Modification of filter medium with nanomaterials to control bioaerosols

People are increasingly wasting their time in indoors environments, in these locations there is a risk of contagion from diseases transmitted by the airways, due to low rates of air exchange. Thus, the number of causative agents of various diseases airborne spreads more rapidly, increasing cases of respiratory problems. Therefore, controlling the microorganisms present in indoor environments has become extremely necessary. An alternative is to develop filters for air conditioners, laminar flow hoods, and clean room exhausts that have antimicrobial properties. There are numerous materials that have an action against fungi and bacteria, among them silver and titanium dioxide. By combining these two materials a composite can be formed which is expected to have a synergistic effect. Thus, this thesis had as main objective the development of modified filter media with those nanomaterials that present antimicrobial capacity. After the modification of the filters, adhesion strength analyzes and peel velocity calculations between the nanomaterials and the fibers were done in order to ensure that they are not released into the environment. The results showed that the inhibition in the real environment was 55.6 ± 9.52, 72.2 ± 4.81 and 81.1 ± 1.92%, adhesion forces 3.44, 14.32 and 12, 24 nN and the average velocities required to release the nanomaterials of 125.2, 46.8 and 35.7 m / s for the silver, titanium dioxide and Ag/TiO2 nanoparticles respectively. These data suggest a considerable decrease in the number of microorganisms when using filters modified with these nanomaterials and have shown that the particles are removed at different speeds. However, with the results obtained it was not possible to point to a filter that satisfies all the evaluated parameters. The Ag/TiO2 modified filter showed greater inhibition capacity of the microorganisms, however, this material can be removed at lower speeds when compared to the other materials. The silver filter has the lowest inhibition rates, but high velocities are required to remove the particles adhered to it. Thus, the most appropriate filter is one that satisfies the operating conditions of the equipment on which it will be used.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)As pessoas consomem cada vez mais o seu tempo em ambientes fechados, e nestes ambientes eleva-se o risco de contágio por doenças transmitidas pelas vias aéreas, devido a baixas taxas de troca de ar. Assim, o número de agentes causadores de várias doenças veiculados pelo ar se propaga mais rapidamente, aumentando os casos de problemas respiratórios. Portanto, controlar os microrganismos presentes nos ambientes internos tornou-se extremamente necessário. Uma alternativa é desenvolver filtros para aparelhos de ar condicionados, capelas de fluxos laminares e exaustões de salas limpas que tenham propriedades antimicrobianas. Existem inúmeros materiais que possuem ação frente a fungos e bactérias, dentre eles a prata e o dióxido de titânio. Com a combinação destes dois materiais pode-se formar um compósito que se espera ter um efeito sinérgico. Assim, esta tese teve como principal objetivo o desenvolvimento de meios filtrantes modificados com esses nanomateriais que apresentam capacidade antimicrobiana. Após a modificação dos filtros, foram feitas análises da força de adesão e os cálculos de velocidade de desprendimento entre os nanomateriais e as fibras, com o intuito de garantir o não carregamento dos materiais para o ambiente. Os resultados mostraram que a inibição em ambiente real foi de 55,6 ±9,52, 72,2±4,81 e 81,1±1,92%, as forças de adesão 3,44, 14,32 e 12,24 nN e as velocidades médias necessárias para desprender os nanomateriais de 125,2, 46,8 e 35,7 m/s para a os filtros de prata, dióxido de titânio e nanocompósito Ag/TiO2 respectivamente. Estes dados sugerem uma diminuição considerável no número de microrganismos quando se usam filtros modificados com estes nanomateriais e demonstraram que as partículas são removidas a diferentes velocidades. No entanto, com os resultados obtidos não foi possível apontar para um filtro que satisfaça todos os parâmetros avaliados. O filtro modificado com Ag/TiO2 apresentou maior poder de inibição dos microrganismos, no entanto, este material pode ser removido com velocidades mais baixas quando comparado com os outros materiais. O filtro de prata apresentou as menores taxas de inibição, mas são necessárias altas velocidades para remover as partículas aderidas a ele. Assim, o filtro mais adequado será aquele que satisfizer as condições operacionais do equipamento no qual ele será utilizado.FAPESP: 2014/11425-

Polymeric Biomaterials for Topical Drug Delivery in the Oral Cavity: Advances on Devices and Manufacturing Technologies

There are several routes of drug administration, and each one has advantages and limitations. In the case of the topical application in the oral cavity, comprising the buccal, sublingual, palatal, and gingival regions, the advantage is that it is painless, non-invasive, allows easy application of the formulation, and it is capable of avoiding the need of drug swallowing by the patient, a matter of relevance for children and the elderly. Another advantage is the high permeability of the oral mucosa, which may deliver very high amounts of medication rapidly to the bloodstream without significant damage to the stomach. This route also allows the local treatment of lesions that affect the oral cavity, as an alternative to systemic approaches involving injection-based methods and oral medications that require drug swallowing. Thus, this drug delivery route has been arousing great interest in the pharmaceutical industry. This review aims to condense information on the types of biomaterials and polymers used for this functionality, as well as on production methods and market perspectives of this topical drug delivery route

Histological and Molecular Evidence of the Positive Performance of Glycerol-Plasticized Chitosan-Alginate Membranes on Skin Lesions of Hyperglycemic Mice

The purpose of this study was to investigate tissue repair of excisional wounds in hyperglycemic animals treated with chitosan-alginate membranes (CAM) produced in the presence of glycerol. 8-week C57B1 male mice were divided into normoglycemic animals with a 0.9% saline solution topical treatment (CTSF); hyperglycemic animals with 0.9% saline solution topical treatment (DMSF) and hyperglycemic animals with glycerol-plasticized chitosan-alginate membrane topical treatment (DMCAM). On post-wound day three, the DMCAM group presented a lower number of leukocytes, mature mastocytes, a higher number of vessels (p < 0.05), and active mastocytes (p < 0.05) when compared to the CTSF and DMSF groups. There were no differences regarding the distribution, deposition, organization, and thickness of collagen fibers. On day 7 there were no differences in the analysis of fibroblasts, mastocytes, and TGF−β1 and VEGF expressions among the groups. Regarding collagen fibers, the DMCAM group presented slight red-orange birefringence when compared to the CTSF and DMSF groups. On day 14 there was a slight concentration of thinner elastic fibers for the DMCAM group, with a greater reorganization of papillary skin and improved red-orange birefringence collagen fibers, as well as net-shaped orientation, similar to intact skin. In addition, improved elastic fiber organization distributed in the entire neo-dermis and a larger presence of elaunin fibers were observed, in a similar pattern found in the intact skin. The use of CAM in cutaneous lesions boosted tissue repair since there was a smaller number of inflammatory cells and mastocytes, and an improvement in collagen deposition and collagen fibers. These results demonstrate the high potential of plasticized chitosan-alginate membrane for skin wound dressing of hyperglycemic patients