A carregar...
Projeto de investigação
Sem título
Financiador
Autores
Publicações
Optical fiber immunosensors based on surface plasmon resonance for the detection of Escherichia coli
Publication . Oliveira, Sandro C.; Soares, Simone; Rodrigues, Andreia C. M.; Gonçalves, Bárbara V.; Soares, Amadeu M. V. M.; Santos, Nuno; Kumar, Santosh; Almeida, Pedro; Marques, Carlos; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); Optical Society of America
Every year, millions of people suffer some form of illness associated with the consumption of contaminated food. Escherichia coli (E. coli), found in the intestines of humans and other animals, is commonly associated with various diseases, due to the existence of pathogenic strains. Strict monitoring of food products for human consumption is essential to ensure public health, but traditional cell culture-based methods are associated with long waiting times and high costs. New approaches must be developed to achieve cheap, fast, and on-site monitoring. Thus, in this work, we developed optical fiber sensors based on surface plasmon resonance. Gold and cysteamine-coated fibers were functionalized with anti-E. coli antibody and tested using E. coli suspensions with concentrations ranging from 1 cell/mL to 105 cells/mL. An average logarithmic sensitivity of 0.21 ± 0.01 nm/log(cells/mL) was obtained for three independent assays. An additional assay revealed that including molybdenum disulfide resulted in an increase of approximately 50% in sensitivity. Specificity and selectivity were also evaluated, and the sensors were used to analyze contaminated water samples, which verified their promising applicability in the aquaculture field.
Effects of Exposure to Urban Atmospheric Particulate Matter Suspended in Seawater on the Mussel Mytilus galloprovincialis
Publication . Rodrigues, Inês; Ferreira, Inês João; Duarte, Regina M. B. O.; Diniz, Mário; DQ - Departamento de Química; UCIBIO - Applied Molecular Biosciences Unit; LAQV@REQUIMTE; MDPI AG
Atmospheric particulate matter (PM) contains numerous constituents, including organic molecules, inorganic ions, and metals, with some of them possessing hazardous properties. Although mainly associated with air pollution, PM can rapidly be transferred from air and land to aquatic ecosystems, and consequently poses a risk to marine biota. The aim of this work was to evaluate how urban atmospheric PM (a standard reference mixture of urban PM, known to contain various organic and inorganic contaminants), suspended in seawater, may cause toxicity in marine organisms. To this purpose, mussels (Mytilus galloprovincialis) were exposed to two concentrations of suspended PM: 5.7 and 11.4 mg/L. After 7, 14, and 21 days, the animals were collected and the gills and digestive gland were analysed for stress biomarkers (CAT, SOD, GPX, GST, MDA, and Ubi). In general, the results show that exposure to different concentrations of PM caused an increase in GST, UBI, and GPx activities compared to their respective controls. The average activities of GST (87.65 ± 30.23 nmol/min/mg of total protein) in the gills of the animals exposed to 11.4 mg/L of PM increased after 21 days of exposure, and the activity of GPx (8.04 ± 3.09 nmol/min/mg of total protein) in the gills increased after 14 days in the animals exposed to 5.7 mg/L of PM. MDA results also provided information on cellular damage, with the most pronounced effects being found in the gills of exposed mussels. This study confirms that mussels are useful as “early warning” indicators of environmental contamination and provides important information on the effects of PM on marine biota.
Elemental quantification of adults zebrafish from different vivaria using X-ray fluorescence
Publication . Leite, F. D.; Pessanha, S.; Barbosa, S.; Borges, A. C.; Pereira, N.; Domingues, I.; Silva, A. L. M.; LIBPhys-UNL; DF – Departamento de Física; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; DCT - Departamento de Ciências da Terra; Elsevier
Zebrafish (Danio rerio) has been used as a model organism in several areas of research, including ecotoxicology, genetics and preclinical research. Investigating the elemental composition of adult zebrafish samples collected from different vivaria can provide valuable insights into various aspects of their physiology, influenced by intrinsic factors, such as gender, and extrinsic factors, including environmental conditions. In this study, adult zebrafish specimens from three different vivaria in Portugal (Biology Department of University of Aveiro (UA), Instituto Gulbenkian de Ciência (IGC) and Instituto de Medicina Molecular João Lobo Antunes (iMM), Lisbon) were analysed using X-ray fluorescence (XRF). The XRF system used was the M4 Tornado (Bruker, Germany) and quantitative analysis was performed using the inbuilt software through the Fundamental Parameters method considering a matrix of 7 % H, 23 % C, 7 % N and 60 % O. Twelve elements were detected and analysed, with Ca and P showing the highest concentrations across all vivaria. Fe, Zn, and Br exhibited significant gender differences in all vivaria, while Ca, Ni, and Cu showed no significant differences between genders or vivaria.
Hybrid nanocomposites of Fe3O4/SiO2-EDTA
Publication . Santos, Gabriela T.A.D.; Estrada, Ana C.; Amorim, Carlos O.; Amaral, João S.; Deuermeier, Jonas; Duarte, Armando C.; Santos, Patrícia S.M.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; Elsevier
Fe3O4/SiO2-EDTA materials have been used for diverse applications and they have been modification by different methods, but a comparison is lacking between their physicochemical characteristics. This work aimed to compare the physicochemical characteristics of the Fe3O4/SiO2-EDTA nanocomposite obtained by four methods, whose modification of the Fe3O4 surface with SiO2-EDTA occurs in one or two steps, with not hazardous chemicals. In the one-step methods (M1 and M2), Fe3O4 particles were coated and functionalized in consecutive steps (by sonication in M1 and mechanical stirring in M2). In the two-step methods (M3 and M4), the Fe3O4 particles were primarily coated with silica and then functionalized with TMS-EDTA (by sonication in M3 and mechanical stirring in M4). The Fe3O4/SiO2-EDTA nanocomposites were characterized by XRD, TEM, EDX, BET, SQUID magnetometry, FTIR, XPS, and zeta potential. The TEM highlighted that the nanocomposites from methods M1 and M2 there is the simultaneous presence of magnetite particles coated and uncoated with silica, while those from M3 and M4 were totally coated, besides the nanocomposites from M2 and M3 showed to be more aggregated than those from the other methods. The presence of EDTA on the surface of the nanocomposites was evidenced by the carboxyl groups in the FTIR spectra and by the nitrogen in the XPS spectra. The nanocomposites from M3 and M4 presented a higher content of nitrogen than those from M1 and M2, and those from M4 also presented a higher content of carbon than those from M3. Overall, the Fe3O4/SiO2-EDTA nanocomposites from two-step methods showed better SiO2 coating and EDTA functionalization than those from one-step methods, and those from M4 presented the best physicochemical characteristics, being this method recommended for their modification for future applications.
In Vitro, Ex Vivo, and In Vivo Evaluation of Silver Nanoparticles Synthesized Using Green Tomato Extract
Publication . Cunha, Daniela; Faria-Silva, Catarina; Carvalho, Filomena A.; Ascensão, Lia; Simões, Pedro; Carvalheiro, Manuela; Simões, Sandra; LAQV@REQUIMTE; DQ - Departamento de Química; MDPI - Multidisciplinary Digital Publishing Institute
Biogenic silver nanoparticles (AgNP) are among the fastest-growing nanomaterials due to the simplicity, efficiency, and sustainability of their biosynthesis using phytochemicals as reducing and coating agents. The agro-food industry generates large quantities of organic waste, a renewable source of biomolecules for AgNP biosynthesis. The main objective of this work was to prepare and characterize biogenic AgNP using a green tomato waste extract (TE) obtained by subcritical water extraction. To the best of our knowledge, this is the first report on the use of such an extract in the synthesis of AgNP. The effects of the TE and AgNO3 concentrations, reaction time, pH, and temperature on AgNP physico-chemical characteristics and on in vitro cytotoxicity against HaCaT and THP-1 cells were assessed. Antimicrobial activity was determined in vitro and ex vivo. The wound-healing capability of AgNP was evaluated in vivo in an incisional wound mouse model. The developed AgNP have a Surface Plasmon Resonance (SPR) band between 402 and 406 nm and a size of ±60 nm, and they are negatively charged (−42 mV) and spherical. In vitro and ex vivo studies prove that AgNP do not compromise skin cells and can decrease cutaneous irritation. The AgNP formulated in a gel revealed similar wound-healing properties to a commercial silver-containing topical ointment. Overall, the biogenic synthesis of AgNP employing an extract of agricultural waste obtained by an eco-friendly method is simple and cost-effective and presents the potential for application in skin disease management.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso para Atribuição do Estatuto e Financiamento de Laboratórios Associados (LA)
Número da atribuição
LA/P/0094/2020