Naked-Eye Detection of Morphine by Au@Ag Nanoparticles-Based Colorimetric Chemosensors

In this study, we report a novel and facile colorimetric assay based on silver citrate-coated Au@Ag nanoparticles (Au@AgNPs) as a chemosensor for the naked-eye detection of morphine (MOR). The developed optical sensing approach relied on the aggregation of Au@Ag NPs upon exposure to morphine, which led to an evident color variation from light-yellow to brown. Au@Ag NPs have been prepared by two different protocols, using high- and low-power ultrasonic irradiation. The sonochemical method was essential for the sensing properties of the resulting nanoparticles. This facile sensing method has several advantages including excellent stability, selectivity, prompt detection, and cost-effectiveness

Naked-Eye Detection of Morphine by Au@Ag Nanoparticles-Based Colorimetric Chemosensors

In this study, we report a novel and facile colorimetric assay based on silver citrate-coated Au@Ag nanoparticles (Au@AgNPs) as a chemosensor for the naked-eye detection of morphine (MOR). The developed optical sensing approach relied on the aggregation of Au@Ag NPs upon exposure to morphine, which led to an evident color variation from light-yellow to brown. Au@Ag NPs have been prepared by two different protocols, using high- and low-power ultrasonic irradiation. The sonochemical method was essential for the sensing properties of the resulting nanoparticles. This facile sensing method has several advantages including excellent stability, selectivity, prompt detection, and cost-effectiveness

Role of polymeric surfactants on the growth of manganese ferrite nanoparticles

The growth kinetics of manganese ferrite (MnFe2O4) nanoparticles was studied by solvothermal reaction of iron and manganese salts in ethylene glycol as a solvent. To explore the mechanism of the nanoparticle formation and development, polyethylene glycol (PEG) with different molecular weights and polyvinyl pyrrolidone (PVP) were used as polymeric surfactants to investigate their effects on the formation of MnFe2O4 nanoparticles. The size evolution and the size distribution not only dependent on the kind of surfactant but also on the time and temperature of reaction process. In the presence of low molecular weight PEG (PEG300), nanoparticles with diameter of 180 nm and narrow size distribution could be produced at 160°C during 12 h of reaction while the nanoparticles with average size of 330 nm were formed by using PEG300 at 200°C and 48 h. Therefore, by increasing the temperature and the time of reaction, the size of nanoparticles was increased and finally reached a critical size and then collapsed. When a large molecular weight surfactant PEG10000 was used, the nanoparticles with average size of 230 nm were formed at 180°C and 60 h. In the case of PEG300 and PEG10000 as lower and higher molecular weights, the separation between building blocks occurred after 60 h and 48 h for 180°C and 200°C, respectively. However, more collapses between primary building blocks were observed by using PEG10000. The nanoparticles were composed of small building blocks and exhibited a spherical mesocrystal structure which was demonstrated from the TEM and scanning electron microscope (SEM) results. The investigation on the growth mechanism of the nanoparticles indicated that the formation of manganese ferrite was followed by the attachment and growth of primary building blocks and their Ostwald ripening process

Experimental Investigation on the Removal of <i>p</i>-Toluic Acid from Aqueous Solution using Functionalized Polymeric Sorbent

<p>Polystyrene-divinylbenzene copolymer (PsDVB) was covalently functionalized with monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) by a simple method. The functionalized sorbents were characterized in terms of functionality and morphology, and used for the removal of <i>p</i>-toluic acid (p-TA) from aqueous solution. It was found that DEA-PsDVB has higher adsorption capacity than MEA- and TEA-PsDVB due to more accessible nitro and hydroxyl groups on its surface. Further investigation on the adsorptive properties of DEA-PsDVB indicated that the maximum uptake of p-TA occurred at the optimum pH of 5.3. The kinetics data was successfully represented by the pseudo-first-order model, and the behavior of the adsorption isotherms followed the Freundlich model well. Thermodynamic studies showed that the adsorption of p-TA onto DEA-PsDVB was an endothermic and spontaneous process along with the positive change in entropy. The regeneration of DEA-PsDVB was performed with 0.1 M NaOH solution, and results showed that 99% of the initial capacity was conserved after eight successive adsorption/regeneration cycles.</p

Sonochemical synthesis of polyoxometalatestabilized gold nanoparticles for point-of-care determination of acetaminophen levels: preclinical study in an animal model

The aim of this study is the accurate and rapid detection of acetaminophen (AP) for point-of-care (POC) clinical diagnosis. Acetaminophen overdose causes acute liver failure and currently there is a lack of rapid quantitative detection methods for this drug in the emergency room. Here, low-frequency sonication (20 kHz) in the presence of phosphomolybdic acid (PMo12) was used to reduce Au3+ to Au0 and stabilize the resulting spherical Au0 nanoparticles (herein AuNPs). These AuNPs@PMo12 were used as nano-probes for the selective detection of acetaminophen in the presence of other commercial drugs. The optical sensing method we describe is based on the aggregation of AuNPs@PMo12 in the presence of acetaminophen, which produces a red-shift in the absorption spectrum of the AuNPs@PMo12, which is characterised by a color change from red to purple that is visible to the naked eye. Furthermore, the quantitative determination of acetaminophen concentrations can be carried out using the eyedropper function in Microsoft's PowerPoint or open access ImageJ software, using RGB (red, green, and blue) values. To prove the feasibility of this novel nanosensor, the concentration of acetaminophen was measured in over-the-counter pharmaceutical tablets and in serum samples taken from mice. This simple sensing approach offers high stability, selectivity, rapid detection time, and cost saving compared to other detection methods, which therefore opens the way for the development of quantitative POC acetaminophen detection using polyoxometalate-stabilized metal nanoparticles.This work has been financially supported by the Iranian National Science Foundation (INSF) (No. 97009286).Peer reviewe

Role of polymeric surfactants on the growth of manganese ferrite nanoparticles

The growth kinetics of manganese ferrite (MnFe2O4) nanoparticles was studied by solvothermal reaction of iron and manganese salts in ethylene glycol as a solvent. To explore the mechanism of the nanoparticle formation and development, polyethylene glycol (PEG) with different molecular weights and polyvinyl pyrrolidone (PVP) were used as polymeric surfactants to investigate their effects on the formation of MnFe2O4 nanoparticles. The size evolution and the size distribution not only dependent on the kind of surfactant but also on the time and temperature of reaction process. In the presence of low molecular weight PEG (PEG(300)), nanoparticles with diameter of 180 nm and narrow size distribution could be produced at 160 degrees C during 12 h of reaction while the nanoparticles with average size of 330 nm were formed by using PEG(300) at 200 degrees C and 48 h. Therefore, by increasing the temperature and the time of reaction, the size of nanoparticles was increased and finally reached a critical size and then collapsed. When a large molecular weight surfactant PEG(10000) was used, the nanoparticles with average size of 230 nm were formed at 180 degrees C and 60 h. In the case of PEG(300) and PEG(10000) as lower and higher molecular weights, the separation between building blocks occurred after 60 h and 48 h for 180 degrees C and 200 degrees C, respectively. However, more collapses between primary building blocks were observed by using PEG(10000). The nanoparticles were composed of small building blocks and exhibited a spherical mesocrystal structure which was demonstrated from the TEM and scanning electron microscope (SEM) results. The investigation on the growth mechanism of the nanoparticles indicated that the formation of manganese ferrite was followed by the attachment and growth of primary building blocks and their Ostwald ripening process. (C) 2012 Elsevier B.V. All rights reserved