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Orozco J.,Catalan Institute of Nanoscience and Nanotechnology | Mercante L.A.,Catalan Institute of Nanoscience and Nanotechnology | Mercante L.A.,National Laboratory for Nanotechnology in Agribusiness LNNA | Pol R.,Catalan Institute of Nanoscience and Nanotechnology | And 2 more authors.
Journal of Materials Chemistry A | Year: 2016

Persistent organic pollutants (POPs) are ubiquitous in the environment as a result of modern industrial processes. We present an effective POPs decontamination strategy based on their dynamic adsorption at the surface of reduced graphene oxide (rGO)-coated silica (SiO2)-Pt Janus magnetic micromotors for their appropriate final disposition. While the motors rapidly move in a contaminated solution, the adsorption of POPs efficiently takes place in a very short time. Characterization of the micromotors both from the materials and from the motion point of view was performed. Polybrominated diphenyl ethers (PBDEs) and 5-chloro-2-(2,4-dichlorophenoxy) phenol (triclosan) were chosen as model POPs and the removal of the contaminants was efficiently achieved. The rGO-coated micromotors demonstrated superior adsorbent properties with respect to their concomitant GO-coated micromotors, static rGO-coated particles and dynamic silica micromotors counterparts. The extent of decontamination was studied over the number of micromotors, whose magnetic properties were used for their collection from environmental samples. The adsorption properties were maintained for 4 cycles of micromotors reuse. The new rGO-coated SiO2 functional material-based micromotors showed outstanding capabilities towards the removal of POPs and their further disposition, opening up new possibilities for efficient environmental remediation of these hazardous compounds. © 2016 The Royal Society of Chemistry. Source

Hamad E.M.,German Jordanian University | Bilatto S.E.R.,Federal University of Sao Carlos | Bilatto S.E.R.,National Laboratory for Nanotechnology in Agribusiness LNNA | Adly N.Y.,Julich Research Center | And 7 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2016

Bonding of polymer-based microfluidics to polymer substrates still poses a challenge for Lab-On-a-Chip applications. Especially, when sensing elements are incorporated, patterned deposition of adhesives with curing at ambient conditions is required. Here, we demonstrate a fabrication method for fully printed microfluidic systems with sensing elements using inkjet and stereolithographic 3D-printing. © The Royal Society of Chemistry 2016. Source

Zamora-Galvez A.,Catalan Institute of Nanoscience and Nanotechnology | Ait-Lahcen A.,Catalan Institute of Nanoscience and Nanotechnology | Ait-Lahcen A.,Hassan II University | Mercante L.A.,Catalan Institute of Nanoscience and Nanotechnology | And 5 more authors.
Analytical Chemistry | Year: 2016

Sulfonamides are known not only to be antimicrobial drugs that lead to antimicrobial resistance but also to be chemotherapeutic agents that may be allergenic and potentially carcinogenic, which represents a potentially hazardous compound once present in soil or water. Herein, a hybrid material based on molecularly imprinted polymer (MIP)-decorated magnetite nanoparticles for specific and label-free sulfonamide detection is reported. The composite has been characterized using different spectroscopic and imaging techniques. The magnetic properties of the composite are used to separate, preconcentrate, and manipulate the analyte which is selectively captured by the MIP onto the surface of the composite. Screen printed electrodes have been employed to monitor the impedance levels of the whole material, which is related to the amount of the captured analyte, via electrochemical impedance spectroscopy. This composite-based sensing system exhibits an extraordinary limit of detection of 1 × 10-12 mol L-1 (2.8 × 10-4 ppb) (S/N = 3), which is close to those obtained with liquid chromatography and mass spectrometry, and it was demonstrated to screen sulfamethoxazole in a complex matrix such as seawater, where according to the literature sulfonamides content is minimum compared with other environmental samples. © 2016 American Chemical Society. Source

Mercante L.A.,National Laboratory for Nanotechnology in Agribusiness LNNA | Scagion V.P.,National Laboratory for Nanotechnology in Agribusiness LNNA | Scagion V.P.,Federal University of Sao Carlos | Pavinatto A.,National Laboratory for Nanotechnology in Agribusiness LNNA | And 4 more authors.
Journal of Nanomaterials | Year: 2015

The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride) (Au@PAH NPs), as well as the capability of this material to form multilayer Layer-by-Layer (LbL) nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc). Film growth was monitored by UV-Vis absorption spectroscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA), revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment. © 2015 Luiza A. Mercante et al. Source

Mercante L.A.,National Laboratory for Nanotechnology in Agribusiness LNNA | Pavinatto A.,National Laboratory for Nanotechnology in Agribusiness LNNA | Iwaki L.E.O.,University of Sao Paulo | Scagion V.P.,National Laboratory for Nanotechnology in Agribusiness LNNA | And 6 more authors.
ACS Applied Materials and Interfaces | Year: 2015

The use of nanomaterials as an electroactive medium has improved the performance of bio/chemical sensors, particularly when synergy is reached upon combining distinct materials. In this paper, we report on a novel architecture comprising electrospun polyamide 6/poly(allylamine hydrochloride) (PA6/PAH) nanofibers functionalized with multiwalled carbon nanotubes, used to detect the neurotransmitter dopamine (DA). Miscibility of PA6 and PAH was sufficient to form a single phase material, as indicated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), leading to nanofibers with no beads onto which the nanotubes could adsorb strongly. Differential pulse voltammetry was employed with indium tin oxide (ITO) electrodes coated with the functionalized nanofibers for the selective electrochemical detection of dopamine (DA), with no interference from uric acid (UA) and ascorbic acid (AA) that are normally present in biological fluids. The response was linear for a DA concentration range from 1 to 70 μmol L-1, with detection limit of 0.15 μmol L-1 (S/N = 3). The concepts behind the novel architecture to modify electrodes can be potentially harnessed in other electrochemical sensors and biosensors. © 2015 American Chemical Society. Source

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