Nano-Anatase-Enhanced Peroxyoxalate Chemiluminescence and Its Sensing Application

This paper reports a new nanosized anatase particle enhanced chemiluminescence sensor that utilizes the catalytic surface of anatase for sensitive detection of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). This chemiluminescence sensor was composed of anatase nanoparticles grafted with the nitrobenzoxadiazole (NBD) fluorophore, bis­(2,4,6-trichlorophenyl)­oxalate (TCPO), and hydrogen peroxide (H₂O₂). The chemiluminescence efficiency of the sensor has been greatly enhanced by 6 times compared with that in the absence of nano-anatase. However, 2,4-D could greatly suppress the chemiluminescence enhancement of anatase nanoparticles probably by adsorbing and competitively reacting with the activated hydrogen peroxide on the anatase surface. The phenomenon has been used to detect 2,4-D by monitoring the quenching of the chemiluminescence of the system. The limit of detection of the chemiluminescence sensor system was estimated to be as low as 0.33 nmol/L. The simple and sensitive sensor reported herein exhibited an effective combination of traditional chemiluminescence with nano-anatase for sensitive detection, thus promoting the advances of chemiluminescence sensing on the basis of nanomaterials

General Strategy for Fine Manipulating Crystal Growth of Water-Soluble Salts

In this work, a general strategy was proposed for fine manipulating intrinsic growth of water-soluble salts belonging to different crystal systems. Various hollow microsphere hierarchical architectures assembled with hopperlike single crystal blocks of cubic KBr, orthorhombic (NH₄)₂SO₄, or hexagonal Na₂SO₃ have been designed and prepared via microemulsions. Intrinsic growth manipulations of different water-soluble salts has been successfully achieved by preventing growth of the outside surface of each single crystal block via a diffusion-limit effect of the interfaces between the oil phase and aqueous droplets. As a result, hopperlike single crystals of water-soluble salts belonging to different crystal systems were formed. Furthermore, octahedral NaCl hopperlike single crystal, rather than their typical cubic shape, has also been fabricated by manipulating their growth rates along different lattice directions in combination with urea as additives. The large amount of fine manipulation of intrinsic growth of water-soluble salts will provide us with a deep understanding of crystallography of inorganic salts, as well as facilitate design and production of water-soluble salts architectures with corresponding shapes, according to the different requirements

Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin

Penicilloic acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis­(phenylenediamine)–Cu²⁺–PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule <i>p</i>-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of <i>p</i>-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods

Fluorescence “Turn On” Detection of Mercuric Ion Based on Bis(dithiocarbamato)copper(II) Complex Functionalized Carbon Nanodots

A new “turn on” fluorescence nanosensor for selective Hg²⁺ determination is reported based on bis­(dithiocarbamato)­copper­(II) functionalized carbon nanodots (CuDTC₂-CDs). The CuDTC₂ complex was conjugated to the prepared amine-coated CDs by the condensation of carbon disulfide onto the nitrogen atoms in the surface amine groups, followed by the coordination of copper­(II) to the resulting dithiocarbamate groups (DTC) and finally by the additional coordination of ammonium N-(dithicarbaxy) sarcosine (DTCS) to form the CuDTC₂-complexing CDs. The CuDTC₂ complex at surface strongly quenched the bright-blue fluorescence of the CDs by a combination of electron transfer and energy transfer mechanism. Hg²⁺ could immediately switch on the fluorescence of the CuDTC₂-CDs by promptly displacing the Cu²⁺ in the CuDTC₂ complex and thus shutting down the energy transfer pathway, in which the sensitive limit for Hg²⁺ as low as 4 ppb was reached. Moreover, a paper-based sensor has been fabricated by printing the CuDTC₂-CDs probe ink on a piece of cellulose acetate paper using a commercial inkjet printer. The fluorescence “turn on” on the paper provided the most conveniently visual detection of aqueous Hg²⁺ ions by the observation with naked eye. The very simple and effective strategy reported here facilitates the development of portable and reliable fluorescence nanosensors for the determination of Hg²⁺ in real samples

Chemiluminescence Switching on Peroxidase-Like Fe₃O₄ Nanoparticles for Selective Detection and Simultaneous Determination of Various Pesticides

To achieve selectivity in direct chemiluminescence (CL) detection is very significant and a great challenge as well. Here, we report a novel concept of developing intrinsically selective CL switching at the surface of Fe₃O₄ nanoparticles for the sensitive detection and simultaneous determination of various pesticides. Fe₃O₄ nanoparticles have peroxidase-like catalytic activity and catalyze the decomposition of dissolved oxygen to generate superoxide anions, so that the CL intensity of luminol was amplified by at least 20 times. The CL signals can be quenched by the addition of ethanol because ethanol readily reacts with superoxide anions as a radical scavenger. However, the quenching effect can be inhibited through the specific binding of target molecules on Fe₃O₄ nanoparticles, leading to CL “turn-on” in the presence of ethanol. The novel CL “switching-on” concept demonstrated unique advantages in the detection of pesticide residues. Using the surface coordinative reactions, nonredox pesticide ethoprophos were sensitively detected with a detection limit of 0.1 nM and had a very wide detection range of 0.1 nM to 100 μM. More importantly, the selectivity of CL switching is tunable through the special surface modification of Fe₃O₄ nanoparticles, and these Fe₃O₄ nanoparticles with different surface groups can generate unique CL response pattern for the simultaneous determination of various pesticides. Meanwhile, the superparamagnetic properties of Fe₃O₄ nanoparticles provide a simple magnetic separation approach to attain interference-free measurement for real detection. The very facile and versatile strategy reported here should open a new window to exploration of selective CL molecular switching and application of magnetic nanoparticles for chemo/biodetection

Increasing Phase Change Latent Heat of Stearic Acid via Nanocapsule Interface Confinement

Latent heat of phase change materials (PCMs) has long been regarded as constant. In this work, it is found that this parameter can be altered when they are in nanoscale. We designed and assembled a nanocapsule-confinement system with stearic acid (SA) sealed in silica nanoshells to investigate the thermodynamics and kinetics of their phase transition in nanoscale. It is interesting that heat storage capacity of the obtained SA@SiO₂ nanocapsules (NCs) could be increased up to 374.2 kJ/kg, about 36.9% more than that of the unconfined SA (273.3 kJ/kg). This is because the high superimposed stress from the curvature effect inside SiO₂ nanoshells would significantly shorten the intermolecular spacing of SA as compared to their unconfined state, which will especially strengthen hydrogen bonds of SA, forming multiple stable hydrogen bond networks. Therefore, breaking and reforming of these hydrogen bonds will no doubt contribute to latent heat of SA when they change from solid to liquid. Our results not only are helpful for understanding phase transition behaviors of phase change materials in nanocapsule interface confinement conditions but also provide a good example to develop new types of heat energy storage composite materials

Surface-Enhanced Raman Scattering Chip for Femtomolar Detection of Mercuric Ion (II) by Ligand Exchange

The chemical sensing for the convenient detection of mercuric ion (II) (Hg²⁺) have been widely explored with the use of various sensing materials and techniques. It still remains a challenge to achieve ultrasensitive but simple, rapid, and inexpensive detection to metal ions. Here we report a surface-enhanced Raman scattering (SERS) chip for the femtomolar (fM) detection of Hg²⁺ by employing silver-coated gold nanoparticles (Au@Ag NPs) together with an organic ligand. 4,4′-Dipyridyl (Dpy) can control the aggregation of Au@Ag NPs via its dual interacting sites to Ag nanoshells to generate strong Raman hot spots and SERS readouts. However, the presence of Hg²⁺ can inhibit the aggregation of Au@Ag NPs by the coordination with Dpy, and as a result the SERS signals of Dpy are quenched. On the basis of these findings, a SERS chip has been fabricated by the assembly of Au@Ag NPs on a piece of silicon wafer and the further modification with Dpy. The exchange of Dpy from the chip into the aqueous Hg²⁺ droplet results in the quenching of Raman signals of Dpy, responding to 10 fM Hg²⁺ that is about 6 orders of magnitude lower than the limit defined by the U.S. Environmental Protection Agency in drinkable water. Each test using the SERS chip only needs a droplet of 20 μL sample and is accomplished within ∼4 min. The SERS chip has also been applied to the quantification of Hg²⁺ in milk, juice, and lake water

Table_1_Clinical safety and possible efficacy of tirofiban in combination with intravenous thrombolysis by recombinant tissue plasminogen activator for early treatment of capsular warning syndrome (CWS).DOCX

The purpose of this study was to assess the efficacy and safety of the combination of tirofiban with intravenous thrombolysis (IVT) in treating patients with capsular warning syndrome (CWS) who failed to respond to the treatment of intravenous thrombolysis alone. Tirofiban was approved for the treatment of CWS patients with fluctuating symptoms or no substantial improvement after intravenous thrombolysis within 24 h in our hospital from October 2019 to June 2021. Patients were evaluated with the National Institutes of Health Stroke Scale (NIHSS) at admission, at 72 h post-thrombolysis, at 1-week, and at 3-months with the modified Rankin Scales (MRS) score. A total of 12 patients received tirofiban and eight patients received control treatment with a history of CWS in our cohort. Among the patients, 13 patients smoked more than one pack of cigarettes a day, 17 had hypertension, 17 had hypercholesterolemia, 7 had diabetes, 1 had the history of cerebral infarction, 2 had atrial fibrillation, 7 had mild big vascular stenosis, 13 had lesions of the perforating branch by imaging, and 19 had acute capsular infarction. In both the tirofiban and control groups, NIHSS scores were significantly reduced after intravenous thrombolysis or 1-week after onset compared with before intravenous thrombolysis (P < 0.001). Before and after intravenous thrombolysis, there were no differences between the tirofiban group and control group (P = 0.970, P = 0.384, respectively). The tirofiban group, however, showed remarkably lower scores in both 1-week NIHSS and 3-month MRS than the control (P = 0.012, P = 0.003, respectively). Our study revealed that tirofiban did not increase the risk of hemorrhage and had favorable clinical efficacy as a remedial treatment for CWS patients with poor prognosis for intravenous thrombolysis, therefore indicating great potential for broader use.</p

Atomic Oxygen Tailored Graphene Oxide Nanosheets Emissions for Multicolor Cellular Imaging

Graphene oxide (GO) has been widely used as a fluorescence quencher, but its luminescent properties, especially tailor-made controlling emission colors, have been seldom reported due to its heterogeneous structures. Herein, we demonstrated a novel chemical oxidative strategy to tune GO emissions from brown to cyan without changing excitation wavelength. The precise tuning is simply achieved by varying reaction times of GO nanosheets in piranha solution, but there is no need for complex chromatography separation procedures. With increasing reaction times, oxygen content on the lattice of GO nanosheets increased, accompanied by the diminution of their sizes and sp² conjugation system, resulting in an increase of emissive carbon cluster-like states. Thereby, the luminescent colors of GO were tuned from brown to yellow, green, and cyan, and its fluorescent quantum yields were enhanced. The obtained multicolored fluorescent GO nanosheets would open plenty of novel applications in cellular imaging and multiplex encoding analysis

Fluorescent Nanohybrid of Gold Nanoclusters and Quantum Dots for Visual Determination of Lead Ions

Highly green emissive gold nanoclusters (Au NCs) are synthesized using glutathione as a stabilizing agent and mercaptopropionic acid as a ligand, and the intensity of fluorescence is specifically sensitive to lead ions. We then fabricated a ratiometric fluorescence nanohybrid by covalently linking the green Au NCs to the surface of silica nanoparticles embedded with red quantum dots (QDs) for on-site visual determination of lead ions. The green fluorescence can be selectively quenched by lead ions, whereas the red fluorescence is inert to lead ions as internal reference. The different response of the two emissions results in a continuous fluorescence color change from green to yellow that can be clearly observed by the naked eyes. The nanohybrid sensor exhibits high sensitivity to lead ions with a detection limit of 3.5 nM and has been demonstrated for determination of lead ions in real water samples including tap water, mineral water, groundwater, and seawater. For practical application, we dope the Au NCs in poly­(vinyl alcohol) (PVA) film and fabricate fluorescence test strips to directly detect lead ions in water. The PVA-film method has a visual detection limit of 0.1 μM, showing its promising application for on-site identification of lead ions without the need for elaborate equipment