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We report protein- and aptamer-based electrochemical biochips for low-cost, one-step, sensitive and accurate multiplex detection of SARS-CoV-2 spike (S) and nucleocapsid (N) proteins, and IgG antibody in unprocessed clinical samples, allowing citizens to achieve rapid diagnosis at home or in community settings., Chemical Communications, 58 (52), ISSN:1359-7345, ISSN:1364-548X

Manipulating O2 activation via nanosynthetic chemistry is critical in many oxidation reactions central to environmental remediation and chemical synthesis. Based on a carefully-designed plasmonic Ru/TiO2–x catalyst, we first report a room-temperature O2 dissociation and spillover mechanism that expedites the "dream reaction" of selective primary C–H bond activation. Under visible light, surface plasmons excited in the negatively-charged Ru nanoparticles decay into hot electrons, triggering spontaneous O2 dissociation to reactive atomic •O. Acceptor-like oxygen vacancies confined at the Ru-TiO2 interface free Ru from oxygen-poisoning by kinetically boosting the spillover of •O from Ru to TiO2. Evidenced by an exclusive isotopic O-transfer from 18O2 to oxygenated products, •O displays a synergistic action with native •O2– on TiO2 that oxidizes toluene and related alkyl aromatics to aromatic acids with extremely high selectivity. We believe the intelligent catalyst design for desirable O2 activation will contribute viable routes for synthesizing industrially important organic compounds., Chemical Science, 12 (46), ISSN:2041-6520, ISSN:2041-6539

Antibiotic resistance genes (ARGs) as an emerging airborne pollutants are a significant and growing concern for public and environmental health. Accurate surveillance and quantitation of low-dose ARGs in the air have become critical in providing evidence-based public risk assessment for population health management. With this work, we introduced a portable and sensitive electrochemical (EC) bioanalytical platform for detecting airborne ARGs, which relied on the EC current response of surface-initiated ARGs hybridization. These low-cost chips for EC ARGs sensing exhibited good thermal (25∼60 °C) and long-term stability (6 days). The prototype of the biosensor system demonstrated an ultralow limit of detection (7.4 fM) and excellent anti-interference performance. For the first time, an EC sensor was applied successfully to identify and quantitate two types of ARGs (floR and bla-TEM genes) from real-world PM2.5 (particulate matter with aerodynamic diameters less than 2.5 μm) samples. Results for PM2.5 collected from Bern (urban area), Basel (suburban area), Zürich (urban area), Sion (airport highway area), and Rigi (rural and high-altitude area) in Switzerland were obtained, in favorable agreement with gel electrophoresis analysis. The results indicated that our EC biosensor offered a reliable and attractive alternative to the current methods for airborne ARG detection. ISSN:2690-0645

Osteoarthritis (OA) is a degenerative disease characterized by chronic inflammation. Indole-3-aldehyde (3-IAld) is a tryptophan metabolite secreted by intestinal flora, which can exert anti-inflammatory effects in multiple inflammatory diseases. However, the potential therapeutic role of 3-IAld in OA and the underlying mechanism remain to be explored.IL-1β was utilized to induce chondrocytes inflammation. Then, cell counting kit-8 was carried out to assess the cytotoxicity of 3-IAld on rat chondrocytes viability. Meanwhile, RT-qPCR, Western blot, and immunofluorescence were performed to evaluate the expression of inflammatory factors, matrix-degrading enzymes and matrix synthesis protein, and the NF-κB pathway in chondrocytes treated with IL-1β alone, with 3-IAld or with siRNA-AhR.Our results showed that 3-IAld did not affect cellular viability at concentrations up to 50 μM. 3-IAld significantly inhibited the expression of pro-inflammatory cytokines (IL-6, iNOS and COX-2), and matrix-degrading enzymes (MMP3, MMP13 and ADAMTS5), upregulated the expression of matrix synthesis protein (aggrecan and collagen-II), and inactivated the NF-κB pathway in IL-1β-treated chondrocytes. However, AhR knockdown could totally abolish the aforementioned therapeutic capabilities and the inactivation of the NF-κB pathway induced by 3-IAld.3-IAld reduced inflammation through the AhR-NF-κB signalling pathway in IL-1β-induced chondrocytes, which is expected to provide a new therapeutic strategy for OA.

Solar-driven molecular oxygen activation by semiconductor photocatalysts is a prototypical reaction manifesting complex interactions among photons, charge carriers, and reactants. In this study, we demonstrate that energetic O2 activation towards volatile organic compound control can be realized via constructing a sophisticated surface hydrogen bond (HB) network having a dual-function. The extensive HBs established between the hydroxyl-rich BiOCl surface and phosphoric acid are first shown to significantly weaken surface Bi–O bonds, enabling facile oxygen vacancy (OV) generation. OVs, which act as reliable electron capture and static O2 activation centers, reinforce the interaction between photons and excitons for rapid charge carrier separation. Moreover, dynamic O2 activation with sluggish kinetics can be surmounted by another type of HB localized between hydroxyl groups of phosphoric acid and OV-adsorbed O2. These unique localized HBs facilitate interfacial electron transfer from BiOCl to O2, displaying a unique energy coupling route between charge carriers and reactants. For simulated indoor toluene oxidation, the substantially boosted O2 activation is shown to accelerate the kinetic processes associated with the primary oxidation of toluene into benzaldehyde and benzoic acid, as well as aromatic ring opening towards deep oxidation. Undesirable intermediate accumulation and catalyst deactivation are thus avoided. The present work highlights the pivotal roles of HBs in robust photocatalytic O2 activation. It will provide novel insights into the design of high-performance catalysts for efficient and safe control of indoor volatile organic compounds.

Chondrocytes senescence is closely related to orthopedic degenerative diseases such as osteoarthritis (OA). Calcium ions (CaFirst, the senescent chondrocytes model was constructed by subcultring primary chondrocytes (P0) to 5th passages (P5). CCK8 and clone formation assay was utilized to assess the proliferation capacity of the chondrocytes. The intracellular CaSenescent chondrocytes exhibited intracellular CaThis study confirmed for the first time that the high expression of Piezo1 mediated senescence in chondrocytes through Ca

Smart air filters are beneficial to provide highly efficient particle removal, treat multiple contaminants simultaneously and conserve energy during air filtration processes. Herein, a type of self-supporting smart air filter (SSSAF) was fabricated by sandwiching the VOC-responsive PZT/PVDF electrospun membrane with two metal mesh electrodes. Besides the high filtration efficiency for sub-micron particles, the SSSAF showed good responses to pressure drop in the range of 0 to 500 Pa via the electroactivity of PZT/PVDF membrane. In addition, the SSSAF achieved VOC sensing function via the swelling properties of PZT/PVDF membrane in organic vapors, demonstrated by its signal to 50 to 200 ppm ethanol vapors. The SSSAF was employed to harvest wind energy, which was further applied to inhibit bacterial growth without the need of additional power input. Our SSSAF was designed to take advantage of the energy carried by the filtration air flow, which is necessary in any filtration system thus brings a stable and innate energy source. The results provide new insight into development of all-in-one smart air filters., Chemical Engineering Journal, 423, ISSN:0300-9467, ISSN:1385-8947, ISSN:1873-3212, ISSN:0923-0467

The investigation of filtration and loading performance of fibrous filters with different structures is of high importance for designing filters with long lifetime used in applications with high soot concentrations. Penetration of the soot agglomerates and NaCl particles (with the mobility diameters of 50, 80, 100, 200 and 300 nm) through two types of composite filter media (with the nanostructured layer of electrospun nanofibers and PTFE membrane, respectively) was analyzed. Meanwhile, evolution of the experimental and modeled pressure drop during the particles loading process at the velocities of 6.7 and 11.1 cm/s was also studied. The cake thickness was measured by a new and non-contact method utilizing a 3D optical profiler which would not alter the cake structure. The results showed that the soot penetration was lower than that of NaCl particles under the same condition, because the soot agglomerates had larger effective interception length than the NaCl particles with the same mobility diameter. The pressure drop of the filters loaded with soot agglomerates increased faster than that with NaCl particles. Furthermore, the pressure drop increased faster at the velocity of 11.1 cm/s because of formation of more compact cake. In addition, the pressure drop of the filter with a lower solidity nanostructured layer increased slower because more particles could penetrate into its inner part. The model data agreed with the experimental data well in the case of soot loading. Our results indicate that the filters which have relatively low filtration efficiency against the standard compact aerosol particles yet sufficient efficiency against the soot agglomerates and an open structure can be used in the applications with high soot concentrations to gain a long lifetime.

The soluble fraction of aerosol particulate matter containing trace metals has the potential to engender toxicity and exacerbate the adverse health effects of particulate matter. In this study, an inertial-impaction-based fluidic chip integrated with electrochemical detection was developed to achieve high collection efficiency and measurements of the bioaccessible metal fraction at the nanogram level. The average collection efficiency for ultrafine and fine particles larger than 50 nm, obtained at a flow rate of 2.5 L/min, was above 70%. The detection ranges of aerosol soluble copper depended on the collection duration and airflow rate. At a working flow rate of 3.1 L/min and collection efficiency of 70%, the microsystem was capable of detecting Cu concentrations above 53 ng/m3, 32 ng/m3 and 8 ng/m3 with 3 h, 5 h and 20 h collection periods, respectively, which were in the range of reported atmospheric concentrations. The detection ratio of real-world samples (i.e. PM10-like aerosol) was 100 ± 14%, indicating excellent aerodynamic collection and reliable electrochemical detection. The collection and sensing performance of the microsystem demonstrates a new step towards an online, mobile, low-cost, and miniaturized routine monitoring system for bioaccessible metals and possibly other soluble components in the aerosols.

Ultrathin, lightweight, and flexible electromagnetic interference (EMI) shielding materials are urgently demanded to address EM radiation pollution. Efficient design to utilize the shields' microstructures is crucial yet remains highly challenging for maximum EMI shielding effectiveness (SE) while minimizing material consumption. Herein, novel cellular membranes are designed based on a facile polydopamine-assisted metal (copper or silver) deposition on electrospun polymer nanofibers. The membranes can efficiently exploit the high-conjunction cellular structures of metal and polymer nanofibers, and their interactions for excellent electrical conductivity, mechanical flexibility, and ultrahigh EMI shielding performance. EMI SE reaches more than 53 dB in an ultra-broadband frequency range at a membrane thickness of merely 2.5 µm and a density of 1.6 g cm-3 , and an SE of 44.7 dB is accomplished at the lowest thickness of 1.2 µm. The normalized specific SE is up to 232 860 dB cm2 g-1 , significantly surpassing that of other shielding materials ever reported. More, integrated functionalities are discovered in the membrane, such as antibacterial, waterproof properties, excellent air permeability, high resistance to mechanical deformations and low-voltage uniform heating performance, offering strong potential for applications in aerospace and portable and wearable smart electronics.

The one-step lining and deacidification process of aged newspapers with double-sided writing combines deacidification and reinforcement processes. Wheat starch paste or carboxymethyl cellulose were prepared using an aqueous solution of Ca(OH)2. The newspapers were lined with Japanese tissue (9 g/m2), using the alkaline adhesive in order to mechanically reinforce the newspapers and at the same time increase the pH of the paper. After treatment, the pH value of the newspaper samples reached an ideal range between 8.0–8.5 when thew.1% Ca(OH)2was used. More notably, the Japanese tissue lining doubled strength and folding endurance. The treatment had little impact on the visual appearance of the writing and even increased the degree of whiteness of the paper. The increase of tensile strength and whiteness was not diminished even when the treated newspaper samples were exposed to accelerated thermal ageing.

The moisture-induced degradations during the use of paper are of growing concern for the existing paper materials stored in libraries, archives and museums. Knowing the moisture profiles is therefore a primary step in order to understand paper deterioration and give an assessment of degradation rate of library collections in their preservation. In this paper, the theoretical models based on 2-D scanning electron microscope real image microstructure were established for describing moisture transport in paper sheet in response with external humidity and the moisture diffusion profiles. The acid-catalyzed hydrolysis kinetic in combination with moisture diffusion theory gave the complementary explanation for the time-dependent natural aging process of a paper sheet and book stacks. The differential equations were solved by a numerical approach based on the finite element method implemented in commercial COMSOL Multiphysics. The 2-D simulation results, with a mesh based directly on SEM characterization of microstructure, could show the equilibrium moisture contents and the degradation rates as a function of relative humidity in cellulose pores and cellulose fibers across the transverse section of paper. For the stacks composed of books, the air gaps between the books provided convenient channels for diffusion and transport, accelerating the moisture transport process in the book stacks.

The hybrid films of reinforcing the aged papers have been employed via layer-by-layer (LBL) assembly deposition of the chitosan lactate/carboxymethyl cellulose complex previously modified with metal oxide. In order to reinforce the films, a vacuum infiltration was adopted in the LBL process. The mechanical properties and structure of the aged papers in relation to fiber morphology were investigated using SEM, FTIR, XPS, and tensile test. The well-dispersed coatings resulted in an excellent improvement in mechanical properties of the modified paper. After only three bilayers deposited, the measured tensile strength and folding endurance for modified aged newspaper samples increased up to 100% and 450%, respectively, as compared to the control sample. This high efficiency was kept even when the modified paper samples exposed to the moist-heat accelerated aging and UV irradiation. The pH of the paper rose to alkalescence rapidly, and the paper samples maintained their coloration close to the original after t...

Air filtration mechanisms in the composite filter media used in practical applications are important and challenging to understand because the component fibers could have various size scales and morphologies. In this work, a three-dimensional digital model of nanofiber-based filter media was reconstructed for the first time based on the X-ray tomography data for the cellulose substrate and the Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) image analysis for the several micrometers thick (3.82–7.90 μm) electrospun polyvinylidene fluoride (PVDF) nanofiber membrane. Besides the high-resolution model where the details of the fibrous structures were fully resolved, another low-resolution model with approximated unresolved structures was also established. Filtration simulations utilizing these models were conducted considering the drag force, Brownian diffusion and aerodynamic slip. The simulated filtration efficiencies agreed well with the experiments for particles of 70–400 nm, including the most penetrating particle size (MPPS, 100–200 nm). Moreover, the structure-resolved models had higher accuracy but higher computational costs, while the unresolved simulations saved much running time but over-predicted the filtration efficiency, especially for smaller particles (, Journal of Membrane Science, 620, ISSN:0376-7388

Microlenses are highly sought as reliable means for high-resolution optical imaging at low illumination intensities. Plano-convex configuration with tunable dimension and curvature is an essential feature in the microlens fabrication. In this study, we present a facile and green route for preparing well-defined microlenses based on polymer phase separation in the presence of supercritical carbon dioxide (scCO2). The behaviors of linear polymethylmethacrylate protruded from cross-linked silicone network in scCO2 environment are investigated from the perspectives of thermodynamics and kinetics. Microlenses with dimensions from 2 to 15 μm and contact angles from 55° to 112° are successfully obtained through the adjustment of the kinetic conditions and outgassing rate. With the tunable focal length, they exhibit intrinsic function of discerning submicroscale patterns that are unable to be observed directly under optical microscope. Moreover, size confinement on the substrate results in the generation of well-ordered microlens arrays, affording great promise for applications in bioimaging, photolithography, light harvesting, and optical nanosensing.

The bacteria and fungi captured on heat insulating materials or air filter media in the ventilation system in civil flights may reentrant into the indoor air which poses a threat to passengers’ health. The E. coli and B. subtilis bacteria survival rates on the heat insulating blankets typically used as padding materials inside the aircraft walls under the mimicked environmental condition were studied. Then the antibacterial performance of positively charged electret and chitosan modified filter media which can be used in the ventilation systems against E. coli bacteria was investigated. Our results showed that the E. coli survival rate deceased to less than 0.2% and that of the B. subtilis decreased to less than 2.1% of the control samples on the hydrophilic and hydrophobic blankets under the mimic conditions after one flight cycle. The survival rate of E. coli on the positively charged electret filter media decreased to less than 30% compared to the uncharged filter media after six hours due to the disruption of their metabolic balance by the positive charges on the fibers surface. Moreover, the E. coli survival rate on the pure nylon, nylon/chitosan and chitosan dipped nylon-6 nanofibrous filter media decreased to 8.4%, 7.1% and 2.8% after 120 min, respectively. This study sheds light on fabrication of the eco-friendly antibacterial filter materials for the ventilation systems., Building and Environment, 180, ISSN:0360-1323

Electret filter materials have attracted wide attention because of their low pressure drop and high filtration efficiency. Few studies have measured the filtration performance and the charging status of the charged filters during soot particle loading. In this study, the polytetrafluoroethylene (PTFE) needle felt filters were charged by a corona discharge method. The filtration efficiency and surface potential were investigated during the soot particle loading process. The effects of NaCl particles, soot particles and A2 dust on surface potential and filtration efficiency were investigated. The reusability of charged filters and the effect of temperature on surface potential were studied. The results indicated that the initial filtration efficiency of charged PTFE needle felt filters (PNFFs) was greatly improved compared with that of uncharged PNFFs. The attenuation rate of the surface potential at 100 °C was faster than that at room temperature. The surface potential decreased with the start of particle deposition on the filters, correspondingly, the filtration efficiency of the charged PNFFs decreased. The efficiency of charged PNFFs loaded by soot particle decreased first and then increased, with the transition point corresponding to 20 Pa of pressure drop growth. With the same increment of pressure drop, soot particles with higher conductivity caused more efficiency degradation than NaCl particles. The reusability of the charged filters was affected by the effectiveness of dust cake removal and the particle conductivity.