Anti-interference Capacity Research Articles

Facile synthesis of fine-grained CoFe2O4 anchored on porous carbon for simultaneous removal of tetracycline and arsenite via peroxymonosulfate activation

The coexistence of tetracycline (TC) and arsenite (As(III)) in livestock wastewater threatens public health, and the heterogeneous Fenton-like system is a practical approach for the simultaneous removal of TC and As(III). In this work, fine CoFe2O4 nanoparticles are facilely anchored on heretically porous carbon (CoFe2O4@PC) via a microwave-assisted calcination method and used for eliminating TC and As(III) via peroxymonosulfate (PMS) activation. The CoFe2O4@PC/PMS system exhibits excellent performance in the simultaneous removal of 96% of 10 mg/L TC and 86% of 50 μM As(III) within 30 min, whereas the porous carbon can boost the mass transfer efficiency and protect CoFe2O4 against Co and Fe ions leaching. The CoFe2O4@PC/PMS system maintains satisfactory activity and stability in a broad pH range (3–11) and anti-interference capacity (anions, humic acid and water matrices). Meanwhile, the CoFe2O4@PC with the strong magnetic property was readily recovered from the reaction solution. Moreover, the cooperation of radical (·OH, ·SO4- and ·O2–) and nonradical (1O2) pathways was documented to play critical roles in enhancing the oxidation of TC and As(III), which effectively reduces the toxicity of degradation intermediates. This work offers a facile strategy for constructing spinel-based catalysts and opens a broad prospect for removing TC and As(III) in livestock wastewater.

Facile and highly selective near-infrared emitting fluorescent indicator for hypochlorous acid signaling and bioimaging

A near-infrared emitting fluorescent chemodosimeter for hypochlorous acid (HOCl), PAM, was designed and synthesized by modifying on the sulfonate porphyrin chromophore with a diaminomaleonitrile substituent to form Schiff-base as the chemodosimetric recognition unit. PAM behaved as a sensitive fluorescence “off-on” reactor to HOCl with satisfying anti-interference capacity over other latent disturbing analytes. The drastic fluorescence enhancement originated from the HOCl-promoted intramolecular cyclization to rigidify the molecular structure to a substituted imidazole, which effectively inhibited the CN isomerization. This chemical process is specific, expeditious and will not release extra compounds other than H2O. 1H NMR, FI-IR, HRMS, and spectral analysis confirmed the proposed mechanism. In addition to facilely synthesis, photo- and chemo-stable, PAM has outstanding features of fully water-soluble, low analytic limitation (6.3 nM), and positive linearity, which makes it practical to quantify HOCl in tap water and serum samples. Furthermore, PAM was efficiently leveraged for monitoring both exogenous and endogenous HOCl in living cells, as well as for differentiating between normal and cancer cells based on differences in basal HOCl levels. The versatility of this probe definitely provided a potential discovery tool for further elucidate the HOCl-associated neurological disorders.

Highly efficient and reusable magnetic anion-exchange microbeads for reactive dye removal

A novel magnetic anion exchange microbead (NAEM) with excellent reuse and anti-fouling performance was developed, and used for removal of an reactive dye sunset yellow (FCF). The NAEM initial adsorption rate was 16.7-, 25.8-, 31.6-, and 31.6-fold that of commercial IRA-958, D201, A520, and IRA-900 resins, respectively. The adsorption of FCF on different anion-exchange resins appeared to be multilayered, implying physical adsorption also contributes to FCF removal. The polyacrylic resin matrix exhibited higher affinity than the polystyrene matrix towards FCF. The equilibrium adsorption capacity for FCF at 298 K was in the following order: NAEM (1.95 mmol/g) > IRA-958 (1.01 mmol/g) > D201 (0.85 mmol/g) > A520 (0.81 mmol/g) > MAER (0.78 mmol/g) > IRA-900 (0.59 mmol/g). NAEM reinforced the anti-interference capacity of FCF adsorption when the concentrations of NaCl or Na2SO4 were lower than 20 mmol/L. After 10 cycles of regeneration, the FCF adsorption capacity of NAEM was 1.76-, 2.79-, 2.81-, 3.05-, and 5.26-fold higher than MAER, IRA-958, D201, A520, and IRA-900, respectively. The high adsorption capacity and excellent reusability may facilitate the practical applications of NAEM in wastewater treatment against reactive dyes.

In situ amplification based on assembly of aptamer sandwiches on nanochannels for ultrasensitive detection of exosomes

Exosomes hold tremendous potential as promising biomarkers for the early diagnosis of cancer. The urgent need for sensitive identification of cancer cell-derived exosomes has emphasized the importance of fabricating innovative approaches. In this work, we propose a novel in situ amplification strategy for ultrasensitive detection of cancer cell-derived exosomes based on the assembly of aptamer sandwiches on nanochannels. Specifically, the nanochannels are functionalized with aptamers targeting the transmembrane receptor protein CD63 to enable selective capture of exosomes. Meanwhile, the aptamers specific to membrane protein EpCAM are employed as anchors for binding with the targeted exosomes. This orchestrated interaction leads to the assembly of aptamer sandwiches, initiating a TdT-mediated polymerization reaction, thereby facilitating in situ amplification. Consequently, ultrasensitive, highly specific, and accurate detection of exosomes can be achieved, with a linear detection range from 2.06 × 103 to 2.06 × 108 particles/mL and a detection limit as low as 6.87 × 102 particles/mL. Moreover, the method shows satisfactory anti-interference capacity for the detection of exosomes in real serum samples, indicating potential applications in early clinical diagnosis of cancer.

Assessing the ecological risk of representative wastewater based on a growth inhibition method with freshwater algae (Raphidocelis subcapitata)

Wastewater contains a vast number of pollutants that potentially threaten the ecosystem after being discharged into the environment. The present study aimed to develop a rapid and sensitive toxicity detection method for assessing the ecological risk of wastewater. Raphidocelis subcapitata was used as the test organism in the algal growth inhibition test, and the anti-interference capacity of R. subcapitata itself and three biomass measuring methods (spectrophotometer, electron particle counter and chlorophyll fluorescence) on sample color and sample particulate matter were examined. The results revealed that chlorophyll fluorometry was more suitable for determining biomass in the growth inhibition test. Furthermore, chlorophyll fluorometry was selected to evaluate the combined toxic effects and sensitivity of R. subcapitata to wastewater from different industries. Microalgae respond differently to the toxicity of wastewater from various sources. The LID values for chemical wastewater 2, urban sewage 1, pharmaceutical wastewater 1, electroplating effluent and pharmaceutical wastewater 2 were 4.0, 3.0, 2.7, 2.4 and 2.0, respectively. The present study investigated the toxicity response of R. subcapitata to wastewater from various industries by growth inhibition experiments to comprehend the possible ecological concerns of wastewater from diverse businesses. This study will provide a significant basis for the design of detection methods and a comprehensive evaluation of toxicity in surface water environments.Graphical

Cyanofuran-based ratiometric fluorescent probe for monitoring hypochlorite and cupric ion in cells and in vivo

Hypochlorite (ClO−) mediates various physiological processes and diseases as a reactive oxygen species. The visualization of the concentration changes of endogenous hypochlorite in cells and in vivo faces great challenges due to the single-signal (spectrum) variation. In this study, a multifunctional ratiometric fluorescent probe IBA was designed and developed for analyzing hypochlorite and Cu2+ independently through a synergetic FRET-PET mechanism. The sensor displayed excellent capacities in anti-interference capacity and sensitivity during the analysis processes of hypochlorite and Cu2+. In particular, IBA showed different fluorescence signal for hypochlorite and Cu2+ meeting the need of independent analysis. And taking advantage of excellent optical properties of the probe in detecting hypochlorite, it successfully monitored the fluctuation of exogenous and endogenous hypochlorite in A549 cells. Moreover, IBA could visualize the changes of hypochlorite in living zebrafish with the fluorescent change between red and green. Overall, the designed novel probe IBA can serve as a potential tool to analyze hypochlorite and Cu2+, and the exploration of the variations of hypochlorite through living imaging shows potential to study the relevant molecular mechanisms and metabolism routes during multifarious physiological activities.

Strong enhancement on acetaminophen removal in thermal-activated peroxymonosulfate with sodium metaborate: Performance, mechanism, and control of chlorinated by-products formation

This study introduced sodium metaborate (NaBO2) into thermal/PMS system to enhance acetaminophen degradation. The added NaBO2 possessed better performance than sodium tetraborate in accelerating the degradation of acetaminophen with thermal/PMS system over the wide pH range from 3.0 to 11.0. NaBO2 could be partly hydrolyzed to the strong buffer capacity of the pair of H3BO3/B(OH)4− to well keep the reaction solution pH at 9.4–9.7 regardless of the initial pH. HOOB(OH)3− and HOOBO were produced via the reactions between PMS and B(OH)4−/BO2−. 1O2 and HO• were the main ROS accountable for acetaminophen degradation in NaBO2/thermal/PMS system. 1O2 was mainly formed from the self-decomposition of PMS and the reactions between PMS and HOOB(OH)3−/HOOBO. HO• was mainly formed from the thermolysis of the O-O bonds of PMS, HOOB(OH)3− and HOOBO. Three elimination pathways of acetaminophen were proposed according to the identified nine elimination intermediates, and the reaction solution toxicity was significantly decreased in NaBO2/thermal/PMS system. Improving NaBO2 dosage, PMS concentration and reaction temperature could accelerate acetaminophen removal. Cl− and Br− significantly promoted acetaminophen removal, while humic acid had the adverse effect. NaBO2/thermal/PMS system had well anti-interference capacity for actual water constituents. Moreover, the added NaBO2 could significantly inhibit the production of chlorinated by-products via the transformation of the free chlorine to the inert product of B(OH)3OCl− in Cl−-containing water treatment with NaBO2/thermal/PMS system. This study provides an effective method for improving the thermal/PMS system oxidation capacity and suppressing the chlorinated by-products production in Cl−-containing water treatment.

A Y-shape-structured electrochemiluminescence biosensor based on carbon quantum dots and locked nucleic acid probe for microRNA determination with single-base resolution

Since microRNAs (miRNAs) are predictors of tumorigenesis, accurate identification and quantification of miRNAs with highly similar sequences are expected to reflect tumor diagnosis and treatment. In this study, a highly selective and sensitive electrochemiluminescence (ECL) biosensor was constructed for miRNAs determination based on Y-shaped junction structure equipped with locked nucleic acids (LNA), graphene oxide-based nanocomposite to enrich luminophores, and conductive matrix. Specifically, two LNA-modified probes were designed for specific miRNA recognition, that is, a dual-amine functionalized hairpin capture probe and a signal probe. A Y-shaped DNA junction structure was generated on the electrode surface upon miRNA hybridizing across the two branches, so as to enhance the selectivity. Carbon quantum dots-polyethylene imine-graphene oxide (CQDs-PEI-GO) nanocomposites were developed to enrich luminophores CQDs, and thus enhancing the ECL intensity. For indirect signal amplification, an electrochemically activated poly(2-aminoterephthalic acid) (ATA) film decorated with gold nanoparticles was prepared on electrode as an effective matrix to accelerate the electron transfer. The fabricated ECL biosensor achieved sensitive determination of miRNA-222 with a limit-of-detection (LOD) as low as 1.95 fM (S/N = 3). Notably, Y-shaped junction structures equipped with LNA probes endowed ECL biosensor with salient single-base discrimination ability and anti-interference capacity. Overall, the proposed Y-shaped ECL biosensor has considerable promise for clinical biomarker determination.

Ingenious integration of Fe0 and multiphased MoS2 to activate peroxymonosulfate for carbamazepine removal at high salinity condition

To tackle high salinity challenge, differently from singlet oxygen-governed systems, extremely abundant and highly reactive sulfate radicals (SO4•─)-dominated systems might be also feasible. Ingenious integration of two active popular catalysts, and optimal selection of reaction parameters could sufficiently activate the added peroxymonosulfate (PMS) to efficiently degrade complicated pollutants within a short time so as to overlook the negative effects of inorganic anions. Herein, zero-valent iron decorated metallic 1T/semiconducting 2H hybrid phased molybdenum disulfide with different Mo/S feeding ratio (Fe0/Nx-MoS2) were constructed and compared to activate PMS for carbamazepine (CBZ) removal, where Fe0/N2-MoS2 (M(Mo):M(S) = 7:30) with ultrathin sheet morphology presented most charming decontamination performance. Optimal Fe0/N2-MoS2 dosage and PMS amount was respectively selected as 75 and 50 mg·L-1 in treating 10 mg·L-1 CBZ at pH = 3.00 via tailoring reaction parameters. CBZ could be completely removed in a short time of 10 min with a high pseudo-first-order kinetic rate constant of 0.939 ± 0.016 min−1. The system exhibits the promising anti-interference capacity toward Cl─, NO3─ and SO42─ of high concentration (even up to 3000 mg·L-1). Electron paramagnetic resonance and scavenging experiments of reactive species suggested that SO4•─ played a dominant function. Furthermore, Mo and Fe bimetallic cycles could efficiently promote PMS activation to produce rich reactive radicals. Degradation pathways and toxicity evolutions for CBZ in the (Fe0/N2-MoS2 + PMS) system were proposed via liquid chromatography time-of-flight mass spectrometer and Toxicity Estimation Software Tool, and we hope that the system would be applied in high salinity wastewater treatment in future.

In-depth insights into Fe(III)-doped g-C3N4 activated peracetic acid: Intrinsic reactive species, catalytic mechanism and environmental application

In this study, we demonstrate that Fe(III)-doped g-C3N4 can efficiently activate peracetic acid (PAA) to degrade electron-rich pollutants (e.g., sulfamethoxazole, SMX) over a wide pH range (3−7). Almost ∼100% high-valent iron-oxo species (Fe(V)) was generated and acted as the dominant reactive species responsible for the micropollutants oxidation based on the analysis result of quenching experiments, 18O isotope-labeling examination and methyl phenyl sulfoxide (PMSO) probe method. Electrochemical testing (e.g., amperometric i−t and linear sweep voltammetry (LSV)) and density functional theory (DFT) calculations illustrated that the main active site Fe atom and PAA underwent electron transfer to form Fe(V) for attacking SMX. Linear free energy relationship (LFER) between the pseudo-first-order rates of different substituted phenols (SPs) and the Hammett constant σ+ depicted the electrophilic oxidation properties. The selective oxidation of Fe(V) endows the established system remarkable anti-interference capacity against water matrices, while the Fe(V) lead to the formation of iodinated disinfection by-products (I-DBPs) in the presence of I−. Fe(III)-doped g-C3N4/PAA system showed excellent degradation efficiency of aquaculture antibiotics. This study enriches the knowledge and research of high-valent iron-oxo species and provides a novel perspective for the activation of PAA via heterogeneous iron-based catalysts and practical environmental applications.

Fluorescent detection of tartrazine based on the supramolecular self-assembly of cationic perylene diimide.

A cationic perylene probe was designed and synthesized for sensitive determination of tartrazine. In the presence of tartrazine, the fluorescence of theperylene probe was quenched by efficient supramolecular self-assembly of theperylene derivate. The quenching iscaused by the synergistic effect of noncovalent interactions including static electricity, π-π stacking, and hydrophobic interaction. Benefiting from these advantages, the probe exhibited excellent sensing performance to tartrazine within 2 min. The detection and quantification limit of tartrazine are as low as 2.42 and 8.07 nmol L-1, respectively, with a wide linear operation range from 15 to 500 nmol L-1. Most importantly, due to the high binding affinity (3.22 × 107 mol L-1) between the perylene probe and tartrazine, the sensing system shows great anti-interference capacity. Subsequently, the visualization application of the approach was evaluated by portable device, and the limits of detection for visual detection for test strip, membrane, and hydrogel were 0.5, 0.5, and 5 μmol L-1, respectively. Theapproach has been applied to monitor tartrazine in various food condiments with recoveries in the range 91.29-108.83%. As far as we know, this is the first report of using perylene-based probe for tartrazine determination, offering a promising strategy for the construction of perylene-based detection system in the field of food safety.

Rapid spectrophotometric determination of peroxydisulfate in water via oxidative coloration of 2,2′azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS) using ferrous ion as catalyst

In this study, a rapid, sensitive and reliable spectrophotometric method for peroxydisulfate (PDS) determination in water was established. The proposed spectrophotometric method was based on the oxidation of 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) to form stable and green-colored ABTS radical (ABTS•+) by ferrous ion (Fe(II))-catalyzed PDS. The formed ABTS•+ performed well linear relationship with PDS concentration (R2 > 0.999) in the range of 0–60 μM at four wavelengths of 415, 650, 732, and 820 nm under optimized conditions. The proposed Fe(II)-ABTS spectrophotometric method was highly sensitive with the absorptivity of 3.595 × 104 M−1 cm−1, 1.530 × 104 M−1 cm−1, 1.945 × 104 M−1 cm−1 and 1.768 × 104 M−1 cm−1 at four detection peaks of 415, 650, 732 and 820 nm, respectively. Additionally, the proposed Fe(II)-ABTS spectrophotometric method possessed well anti-interference capacity to common natural water constituents and was reliable to determine PDS concentration in water. What’s more, the proposed Fe(II)-ABTS spectrophotometric method was successfully applied in monitoring the change of PDS concentration during the degradation of diclofenac in heat-activated PDS process. In a word, the proposed Fe(II)-ABTS spectrophotometric method could be employed as a promising approach for the rapid and accurate measurement of PDS in water, and this study provided a new perspective for the measurement of PDS by the visible spectrophotometry.

Construction of a novel sensor based on activated nanodiamonds, zinc oxide, and silver nanoparticles for the determination of a selective inhibitor of cyclic guanosine monophosphate in real biological and food samples

In the present work, we developed a highly sensitive and selective method for the determination of sildenafil (SIL) using a modified glassy carbon electrode (GCE) with activated nanodiamonds, zinc oxide, and silver nanoparticles nanocomposite (AND@ZnO-Ag/GCE). Various voltammetric techniques, including CV, DPV, and EIS, were employed to investigate the electrochemical process of SIL on the modified electrode. The resulting AND@ZnO-Ag/GCE electrode exhibited enhanced electron transfer between the electrode and the analyte, resulting in an excellent electrocatalytic performance for SIL oxidation under optimized conditions. The analytical performance of the AND@ZnO-Ag/GCE sensor demonstrated two linear responses within the concentration range of 0.01–0.08 μM and 0.08–14.6 μM, with a remarkably low detection limit of 7.08 nM. Moreover, the modified sensor (AND@ZnO-Ag/GCE) exhibited high selectivity and anti-interference capacity. It successfully detected trace amounts of SIL in biological and food samples, yielding satisfactory results. Furthermore, this work provides insights into the potential adulteration of energy drinks with sildenafil, addressing an area that has received limited attention in previous research.

Optimization of Levenberg Marquardt Algorithm Applied to Nonlinear Systems

As science and technology advance, industrial manufacturing processes get more complicated. Back Propagation Neural Network (BPNN) convergence is comparatively slower for processing nonlinear systems. The nonlinear system used in this study to evaluate the optimization of BPNN based on the LM algorithm proved the algorithm’s efficacy through a MATLAB simulation analysis. This paper examined the application impact of the enhanced approach using the Continuous stirred tank reactor (CSTR) control system as an example. The study’s findings demonstrate that the LM optimization algorithm’s identification error exceeds 10-5. The research’s suggested control approach for reactant concentration CA in CSTR systems provides a better tracking effect and a stronger anti-interference capacity. Compared to the PI control method, the overall control effect is superior. As a result, the optimization model for nonlinear systems has a greatly improved processing accuracy. With some data support for the accuracy study of neural network models and the application of nonlinear systems, the suggested LM-BP optimization algorithm is evidently more appropriate for nonlinear systems.

Enhanced photochemical degradation and transformation of ciprofloxacin in a UV/calcium peroxide system: pH effects, defluorination kinetics, and different components numerical analysis

Advanced oxidation processes (AOPs) are highly efficient for the removal of antibiotics from water. The activation of hydrogen peroxide (H2O2) by ultraviolet (UV) has garnered increasing attention. This study describes the enhanced photochemical degradation of emerging contaminants in water using a UV-activated calcium peroxide (UV/CaO2) system, wherein CaO2 can gently produce H2O2 when exposed to UV light. The UV/CaO2 system can expeditiously and efficiently eradicate ciprofloxacin (CIP), in which hydroxyl radicals (•OH) and superoxide anions (O2•-) played critical roles. The superlative rate constant was 0.024 min−1 at an optimal dosage of 0.1 g L−1, which was a 16-fold increase over the rate of pure UV photolysis. The UV/CaO2 system had an excellent defluorination capacity (80% within 60 min). Further, this technology was intensely evaluated over a wide range of pH for the removal of CIP, including H2O2 yields, defluorination rates, as well as correlations with the reactive species generated during the reactions for numerical analysis. The UV/CaO2 system had an excellent anti-interference capacity over a wide pH range. Three major degradation pathways were proposed for the degradation of CIP, together with predictions of the physiological toxicity of these transformation intermediates. This study provides strong technical support for the promotion of this UV/CaO2 water treatment platform, as well as the decontamination and defluorination of water matrixes contaminated with fluoroquinolones.

Facile synthesis of nitrogen-doped porous graphene for efficient adsorption of tetracycline: Behavior and mechanism

Developing economic and efficient adsorbents is critically important for antibiotic residual removal from contaminated water. Here, Nitrogen-doped porous graphene-like carbon (NPGC) adsorbents were successfully synthesized by self-blowing and doping method, where glucose was used as the carbon source, zinc nitrate was acted as the nitrogen source and the derived ZnO was as the porogen. The obtained NPGC possessed a graphene-like porous structure with moderate nitrogen doping. The removal capacity of NPGC was as high as 451.2 mg g−1 in 50 mg L−1 TC solution, which is much higher than graphene, carbon nanotubes, and activated carbon, due to the larger specific surface area and micro/mesopores on graphene sheets. The adsorption isotherms and kinetics for TC onto NPGC were well-fitted with Langmuir model and pseudo-second-order model. The adsorptive ability of NPGC increased linearly with the increasing graphitic N content due to the enhanced π-π interaction and hydrophobic effect between TC and NPGC. The NPGC also showed potential environmental application as revealed by anti-interference capacity in the interference (coexisting ions and humic acid) and reusability. This work not only provides a facile strategy to develop economic and scalable N-doped graphene, but also systematically studies the adsorption mechanism of TC onto N-doped carbon adsorbents.

Highly sensitive, ultra-reliable flexible piezoelectret sensor for non-contact sitting motion tracking and physiological signal monitoring

Non-contact, cost-effective, multifunctional and robust monitoring platform without mechanical wearing burden is highly desired to enhance the immersive experience for users during the long-term health management. However, most reported intelligent electronics in human life need to be adhered conformably to key human body parts for accurate signal detection, giving rising to activity interference and wearing burden in the long-term usage. Herein, a highly sensitive flexible film pressure sensor with a folded structure configuration assembled from irradiation-cross linked polypropylene (IXPP) piezoelectret film featured with piezoelectric-like dynamic electrical output attributes are reported. Such simple folded structure incorporated specially into the device design endows the piezoelectric film sensor with merits such as enhanced sensitivity, high signal-to-noise ratio and excellent anti-interference capacity. Consequently, the sensor can achieve a linear pressure sensitivity of 92 pC/kPa over a wide pressure range of 0.6–62.4 kPa, a pressure resolution of 0.98%, and fast response/recovery time of 40 ms. The flexible piezoelectric film sensors are embedded into cushions and attached to the back of chairs for application demonstrations of non-contact sensing. Remarkably, low-frequency human motion and weak physiological signal detection are achieved in a non-contact mode by a highly sensitive piezoelectric sensing principle in an all-in-one configuration, simplifying the signal processing and monitoring system design. A vital sign monitoring system based on the intelligent cushion is further developed to unlock the health status of sedentary crowd. This is the first work that ever use commercially available irradiated cross-linked polypropylene (IXPP) film to design pressure sensor and such sensors are successfully connected to the commercial “C-life” smart home ecosystem, presenting strong practicability and application prospects of such films in smart households and remote healthcare beyond the laboratory.

A UWB Metal Waveguide Slot Array Antenna Based on Hybrid Resonant Structural Components

Due to their high reliability, anti-interference, and power capacity, metal waveguide slot array antennas are commonly used in harsh and extreme working conditions. However, the fractional bandwidth of waveguide slot array antennas is usually not wide enough (<20%), which limits the performance of the microwave system. Aiming at expanding the bandwidth, this letter proposes a metal slot array antenna utilizing hybrid resonant structures. Five resonance frequency points are simultaneously excited and are subtly arranged, resulting in a great expansion of the working frequency band. The measured results of the metal slot array antenna demonstrate that the working frequency band is from 7.35 to 10.05 GHz and the fractional bandwidth is expanded to 31%. The average realized gain is 15 dBi and the polarization is lower than −20 dB in the whole working frequency band. Therefore, this ultrawideband metal slot array antenna can not only enable the electronic equipment to work in harsh environments, such as space, but also improve the system performance in applications, such as wideband satellite communication and wideband radar imaging.

Amorphous Fe-Containing Phosphotungstates Featuring Efficient Peroxidase-like Activity at Neutral pH: Toward Portable Swabs for Pesticide Detection with Tandem Catalytic Amplification.

Peroxidase-mimetic materials are intensively applied to establish multienzyme systems because of their attractive merits. However, almost all of the nanozymes explored exhibit catalytic capacity only under acidic conditions. The pH mismatch between peroxidase mimics in acidic environments and bioenzymes under neutral conditions significantly restricts the development of enzyme-nanozyme catalytic systems especially for biochemical sensing. To solve this problem, here amorphous Fe-containing phosphotungstates (Fe-PTs) featuring high peroxidase activity at neutral pH were explored to fabricate portable multienzyme biosensors for pesticide detection. The strong attraction of negatively charged Fe-PTs to positively charged substrates as well as the accelerated regeneration of Fe2+ by the Fe/W bimetallic redox couples was demonstrated to play important roles in endowing the material with peroxidase-like activity in physiological environments. Consequently, integrating the developed Fe-PTs with acetylcholinesterase and choline oxidase led to an enzyme-nanozyme tandem platform with good catalytic efficiency at neutral pH for organophosphorus pesticide response. Furthermore, they were immobilized onto common medical swabs to fabricate portable sensors for paraoxon detection conveniently based on smartphone sensing, showing excellent sensitivity, good anti-interference capacity, and low detection limit (0.28 ng/mL). Our contribution expands the horizon of acquiring peroxidase activity at neutral pH, and it will also open avenues to construct portable and effective biosensors for pesticides and other analytes.

Afterglow nanoparticles with 2,5,8,11-tetra-tert-butylperylene as blue emitter for background-free lateral flow immunoassay

Afterglow luminescence materials have attracted much attention as a result of their particular properties of maintaining emission after ceasing the light excitation, thus it has the potential to eliminate the interference of background signal and light scattering originated from the excitation with suitable time-resolved signal collection technique. However, it’s a critical challenge for most presented afterglow materials to prepare the nanoparticles with uniform morphology on the nanometer scale for lateral flow immunoassay (LFIA). Here, we developed the photochemical afterglow system which was facile to obtain the nanoparticles for LFIA, consisting of photosensitizer, photoenergy cache unit, and the emitter. The blue emitter 2,5,8,11-tetra-tert-butylperylene (TBPe) was introduced to verify the anti-interference capacity of the proposed afterglow materials. The afterglow nanoparticles (AG-NPs) based on the system were further prepared and adopted as the signal label in LFIA. The detection limit of C-reactive protein (CRP) with afterglow LFIA was as low as 49 ng/mL. The obtained results with afterglow as signal showed advantages than that with fluorescence as signal due to the eliminating background fluorescence arose by real-time excitation light.