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1.
Molecules ; 27(19)2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36234749

RESUMO

This work studied the feasibility of using a novel microreactor based on torus geometry to carry out a sample pretreatment before its analysis by graphite furnace atomic absorption. The miniaturized retention of total arsenic was performed on the surface of a magnetic sorbent material consisting of 6 mg of magnetite (Fe3O4) confined in a very small space inside (20.1 µL) a polyacrylate device filling an internal lumen (inside space). Using this geometric design, a simulation theoretical study demonstrated a notable improvement in the analyte adsorption process on the solid extractant surface. Compared to single-layer geometries, the torus microreactor geometry brought on flow turbulence within the liquid along the curvatures inside the device channels, improving the efficiency of analyte-extractant contact and therefore leading to a high preconcentration factor. According to this design, the magnetic solid phase was held internally as a surface bed with the use of an 8 mm-diameter cylindric neodymium magnet, allowing the pass of a fixed volume of an arsenic aqueous standard solution. A preconcentration factor of up to 60 was found to reduce the typical "characteristic mass" (as sensitivity parameter) determined by direct measurement from 53.66 pg to 0.88 pg, showing an essential improvement in the arsenic signal sensitivity by absorption atomic spectrometry. This methodology emulates a miniaturized micro-solid-phase extraction system for flow-through water pretreatment samples in chemical analysis before coupling to techniques that employ reduced sample volumes, such as graphite furnace atomic absorption spectroscopy.


Assuntos
Arsênio , Grafite , Microextração em Fase Líquida , Arsênio/análise , Óxido Ferroso-Férrico , Cromatografia Gasosa-Espectrometria de Massas , Grafite/química , Microextração em Fase Líquida/métodos , Fenômenos Magnéticos , Neodímio , Espectrofotometria Atômica/métodos , Água/química
2.
Molecules ; 26(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34299425

RESUMO

This study presents the feasibility of using various functionalized substrates, Fe3O4 nanoparticles (NPs) and Al2O3 spheres, for the removal of Cd from aqueous solution. To improve the materials' affinity to Cd, we explored four different surface modifications, namely (3-Aminopropyl) triethoxysilane (APTES), L-Cysteine (Cys) and 3-(triethoxysilyl) propylsuccinic anhydride (CAS). Particles were characterized by FTIR, FIB-SEM and DLS and studied for their ability to remove metal ions. Modified NPs with APTES proved to be effective for Cd removal with efficiencies of up to 94%, and retention ratios up to 0.49 mg of Cd per g of NPs. Batch adsorption experiments investigated the influence of pH, contact time, and adsorbent dose on Cd adsorption. Additionally, the recyclability of the adsorbent and its potential phytotoxicity and animal toxicity effects were explored. The Langmuir, Freundlich, pseudo-first-order and pseudo-second-order models were applied to describe the behavior of the Cd adsorption processes. The adsorption and desorption results showed that Fe3O4 NPs modified with APTES are promising low-cost platforms with low phytotoxicity for highly efficient heavy metal removal in wastewater.

3.
Sensors (Basel) ; 19(19)2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31554249

RESUMO

Composting is considered an option for the disposal of organic waste; however, the development of portable and low-cost systems for its monitoring is of high interest. Therefore, in this study, respirometric microsystems were designed and tested including two integrated oxygen sensors for the measurement of compost samples under static and dynamic conditions with high portability and ease of use. The cost of each sensor was calculated as 2 USD, while the cost of the whole respirometric microsystem was calculated as 6 USD. The electronic system for real-time monitoring was also designed and implemented. The designed systems were tested for over 6 weeks for the determination of compost quality using real samples. The respirometric microsystem was compared to a commercial respirometry system and a standard laboratory test using hierarchical analysis which included costs, portability accuracy, analysis time, and integration of new technologies. The analysis showed a global score of 6.87 for the respirometric microsystem compared to 6.70 for the standard laboratory test and 3.26 for the commercial system.

4.
J Water Health ; 15(6): 932-941, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29215357

RESUMO

A new rapid, sensitive and selective method for rotavirus detection in water samples is described in this paper. Amino pink magnetic microparticles were functionalized with monoclonal antibodies and used to capture, concentrate, separate and detect infectious rotavirus particles in distilled and drinking water samples. The fluorescence of the microparticles was used to determine the presumptive presence of rotaviruses by using confocal microscopy. Atomic force microscopy and transmission electron microscopy were used to confirm the presence of the anti-rotavirus antibodies attached to the surface of the magnetic microparticles as well as that of viruses attached through the antibody. In addition, RNA extraction, quantification and amplification were carried out to validate the microscopic observations. The selectivity of the microparticles was tested in a sample containing a mix of enteric viruses. It was concluded that functionalizing fluoromagnetic microparticles with anti-rotavirus monoclonal antibodies constituted a fast, simple and reliable technique for detecting as low as 10 Rotavirus particles in 1 L of artificial or real water in just 2 hours.


Assuntos
Água Potável/virologia , Monitoramento Ambiental/métodos , Fluorimunoensaio , Rotavirus/isolamento & purificação , Microbiologia da Água , Separação Imunomagnética , Microscopia Confocal
5.
Sensors (Basel) ; 17(10)2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-28937645

RESUMO

Bioelectrochemical sensing of Mycobacterium tuberculosis through electro-immunosensors is a promising technique to detect relevant analytes. In general, immunosensors require the formation of organic assemblies by the adsorption of molecular constituents. Moreover, they depend on the correct immobilization of the bio-recognition element in the biosensor. These procedures cannot be easily monitored without the use of invasive methods. In this work, an impedance analysis technique was used, as a non-invasive method, to measure and differentiate the manufacturing stages of the sensors. Biomicrosystems were fabricated through physical vapor deposition (PVD) of 80 nm Au nanolayers on 35 µm copper surfaces. Later, the surface was modified through thiolation methods generating a self-assembled-monolayer (SAM) with 20 mM 4-aminothiophenol (4-ATP) on which a polyclonal antibody (pAb) was covalently attached. Using impedance analysis, every step of the electro-immunosensor fabrication protocol was characterized using 40 independent replicas. Results showed that, compared to the negative controls, distilled water, and 0.5 µg/mL HSA, a maximum variation of 171% between each replica was achieved when compared to samples containing 0.5 µg/mL of ESAT-6 M. tuberculosis immunodominant protein. Therefore, this development validates a non-invasive method to electrically monitor the assembly process of electro-immunosensors and a tool for its further measure for detection of relevant antigens.


Assuntos
Anticorpos Antibacterianos/análise , Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Técnicas Biossensoriais/métodos , Eletroquímica/métodos , Microtecnologia/métodos , Mycobacterium tuberculosis/isolamento & purificação , Compostos de Anilina/química , Anticorpos Antibacterianos/metabolismo , Compostos de Sulfidrila/química
6.
Sensors (Basel) ; 17(9)2017 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-28902147

RESUMO

Chloride presence affects different environments (soil, water, concrete) decreasing their qualities. In order to assess chloride concentration this paper proposes a novel sensor for detecting and measuring it. This sensor is based on electric changes of commercial monocalcium aluminate (CA) when it interacts with chloride aqueous solutions. CA is used as a dielectric material between two coplanar capacitors. The geometry proposed for this sensor allows to assess the chloride content profile, or to make four times the same measurement. Besides, the experimental design gives us the possibility of study not just the chloride effect, but also the time and some geometric effects due to the sensor design. As a result, this sensor shows a limit of detection, sensitivity, and response time: 0.01 wt % Cl- and 0.06 wt % Cl-, and 2 min, respectively, comparable with other non invasive techniques as optical fibre sensors.

7.
Anal Bioanal Chem ; 408(11): 2827-37, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26780711

RESUMO

Point-of-care detection is a widely studied area that attracts effort and interest from a large number of fields and companies. However, there is also increased interest from the general public in this type of device, which has driven enormous changes in the design and conception of these developments and the way data is handled. Therefore, future point-of-care detection has to include communication with front-end technology, such as smartphones and networks, automation of manufacture, and the incorporation of concepts like the Internet of Things (IoT) and cloud computing. Three key examples, based on different sensing technology, are analyzed in detail on the basis of these items to highlight a route for the future design and development of point-of-care detection devices and their data capture and handling.


Assuntos
Diagnóstico , Sistemas Automatizados de Assistência Junto ao Leito , Gasometria , Humanos , Papillomaviridae/isolamento & purificação
8.
Nanomaterials (Basel) ; 14(11)2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38869535

RESUMO

The ceramic tile industry, with significant energy and material demands in its manufacturing processes, has employed technological innovations in energy efficiency, advanced equipment and tile thickness reduction to address these challenges. This study aimed to assess the impact of Ag2O, CuFe2O4, Fe3O4, and SiO2 nanoparticles (0%, 1%, and 5% by weight) on the mechanical strength, water absorption, and apparent thermal conductivity of ceramic tiles, as well as their capacity to reduce energy and raw material consumption. This reduction translates into a decrease in environmental impacts, which have been evaluated through life cycle assessment (LCA) methodology applied to the manufacturing processes. Nanoparticles (Ag2O, CuFe2O4, Fe3O4, and SiO2) were initially screened on TF clay (0%, 1%, 5% w/w), and the most effective were applied to CR1 and CR2 clays (0%, 1%, 5% w/w). Findings indicated a 32% increase in temperature gradient and a 16% improvement in flexural strength with the addition of Fe3O4 nanoparticle at 1% (w/w) in TF clay. Furthermore, there was a potential 48% reduction in energy consumption, and up to 16% decrease in tile weight or thickness without affecting the flexural strength property of the test tiles. LCA results demonstrated that the addition of Fe3O4 nanoparticle has potential reductions of up to 20% in environmental impacts. This study suggests that nanoparticle addition offers a viable alternative for reducing energy and material consumption in the ceramic tile industry. Future research should focus on assessing the economic impact of transitioning to a sustainable business model in the ceramic tile industry with nanoparticles addition.

9.
Membranes (Basel) ; 14(5)2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38786942

RESUMO

Agricultural and animal farming practices contribute significantly to greenhouse gas (GHG) emissions such as NH3, CH4, CO2, and NOx, causing local environmental concerns involving health risks and water/air pollution. A growing need to capture these pollutants is leading to the development of new strategies, including the use of solid adsorbents. However, commonly used adsorbent materials often pose toxicity and negative long-term environmental effects. This study aimed to develop responsive eco-friendly cryogels using xylan extracted from coffee parchment, a typical residue from coffee production. The crosslinking in cryogels was accomplished by "freeze-thawing" and subsequent freeze-drying. Cryogels were characterized in terms of morphology by using scanning electron microscopy, porosity, and density by the liquid saturation method and also moisture adsorption and ammonia adsorption capacity. The analysis showed that the porosity in the cryogels remained around 0.62-0.42, while the apparent densities varied from 0.14 g/cm3 to 0.25 g/cm3. The moisture adsorption capacity was the highest at the highest relative humidity level (80%), reaching 0.25-0.43 g of water per gram of sample; the amount of water adsorbed increased when the xylan content in the cryogel increased up to 10% w/v, which was consistent with the hygroscopic nature of xylan. The ammonia adsorption process was modeled accurately by a pseudo-second-order equation, where the maximum adsorption capacity in equilibrium reached 0.047 mg NH3/g when xylan reached 10% w/v in cryogels, indicating a chemisorption process. The cryogels under investigation hold promise for ammonia adsorption applications and GHG separation, offering a sustainable alternative for gas-capturing processes.

10.
Chemosphere ; 358: 142081, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38677608

RESUMO

In recent years, the escalating concerns surrounding environmental pollution and the need for sustainable wastewater treatment solutions have underscored the significance of developing technologies that can efficiently treat wastewater while also reducing negative ecological effects. In this context, our study aims to contribute to the advancement of sustainable technologies for wastewater treatment, by investigating the effects that bare magnetite nanoparticles and those functionalized with the enzyme laccase could have in an aquatic animal, zebrafish, at various life cycle stages. Exposure to magnetite nanoparticles shows some effects on embryo hatching, survival rates, or larval behavior at higher concentrations. For both treatments, the hatching percentages were close to 80% compared to 93% for the control group. At the end of the observations in larvae, survival in all the evaluated groups was higher than 90%. Additionally, we evaluated the accumulation of nanoparticles in various stages of zebrafish. We found that, although there was accumulation during embryonic stages, it did not affect normal development or subsequent hatching. Iron levels in different organs such as gills, muscles, gastrointestinal tract, and brain were also evaluated in adults. Animals treated with a mix of food and nanoparticles at 10 µg/mL (Food group) presented a higher concentration of iron accumulation in muscle, gastrointestinal tract, and gills compared to the untreated control group. Although iron levels increased depending on the dose and exposure method applied, they were not statistically significant from the control groups. Our findings suggest that bionanocomposites evaluated here can be considered safe for removal of contaminants in wastewater without toxic effects or detrimental accumulation fish's health.


Assuntos
Nanocompostos , Águas Residuárias , Poluentes Químicos da Água , Peixe-Zebra , Animais , Nanocompostos/toxicidade , Nanocompostos/química , Águas Residuárias/química , Águas Residuárias/toxicidade , Poluentes Químicos da Água/toxicidade , Nanopartículas de Magnetita/toxicidade , Nanopartículas de Magnetita/química , Larva/efeitos dos fármacos , Purificação da Água/métodos , Embrião não Mamífero/efeitos dos fármacos , Lacase/metabolismo , Modelos Animais , Ferro/toxicidade , Ferro/química
11.
Micromachines (Basel) ; 15(7)2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39064443

RESUMO

Microfluidic separators play a pivotal role in the biomedical and chemical industries by enabling precise fluid manipulations. Traditional fabrication of these devices typically requires costly cleanroom facilities, which limits their broader application. This study introduces a novel microfluidic device that leverages the passive Zweifach-Fung principle to overcome these financial barriers. Through Lagrangian computational simulations, we optimized an eleven-channel Zweifach-Fung configuration that achieved a perfect 100% recall rate for particles following a specified normal distribution. Experimental evaluations determined 2 mL/h as the optimal total flow rate (TFR), under which the device showcased exceptional performance enhancements in precision and recall for micrometer-sized particles, achieving an overall accuracy of 94% ± 3%. Fabricated using a cost-effective, non-cleanroom method, this approach represents a significant shift from conventional practices, dramatically reducing production costs while maintaining high operational efficacy. The cost of each chip is less than USD 0.90 cents and the manufacturing process takes only 15 min. The development of this device not only makes microfluidic technology more accessible but also sets a new standard for future advancements in the field.

12.
PLoS One ; 19(4): e0302031, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38603692

RESUMO

Chronic neuroinflammation is characterized by increased blood-brain barrier (BBB) permeability, leading to molecular changes in the central nervous system that can be explored with biomarkers of active neuroinflammatory processes. Magnetic resonance imaging (MRI) has contributed to detecting lesions and permeability of the BBB. Ultra-small superparamagnetic particles of iron oxide (USPIO) are used as contrast agents to improve MRI observations. Therefore, we validate the interaction of peptide-88 with laminin, vectorized on USPIO, to explore BBB molecular alterations occurring during neuroinflammation as a potential tool for use in MRI. The specific labeling of NPS-P88 was verified in endothelial cells (hCMEC/D3) and astrocytes (T98G) under inflammation induced by interleukin 1ß (IL-1ß) for 3 and 24 hours. IL-1ß for 3 hours in hCMEC/D3 cells increased their co-localization with NPS-P88, compared with controls. At 24 hours, no significant differences were observed between groups. In T98G cells, NPS-P88 showed similar nonspecific labeling among treatments. These results indicate that NPS-P88 has a higher affinity towards brain endothelial cells than astrocytes under inflammation. This affinity decreases over time with reduced laminin expression. In vivo results suggest that following a 30-minute post-injection, there is an increased presence of NPS-P88 in the blood and brain, diminishing over time. Lastly, EAE animals displayed a significant accumulation of NPS-P88 in MRI, primarily in the cortex, attributed to inflammation and disruption of the BBB. Altogether, these results revealed NPS-P88 as a biomarker to evaluate changes in the BBB due to neuroinflammation by MRI in biological models targeting laminin.


Assuntos
Barreira Hematoencefálica , Laminina , Animais , Barreira Hematoencefálica/diagnóstico por imagem , Barreira Hematoencefálica/metabolismo , Laminina/metabolismo , Doenças Neuroinflamatórias , Células Endoteliais/metabolismo , Inflamação/diagnóstico por imagem , Inflamação/metabolismo , Imageamento por Ressonância Magnética/métodos
13.
Polymers (Basel) ; 15(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36987237

RESUMO

The objective of this study was to assess the effectiveness of functionalized bionanocompounds with ice nucleation protein (INP) as a novel approach for freezing applications in terms of how much energy is used during each step of freezing when water bionanocompound solutions were compared with pure water. According to the results of the manufacturing analysis, water required 28 times less energy than the silica + INA bionanocompound and 14 times less than the magnetite + INA bionanocompound. These findings showed that water used the least energy during the manufacturing process. In order to determine the associated environmental implications, an analysis of the operating stage was also conducted, taking the defrosting time of each bionanocompound during a 4 h work cycle into account. Our results showed that bionanocompounds may substantially reduce the environmental effects by achieving a 91% reduction in the impact after their use during all four work cycles in the operation stage. Additionally, given the energy and raw materials needed in this process, this improvement was more significant than at the manufacturing stage. The results from both stages indicated that, when compared with water, the magnetite + INA bionanocompound and the silica + INA bionanocompound would save an estimated 7% and 47% of total energy, respectively. The study's findings also demonstrated the great potential for using bionanocompounds in freezing applications to reduce the effects on the environment and human health.

14.
Front Bioeng Biotechnol ; 11: 1176557, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37180035

RESUMO

Microfluidics is an interdisciplinary field that encompasses both science and engineering, which aims to design and fabricate devices capable of manipulating extremely low volumes of fluids on a microscale level. The central objective of microfluidics is to provide high precision and accuracy while using minimal reagents and equipment. The benefits of this approach include greater control over experimental conditions, faster analysis, and improved experimental reproducibility. Microfluidic devices, also known as labs-on-a-chip (LOCs), have emerged as potential instruments for optimizing operations and decreasing costs in various of industries, including pharmaceutical, medical, food, and cosmetics. However, the high price of conventional prototypes for LOCs devices, generated in clean room facilities, has increased the demand for inexpensive alternatives. Polymers, paper, and hydrogels are some of the materials that can be utilized to create the inexpensive microfluidic devices covered in this article. In addition, we highlighted different manufacturing techniques, such as soft lithography, laser plotting, and 3D printing, that are suitable for creating LOCs. The selection of materials and fabrication techniques will depend on the specific requirements and applications of each individual LOC. This article aims to provide a comprehensive overview of the numerous alternatives for the development of low-cost LOCs to service industries such as pharmaceuticals, chemicals, food, and biomedicine.

15.
HardwareX ; 16: e00493, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38045919

RESUMO

Although microparticles are frequently used in chemistry and biology, their effectiveness largely depends on the homogeneity of their particle size distribution. Microfluidic devices to separate and purify particles based on their size have been developed, but many require expensive cleanroom manufacturing processes. A cost-effective, passive microfluidic separator is presented, capable of efficiently sorting and purifying particles spanning the size range of 15 µm to 40 µm. Fabricated from Polymethyl Methacrylate (PMMA) substrates using laser ablation, this device circumvents the need for cleanroom facilities. Prior to fabrication, rigorous optimization of the device's design was carried out through computational simulations conducted in COMSOL Multiphysics. To gauge its performance, chitosan microparticles were employed as a test case. The results were notably promising, achieving a precision of 96.14 %. This quantitative metric underscores the device's precision and effectiveness in size-based particle separation. This low-cost and accessible microfluidic separator offers a pragmatic solution for laboratories and researchers seeking precise control over particle sizes, without the constraints of expensive manufacturing environments. This innovation not only mitigates the limitations tied to traditional cleanroom-based fabrication but also widens the horizons for various applications within the realms of chemistry and biology.

16.
Polymers (Basel) ; 14(12)2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35745904

RESUMO

In this work, five different magnetic biofilters, containing magnetic nanoparticles (142 nm), immobilized laccase on nanoparticles (190 nm) and permanent magnetic elements, such as neodymium magnets and metallic meshes, were designed, manufactured and tested. The five types of filters were compared by measuring the decolorization of Congo Red dye inside bioreactors, the half-life of the filters and the amount of magnetic nanoparticle and enzyme lost during multiple cycles of operation. Filters containing laccase immobilized on magnetite (Laccase-magnetite), permanent magnets and metallic mesh presented the highest Congo Red decolorization (27%) and the largest half-life among all types of filters (seven cycles). The overall dye decolorization efficiencies were 5%, 13%, 17%, 23%, and 27% for the paper filter, paper filter with magnetite, paper filter with Laccase-magnetite, paper filter with Laccase-magnetite with magnets and paper filter with Laccase-magnetite with magnets and metallic mesh, respectively. Although the highest losses of magnetite occurred when using the filters containing magnets (57 mg), the use of permanent magnetic elements in the filters increased the half-life of the filter three-fold compared to the filters without enzymatic properties and two-fold compared to the filters with Laccase-magnetite. Results indicate that the novel use of permanent magnetic elements improved the nanoparticle retention in the filters and promoted the mass transfer between the dye and the biocatalyst to enhance wastewater treatment.

17.
Membranes (Basel) ; 12(3)2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-35323773

RESUMO

The presence of micropollutants in wastewater is one of the most significant environmental challenges. Particularly, pollutants such as pharmaceutical residues present high stability and resistance to conventional physicochemical and biological degradation processes. Thus, we aimed at immobilizing a laccase enzyme by two different methods: the first one was based on producing alginate-laccase microcapsules through a droplet-based microfluidic system; the second one was based on covalent binding of the laccase molecules on aluminum oxide (Al2O3) pellets. Immobilization efficiencies approached 92.18% and 98.22%, respectively. Laccase immobilized by the two different methods were packed into continuous flow microreactors to evaluate the degradation efficiency of acetaminophen present in artificial wastewater. After cyclic operation, enzyme losses were found to be up to 75 µg/mL and 66 µg/mL per operation cycle, with a maximum acetaminophen removal of 72% and 15% and a retention time of 30 min, for the laccase-alginate microcapsules and laccase-Al2O3 pellets, respectively. The superior catalytic performance of laccase-alginate microcapsules was attributed to their higher porosity, which enhances retention and, consequently, increased the chances for more substrate-enzyme interactions. Finally, phytotoxicity of the treated water was lower than that of the untreated wastewater, especially when using laccase immobilized in alginate microcapsules. Future work will be dedicated to elucidating the routes for scaling-up and optimizing the process to assure profitability.

18.
Biosens Bioelectron ; 202: 114005, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35078142

RESUMO

Wearables are becoming pervasive in our society, but they are still mainly based on physical sensors with just few optical and electrochemical exceptions. Sweat, amongst other body fluids, is easily and non-invasively accessible, abundant, and relatively poor of interfering species. The biomarkers of interest in sweat space from ions and small molecules to whole organisms. Heavy metals have been found being biomarkers of several diseases and pathological conditions. Copper in particular is correlated to Wilson's disease and liver cirrhosis among others. Nevertheless, several issues such as sampling conditions, sweat rate normalization, reliable continuous monitoring, and typically expensive fabrication methods still needs to be addressed in sweat analysis with wearables. Herein, we propose a fully printed wearable microfluidic nanosensor with an integrated wireless smartphone-based readout. Our system can easily be applied on the skin and actively stimulate perspiration, normalizing the heavy metals concentration with respect to the volume of the sample and the sweat rate. The system has a limit of detection of 396 ppb, a linear range up to 2500 ppb and a sensitivity of 2.3 nA/ppb.


Assuntos
Técnicas Biossensoriais , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/métodos , Cobre/análise , Atenção à Saúde , Microfluídica , Suor/química
19.
Nanomaterials (Basel) ; 12(3)2022 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-35159834

RESUMO

Magnetite-based nanocomposites are used for biomedical, industrial, and environmental applications. In this study, we evaluated their effects on survival, malformation, reproduction, and behavior in a zebrafish animal model. Nanoparticles were synthesized by chemical coprecipitation and were surface-functionalized with (3-aminopropyl) triethoxysilane (APTES), L-cysteine (Cys), and 3-(triethoxysilyl) propylsuccinic anhydride (CAS). All these nanocomposites were designed for the treatment of wastewater. Zebrafish embryos at 8 h post-fertilization (hpf) and larvae at 4 days post-fertilization (dpf) were exposed to the magnetic nanocomposites Fe3O4 MNP (magnetite), MNP+APTES, MNP+Cys, MNP+APTES+Cys, and MNP+CAS, at concentrations of 1, 10, 100, and 1000 µg/mL. Zebrafish were observed until 13 dpf, registering daily hatching, survival, and malformations. Behavior was tested at 10 dpf for larvae, and reproduction was analyzed later in adulthood. The results showed that the toxicity of the nanocomposites used were relatively low. Exploratory behavior tests showed no significant changes. Reproduction in adults treated during development was not affected, even at concentrations above the OECD recommendation. Given the slight effects observed so far, these results suggest that nanocomposites at the concentrations evaluated here could be a viable alternative for water remediation because they do not affect the long-term survival and welfare of the animals.

20.
Polymers (Basel) ; 14(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35458259

RESUMO

The polymeric ouzo effect is an energy-efficient and robust method to create nanoparticles with biologically degradable polymers. Usually, a discontinuous or semi-continuous process is employed due to its low technical effort and the fact that the amount of dispersions needed in a laboratory is relatively small. However, the number of particles produced in this method is not enough to make this process economically feasible. Therefore, it is necessary to improve the productivity of the process and create a controllable and robust continuous process with the potential to control parameters, such as the particle size or surface properties. In this study, nanoparticles were formulated from polycaprolactone (PCL) in a continuous process using additively manufactured micromixers. The main goal was to be able to exert control on the particle parameters in terms of size and zeta potential. The results showed that particle size could be adjusted in the range of 130 to 465 nm by using different flow rates of the organic and aqueous phase and varying concentrations of PCL dissolved in the organic phase. Particle surface charge was successfully shifted from a slightly negative potential of -14.1 mV to a negative, positive, or neutral value applying the appropriate surfactant. In summary, a continuous process of nanoprecipitation not only improves the cost of the method, but furthermore increases the control over the particle's parameters.

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