Monografias, Dissertações e Teses
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Item Membranas eletrofiadas a partir de poliácido láctico e mesocarpo de buriti (Mauritia flexuosa): produção, caracterização e potencial antimicrobiano(Universidade Brasil, 2022) Furtado, Dênis Rômulo Leite; Costa, Adriana Pavinatto da; Rodrigues, Bruno Vinícius ManzolliMedicinal plants have always been widely used as a preventive or curative form for diseases. Among them, we can mention buriti, a fruit widely used in folk medicine for the treatment of dermatological diseases, wound healing and as an antimicrobial agent. After the emergence of nanotechnology, the development of biomaterials that associate different materials, including medicinal plants, has been growing a lot. Among the nanostructuring techniques used, electrospinning stands out for producing membranes at nanometer scales with interesting properties for biomedical applications. In this context, the objective of this work was to produce, characterize and evaluate the antimicrobial activity of electrospun membranes formed from poly(lactic acid) (PLA) and buriti mesocarp (Mauritia flexuosa) (MESOBU). The membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared absorption spectroscopy (FTIR) and contact angle measurements. Antimicrobial evaluation (in vitro), was performed using bacterial Staphylococcus aureus, Pseudomonas aeruginosa and Echerichia coli, as well as Candida albicans fungus, using disk diffusion and microdilution methods.The data obtained were analyzed in a statistical program Graphpad Prism software, version 8.0.1, considering a significance level of 5% (p < 0.05). SEM images demonstrated the formation of homogeneous fibers, randomly organized and without the presence of defects. The FTIR spectra showed the main vibrational bands for chemical groups forming PLA, and hydrophilicity measurements show that the formed membranes have hydrophobic characteristics. In the disk diffusion and microdilution test, the PLAMESOBU 1% membrane showed antimicrobial activity against all tested microorganisms; the PLAMESOBU 0.5% membrane only showed antimicrobial activity in the microdilution test. In view of the observed results, PLAMESOBU membranes showed a promising potential for use as a biomaterial.Item Sensores eletroquímicos a base de policaprolactona/óxido de grafeno a partir de fontes de matéria-prima biodegradáveis(Universidade Brasil, 2020) Furquim, Fabiana Cristina; Rodrigues, Bruno Vinícius Manzolli; Costa, Adriana Pavinatto daEndocrine disrupting compounds (EDCs) represent a class of harmful substances for living organisms due to its ability to disrupting the human and animal endocrine hormonal system. Among several EDCs, a xenobiotic known as Bisphenol A (BPA; 4,4'-dihydroxy-2,2-diphenylpropane) has become a crucial public health problem in the last few years. BPA is an organic compound that has been widely used in plastic food packaging, children's toys and even medical materials, and it has been now considered an emerging pollutant capable of causing damage to living organisms, especially in the endocrine system, even at low concentrations (1 pM). In this context, aiming at the detection and quantification of BPA, different methods have been proposed in the last years focusing on simple and reliable strategies. In the last decade, the use of electrospinning technique for the design of sensors/sensory platforms has stood out due to the possibility of producing ultrathin polymeric fiber networks (100 nm < diameter < 1000 nm) and nanofibers (diameter < 100 nm) in a relatively simple and versatile way. The generation of polymeric fibers in these dimensions has a huge influence on the sensitivity of the final devices, due to the improvement of the interconnectivity and increase of the surface area. In addition, electrospinning technique allows the incorporation of chemically functional compounds to the fibers, such as graphene and its derivatives, which may expand and/or maximize the properties of the final materials. Thus, the present work approached the development of a nanostructured electrochemical sensor for the detection of Bisphenol A, based on a sustainable and low-cost route. The design of this sensory platform was based on the electrospinning of a low cost and biodegradable polyester, name polycaprolactone (PCL), with the combination of this material with graphene derivatives (graphene oxide - GO and graphene quantum dots - GQDs) obtained from the complete or incomplete carbonization of citric acid. The incorporation of these derivatives was considered in two ways: i) direct addition to the polymeric solution, before electrospinning process; ii) adsorption of the derivatives directly to the surface of electrospun PCL membranes. Among the tested platforms, the nanomaterials produced from PCL (5 min of electrospinning) on a glass substrate coated with tin oxide and doped with fluorine (FTO), using a voltage of 10kV, and swollen in GO solution for 3 h [adsorption process, ii)], presented higher current intensity, verified by cyclic voltammetry analyzes. Therefore, this platform was chosen for further testing aiming at BPA detection. The sensors revealed a high sensitivity for BPA with a very low detection limit of approximately 23 nM. In addition, the sensors showed good reproducibility, with a relative standard deviation (RSD) of 7.9%, while the sensor's response to 2 µM BPA was 5.7% for seven successive measurements. These results open up a window of applications for this nanostructured material, due to the easy combination of a biodegradable polyester with GO obtained through a sustainable and low-cost process.Item Produção, caracterização e avaliação microbiológica de nanofibras eletrofiadas formadas por blendas de PLA e Copaíba (C. Luetzelburgii Harms)(Universidade Brasil, 2022) Sousa, Janayna Batista Barbosa de; Costa, Adriana Pavinatto da; Rodrigues, Bruno Vinícius ManzolliThe interest of the medical-pharmaceutical industry in the production and use of biomaterials is increasing. These can originate from natural macromolecules (biopolymers) or synthetically or semi-synthetically. However, when replacing or filling defective or even nonfunctional body parts, they must perform their role in the safest way possible, due to the intimate contact with membranes, cells and tissues. The objective of this study was to produce a biomaterial from poly(lactic acid) (PLA) associated with copaiba extract (Copaifer luetzelburgii), here identified by EC, at concnetrations of 0.5 and 1.0% and to verify some of its physicochemical and antimicrobial properties. To characterize the properties, analysis of absorption spectroscopy in the infrared region (FTIR) and contact angle test (AC) were performed). For antimicrobial test, 6 mm diameter discs of electrospun material PLA+EC (PLAEC) were seeded at concentrations of 0.5% and 1% in plates, in the presence of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Enterococus fecalis and Candida albicans. All microorganisms were seeded on Mueller Hinton agar and then PLAEC discs were added to the medium. PLA disks were used as a negative control and standard antibiotics (antibiogram method): amikacin for gram-negative bacteria and teicoplamin for gram-positive bacteria, and all samples were subjected to ultraviolet radiation for 90 min in an appropriate oven, in order to avoid any type of contamination. The FTIR spectra showed the main vibrational for chemical groups forming PLA and hydrophilicity measurements show that all membranes formed have hydrophobic characteristics. All PLAEC samples proved to be effective against all mentioned microorganisms, in both concentrations tested. Based on the results, it is suggested that the studied biomaterial is promising for clinical use, in infectious processes, serving as an alternative in the antimicrobial choice.