Graphene-based Janus micromotors for the dynamic removal of pollutants

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 (SiO)-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 SiO 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

Compostos magnéticos moleculares: o desenvolvimento de novos materiais magnéticos nanoestruturados

The development of new magnetic materials has attracted attention of researchers of different areas. In the last decades, a distinguished class of materials emerged in magnetism, in which the magnetic moment is delocalized over molecules. By varying the synthetic conditions it is possible to obtain a large variety of structures and properties using the same starting molecules. These materials have a great scientific appeal due to the possibility of presenting not only magnetic, but also optical or electrical transport properties. In this review we will present an overview of some molecular magnetic compounds, in particular molecular nanomagnets

Diplomasi Indonesia terhadap Unesco dalam Meresmikan Subak sebagai Warisan Budaya Dunia

This research is about Indonesia diplomacy effort to UNESCO to inaugurate Subak in Bali as a world cultural heritage from Indonesia in 2012. Subak Bali is a cultural heritage, it is an irrigation system that regulates the division of water management based on the mindset of harmony and togetherness, it based on formal rules and religious values. Many claims by other countries that take Indonesian culture, such as batik claiming by Malaysia, its make Indonesian government ask to UNESCO to recognize Subak as Indonesian culture. Many participants help the government to get the legally, its come from local community and also the government. Subak get legally as a Indonesia heritage culture after 10 years by some process like selection, filtration and fit and proper test. This research applies realist perspective, where it focuses on state as the main actor in international politics. Indonesia wants show to the world that Indonesia also has a heritage culture. To explain this research, the author used theory of diplomacy. This research is a qualitative descriptive research. It uses the library method by taking the data from books, journals, articles, internet and other source. The author visit Department Cultural of Bali to direct research. This research applies realist perspective, where it focuses on state as the main actor in international politics. Indonesia wants show to the world that Indonesia also has a heritage culture. To explain this research, the author used theory of diplomacy. This research is a qualitative descriptive research. It uses the library method by taking the data from books, journals, articles, internet and other source. The author visit Department Cultural of Bali to direct research. The result of this research indicate that Indonesian government did multi-track diplomacy effort to get legally Subak as a world cultural heritage of Indonesia from UNESCO on 2012. The effort get a feedback from UNESCO on Mei 2012, when the Bali Heritage culture The Cultural Landscape of Bali : Subak System as a Manifestation of The Tri Hita Karana was approved to be a World Cultural heritage. It assigned in the 36th session of UNESCO in St. Petersbug, Russia on 29 June 2012. The result of this research indicate that Indonesian government did multi-track diplomacy effort to get legally Subak as a world cultural heritage of Indonesia from UNESCO on 2012. The effort get a feedback from UNESCO on Mei 2012, when the Bali Heritage culture The Cultural Landscape of Bali : Subak System as a Manifestation of The Tri Hita Karana was approved to be a World Cultural heritage. It assigned in the 36th session of UNESCO in St. Petersbug, Russia on 29 June 2012. Keywords: subak, UNESCO, cultural heritage of Bali, multy-track diplomacy Keywords: subak, UNESCO, cultural heritage of Bali, multy-track diplomac

Recent Progress in Stimuli-Responsive Antimicrobial Electrospun Nanofibers

Electrospun nanofibrous membranes have garnered significant attention in antimicrobial applications, owing to their intricate three-dimensional network that confers an interconnected porous structure, high specific surface area, and tunable physicochemical properties, as well as their notable capacity for loading and sustained release of antimicrobial agents. Tailoring polymer or hybrid-based nanofibrous membranes with stimuli-responsive characteristics further enhances their versatility, enabling them to exhibit broad-spectrum or specific activity against diverse microorganisms. In this review, we elucidate the pivotal advancements achieved in the realm of stimuli-responsive antimicrobial electrospun nanofibers operating by light, temperature, pH, humidity, and electric field, among others. We provide a concise introduction to the strategies employed to design smart electrospun nanofibers with antimicrobial properties. The core section of our review spotlights recent progress in electrospun nanofiber-based systems triggered by single- and multi-stimuli. Within each stimulus category, we explore recent examples of nanofibers based on different polymers and antimicrobial agents. Finally, we delve into the constraints and future directions of stimuli-responsive nanofibrous materials, paving the way for their wider application spectrum and catalyzing progress toward industrial utilization

Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

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

Graphene-based Janus micromotors for the dynamic removal of pollutants

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 (SiO)-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 SiO 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.This study was supported by the European Commission Program, FP7-OCEAN, SMS Project (613844). ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295). The Nanobiosensors and Bioelectronics Group acknowledges the support from the Generalitat de Cataluña (Grant 2014 SGR 260). L. A. M. acknowledges the financial support from the FAPESP-BEPE (2014/26088-4) project.Peer Reviewe

Graphene Quantum Dots-Based Nanocomposites Applied in Electrochemical Sensors: A Recent Survey

Graphene quantum dots (GQDs) have been widely investigated in recent years due to their outstanding physicochemical properties. Their remarkable characteristics allied to their capability of being easily synthesized and combined with other materials have allowed their use as electrochemical sensing platforms. In this work, we survey recent applications of GQDs-based nanocomposites in electrochemical sensors and biosensors. Firstly, the main characteristics and synthesis methods of GQDs are addressed. Next, the strategies generally used to obtain the GQDs nanocomposites are discussed. Emphasis is given on the applications of GQDs combined with distinct 0D, 1D, 2D nanomaterials, metal-organic frameworks (MOFs), molecularly imprinted polymers (MIPs), ionic liquids, as well as other types of materials, in varied electrochemical sensors and biosensors for detecting analytes of environmental, medical, and agricultural interest. We also discuss the current trends and challenges towards real applications of GQDs in electrochemical sensors

Molecularly imprinted polymer-decorated magnetite nanoparticles for selective sulfonamide detection

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 mol L (2.8 × 10 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.This work was supported by The European Commission Program, FP7-OCEAN, SMS Project (613844). ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295). Nanobiosensors and Bioelectronics Group acknowledges Supramolecular NanoChemistry and Materials group (Dr. Carlos Carbonell and Prof. Daniel Maspoch at ICN2) for BET measurements, and the support from Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (2014 SGR 260). L.A.M acknowledges financial support from FAPESP-BEPE (2014/26088-4) project.Peer Reviewe

Chitosan/Gold Nanoparticles Nanocomposite Film for Bisphenol A Electrochemical Sensing

Bisphenol A (BPA) is considered an endocrine-disrupting compound and can cause toxicological effects, even at low doses. The development of sensitive and reliable sensors that would allow the detection of such contaminant is highly pursued. Herein, we report an electrochemical sensing strategy based on a simple and low-cost nanocomposite film sensor platform for BPA detection. The platform was developed by modifying a fluorine-doped tin oxide (FTO) electrode with layer-by-layer (LbL) films of chitosan (Chi) and gold nanoparticles functionalized with a polythiophene derivative (AuNPs:PTS). The growth of the Chi/AuNPs:PTS LbL films was monitored by UV–Vis spectroscopy. Electrochemical characterization revealed that the three-bilayer film exhibited the highest electrocatalytic performance and differential-pulse voltammetry (DPV) measurements demonstrated that the modified electrode was suitable for BPA detection through a quasi-reversible and adsorption-controlled electrochemical oxidation and reduction process. The developed sensor exhibited a linear response range from 0.4 to 20 μmol L−1, with a detection limit of 0.32 μmol L−1. The sensor showed good reproducibility with relative standard deviations of 2.12% and 3.73% to intra- and inter-electrode, respectively. Furthermore, the platform demonstrated to be suitable to detect BPA in real water samples, as well as selective for BPA detection in solutions with 100-fold excess of common interfering compounds