Deposition of aerosols onto upper ocean and their impacts on marine biota Andreia Ventura, Eliana F. C. Simões, Antoine S. Almeida, Roberto Martins, Armando C. Duarte, et al. Atmosphere, 2021 Atmospheric aerosol deposition (wet and dry) is an important source of macro and micronutrients (N, P, C, Si, and Fe) to the oceans. Most of the mass flux of air particles is made of fine mineral particles emitted from arid or semi-arid areas (e.g., deserts) and transported over long distances until deposition to the oceans. However, this atmospheric deposition is affected by anthropogenic activities, which heavily impacts the content and composition of aerosol constituents, contributing to the presence of potentially toxic elements (e.g., Cu). Under this scenario, the deposition of natural and anthropogenic aerosols will impact the biogeochemical cycles of nutrients and toxic elements in the ocean, also affecting (positively or negatively) primary productivity and, ultimately, the marine biota. Given the importance of atmospheric aerosol deposition to the oceans, this paper reviews the existing knowledge on the impacts of aerosol deposition on the biogeochemistry of the upper ocean, and the different responses of marine biota to natural and anthropogenic aerosol input.
Assessing reactive oxygen and nitrogen species in atmospheric and aquatic environments: Analytical challenges and opportunities Eliana F.C. Simões, Antoine S. Almeida, Armando C. Duarte, Regina M.B.O. Duarte Trac Trends in Analytical Chemistry, 2021 Reactive oxygen and nitrogen species (ROS and RNS) play a crucial role in biotic and abiotic processes. In the atmosphere, ROS/RNS are usually associated with air pollution. The ability of certain air particulate matter constituents to influence the formation and cycling of ROS/RNS at the atmosphere-biosphere-hydrosphere interfaces is important for the observed linkages between atmospheric aerosols and adverse health and climate effects. Atmosphere-hydrosphere ROS/RNS exchange fluxes affect the chemical composition of the atmosphere and surface waters compartments, acting both as a source and sink for ROS/RNS. Therefore, detecting and measuring ROS/RNS in this interface is of utmost importance. This article presents a critical review on the analytical challenges and limitations of the existing methodologies to measure ROS/RNS in air particles and surface waters. It also addresses the suitability of novel methodologies based on carbon nanoparticles as potential tools for the detection of ROS/RNS in atmospheric aerosols and aquatic compartments.
Hypochlorite fluorescence sensing by phenylboronic acid-alizarin adduct based carbon dots Eliana F.C. Simões, Luís Pinto da Silva, Joaquim C.G. Esteves da Silva, João M.M. Leitão Talanta, 2020 The selective fluorescence sensing of hypochlorite (ClO-) was achieved at pH 7.4 by a simple analytical procedure through the fluorescence quenching of autoclave synthesized carbon dots (CDs), which used as precursor an adduct formed between 3-aminophenylboronic acid (APBA) and alizarin red S (ARS). The use of this adduct allowed the preparation of CDs with a red shifted emission (560 nm) and excitation in the visible range (490 nm). Quantification of hypochlorite was achieved at physiological pH (pH 7.4) in aqueous solutions by fluorescence quenching with a linearity range of 0-200 μM (limit of detection of 4.47 μM, and limit of quantification of 13.41 μM). The selectivity of hypochlorite sensing was confirmed by comparison with other potential analytes, such as glucose, fructose and hydrogen peroxide. Finally, the validity of the proposed assay was further demonstrated by performing recovery assays in different matrices. Thus, this CDs allows the fluorescent sensing of ClO- with spectral properties more suitable for in vitro/in vivo applications.
Glucose Sensing by Fluorescent Nanomaterials Guilherme P. C. Mello, Eliana F. C. Simões, Diana M. A. Crista, João M. M. Leitão, Luís Pinto da Silva, et al. Critical Reviews in Analytical Chemistry, 2019 Diabetes mellitus is a chronic disease and leading cause of death worldwide, affecting more than 420 million people. High blood glucose levels are a common effect of uncontrolled diabetes, which can cause serious health damage. Diabetic individuals must measure their blood glucose levels regularly in order to control glycemic levels and minimize the effects of the disease. Glucose sensors have been used in the management of diabetes for more than 50 years, when Clark and Ann Lyons developed the first glucose enzyme electrode in 1962. Electrochemical sensors have become the leading technology for glucose concentration measuring with most of the commercially available devices being based on amperometric detection. However, the detection of glucose in the blood is still an object of intense research. The development of new fluorescent nanomaterials begins to constitute an alternative for glucose blood quantification. These sensors include carbon dots, quantum dots, graphene quantum dots, gold, silver and upconversion nanoparticles. This paper reviews the last 10 year fluorescent nanoparticles based technologies proposed for glucose monitoring and provide an insight into emerging optical fluorescence glucose biosensors.
3-Hydroxyphenylboronic Acid-Based Carbon Dot Sensors for Fructose Sensing Diana M. A. Crista, Guilherme P. C. Mello, Olena Shevchuk, Ricardo M. S. Sendão, Eliana F. C. Simões, et al. Journal of Fluorescence, 2019 The selective fluorescence sensing of fructose was achieved by fluorescence quenching of the emission of hydrothermal-synthesized carbon quantum dots prepared by 3-hydroxyphenylboronic acid. Quantification of fructose was possible in aqueous solutions with pH of 9 (Limit of Detection LOD and Limit of Quantification LOQ of 2.04 and 6.12 mM), by quenching of the emission at 376 nm and excitation ~380 nm with a linearity range of 0–150 mM. A Stern-Volmer constant (KSV) of 2.11 × 10−2 mM−1 was obtained, while a fluorescent quantum yield of 31% was calculated. The sensitivity of this assay towards fructose was confirmed by comparison with other sugars (such as glucose, sucrose and lactose). Finally, the validity of the proposed assays was further demonstrated by performing recovery assays in different matrixes. Graphical Abstract
Sulfur and nitrogen co-doped carbon dots sensors for nitric oxide fluorescence quantification Eliana F.C. Simões, João M.M. Leitão, Joaquim C.G. Esteves da Silva Analytica Chimica Acta, 2017 Microwave synthetized sulfur and nitrogen co-doped carbon dots responded selectively to nitric oxide (NO) at pH 7. Citric acid, urea and sodium thiosulfate in the proportion of 1:1:3 were used respectively as carbon, nitrogen and sulfur sources in the carbon dots microwave synthesis. For this synthesis, the three compounds were diluted in 15 mL of water and exposed for 5 min to a microwave radiation of 700 W. It is observed that the main factor contributing to the increased sensitivity and selectivity response to NO at pH 7 is the sodium thiosulfate used as sulfur source. A linear response range from 1 to 25 μM with a sensitivity of 16 μM-1 and a detection limit of 0.3 μM were obtained. The NO quantification capability was assessed in standard and in fortified serum solutions.
Carbon dots prepared from citric acid and urea as fluorescent probes for hypochlorite and peroxynitrite Eliana F. C. Simões, João M. M. Leitão, Joaquim C. G. Esteves da Silva Microchimica Acta, 2016 Carbon dots (CDs) were prepared from citric acid and urea, and their fluorescence was found to be quenched by hypochlorite and peroxynitrite. Microwave based synthesis gives CDs with excitation/emission wavelength-dependent quantum yields (8 % at 400/520 nm; 10 % at 360/451 nm; 12 % at 350/420 nm). Quenching of fluorescence depends on pH values, and response is most selective and sensitive to hypochlorite at pH 4, and to peroxynitrite at pH 9. The lower detection limits are 0.5 and 1.5 μM, respectively. The method was successfully applied to quantify hypochlorite and peroxynitrite in standard solutions and in spiked dilute serum samples. Graphical abstractFluorescence quenching probes based in carbon dots nanoparticles prepared from citric acid and urea were developed for the quantification of hypochlorite at pH 4 and peroxynitrite at pH 9.
Peroxynitrite and nitric oxide fluorescence sensing by ethylenediamine doped carbon dots Eliana F.C. Simões, Joaquim C.G. Esteves da Silva, João M.M. Leitão Sensors and Actuators B Chemical, 2015 The selective fluorescence sensing of nitric oxide (NO) and peroxynitrite anion (ONOO − ) in the presence of the principal reactive oxygen and nitrogen species (ROS/RNS) was achieved by fluorescence quenching through the pH variation of microwave synthesized fluorescent carbon dots (CDs) prepared from citric acid (CA) and ethylenediamine (EDA). The highest NO and ONOO − sensitivity, with the lowest sensitivity to the principal ROS/RNS, was demonstrated respectively at pH 4 and 10. The optimum synthesis and sensing conditions of CDs were obtained by multivariate full factorial experimental design methodologies: for NO, at pH 4, 2.5 g of CA and 1000 μL of EDA diluted in 15 mL of water exposed for 5 min to a microwave radiation of 700 W; for ONOO − , at pH 7, 10–0.25 g of CA and 500 μL of EDA diluted in 15 mL of water exposed for 5 min to a microwave radiation of 700 W. In these optimized conditions the synthesized CDs have a quantum yield about 40%. The quantification of NO at pH 4 and of ONOO − at pH 7 and 10 were done in standard and in fortified serum solutions. Also the quantification of NO and of ONOO − in standard solutions was performed in the presence respectively of ONOO − and NO.
Nanomaterials for in vivo no sensing Nitric Oxide Emerging Developments Therapeutic Role in Disease States and Health Effects, 2015
Fluorescence sensing by functionalized carbon dots nanoparticles Chemical Functionalization of Carbon Nanomaterials Chemistry and Applications, 2015
