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Gold nanoparticle (AuNP)-mediated photothermal therapy represents an alternative to the effective ablation of cancer cells. However, the photothermal response of AuNPs must be tailored to improve the therapeutic efficacy of plasmonic photothermal therapy (PPT) and mitigate its side effects. This study presents an alternative to ease the tuning of photothermal efficiency and target selectivity. We use laser-treated spherical and anisotropic AuNPs of different sizes and biocompatible folic acid (FA)-conjugated AuNPs (FA-AuNPs) in the well-known human epithelial cervical cancer (HeLa) cell line. We show that large AuNPs produce a more significant photothermal heating effect than small ones. The thermal response of the spherical AuNPs of 9 nm was found to reach a maximum increase of 3.0 ± 1 °C, whereas with the spherical AuNPs of 14 nm, the temperature increased by over 4.4 ± 1 °C. The anisotropic AuNPs of 15 nm reached a maximum of 4.0 ± 1 °C, whereas the anisotropic AuNPs of 20 nm reached a significant increase of 5.3 ± 1 °C in the cell culture medium (MEM). Notably, the anisotropic AuNPs of 20 nm successfully demonstrate the potential for use as a photothermal agent by showing reduced viability down to 60% at a concentration of 100 µM. Besides, we reveal that high concentrations of reactive oxygen species (ROS) are formed within the irradiated cells. In combination with stress by photothermal heating, it is likely to result in significant cell death through acute necrosis by compromising the plasma membrane integrity. Cell death and ROS overproduction during PPT were characterized and quantified by transmission electron microscopy (TEM) and confocal fluorescence microscopy with different fluorescent markers. In addition, we show that FA-AuNPs induce cell death through apoptosis by internal damage, whereas diminish the ROS formation during PPT treatment. Our findings suggest the ability of plasmon-mediated ROS to sensitize cancer cells and make them vulnerable to photothermal damage, as well as the protective role of FA-AuNPs from excessive ROS formation, whereas reducing the risk of undesired side effects due to the necrotic death pathway. It allows an improvement in the efficacy of the AuNP-based photothermal therapy and a reduction in the number of exposures to high temperatures required to induce thermal stress.

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In this work was explored how the confinement of two ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride (bmimCl) and 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4), inside toluene/benzyl-n-hexadecyldimethylammonium chloride (BHDC) reverse micelles (RMs) affects the Cl(-) nucleophilicity on the bimolecular nucleophilic substitution (SN2) reaction between this anion and dimethyl-4-nitrophenylsulfonium trifluoromethanesulfonate. The results obtained show that, upon confinement, the ionic interactions between the ILs with the cationic surfactant polar head group and the surfactant counterion modify substantially the performance of both ILs as solvents. In toluene/BHDC/bmimCl RMs, the Cl(-) interacts strongly with bmim(+) (and/or BHD(+)) in such a way that its nucleophilicity is reduced in comparison with neat IL. In toluene/BHDC/bmimBF4 RMs, an ionic exchange equilibrium produces segregation of bmim(+) and BF4(-) ions, changing the composition of the RMs interface and affecting dramatically the Cl(-) availability. These results show the versatility of this kind of organized system to alter the ionic organization and influence on reaction rate when used as nanoreactors.

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Objetivos: En este trabajo se determinaron los niveles de residualidad de plaguicidas organoclorados y organofosforados en muestras de sangre periférica de trabajadores agrícolas –fumigadores– en el municipio de Barcelona, Quindío, Colombia. Método: Los trabajadores fueron escogidos al azar dentro de los principales cultivos abastecedores de frutas y verduras de la región. Para la extracción y determinación de los analitos en sangre, se usó la técnica de micro-extracción en fase sólida en modo head space y cromatografía de gases capilar dotado con un detector de micro captura de electrones. Resultados: Como resultado se encontraron residuos de 21 plaguicidas de tipo organoclorados y organofosforados; la mayoría de estos en alta concentración (>0.01 ppm) y prohibidos por la legislación nacional e internacional, sugiriendo que aún siguen siendo utilizados ilegalmente. De la residualidad encontrada, los plaguicidas más representativos fueron: beta-BHC y endosulfan, hallados en el 50 por ciento de las personas evaluadas. Asimismo, se descubrió que entre el 20 y 40 por ciento de las personas tenían residuos de endrin aldehído, forato, sulfotep, disulfoton y thionazin, en circunstancia que la mayoría de estos son de categoría toxicología I y II, comprobando el alto riesgo al que se exponen constantemente los individuos que aplican estos compuestos y la falta de atención e información por parte de las entidades responsables de autorización y fiscalización de su uso. Conclusiones: En este sentido, los resultados encontrados en este trabajo demuestran la importancia de continuar con los estudios de monitoreo y control de calidad de los principales alimentos, fuentes hídricas y trabajadores agrícolas, para así informar a la población acerca de los riesgos a los que está expuesta.

Aim: To determine the levels of organochlorine and organophosphorus pesticide residues in peripheral blood samples of farm-workers in Barcelona, Quindío, Colombia. Methods: Farm-workers were randomly chosen to cover the major suppliers of fruits and vegetables crops in the region. Solid phase micro extraction in head space mode and capillary gas chromatography with a micro electron capture detector were used for extraction and determination of analytes from blood. Results: Twenty-one pesticides residues among organochlorine and organophosphorusclasses were found. Most of these pesticides were at high concentrations (>0.01 ppm) and represented concentrations forbidden by national and international legislation. Beta-BHC and endosulfan were found in 50 percent of persons tested. Residues of endrinaldehyde, phorate, sulfotep, disulfoton and thionazinwere found amongst 20-40 percent of the persons tested. Conclusions: These results demonstrate the high risks that farm-workers are exposed to, suggesting poor attention and provision of information by entities responsible for permits and supervision. Furthermore, we highlight the need for monitoring and quality control of food, water sources and farm-workers, and the necessity to inform workers and the community of the risks to which they are exposed.

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The behavior of two ionic liquids (ILs) with high electron donor ability such as 1-butyl-3-methylimidazolium trifluoromethanesulfonate (bmimTfO) and 1-butyl-3-methylimidazolium trifluoroacetate (bmimTfA) entrapped in anionic and cationic reverse micelles (RMs) was investigated using dynamic light scattering (DLS) and FT-IR spectroscopy. The systems studied were chlorobenzene/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT)/bmimTfO, chlorobenzene/AOT/bmimTfA, chlorobenzene/benzyl-n-hexadecyldimethylammonium chloride (BHDC)/bmimTfO and chlorobenzene/BHDC/bmimTfA. DLS results reveal the formation of RMs containing bmimTfO and bmimTfA as polar components since the droplet size values increase as Ws (Ws = [IL]/[surfactant]) increases. To the best of our knowledge this is the first report where it is shown that both ILs are entrapped by AOT and BHDC surfactants to effectively create RMs. Furthermore, it is shown that the RMs consist of discrete spherical and non-interacting droplets of IL stabilized by the surfactants. The larger droplet size values and the larger changes obtained for bmimTfO entrapped in AOT and BHDC RMs in comparison with those for bmimTfA in both RMs can be explained considering the different IL-surfactant interactions. The FT-IR results suggest that the ionic interactions (with the surfactant polar head groups, surfactant counterions or with the IL counterions) are substantially modified upon confinement. These interactions produce segregation of ILs's ions altering the composition of the RM interfaces. These facts show the versatility of this kind of organized systems to alter the ionic organization, information that can be very important if these media are used as nanoreactors because unique microenvironments can be easily created simply changing the RM components and Ws.

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In this work, we have investigated the behavior of the square-planar mixed-ligand transition-metal complex N,N,N',N'-tetramethylethylenediamine copper (II) acetylacetonate tetraphenylborate, [Cu(acac)(tmen)][B(C(6)H(5))(4)], in anionic benzene/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles (RMs) as well as in cationic benzene/benzyl-n-hexadecyl dimethylammonium chloride (BHDC) RMs with and without water, using absorption spectroscopy. In the absence of water, W(0)=[H(2)O]/[surfactant]=0, our results show that the Cu complex structures are not the same in both reversed micellar media. In the BHDC RMs, due to the Cl(-) counterion present in the system, the Cu complex structure that exists at the interface is the neutral [Cu(acac)(tmen)(Cl)]. In contrast, in AOT RMs the surfactant sulfonate anion cannot act as a ligand and therefore the complex structure is square planar [Cu(acac)(tmen)](+). When water is added to both reversed micellar systems, different situations are observed. At low water content, the water sequestrated by BHDC RMs is unable to act as electron donor because the oxygen nonbonding electron pairs are completely involved in the cationic BHDC polar head group solvation through an ion-dipole interaction. On the contrary, in AOT RMs the results suggest that since the water molecules solvate the sulfonate group through hydrogen bonding interactions, the bulk hydrogen bond network is destroyed at the interface and therefore, the nonbonding electron pairs are more available to interact with the Cu complex. Thus, the electron donor ability of water in AOT RMs is enhanced in comparison with the BHDC RMs and bulk water, giving a remarkable electron donor character to the AOT reversed micellar interfacial water.