Selective Properties Research Articles

Synthesis and Characterization of MgO-Fe₂O₃/γ-Al₂O₃ Nanocomposites: Enhanced Photocatalytic Efficiency and Selective Anticancer Properties

In the present work, we achieved the fabrication of MgO-Fe2O3/γ-Al2O3 NCs using a deposition–coprecipitation process. XRD, TEM, and SEM with EDX, XPS, FTIR, and PL spectroscopy were applied to examine the physicochemical properties of the samples. XRD analysis confirmed the successful incorporation of γ-Al2O3, MgO, and Fe2O3 phases. TEM and SEM images indicate that the nanocomposites exhibited an agglomerated morphology with spherical shapes and particle sizes in the range of 6–12 nm. EDX and XPS spectra revealed a composition of MgO-Fe2O3/γ-Al2O3 NCs. FTIR spectra identified characteristic vibrational bands corresponding to the chemical bonds present in the samples, confirming their successful synthesis. PL analysis showed the reduced recombination rate of electron–hole pairs and enhanced charge separation efficiency, which are important factors for improved photocatalytic activity. Photocatalysis results show that the MgO-Fe2O3/γ-Al2O3 NCs exhibited significantly higher photocatalysis efficiencies of 87.5% for Rh B and 90.4% for MB after 140 min, compared to γ-Al2O3 NPs and Fe2O3/γ-Al2O3 NPs. In addition, prepared MgO-Fe2O3/γ-Al2O3 NCs demonstrated superior stability after six runs. Biochemical data showed that the MgO-Fe2O3/γ-Al2O3 NCs exhibited significant toxicity toward A549 cancer cells while displaying low toxicity toward IMR90 normal cells. The IC50 values (µg/mL ± SD) for γ-Al2O3 NPs, Fe2O3/γ-Al2O3 NPs, and MgO-Fe2O3/γ-Al2O3 NCs were 16.54 ± 0.8 µg/mL, 14.75 ± 0.4 µg/mL, and 11.40 ± 0.6 µg/mL, respectively. These results suggest that the addition of Fe2O3 and MgO to γ-Al2O3 not only enhances photocatalytic activity but also improves biocompatibility and anticancer properties. This study highlights that the MgO-Fe2O3/γ-Al2O3 NCs warrant further exploration of their potential applications in environmental remediation and biomedicine.

Spiro-Fused vs 575-Ringed Boron-Doped Polycyclic π-Systems: Selective Synthesis, Reactivity and Properties.

Incorporation of heteroatoms and/or non-hexagonal rings into polycyclic aromatic hydrocarbons (PAHs) can alter their intrinsic structures and physical properties. However, it is challenging to construct PAHs featuring boron/carbon composition and non-hexagonal combination. Herein, we disclose the selective synthesis of spiro-type and pentagon/heptagon-containing boron-doped polycyclic π-systems by the Scholl reaction. Two spiro-fused organoboranes 1 and 2 and one 575-ringed boron-doped nanographene 3 were synthesized. The key point is that the boron-edged π-system enabled unexpected spiro-formation via dearomatization, whereas the boron-centered π-system enabled desired 575-ringed π-extension via cyclodehydrogenation. The thus-obtained molecules exhibit the intriguing but fully distinct reactivity, electronic structures and properties, for instance, while 2 may react with Brønsted acid to display reversible chemochromism and further convert into 1, 3 possesses very broad absorption, short excited-state lifetime and no fluorescence nature. As disclosed, the boron atom together with the spirocycle region or 575-ringed structural motif significantly contribute to their characteristic properties. Thus, this study sheds light on control over the Scholl reaction using organoborane π-systems and will promote the exploration of more sophisticated polycyclic π-systems as organic reactive and optical scaffolds.

Integrated design of aluminum-enriched high-entropy refractory B2 alloys with synergy of high strength and ductility.

Refractory high-entropy alloys (RHEAs) are promising high-temperature structural materials. Their large compositional space poses great design challenges for phase control and high strength-ductility synergy. The present research pioneers using integrated high-throughput machine learning with Monte Carlo simulations supplemented by ab initio calculations to effectively navigate phase selection and mechanical property predictions, developing single-phase ordered B2 aluminum-enriched RHEAs (Al-RHEAs) demonstrating high strength and ductility. These Al-RHEAs achieve remarkable mechanical properties, including compressive yield strengths up to 1.7 gigapascals, fracture strains exceeding 50%, and notable high-temperature strength retention. They also demonstrate a tensile yield strength of 1.0 gigapascals with a ductility of 9%, albeit with B2 ordering. Furthermore, we identify valence electron count domains for alloy ductility and brittleness with the explanation from density functional theory and provide crucial insights into elemental influence on atomic ordering and mechanical performance. The work sets forth a strategic blueprint for high-throughput alloy design and reveals fundamental principles governing the mechanical properties of advanced structural alloys.

A Multifunctional Tb(III)-Based Metal-Organic Framework for Chemical Conversion of CO2, Fluorescence Sensing of Trace Water and Metamitron.

The utilization of metal-organic frameworks (MOFs) as fluorescent sensors for the detection of environmental and chemical reagent pollutants as well as heterogeneous catalysis for CO2 conversion represents a crucial avenue of research with significant implications for the protection of human health. In this work, a Tb(III)-based three-dimensional metal-organic framework, [Tb(L)·4DMF]n (Tb-MOF) (H3L = 5'-(4-carboxy-3-hydroxyphenyl)-3,3″-dihydroxy-[1,1':3',1″-terphenyl]-4,4″-dicarboxylic acid), has been structurally conformed by single-crystal X-ray crystallography. It possesses a 1D rhombus channel along the [010] direction, featuring a pore size of 6.02 × 9.13 Å. Tb-MOF was proved to be a multifunctional material for a fluorescent sensor and CO2 cycloaddition heterogeneous catalyst material. Fluorescence sensing studies revealed that Tb-MOF demonstrates high sensitivity, selectivity, and favorable regeneration properties, making it an effective chemosensor for detecting the metamitron (MMT) pesticide and trace water in organic solvents. The mechanism of fluorescence quenching by MMT and water was elucidated by a combination of XRD, UV-vis absorption spectra, IR spectra, theoretical calculations, and fluorescence lifetimes. The material was also utilized for the sensing of MMT and water in paper strips. Additionally, the open Tb3+ site as Lewis acidic centers makes Tb-MOF achieve efficiently catalytic conversion for CO2 and epoxides to cyclic carbonates. Moreover, a possible catalytic mechanism for the conversion of carbon dioxide to cyclic carbonates was proposed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments. It also exhibited recyclability for up to five cycles without noticing an appreciable loss in sensing or catalytic efficiency.

Novel honeycomb 3D Co/In-MOF with rigid ligand are used for efficient C1-C3 light hydrocarbons adsorption separation, fluorescence sensing and selective dye adsorption

Gas adsorption and separation, fluorescence sensing and dye adsorption have always attracted much attention and discussion as hot areas of applied research on metal–organic frameworks (MOFs). In this study, two structurally distinct three-dimensional (3D) MOFs, {[NH2Me2]2[Co3(L1)2]·6DMA·8H2O}n (Co-1) and {[NH2Me2]2[In2(L1)2]·7DMF·4H2O}n (In-1), were successfully synthesized by the reaction of rigid ligand L1 (L1 = 4-(2,6-bis(4′-carboxy-[1,1′-biphenyl]-4-yl)pyridin-4-yl)isophthalic acid) with Co2+ and In3+ under solvent-heated conditions, both of which have unique honeycomb structures. Co-1 exhibits high adsorption capacity for C3H6 and C3H8 (298 K: C3H6, 142.88; C3H8, 136.66 cm3·g−1). Meanwhile, it shows selective adsorption properties as high as 39.63, 42.94, 9.07, 4.12 and 3.04 for C3H6/CH4, C3H8/CH4, C2H2/CH4, CO2/CH4 and C2H2/CO2. The C2H2/CO2 breakthrough experiment has validated the practical separation potential of Co-1 for binary mixtures, with a dynamic separation coefficient reaching up to 2.34. Furthermore, the intrinsic mechanism for the differences in the adsorption and separation properties caused by the framework structures on the microscopic scale are revealed by the density functional theory (DFT). In-1 is a bifunctional MOF capable of rapidly and accurately detecting CrO42− and Cr2O72− ions in water via fluorescence sensing, and selectively adsorbing the cationic dye methylene blue (MB) through electrostatic interaction with high efficiency. 21.74 mg·g−1 of MB (10 mg·L−1, 24 mL) is adsorbed by 10 mg In-1 in 50 min. Kinetic, adsorption isotherm and thermodynamic analyses show that the adsorption process of MB on In-1 is mainly driven by chemisorption, which exhibits a homogeneous monomolecular layer adsorption, and that the process is a spontaneous and heat-absorbing reaction

The challenge of harvesting common sole (Solea solea) in highly selective trawl fisheries

Common sole (Solea solea) is an economically important species in several European trawl fisheries, yet little is known about the size selective properties of codends used in bottom trawl fisheries targeting sole. This study presents results from a sea trial conducted in the inner Danish waters where common sole is fished in a seasonal trawl fishery using a 90 mm diamond mesh codend with a mandatory large mesh escape panel. To improve understanding of the selectivity in this gear, we in addition tested a plain 90 mm diamond mesh codend without an escape panel. This combination of codend mesh size and large mesh escape panel is part of an ambitious management plan aimed at eliminating bycatch of cod (Gadus morhua) in trawl fisheries in the inner Danish waters. In the fishery for common sole, we found a severe mismatch between gear regulations and minimum conservation reference size of the target species. The outcome is a highly inefficient fishery in which only 22 % (CI: 18–27 %) by weight of the marketable sole is retained in the 90 mm diamond mesh codend. Further, we estimated that 25 % (CI: 16–35 %) of the sole entering the codend would contact the mandatory escape panel and escape, resulting in a total loss of 83 % (CI: 79–87 %) of marketable sole through the mandatory gear. The inefficiency in this fishery demonstrates the need for other means than gear specifications to regulate this type of fishery.

Adsorption‐Based Electrochemical Sensor Design for the Aqueous Detection of Paracetamol

This study investigates the critical role of adsorption in the development of electrochemical sensors, focusing on carbon (Vulcan XC72R, acetylene black, and graphite) and zeolite (high‐silica ZSM‐5 and all‐silica zeolite β) materials. Based on the paracetamol adsorption characteristics of these materials, an optimized disposable electrochemical sensor is created. This sensor exhibits a linear range of up to 5 μM and a remarkable detection limit of 150 nM (S/N = 3), ≈1000‐time improvement over the blank sensor. Moreover, paracetamol can be measured selectively because glucose has no adsorption affinity for the selected sensor materials. These findings underscore the significance of adsorption properties in sensor material selection in enhancing sensitivity and robustness against interfering species.

Quasi-linear homogenization for large-inertia laminar transport across permeable membranes

Porous membranes are thin solid structures that allow the flow to pass through their tiny openings, called pores. Flow inertia may play a significant role in several filtration flows of natural and engineering interest. Here, we develop a predictive macroscopic model to describe solvent and solute flows past thin membranes for non-negligible inertia. We leverage homogenization theory to link the solvent velocity and solute concentration to the jumps of solvent stress and solute flux across the membrane. Within this framework, the membrane acts as a boundary separating two distinct fluid regions. These jump conditions rely on several coefficients, stemming from closure problems at the microscopic pore scale. Two approximations for the advective terms of Navier–Stokes and advection–diffusion equations are introduced to include inertia in the microscopic problem. The approximate inertial terms couple the micro- and macroscopic fields. Here, this coupling is solved numerically using an iterative fixed-point procedure. We compare the resulting models against full-scale simulations, with a good agreement both in terms of averaged values across the membrane and far-field values. Eventually, we develop a strategy based on unsupervised machine learning to improve the computational efficiency of the iterative procedure. The extension of homogenization towards weak-inertia flow configurations as well as the performed data-driven approximation may find application in preliminary analyses as well as optimization procedures towards the design of filtration systems, where inertia effects can be instrumental in broadening the spectrum of permeability and selectivity properties of these filters.

Theoretical studies of two phase-independent frequency spectrum models in atomic selective photoionization processes

Abstract The laser frequency spectrum, whose full width at half-maximum in the frequency domain is laser bandwidth, plays a critical role in atomic multi-step photoionization processes, and it has a significant influence on isotopic selective photoionization results. In this study, two phase-independent frequency spectrum models, that is, mode jitter model based on the “mode jitter” phenomenon and the multi-longitudinal mode model based on multi-longitudinal mode output, are proposed for describing the spectral characteristics in the frequency domain. In the mode jitter model, it is assumed that there is a varying longitudinal mode in every laser pulse, with different central frequencies between adjacent pulses in the pulse train; in the multi-longitudinal model, it is assumed that multiple longitudinal modes are output simultaneously with fixed central frequencies. Selective photoionization properties of these two frequency spectrum models and the chaotic field model are simulated and compared with each other under the Lorentzian frequency spectrum condition. Influences of the excitation intensity, laser frequency spectral line-shape, and cut-off frequency on selective photoionization processes are calculated and compared among the above-mentioned three frequency spectrum models. Finally, the measurement of the laser frequency spectrum and the introduction of individual longitudinal mode’s bandwidth are discussed.

Bayesian Selection of Relaxed-clock Models: Distinguishing Between Independent and Autocorrelated Rates.

In Bayesian molecular-clock dating of species divergences, rate models are used to construct the prior on the molecular evolutionary rates for branches in the phylogeny, with independent and autocorrelated rate models being commonly used. The two classes of models, however, can result in markedly different divergence time estimates for the same dataset, and thus selecting the best rate model appears important for obtaining reliable in- ferences of divergence times. However, the properties of Bayesian rate model selection are not well understood, in particular when the number of sequence partitions analysed increases and when age calibrations (such as fossil calibrations) are misspecified. Further- more, Bayesian rate model selection is computationally expensive as it requires calculation of marginal likelihoods by MCMC sampling, and therefore methods that can speed up the model selection procedure without compromising its accuracy are desirable. In this study, we use a combination of computer simulations and real data analysis to investigate the sta- tistical behaviour of Bayesian rate model selection and we also explore approximations of the likelihood to improve computational efficiency in large phylogenomic datasets. Our simulations demonstrate that the posterior probability for the correct rate model converges to one as more molecular sequence partitions are analysed and when no calibrations are used, as expected due to asymptotic Bayesian model selection theory. Furthermore, we also show the model selection procedure is robust to slight misspecification of calibrations, and reliable inference of the correct rate model is possible in this case. However, we show that when calibrations are seriously misspecified, calculated model probabilities are com- pletely wrong and may converge to one for the wrong rate model. Finally, we demonstrate that approximating the phylogenetic likelihood under an arcsine branch-length transform can dramatically reduce the computational cost of rate model selection without compro- mising accuracy. We test the approximate procedure on two large phylogenies of primates (372 species) and flowering plants (644 species), replicating results obtained on smaller datasets using exact likelihood. Our findings and methodology can assist users in selecting the optimal rate model for estimating times and rates along the Tree of Life.

An innovative and efficient strategy for removing Congo red using magnetic hollow Zn/Co zeolitic imidazolate framework composite

The discharge of wastewater containing Congo red (CR) poses a significant threat to aquatic ecosystems and human health, underscoring the urgent need for effective removal methods. In this study, we have developed a novel strategy for efficient removing CR, utilizing the synthesized magnetic hollow Zn/Co zeolitic imidazolate framework composite (MH-ZIF). Comprehensive characterization of MH-ZIF and comparison with contrasting materials were conducted. The adsorption behavior of MH-ZIF towards CR followed the pseudo-second-order kinetic model and Langmuir isothermal adsorption model, demonstrating monolayer chemisorption. Remarkably, MH-ZIF exhibited an impressive adsorption capacity of 1167.9 mg g−1 for CR at 293 K. The addition of merely 0.15 g L−1 of MH-ZIF achieved nearly complete adsorption of CR within a concentration of 150 mg L−1. With the assistance of an external magnetic field, CR adsorbed on MH-ZIF can be effectively and swiftly removed within just 30 s. Hence, MH-ZIF demonstrates great promise in effectively removing CR from wastewater, attributed to its high adsorption capacity, selectivity, and magnetic properties.

Quantitative study of competitive and selective immobilization of Pb(II)-Ni(II)-Zn(II)-MB(I) by biogenic monohydrocalcite composite and its potential environmental effects

The study of the competitive and selective immobilization properties and mechanisms of pollutants immobilized by metastable biogenic monohydrocalcite is of great importance for the assessment of the eco-environmental effects and applications of hydrated calcite at the Earth’s poles. Microbial culture technology was used to induce the synthesis of biogenic monohydrocalcite (BMHC), and mineral characterization, batch adsorption experiments and chemical analyses were further used to investigate the sequestration characteristics, action mechanism, and environmental effects of BMHC on Pb(II)-Ni(II)-Zn(II)-methylene blue (MB) compound pollution. The results show that BMHC is an organic-inorganic mineral composite (about 3.60 % organic matter, Mg/Ca ≈ 0.07). The adsorption and immobilization processes of Pb(II), Ni(II), Zn(II), and MB(I) by BMHC are all better fitted by the pseudo-second-order kinetic equation. The passivation ability of BMHC for contaminants is ranked as Pb(II) ≫ Zn(II) > Ni(II) > MB(I). BMHC exhibits an excellent selective sequestration capacity of Pb(II) (k ≥ 31.89), which is related to the solubility product of the carbonate minerals, the initial concentration of Pb(II), ion exchange and mineral phase transformation. Based on these results, it is proposed that the synthesis and transformation of monohydrocalcite under global warming at the Earth's poles may influence the biogeochemical cycling of environmental pollutants. The study provides a theoretical basis for the environmental effects and geochemical action of biogenic monohydrocalcite and its applications.

Channel width modulates the permeability of DNA origami-based nuclear pore mimics.

Nucleoporins (nups) in the nuclear pore complex (NPC) form a selective barrier that suppresses the diffusion of most macromolecules while enabling rapid transport of nuclear transport receptor (NTR)-bound cargos. Recent studies have shown that the NPC may dilate and constrict, but how altering the NPC diameter affects its selective barrier properties remains unclear. Here, we build DNA nanopores with programmable diameters and nup arrangements to model the constricted and dilated NPCs. We find that Nup62 proteins form a dynamic cross-channel barrier impermeable to hepatitis B virus (HBV) capsids when grafted inside 60-nm-wide nanopores but not in 79-nm pores, where Nup62 cluster locally. Furthermore, importin-β1 substantially changes the dynamics of Nup62 assemblies and facilitates the passage of HBV capsids through the 60-nm NPC mimics containing Nup62 and Nup153. Our study shows that transport channel width is critical to the permeability of nup barriers and underscores NTRs' role in dynamically remodeling nup assemblies and mediating the nuclear entry of viruses.

Thin Film Composite Mixed-Matrix Membranes Based on Matrimid and Zeolitic Imidazolate Frameworks for CO2/N2 Separation Performance.

Membrane-based gas separation processes are a technology in continuous evolution. Various types of polymer membranes have been developed, many exhibiting high CO2 permeability and selective properties over competing gases such as N2 and CH4. In order to be competitive, membranes must be less-expensive, more stable, and more efficient, and their production must be scalable. One solution is to develop thin-film composites with mixed-matrix membranes (TFC_MMM) that have the potential to boost productivity while maintaining low costs. In this work, TFC_MMMs containing Matrimid mixed with 12 wt % ZIF-94 were prepared by kiss coating on a porous support. The SEM analysis showed that defect-free membranes with a 3 μm selective layer have been obtained. At 1 bar, the addition of ZIF resulted in improved the separation performance for the CO2/N2 pair, with CO2 permeance of 4 GPU and CO2/N2 selectivity of 40, surpassing neat TFC-Matrimid (CO2 permeance ≈ 3 GPU, CO2/N2 selectivity ≈ 29). The use of ZIF-94 also had a stabilizing effect on the membranes against CO2 plasticization at high pressure.

Discovery of a Novel Macrocyclic Noncovalent CDK7 Inhibitor for Cancer Therapy.

Cyclin-dependent kinase 7 (CDK7) is a key regulator of the cell cycle and transcription, making it a promising target for cancer therapy. Although current CDK7 inhibitors have improved in their selectivity and druglike properties, CDK7 inhibitors have failed to progress through clinical development due to severe gastrointestinal and hematotoxic side effects. To mitigate these limitations, we have developed novel, macrocyclic, noncovalent CDK7 hit compounds 2 and 3 using a macrocyclization platform that has optimized these compounds from SY-5609, a leading clinical asset. We conducted extensive structure-activity relationship (SAR) studies to improve their potency, enhance oral bioavailability, and reduce intestinal distribution, which resulted in compound 13. Compound 13 exhibits potent in vitro activity, good ADME properties, and robust in vivo antitumor activity in xenograft models as a monotherapy. Notably, compound 13 with lower basicity demonstrated improved Caco-2 permeability, reduced blood/plasma ratio, and reduced intestinal distribution in rats, thus mitigating gastrointestinal and hematotoxic side effects.

Numerical Simulation of Autoresonant Ion Oscillations in an Anharmonic Electrostatic Trap.

This work presents the results of modeling the ion dynamics in the ART-MS (Autoresonant Trap Mass Spectrometry) device in the quasi-static approximation. This instrument utilizes an anharmonic, purely electrostatic trap for ion confinement and a radio frequency (RF) voltage source with decrementally varying frequency for selective ion extraction. The autoresonant interaction between the oscillatory motion of the ion and the RF voltage increases the amplitude of some confined ions, allowing their selective extraction. Numerical modeling shows that the extraction of ions with a given mass occurs not only at the fundamental frequency but also at its harmonics. This effect reduces the selective properties of devices of this type because along with the main mass component for a given frequency, it is possible to enter the detector channel of ions with another mass, for which this frequency corresponds to the second or higher harmonics, even a superposition of some of these harmonics of different ions.

Distributed Least Product Relative Error estimation for semi-parametric multiplicative regression with massive data

Distributed systems have been widely used for massive data analysis, but few studies focus on multiplicative regression models. We consider a communication-efficient surrogate likelihood method using the Least Product Relative Error criterion for semi-parametric multiplicative models on massive datasets. The non-parametric component is efficiently handled via B-spline approximation. We derive the asymptotic properties for both parametric and non-parametric components, while the SCAD and adaptive Lasso penalty functions are developed and their oracle properties for variable selection are validated. Simulation studies and an application to an energy prediction dataset are used to demonstrate the effectiveness and practical utility of the proposed method.

Discovery of benzo[c]phenanthridine derivatives with potent activity against multidrug-resistant Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb), the pathogen responsible for tuberculosis (TB), is the leading cause of bacterial disease-related death worldwide. Current antibiotic regimens for the treatment of TB remain dated and suffer from long treatment times as well as the development of drug resistance. As such, the search for novel chemical modalities that have selective or potent anti-Mtb properties remains an urgent priority, particularly against multidrug-resistant (MDR) Mtb strains. Herein, we design and synthesize 35 novel benzo[c]phenanthridine derivatives (BPDs). The two most potent compounds, BPD-6 and BPD-9, accumulated within the bacterial cell and exhibited strong inhibitory activity (MIC90 ~2 to 10 µM) against multiple Mycobacterium strains while remaining inactive against a range of other Gram-negative and Gram-positive bacteria. BPD-6 and BPD-9 were also effective in reducing Mtb survival within infected macrophages, and BPD-9 reduced the burden of Mycobacterium bovis BCG in the lungs of infected mice. The two BPD compounds displayed comparable efficacy to rifampicin (RIF) against non-replicating Mtb (NR-Mtb). Importantly, BPD-6 and BPD-9 inhibited the growth of multiple MDR Mtb clinical isolates. Generation of BPD-9-resistant mutants identified the involvement of the Mmr efflux pump as an indirect resistance mechanism. The unique specificity of BPDs to Mycobacterium spp. and their efficacy against MDR Mtb isolates suggest a potential novel mechanism of action. The discovery of BPDs provides novel chemical scaffolds for anti-TB drug discovery.IMPORTANCEThe emergence of drug-resistant tuberculosis (TB) is a serious global health threat. There remains an urgent need to discover new antibiotics with unique mechanisms of action that are effective against drug-resistant Mycobacterium tuberculosis (Mtb). This study shows that novel semi-synthetic compounds can be derived from natural compounds to produce potent activity against Mtb. Importantly, the identified compounds have narrow spectrum activity against Mycobacterium species, including clinical multidrug-resistant (MDR) strains, are effective in infected macrophages and against non-replicating Mtb (NR-Mtb), and show anti-mycobacterial activity in mice. These new compounds provide promising chemical scaffolds to develop potent anti-Mtb drugs of the future.

Ultrasensitive and Stretchable Strain Sensors Based on Laser-Induced Graphene With ZnO Nanoparticles.

Laser-induced graphene (LIG) has attracted considerable attention for its use in flexible and stretchable sensors, owing to its electrical/mechanical properties and scalable fabrication processes. Although laser scanning facilitates the formation of LIG and its strain sensor, the strain-sensing sensitivity enhancement of LIG remains limited by the material's properties and structural design. In this study, we demonstrate a substantial improvement in sensitivity that was achieved by fabricating a LIG using ZnO nanoparticle (NP)-assisted photothermal enhancement. The results show that ZnO NPs selectively reduce the threshold fluence needed to convert polyimide (PI) into LIG. By transferring the LIG formed on PI to poly(dimethylsiloxane), we fabricate a stretchable strain sensor with ultrahigh sensitivity and a gauge factor of 1214 at 10% strain, which is approximately 60 times higher than the gauge factor without ZnO NPs. Using the selective graphenization properties of LIG, a flexible, dual-sided integrated sensor sheet that is equipped with flexible strain and ultraviolet (UV) sensors is demonstrated. This sheet enables simultaneous monitoring of UV intensity and joint bending angles of sports wearable devices. We validated the developed sensors by attaching them to a runner's body to monitor and simulate forefoot and heel strikes, demonstrating the sensor's ultrahigh sensitivity and long-term stability without the need for a camera. These findings highlight the potential of the proposed method for developing multifunctional sensor applications with ultrahigh sensitivity and stability.

Flexible Au@Ag/PDMS SERS imprinted membrane combined with molecular imprinting technology for selective detection of MC-LR

In this study, a core–shell structured bimetallic nano-cube, Au@Ag NCs, was prepared by seed-mediated growth procedure. The array structure of Au@Ag NCs was achieved at the interface through the autonomous assembly technique at the three-phase boundary. Employing polydimethylsiloxane (PDMS) as a flexible carrier, the array structure was effortlessly transferred to the PDMS membrane, bypassing the need for rigid substrates through a simple “pasting” method. This yielded a highly flexible and transparent SERS substrate with an array structure (Au@Ag NCs/PDMS membrane, AAP). In order to promote the selective detection property to the practical samples, molecularly imprinted polymers (MIPs) were coated on the surface of membrane to prepare the imprinted membrane (Au@Ag NCs/PDMS-MIMs, AAP-MIMs). It was demonstrated from the results that the AAP-MIMs exhibited high SERS sensitivity, stability, and uniformity. Furthermore, the flexible substrate possessed commendable mechanical strength, and facilitated the detection of analytes on irregular surfaces. In summary, this substrate held promising potential for practical on-site detection and analysis of specific target substances.