One-pot preparation of cross-linked amphiphilic fluorescent polymer based on aggregation induced emission dyes

A facile and novel AIE vesicle as nanoprobe for simple and rapid detection of TNT in water

Trinitrotoluene (TNT) in water will damage biological tissues and organs of the human body due to its high toxicity and risk. However, the simple and rapid detection of TNT in water is always a challenging task. Herein, we reported a novel aggregation-induced emission-a vesicle (AIE-a-V) as fluorescent nanoprobe for the detection of TNT in water by π-π self-assembly of π-π stacking induced aggregation-emission. The AIE-a-V was spherical in shape with a hydrodynamic diameter of ∼106 nm and possessed robust stability. In addition, the AIE-a-V showed strong fluorescence and its fluorescence would quickly disappear after contact with TNT. Based on this, without any cumbersome operation, the AIE-a-V could detect the presence of TNT in water within 60 s, and its minimum detectable concentration was as low as 50 nM. Moreover, the AIE-a-V could selectively detect TNT in water and would not be affected by other components, including other aromatic compounds, toxic metals, and acid-base. Therefore, the new AIE-a-V with simplicity, rapidity, sensitivity and selectivity have great application potential in the detection of TNT in water.

MUSA LUBNA, NOUR HAMID ABDURAHMAN, Y. QUDSIEH ISAM. Potential of Low Carbon Nanotubes Dosage on Chromium Removal from Water

This paper involves a method of eliminating hexavalent chromium (Cr (VI)) from the synthetic water via a low dosage of carbon nanotubes (CNT). The ability of CNT to remove Cr(VI) from synthetic water through the adsorption process was studied in batch experimentation. The findings revealed up to 100% elimination of Cr(VI) in the 0.07 mg/L Cr(VI) concentration. These excessive elimination proficiencies were credited to the powerful adsorption of chromium ions to the physical properties of the CNT. A pattern layout was created in these experimental runs in order to locate the ideal situation of the Cr(VI) deletion from synthetic water. To accomplish the purposes of the experiment, there were 4 independent variables influencing several points, namely the CNT dosage, the pH of the water, the agitation speed, and the contact time. The StatGraphics Centurion XV software has been used to create the adsorption equivalence and to discover the major impacts to the elimination of Cr(VI). The results show that the adsorption capability of the carbon nanotubes was considerably reliant on the pH of the Cr(VI) solution, supported by the CNT dosage, the contact time, and the agitation speed. The expected optimization, using the adsorption equation, shows that a 1 mg CNT dosage with a pH=2, 120 minutes contact time, and moderate agitation rate at 150 rpm is the most optimal. ABSTRAK: Kajian ini melibatkan kaedah bagi menyingkirkan kromium (VI) dari air sintetik menggunakan karbon tiub nano berdos rendah. Eksperimen kelompok dilakukan bagi menentukan keupayaaan karbon tiub nano menyingkirkan Cr(VI) dari air sintetik melalui proses penjerapan. Dapatan kajian menunjukkan Cr(VI) telah disingkirkan sebanyak 100% dari kepekatan 0.07 mg/L Cr(VI). Kecekapan penyingkiran ini adalah disebabkan penjerapan ion-ion kromium yang kuat terhadap sifat fizikal nano tiub karbon tersebut. Rekabentuk eksperimen telah dibina bagi menentukan peringkat optima penyingkiran Cr(VI) dari air sintetik. Bagi mencapai matlamat kajian, empat faktor yang terdiri daripada dos nano tiub karbon, pH air, kelajuan goncangan dan masa sentuhan diukur. Perisian StatGraphics Centurion XV telah digunakan bagi mendapatkan nilai setara proses penjerapan dan kesan utama yang menyebabkan tersingkirnya Cr(VI). Dapatan kajian menunjukkan keupayaan penjerapan oleh nano tiub karbon sangat bergantung kepada pH larutan Cr(VI), disusuli dengan dos nano tiub karbon masa sentuhan dan kelajuan goncangan. Penjerapan optimum Cr(VI) dapat dicapai pada tahap 1 mg dos nano tiub karbon, larutan pada pH 2, masa sentuhan selama 120 minit dengan kelajuan goncangan sebanyak 150 rpm.

Redox mechanisms of conversion of Cr(VI) to Cr(III) by graphene oxide-polymer composite

Alternative methods of aqueous chromium removal have been of great research interest in recent years as Cr (VI) is a highly toxic compound causing severe human health effects. To achieve better removal of Cr (VI), it is essential to understand the chemical reactions that lead to the successful removal of Cr species from the solution. Recent studies have demonstrated that graphene oxide (GO) based polymer beads cannot only adsorb Cr (VI) via electrostatic attractions but also reduce it to Cr (III), which is a much less toxic form of chromium. This conversion and the functional groups involved in this conversion, until now, were not elucidated. In the present study, we employed X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy to investigate the conversion pathway of Cr (VI) to Cr (III) in graphene-based polymer beads. The results showed that alcoholic groups are converted to carboxylic groups while reducing Cr (VI) to Cr (III). The inclusion of GO in the polymer beads dramatically increased the potential of Cr (VI) uptake and conversion to Cr (III), indicating polymers and nanomaterials containing alcohol groups can remove and convert chromium in water. Other functional groups present in the polymer bead play an important role in adsorption but are not involved in the conversion of Cr (VI) to Cr (III).

Use of Response Surface Methodology To Develop and Optimize the Composition of a Chitosan-Polyethyleneimine-Graphene Oxide Nanocomposite Membrane Coating To More Effectively Remove Cr(VI) and Cu(II) from Water

Response surface methodology was successfully used to optimize the amounts of chitosan (CS), polyethyleneimine (PEI), graphene oxide (GO), and glutaraldehyde (GLA) to produce a multifunctional nanocomposite membrane coating able to remove positively and negatively charged heavy metals, such as Cr(VI) and Cu(II). Batch experiments with different concentrations of the four coating components (GO, CS, PEI, and GLA) on cellulose membranes were carried out with solutions containing 10 ppm Cr(VI) and Cu(II) ions. Reduced quadratic equations for the Cr(VI) and Cu(II) removal were obtained based on the observed results of the batch experiments. The numerical analysis resulted in an optimized solution of soaking for 30 min in CS, 1.95% PEI, 1000 ppm GO, and 1.68% GLA with predicted removal of 90 ± 10 and 30 ± 3% for Cr(VI) and Cu(II), respectively, with a desirability of 0.99. This mathematically optimized solution for the coating was experimentally validated. To determine the best membrane material for the coating, stability of the nanocomposite coating was determined using attenuated total reflectance-infrared spectroscopy in eight membrane materials before and after exposure to four solutions with different water chemistries. The glass microfiber (GMF) membranes were determined to be one of the best materials to receive the coating. Then, the coated GMF filter was further investigated for the removal of Cr(VI) and Cu(II) in single and binary component solutions. The results showed that the coatings were able to remove successfully both heavy metal ions, suggesting its ability to remove positively and negatively charged ions from water.

Ultrasensitive detection of heparin by exploiting the silver nanoparticle-enhanced fluorescence of graphitic carbon nitride (g-C3N4) quantum dots

A composite (Ag-g-CNQDs) was prepared from graphitic carbon nitride quantum dots and silver nanoparticles by water phase synthesis. Aided by metal-enhanced fluorescence, the composite exhibits excitation-dependent red emission with a peak at 600 nm with a quantum yield of 21%. If the composite is coated with polyethylenimine (PEI) to form the Ag-g-CNQD/PEI complexe, fluorescence is strongly reduced. Upon addition of heparin, the fluorescence of the system is enhanced because PEI has a higher affinity for heparin than Ag-g-CNQDs. The effect was used to design a fluorometric  assay for heparin. The emission at 600 nm increases linearly in the 0.025 to 2.5 μM heparin concentration range, with a 8.2 nM limit of detection. Graphical abstract Schematic illustration for fabricating a composite consisting of silver nanoparticles and graphitic carbon nitride quantum dots (Ag-g-CNQDs). Its red fluorescence is weak in presence of polyethyleneimine but restored on addition of heparin. This forms the basis for a new method for heparin detection.

Facile fabrication of AIE/AIEE-active fluorescent nanoparticles based on barbituric for cell imaging applications

Compounds 1–4 were synthesized, and the optical properties and mechanisms were investigated. Compound 4 was applied to the cell imaging.

Polymeric AIE-based nanoprobes for biomedical applications: recent advances and perspectives

The development of polymeric luminescent nanomaterials for biomedical applications has recently attracted a large amount of attention due to the remarkable advantages of these materials compared with small organic dyes and fluorescent inorganic nanomaterials. Among these polymeric luminescent nanomaterials, polymeric luminescent nanomaterials based on dyes with aggregation-induced emission (AIE) properties should be of great research interest due to their unique AIE properties, the designability of polymers and their multifunctional potential. In this review, the recent advances in the design and biomedical applications of polymeric luminescent nanomaterials based on AIE dyes is summarized. Various design strategies for incorporation of these AIE dyes into polymeric systems are included. The potential biomedical applications such as biological imaging, and use in biological sensors and theranostic systems of these polymeric AIE-based nanomaterials have also been highlighted. We trust this review will attract significant interest from scientists from different research fields in chemistry, materials, biology and interdisciplinary areas.

Label-free detection of Pb2+ based on aggregation-induced emission enhancement of Au-nanoclusters

The luminescence intensity of the glutathione capped Au-nanoclusters could be enhanced due to the formation of aggregates, and was employed for the visual detection of Pb²⁺.

Preparation of emissive glucose-containing polymer nanoparticles and their cell imaging applications

Water dispersible, bright and biocompatible fluorescent glycopolymer nanoparticles were facilely fabricated, and their cellular imaging application was successfully demonstrated.

Fabrication of photostable PEGylated polymer nanoparticles from AIE monomer and trimethylolpropane triacrylate

Fabrication of biocompatible and photostable PEGylated nanoparticles from AIE monomer and trimethylolpropane triacrylate for cellular imaging.

Preparation of biocompatible and photostable PEGylated red fluorescent nanoparticles for cellular imaging

Biocompatible and photostable PEGylated red fluorescent nanoparticles were preparedviasurface-initiated ATRP and their cellular imaging application was successfully demonstrated.