results showed a significantly higher adhesion of cell onto the mPECs containing Chitosan and Alginate with respect to the hydrogels prepared with Chitosan only, thus suggesting an important role of the chemical composition in guiding cell response. Ongoing studies are devoted to assess cell proliferation and to investigate the influence of chemical composition on the physical-chemical and mechanical properties of the samples and to correlate such feature to cell response

    Comparison between essential oils and supercritical extracts into chitosan-based edible coatings on strawberry quality during cold storage

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    Plant extracts are being studied in the development of novel edible food coatings. The antioxidant and antimicrobial compounds that naturally occur in some plants are the key substances that contribute to preserving food quality. Besides the plant material, the method utilized to produce the extract influences its chemical and preservative characteristics. In general, hydrodistillation produce plant products (essential oils) that are well recognized for containing high concentration of antioxidant or antimicrobial volatile compounds. Supercritical fluid technology produces high quality bioactive extracts with higher yield but lower concentration of volatile compounds, in comparison with hydrodistillation. In this work, six different natural extracts of five different plants were produced by hydrodistillation and supercritical fluid extraction, and their antioxidant and antimicrobial activities were compared. The most active extracts were used to produce chitosan-based edible coatings with the aim of assessing the effect of essential oils versus supercritical extracts on the preservation of strawberriesThe authors gratefully acknowledge the financial support from Comunidad de Madrid through the Programa de I+D en Tecnologías, Spain (ALIBIRD-CM S2013/ABI-2728). Somaris E. Quintana is grateful for the funding provided by Gobernación de Bolivar and Fundación Ceiba, Colombia. Olimpia Llalla is grateful to Programa Nacional de Innovación Agraria-PNIS of Perú (Contract No. 152-2018-INIA-PNIAPASANTIA

    Laser-induced breakdown spectroscopy analysis of copper and nickel in chelating resins for metal recovery in wastewater

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    Recovery of heavy metals from industrial waste streams is becoming an important challenge due to increasing wastewater production. Chelating resins provide an effective treatment for selective adsorption of metals. Several analytical techniques can be used to assess the adsorption performance, but LIBS offers the unique advantage of in-process continuous monitoring. In this work, LIBS measurements of copper and nickel spectra were performed on single and bi-component resin samples. Single component calibration curves for copper and nickel were obtained with high correlation (R2 = 0.99 and R2 = 0.98 respectively). Bi-component resin measurements reveal good prediction accuracy for nickel and copper concentrations, the mean relative error in concentration prediction being 4.69% and 7.98% respectively. From the calibration curves, the prediction of concentration shows a high correlation with the real values (R2 = 0.99 for copper and 0.98 for nickel).This research was developed in the framework of the projects TEC2016-76021-C2-2-R (AEI/FEDER, UE), PID2019-107270RB-C21/AEI/10.13039/501100011033, CTM2017-87740-R, RTI2018-093310-B-I00 and grant BES-2017-080076, all financed by the Spanish Ministry of Science, Innovation and Universities

    Uji Aktivitas Antidiabetes Kombinasi Ekstrak Terstandar Daun Salam (Syzigium polyanthum Walp.) dan Daun Ganitri (Elaeocarpus ganitri Roxb.) Pada Tikus Putih (Rattus norvegicus) Jantan Galur Wistar yang Diinduksi Streptozotosin

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    Diabetes melitus merupakan penyakit yang ditandai dengan keadaan kadar gula darah melebihi normal. Pengobatan antidiabetikum oral dalam jangka waktu yang panjang dapat mengakibatkan resistensi dan menimbulkan efek samping. Penggunaan obat tradisional dari tanaman dapat dijadikan salah satu alternatif pengobatan dari bahan alam yang memiliki efek samping rendah. Tanaman yang dapat berkhasiat sebagai antiabetes yaitu daun ganitri dan daun salam. Tujuan penelitian ini adalah mendapakan variasi dosis yang paling efektif pada kombinasi dua bahan alam yang berpontensi sebagai kandidat obat antidiabetes yang lebih aman dan efek lebih baik sehingga dapat dijadikan alternatif pengobatan. Metode penelitian ini berisfat eksperimental dengan menggunakan hewan uji berjumlah 36 ekor tikus (Rattus norvegicus) dibagi menjadi 9 kelompok uji kontrol sehat, kontrol +, kontrol -, K1 dosis 100 mg, K2 dosis 62,5 mg, K3 dosis 100 mg:62,5 mg, K4 dosis 50 mg:31,2mg, K5 dosis 100 mg:31,2mg, K6 dosis 50mg:62,5 mg. Hewan uji dibuat diabetes diabetes melitus dengan diinduksi streptozotosin 40 mg/kgBB secara ip, pengukuran glukosa darah dilakukan tiap 7 hari selama 14 hari perlakuan menggunakan alat glukometer. Hasil penelitian kombinasi EADG dosis 100 mg/kgBB dan EEDS 62,5 mg/kgBB (kelompok kontrol 3) setelah 14 hari menunjukan penurunan glukosa darah yang signifikan. Kesimpulan kombinasi ekstrak akuades daun ganitri dan ekstrak etanol daun salam memiliki efek menurunkan kadar glukosa darah lebih baik dibandingkan dengan glimepiride (Amaryl 0,036 mg/kgBB)

    Synthesis and Characterization of Hydrogel-Based Hyaluronic Acid-Chitosan-Allium sativum Extract for Intraperitoneal Antiadhesion Application

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    Peritoneal Adhesion is a severe case that frequently occurs in patients after laparotomy surgery. Adhesions are pathological attachment that usually appears between the omentum, intestine, and abdominal wall. Several barriers are made to prevent adhesions, including liquid barriers such as sodium hyaluronate and carboxymethyl cellulose (CMC) but are fast absorbed-time hydrogel. The solid barrier has weakness of difficulty in covering all parts of the wound surface. The study aims to synthesize degradable hydrogel from N,O-Carboxymethyl Chitosan (NOCC), Aldehyde-Hyaluronic Acid, and the addition of Allium sativum (garlic oil). The best sample with the concentration of A-HA/NOCC 30 : 10 g/ml was obtained. The composite hydrogel of NOCC/AHA/Allium sativum has susceptible antimicrobial properties. In vitro cytotoxicity assay showed that hydrogel is nontoxic. The degradation time is for two weeks. The in vivo evaluation in a mouse model with an abrasion defect side was done to identify the effectiveness of the NOCC/AHA/A. sativum as antiperitoneal adhesion. Seven days after surgery, the observation of adhesion was performed. Based on all assay results, it can be resumed that the NOCC/AHA/A. sativum hydrogel possibly acts as an innovation to prevent postoperative intraperitoneal adhesion