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A flexible polyaniline-based self-powered electrochromic smart window based on the highly conductive and stable Ag@Au–Co alloy nanowire network was successfully fabricated.

Colorimetric and fluorescent probes have emerged as a potent tool for pH sensing due to easy operation and high sensitivity. However, most of the existing bimodal probes require complicated synthesis, which greatly limits their wide applications. Herein, a simple fluorescent dye (called BFCUR) featuring a D-π-A-π-D conjugated system was developed from the natural polyphenol curcumin (CUR). BFCUR exhibited significant red-shift in UV absorption and fluorescence emission as pH increased because of the deprotonation of the phenolic hydroxyl groups, which resulted in the enhanced intramolecular charge transfer (ICT). The ratiometric pH detection of BFCUR was achieved with remarkable accuracy by monitoring both the absorbance ratio A500/A650 and the fluorescence intensity ratio I622/I743 under various pH values. In addition, the clear color changes of BFCUR under different pH conditions were visible, which enabled BFCUR to be used in test strips for rapid, visual pH detection. Moreover, BFCUR exhibited low cytotoxicity, and was successfully applied for intracellular pH detection, where the fluorescence intensity was linearly related to pH value. This study highlighted the great potential of CUR-derived BFCUR as colorimetric and fluorescent probes for ratiometric-pH sensing and cell imaging.

This work aimed to study the experiment of Mycobacterium tuberculosis (MTB) detection via magnetic nanoparticle (MNP) capture combined with polymerase chain reaction (PCR) technology. Thirty sputum samples were collected, MTB was isolated and cultured, and DNA templates were prepared. Fe3O4-polyethylene imide (PEI) MNPs were prepared, and PCR was adopted to test the 30 samples. Within the range of 0–600 °C, as the temperature rose, the quality of Fe3O4-PEI MNPs was gradually reduced. MNPs were positively charged when the pH value was 2–8. The highest capture rate of MTB with OD500 = 0.4 was 71%. The highest capture rate of MTB with OD500 = 0.6 was 58%. The highest capture rate of MTB with OD500 = 0.8 was 26%. When the temperature was heated to 900 ˚C, the thermal weight loss of MTB was about 85% if MNP wasn’t added. The thermal weight loss of MNP-captured MTB was about 45%, while that of uncaptured MTB was about 71%. In summary, polyethyleneimine could enhance the adsorption of MNP to MTB, and the capture rate gradually increased over time. The lipid of the cell wall of MTB was involved in the interaction between MTB and MNP.

BACKGROUND Brain tissue hypoxia is a common consequence of traumatic brain injury (TBI) due to the rupture of blood vessels during impact and it correlates with poor outcome. The current magnetic resonance imaging (MRI) techniques are unable to provide a direct map of tissue hypoxia. PURPOSE To investigate whether GdDO3NI, a nitroimidazole-based T1 MRI contrast agent allows imaging hypoxia in the injured brain after experimental TBI. STUDY TYPE Prospective. ANIMAL MODEL TBI-induced mice (controlled cortical impact model) were intravenously injected with either conventional T1 agent (gadoteridol) or GdDO3NI at 0.3 mmol/kg dose (n = 5 for each cohort) along with pimonidazole (60 mg/kg) at 1 hour postinjury and imaged for 3 hours following which they were euthanized. FIELD STRENGTH/SEQUENCE 7 T/T2 -weighted spin echo and T1 -weighted gradient echo. ASSESSMENT Injured animals were imaged with T2 -weighted spin-echo sequence to estimate the extent of the injury. The mice were then imaged precontrast and postcontrast using a T1 -weighted gradient-echo sequence for 3 hours postcontrast. Regions of interests were drawn on the brain injury region, the contralateral brain as well as on the cheek muscle region for comparison of contrast kinetics. Brains were harvested immediately post-imaging for immunohistochemical analysis. STATISTICAL TESTS One-way analysis of variance and two-sample t-tests were performed with a P

Lysosomal pH is an important indicator for the physiological state of eukaryotic cells. The real-time detection of intracellular lysosomal pH is critical for understanding and studying many physiological and pathological processes of cells. Herein, we designed and synthesized a series of novel pH sensors, namely W1, W2 and W3. By comparing the spectroscopic properties of the three molecules and their ability to target lysosomes in living cells, a specific probe W1 was selected for the quantitative analysis of lysosomal pH changes in live cells. W1 shows a fast, sensitive and highly selective red fluorescence response to an acidic pH value. The p

Highly selective fluorescent K+ sensors are of great importance for monitoring K+ fluctuations in various biological processes. In particular, highly efficient ratiometric K+ sensors that can emit ...

The concentration of potassium ion is an important indicator for human health, and its abnormality is often accompanied by various diseases. However, most tools currently used to study potassium ion transport are low throughput. Herein, we reported a new K

The continuous advancement of modern electronic equipment requires increasing the conductivity of electrically conductive adhesives (ECAs), but the gap between discrete silver flakes in conventiona...

The potassium ion (K+) plays significant roles in many biological processes. To date, great efforts have been devoted to the development of K+ sensors for colorimetric, fluorescent, and photoacoustic detection of K+ separately. However, the development of molecular K+ probes for colorimetric detection of urinary K+, monitoring K+ fluxes in living cells by fluorescence imaging, and photoacoustic imaging of K+ dynamics in deep tissues still remains an open challenge. Herein, we report the first molecular K+ probe (NK2) for colorimetric, fluorescent, and photoacoustic detection of K+. NK2 is composed of 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF) as the chromophore and phenylazacrown-6-lariat ether (ACLE) as the K+ recognition unit. Predominate features of NK2 include a short synthetic procedure, high K+ selectivity, large detection range (5–200 mM), and triple-channel detection manner. NK2 shows good response to K+ with obvious color changes, fluorescence enhancements (about threefold), and photoacoustic intensity changes. The existence of other metal ions (including Na+, Mg2+, Ca2+, Fe2+) and pH changes (6.5–9.0) have no obvious influence on K+ sensing of NK2. Portable test strips stained by NK2 can be used to qualitatively detect urinary K+ by color changes for self-diagnosis of diseases induced by high levels of K+. NK2 can be utilized to monitor K+ fluxes in living cells by fluorescent imaging. We also find its excellent performance in photoacoustic imaging of different K+ concentrations in the mouse ear. NK2 is the first molecular K+ probe for colorimetric, fluorescent, and photoacoustic detection of K+ in urine, in living cells, and in the mouse ear. The development of NK2 will broaden K+ probes’ design and extend their applications to different fields.

The first NIR fluorescent mitochondria-targeting K+ sensor, denoted as TAC-Rh, was developed. The produced sensor consists of a rhodamine analog as the fluorophore and triazacryptand (TAC) as the K+ recognition unit. Compared to the K+ sensors reported previously, TAC-Rh exhibits two unique optical properties: the largest Stokes shifts (120 nm) and the longest emission peak wavelength (720 nm). With the assistance of this novel sensor, real-time changes of K+ concentrations in mitochondria during apoptosis were monitored for the first time. Moreover, it was also the first time that the relationship between mitochondrial K+ flux and apoptosis was investigated in real time using fluorescence imaging.

A transparent-to-gray electrochromic device (ECD) based on an asymmetric viologen was fabricated and characterized. The core material derived from novel bipyridine salt (named 1-(2-(diethoxy-phosphoryl)ethyl)-1′-(4-vinylbenzyl)-[4,4′-bipyridine]-1,1′-diium chloride bromide, DVB) combined with complementary species of ferrocene was assembled in a device with a simple configuration of ITO/EC solution/ITO. The device was first converted to blue color from transparent when 1.0 V was applied, and then neutral gray color when the potential bias was increased to 2.0 V. Meanwhile, the corresponding optical contrasts (ΔT) were 54.5% and 22% at 392 nm and 605 nm, respectively. In addition, a good coloration efficiency of 128.9 cm2 C−1 at 2.0 V and fast switching time (

Cu-chlorophyllin-bonded carbon dots (CCPh-CDs) have been synthesized at room temperature, and the energy/electron co-transfer behavior between Cu-chlorophyllin molecules (CCPh) and carbon dots (CDs) is investigated via various techniques. The mean diameters of CDs and CCPh-CDs are 2.8 nm and 3.1 nm, respectively, measured by HRTEM. The absorption spectra of CCPh-CDs show two parts: the absorptions of CDs and CCPh are in the wavelength range of 300–500 nm. The PL spectra of CCPh-CDs exhibit very weak intensities, and with the decreasing of CCPh content on CDs, the corresponding intensity increases. Luminescent decay spectra show that the PL decay times of CCPh and CCPh-CDs with the highest CCPh content are single-exponentially fitted to be 3.20 ns and 12.64 ns, respectively. Furthermore, based on the electron transfer and reducibility of CCPh-CDs, Ag/Ag2O nanoparticles with a mean diameter of 10 nm can be easily prepared at room temperature under ultraviolet irradiation. The PL measurement result reveals that both electron transfer and FRET behavior take place from CCPh-CDs to Ag.

Real-time monitoring of dissolved oxygen (DO) and pH is of great significance for understanding cellular metabolism. Herein, a dual optical pH/O

Highly selective fluorescent K

In this study, we aimed to synthesize magnetically well-dispersed nanosensors for detecting dissolved oxygen (DO) in water, and explore their biological applications. Firstly, we synthesized two kinds of magnetic nanoparticle with average sizes of approximately 82 nm by one-step emulsion polymerization: polystyrene magnetic nanoparticles (Fe3O4@Os1-PS) and polymethylmethacrylate magnetic nanoparticles (Fe3O4@Os1-PMMA). Both types of nanoparticle present good dispersibility and fluorescence stability. The nanoparticles could be used as oxygen sensors that exhibited a high DO-sensitivity response in the range 0-39.30 mg/L, with a strong linear relationship. The nanoparticles have good magnetic properties, and so they could be recycled by magnet for further use. Recovered Fe3O4@Os1-PS still presented high stability after continued use in oxygen sensing for one month. Furthermore, Fe3O4@Os1-PS was employed for detecting the bacterial oxygen consumption of Escherichia coli (E-coli) to monitor the metabolism of bacteria. The results show that Fe3O4@Os1-PS provide high biocompatibility and non-toxicity. Polystyrene magnetic nanoparticles therefore present significant potential for application in biological oxygen sensing.

Here, the authors report a highly efficient integrated ideal-bandgap perovskite/bulk-heterojunction solar cell (IPBSC) with an inverted architecture, featuring a near infrared (NIR) polymer DTBTI-based bulk-heterojunction (BHJ) layer atop guanidinium bromide (GABr)-modified FA

We numerically investigate metasurfaces based on the well-known V-shaped antennas operating in high-order modes and short-period modes for shaping the wavefront of light. By careful arrangement of the V-shaped antennas, we design two novel super cells with large phase gradients. As a proof of concept, we design two novel metasurfaces by simulation to operate in high-order modes and short-period modes. In particular, the short-period combination can be equivalent to a metasurface operating in the second-order mode. Based on the new concept, we further arrange two azimuthal phase gradient metasurfaces to generate optical vortex beams with topological charges n = 3 and n = 2. Our results will further extend photonic research and new applications of metasurfaces.

Cellular pH and oxygen are the two important parameters to evaluate cell metabolism and functions of subcellular structures. Herein, we developed graft copolymers-based dual pH and oxygen luminescent nanoprobes with excellent sensitivity and quantum yields for both extracellular sensing and intracellular imaging. The oxygen probe platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) was encapsulated into the hydrophobic core formed by poly(e-caprolactone) (PCL), while pH sensitive fluorescein moieties were polymerized in hydrophilic chains of poly(oligo(ethylene glycol) methacrylate) (POEGMA). The quantum yield of oxygen and pH probe in the nanoprobes was separately achieved to be ˜0.15 under nitrogen and ˜0.78 at pH 8. Through tuning the polymer structures, the nanoprobes without the [2-(methacryloyloxy)ethyl] trimethylammonium chloride (MATMA) components (M1) was demonstrated to be extracellular probes; while the other nanoprobes with the MATMA moieties (M2) was demonstrated to be intracellular probe. Both nanostructured probes (＜150 nm) exhibited fast, highly sensitive and reproducible responses to pH and dissolved oxygen (DO). Clear cell density dependent extracellular acidification and oxygen consumption were observed by using M1 during the growth of macrophages and E.coli. Whereas, M2 showed the ability for analysis of pH and DO in the macrophage cells through bioimaging. Clear emission intensity changes under confocal were observed between hypoxia and normoxia conditions as well as between pH 4.5 and 7.5, suggesting that these nanoprobes are capable of cell metabolism monitoring and intracellular pH and DO analysis. This study provided a feasible way to design extracellular or intracellular multi-parameters sensing systems, simultaneously with excellent optical and sensing properties for biological applications.

Monitoring cell metabolism is crucial for understanding cell life activity and cytopathic mechanism. Glucose and oxygen are very important parameters for cell metabolism. In this work, core/shell nanomaterials as novel tricolor ratiometric luminescence nanosensors were prepared for real-time monitoring of intracellular oxygen and glucose levels. The nanosensors were achieved by covalently embedding of red emitting oxygen probes and yellow emitting reference probes into the hydrophobic cores and covalently grafting blue emitting glucose probes onto hydrophilic shells. This system realized simultaneous detection of glucose and oxygen through two different luminescent signals without enzyme assistance, and the two kinds of detection signals didn’t interfere with each other. The nanosensors could sensitively detect glucose in the range of 0.01 to 5.0 mM and simultaneously detect dissolved oxygen in the range of 0.05 to 39.3 mg/L, indicating the suitableness for intracellular glucose and oxygen monitoring. Because of the small sizes (