Multifunctional Fe₃O₄ nanoparticles for highly sensitive detection and removal of Al(III) in aqueous solution

Multifunctional rhodamine B appended ROMP derived fluorescent probe detects Al3+ and selectively labels lysosomes in live cells

There a few reports of rhodamine-based fluorescent sensors for selective detection of only Al3+, due to the challenge of identifying a suitable ligand for binding Al3+ ion. The use of fluorophore moieties appended to a polymer backbone for sensing applications is far from mature. Here, we report a new fluorescent probe/monomer 4 and its ROMP derived polymer P for specific detection of Al3+ ions. Both monomer 4 and its polymer P exhibit high selectivity toward only Al3+ with no interference from other metal ions, having a limit detection of 0.5 and 2.1 µM, respectively. The reversible recognition of monomer 4 and P for Al3+ was also proved in presence of Na2EDTA by both UV-Vis and fluorometric titration. The experimental data indicates the behavior of 4 and P toward Al3+ is pH independent in medium conditions. In addition, the switch-on luminescence response of 4 at acidic pH (0 < 5.0), allowed us to specifically stain lysosomes (pH ~ 4.5-5.0) in live cells.

Mitigation of environmentally-related hazardous pollutants from water matrices using nanostructured materials - A review

An unprecedented rise in population growth and rapid worldwide industrial development are associated with the increasing discharge of a range of toxic and baleful compounds. These toxic pollutants including dyes, endocrine-disrupters, heavy metals, personal care products, and pharmaceuticals are destructing nature's balance and intensifying environmental toxicity at a disquieting rate. Therefore, finding better, novel and more environmentally sound approaches for wastewater remediation are of great importance. Nanoscale materials have opened up some new horizons in various fields of science and technology. Among a range of treatment technologies, nanostructured materials have recently received incredible interest as an emerging platform for wastewater remediation owing to their exceptional surface-area-to-volume ratio, unique electrical and chemical properties, quantum size effects, high scalability, and tunable surface functionalities. An array of nanomaterials including noble metal-based nanostructures, transition metal oxide nanomaterials, carbon-based nanomaterials, carbon nanotubes, and graphene/graphene oxide nanomaterials to their novel nanocomposites and nanoconjugates have been attempted as the promising catalysts to overcome environmental dilemmas. In this review, we summarized recent advances in nanostructured materials that are particularly engineered for the remediation of environmental contaminants. The toxicity of various classes of relevant tailored nanomaterials towards human health and the ecosystem along with perspectives is also presented. In our opinion, an overview of the up-to-date advancements on this emerging topic may provide new ideas and thoughts for engineering low-cost and highly-efficient nanostructured materials for the abatement of recalcitrant pollutants for a sustainable environment.

A novel pyrazole bearing imidazole frame as ratiometric fluorescent chemosensor for Al3+/Fe3+ ions and its application in HeLa cell imaging

New pyrazole bearing imidazole derivative was successfully synthesized and thoroughly characterized by various spectroanalytical techniques. The sensor DIBI shows a highly selective and sensitive fluorescent response with the addition of Al³⁺/Fe³⁺ ions in acetonitrile-water mixture. The strong fluorescent molecule exhibits a notable ratiometric emissions at 462 nm and 470 nm for Al³⁺ and Fe³⁺ ions, respectively (λ_ex = 280 nm). Job's plot studies conclude that the coordination between DIBI with Al³⁺/Fe³⁺ was 1:1 binding stoichiometry. The limit of detection of DIBI with Al³⁺/Fe³⁺ was calculated as 2.12 × 10^-7 M and 1.73 × 10^-6 M, respectively. The TD-DFT calculations further supported the photonics performances of the free probe and its complexes. The reversibility and reusability of the sensor molecule are studied using EDTA. The probe was used to track Al³⁺/Fe³⁺ in cancer cells via fluorescence microscopy.

Siderophore coated magnetic iron nanoparticles: Rational designing of water soluble nanobiosensor for visualizing Al3+ in live organism

This article aims to establish the judicious use of iron-binding chemistry of microbial chelators in order to functionalize the surface of iron nanoparticles to develop non-toxic nanobiosensor. Anchoring a simple siderophore 2,3-dihydroxybenzoylglycine (H₃L), which bears catechol and carboxyl functionalities in tandem, on to the surface of Fe₃O₄ nanoparticles has developed a unique nanobiosensor HL-FeNPs which showed highly selective and sensitive detection of Al³⁺ in 100% water at physiological pH. The biosensor HL-FeNPs, with 20nM limit of detection, behaves reversibly and instantly. In-vivo bio-imaging in live brine shrimp Artemia confirmed that HL-FeNPs could be used as fluorescent biomarker for Al³⁺ in live whole organisms. Magnetic nature of the nanosensor enabled HL-FeNPs to remove excess Al³⁺ by using external magnet. To our knowledge, the possibility of microbial chelator in the practical development of Al³⁺ selective nanobiosensor is unprecedented.

Facile synthesis of a water-soluble fluorescence sensor for Al3+ in aqueous solution and on paper substrate

In this study, a facile water-soluble fluorescence sensor 2-((2-hydroxybenzylidene)-amino)-2-(hydroxymethyl)propane-1,3-diol (ST) was synthesized via one-step reaction, and its fluorescence sensing performance for Al³⁺ both in aqueous solution and on paper substrate was evaluated. The results showed that ST exhibited an specific fluorescence "turn-on" response to Al³⁺ over other cations in aqueous solution as well as on the test paper. The limit of detection was found to be 3.2×10^-7M, which revealed that the obtained Schiff-base based fluorescence chemosensor ST possessed a great potential for the rapid, quantitative and qualitative detection of Al³⁺.

Rhodamine B-based ordered mesoporous organosilicas for the selective detection and adsorption of Al(iii)

A novel “Off–On” solid chemosensor for Al³⁺ was constructed by combining ordered mesoporous silica with a rhodamine B derivative.

Multifunctional optical sensing probes based on organic–inorganic hybrid composites

Several hybrid sensing materials, which are prepared by the covalent grafting of organic fluorescent molecules onto inorganic supports, have emerged as a novel and promising class of hybrid sensing probes and have attracted tremendous interest.

White emission magnetic nanoparticles as chemosensors for sensitive colorimetric and ratiometric detection, and degradation of ClO⁻ and SCN⁻ in aqueous solutions based on a logic gate approach

Fluorescent chemosensors for detecting single anions have been largely synthesized. However, the simultaneous detection and degradation of multiple anions remain a major challenge. Herein we report the synthesis of a white emission nanoprobe on the basis of a Coumarin-Rhodamine CR1-Eu complex coordinated to dipicolinic acid (dpa)-PEG-Fe3O4 nanoparticles for the selective detection of ClO(-) and SCN(-) ions on controlling by a logic gate. The obtained nanoprobe exhibits three individual primary colors (blue, green, and red) as well as white emission at different excitation energies. Interestingly, this nanoprobe shows a marked rose red to violet emission color change in response to ClO(-), a reversible violet to rose red emission color change in response to SCN(-), and high ClO(-) and SCN(-) selectivity and sensitivity with a detection limit of 0.037 and 0.250 nM, respectively. Furthermore, the SCN(-) and ClO(-) can degrade simultaneously through the redox reaction between ClO(-) and SCN(-).

A strongly coupled Au/Fe3O4/GO hybrid material with enhanced nanozyme activity for highly sensitive colorimetric detection, and rapid and efficient removal of Hg(2+) in aqueous solutions

We have developed an efficient strategy for synthesizing a strongly coupled Au/Fe3O4/GO hybrid material to improve the catalytic activity, stability, and separation capability of Au nanoparticles (NPs) and Hg(2+). The hybrid material can be synthesized by the direct anchoring of Au and Fe3O4 NPs on the functional groups of GO. This approach affords strong chemical attachments between the NPs and GO, allowing this hybrid material to ultrasensitively detect Hg(2+) in aqueous solutions with a detection limit as low as 0.15 nM. In addition, the deposition of Hg(0) on the surface of Au/Fe3O4/GO could be quickly (within 30 min) and efficiently (>99% elimination efficiency) removed by the simple application of an external magnetic field and then Au/Fe3O4/GO could be subsequently reused at least 15 times, with the elimination efficiency remaining high (>96%).

Two Different Emission-Wavelength Fluorescent Probes for Aluminum Ion based on Tunable Fluorophores in Aqueous Media

Two simply and highly selective aluminium ion fluorescent probes based on 4-aminoantipyrine derivate have been successfully synthesized and systemically characterized, The investigation of absorption and emission spectra revealed that the compounds exhibited highly selective fluorescence behaviours toward Al(3+) in aqueous media and showed differential fluorescent emission peaks corresponding to blue and green. which resulted from different fluorophores, and the fluorescence process is attributed to the Photoinduced Electron Transfer (PET) mechanism, In addition, the association constants between sensors L1 and L2 with aluminum ion are 1.58 × 10(6) M(-1) and 8.72 × 10(6) M(-1), respectively, which were obtained by fluorescent titration experiments. Moreover, the binding site of sensors with Al(3+) were determined by (1)HNMR titration experiments.

Europium(III) complex-functionalized magnetic nanoparticle as a chemosensor for ultrasensitive detection and removal of copper(II) from aqueous solution

Ultrasensitive, accurate detection and separation of heavy metal ions is very important in environmental monitoring and biological detection. In this paper, a highly sensitive and specific detection method for Cu(2+) based on the fluorescence quenching of a europium(III) hybrid magnetic nanoprobe is presented. This nanoprobe can detect Cu(2+) over a wide pH range (5.0-10.0) with a detection limit as low as 0.1 nM and it can be used for detecting Cu(2+) in living cells. After the magnetic separation, the Cu(2+) concentration decreased to 1.18 ppm, which is less than the US EPA drinking water standard (1.3 ppm), and more than 70% Cu(2+) could be removed when the amount of nanocomposite 1 reached 1 mg.

Recent advances in surface chemistry strategies for the fabrication of functional iron oxide based magnetic nanoparticles

The synthesis of superparamagnetic nanostructures, especially iron-oxide based nanoparticles (IONPs), with appropriate surface functional groups has been intensively researched for many high-technological applications, including high density data storage, biosensing and biomedicine. In medicine, IONPs are nowadays widely used as contrast agents for magnetic resonance imaging (MRI), in hyperthermia therapy, but are also exploited for drug and gene delivery, detoxification of biological fluids or immunoassays, as they are relatively non-toxic. The use of magnetic particles in vivo requires IONPs to have high magnetization values, diameters below 100 nm with overall narrow size distribution and long time stability in biological fluids. Due to the high surface energies of IONPs agglomeration over time is often encountered. It is thus of prime importance to modify their surface to prevent aggregation and to limit non-specific adsorption of biomolecules onto their surface. Such chemical modifications result in IONPs being well-dispersed and biocompatible, and allow for targeted delivery and specific interactions. The chemical nature of IONPs thus determines not only the overall size of the colloid, but also plays a significant role for in vivo and in vitro applications. This review discusses the different concepts currently used for the surface functionalization and coating of iron oxide nanoparticles. The diverse strategies for the covalent linking of drugs, proteins, enzymes, antibodies, and nucleotides will be discussed and the chemically relevant steps will be explained in detail.

Three-dimensional conducting oxide nanoarchitectures: morphology-controllable synthesis, characterization, and applications in lithium-ion batteries

We report the synthesis, characterization and applications in Li-ion batteries of a set of 3-dimensional (3-D) nanostructured conducting oxides including fluorinated tin oxide (FTO) and aluminum zinc oxide (AZO). The morphology of these 3-D conducting oxide nanoarchitectures can be directed towards either mono-dispersed hollow nanobead matrix or mono-dispersed sponge-like nanoporous matrix by controlling the surface charge of the templating polystyrene (PS) nanobeads, the steric hindrance and hydrolysis rates of the precursors, pH of the solvents etc. during the evaporative co-assembly of the PS beads. These 3-D nanostructured conducting oxide matrices possess high surface area (over 100 m(2) g(-1)) and accessible interconnected pores extending in all three spatial dimensions. By optimizing the temperature profile during calcination, we can obtain large area (of a few cm(2)) and crack-free nanoarchitectured films with thickness over 60 μm. As such, the sheet resistance of these nanoarchitectured films on FTO glass can reach below 20 Ω per square. The nanoarchitectured FTO electrodes were used as anodes in Li-ion batteries, and they showed an enhanced cycling performance and stability over pure SnO2.

Fluorescent and colorimetric magnetic microspheres as nanosensors for Hg2+ in aqueous solution prepared by a sol-gel grafting reaction and host-guest interaction

Fluorescent sensing TSRh6G-β-cyclodextrin fluorophore/adamantane-modified inclusion complex magnetic nanoparticles (TFIC MNPs) have been synthesized via the cooperation of a host-guest interaction and sol-gel grafting reaction. Powder X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and UV-visible absorption and emission spectroscopy have been employed to characterize the material. Fluorescence and UV-visible spectra have shown that the resultant multifunctional nanoparticle sensors exhibit selective 'turn-on' type fluorescent enhancements and a clear color change from light brown to pink with Hg(2+). Owing to a larger surface area and high permeability, TFIC MNPs exhibit remarkable selectivity and sensitivity for Hg(2+), and its detection limit measures up to the micromolar level in aqueous solution. Most importantly, magnetic measurements have shown that TFIC magnetic nanoparticles are superparamagnetic and they can be separated and collected easily using a commercial magnet. These results not only solve the limitations in practical sensing applications of nanosensors, but also enable the fabrication of other multifunctional nanostructure-based hybrid nanomaterials.