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Developing non-noble-metal electrocatalyst with efficient and durable activity is a urgent task for addressing the sluggish reaction kinetics of electrochemical water oxidation. Structural evolution of the electrocatalyst is an important strategy for achieving enhanced performance. Herein, in situ evolution of surface Co2CrO4 to CoOOH/CrOOH (CoOOH/CrOOH-Co2CrO4) by an electrochemical method under alkaline conditions was designed for enhancing the electrocatalytic performance of water oxidation. The experiments demonstrated that the synergy between CoOOH/CrOOH and Co2CrO4 resulted in a marked increase in the number of active sites and improved the rate of charge transfer, which enhanced the activity for water oxidation. At a geometrical current density of 20 mA cm−2, the overpotential of the oxygen evolution reaction was 244 mV and the turnover frequency was 0.536 s−1 in 1.0 M NaOH.

A visible-light-driven self-powered photoelectrochemical (PEC) aptasensor was developed for ampicillin (AMP) detecting based on carbon dots (CDs) hybrid MIL-68(In)-derived In2O3 In2S3 hollow tubular heterojunction (CDs/In2O3 In2S3). In2S3 nanosheets uniformly grew in-situ on the surface of In2O3 hollow tubes, forming a close contact heterogeneous interface, which significantly promoted the transfer and separation of photo-generated carriers, and provided a large specific surface area and rich active sites for the PEC aptasensing platform. Furthermore, the CDs/In2O3 In2S3/ITO electrode, which was obtained by dipping assembly, showed remarkable and stable photoelectric signals at zero-bias under visible light irradiation. The amino-functionalized AMP aptamer was fixed on the working electrode as a biological recognition element, and the concentration of AMP was determined by observing the change in photocurrent intensity caused by the specific capture of AMP molecules in solution. Under optimized conditions, the developed PEC aptasensor displayed a relatively wide linear range from 0.001 ng mL−1 to 300 ng mL−1, as well as a low detection limit (LOD) of 0.06 pg mL−1. Besides, the novel self-powered PEC AMP-aptasensor exhibited excellent reproducibility, good stability and selectivity, which open a potential avenue for antibiotic residues detection in environmental media.

Steady and efficient sensitized emission of Eu2+ to Eu3+ can be achieved through a rare mixed-valence Eu-MOF (L4EuIII2EuII). Compared with the sensitization of other substances, the similar ion radius and configuration of the extranuclear electron between Eu2+ and Eu3+ make sensitization easier and more efficient. The sensitization of Eu2+ to Eu3+ is of great assistance for the self-enhanced luminescence of L4EuIII2EuII, the longer luminous time, and the more stable electrochemiluminescence (ECL) signal. Simultaneously, L4EuIII2EuII possesses near-infrared (NIR) fluorescence of around 900 nm and a mighty self-luminous characteristic, which render it useful as a NIR fluorescent probe and as a luminophore to establish a NIR ECL biosensor. This NIR biosensor can greatly reduce the damage to the detected samples and even achieve a nondestructive test and improve the detection sensitivity by virtue of strong susceptibility and environmental suitability of NIR. In addition, the CeO2@Co3O4 triple-shelled microspheres further enhanced the ECL intensity due to two redox pairs of Ce3+/Ce4+ and Co2+/Co3+. The NIR ECL biosensor based on these strategies owns an ultrasensitive detection ability of CYFRA 21-1 with a low limit of detection of 1.70 fg/mL and also provides a novel idea for the construction of a highly effective nondestructive immunodetection biosensor.

Herein, a dual-mode sensing platform using cationic N,N-bis(2-(trimethylammonium iodide)propylene)perylene-3,4,9,10-tetracarboxydiimide (PDA+)-assembled DNA strands as a quencher was suggested for estradiol (E2) detection. The aptamer chain was initially anchored with the Ru(II) novel molecule (Ru complex), which was recombined with carbohydrazide (CON4H6) and tris(4,4'-dicarboxylicacid-2,2'-bipyridyl)ruthenium(II) dichloride [Ru(dcbpy)32+] modified on copper oxide (CuO) nanospheres. Intramolecular electrochemiluminescence (ECL) occurring between CON4H6 and Ru(dcbpy)32+ effectively improved the reaction rate and increased the ECL efficiency. By employing effective van der Waals' force, PDA+ was endowed with an efficient ECL quenching probe on an electrode. The signal on the ECL interface can be converted into quenching because of energy transfer between the intercalator and the emitter. Notably, cationic PDA+ possessing a large planar π-π skeleton improved advantageous activity of redox and DNA aptamer indurative loading capacity and directly generated a well-defined cathodic peak to execute the EC bio-detection. This method not only avoids the difficulty of assembling various signal indicators but also improves the sensitivity greatly using the quenching mechanism. In addition, disparate double-response signals coming from different principles of transduction are in a position to verify each other to improve the accuracy. Hence, examination areas of 0.001-100 nM with E2 for ECL and EC were obtained, supplying a novel sensing strategy with promising ideas and perspectives of detection platform construction.

A novel ratiometric electrochemical (EC) sensing platform was established for sensitive immunoassay of target cytokeratin 19 fragment 21-1 (CYFRA21-1) biomarker by combining competitive immunoreact...

Herein, a label-free electrochemical immunosensor based on differential pulse voltammetry (DPV) and amperometric i-t curve (i-t) dual-mode analysis is proposed for early quantitative detection of procalcitonin (PCT). Due to the advantages of high chemical stability and biocompatibility, graphite carbon nitride (g-C3N4) was adopted as a high-capacity sensing interface to carry signal indicators. As an effective indicator of chronoamperometry, nickel cobalt sulfide (NiCo2S4) was uniformly dispersed on the surface of g-C3N4 through in-situ hydrothermal synthesis, which not only promotes the activation of bimetallic activity, but also effectively prevents the aggregation of NiCo2S4. At the same time, in order to establish a dual-mode analysis platform to improve accuracy and sensitivity, highly conductive carbon nanotubes (CNTs) were hybridized with composite materials to load Ag nanoparticles (Ag NPs), which have excellent oxidizing properties and are used as indicators of DPV. On account of this advanced sensing strategy, a wide linear response (DPV: 0.05 ng mL-1-50 ng mL-1 and i-t: 1.00 pg mL-1-10.00 ng mL-1) and a low detection limit (DPV: 16.70 pg mL-1 and i-t: 0.33 pg mL-1) are demonstrated. The immunosensor synthesized by this method has good stability and sensitivity, which could be applied in clinical diagnosis and treatment.

As a carbon-free reaction process, the electrocatalytic nitrogen reduction reaction (eNRR) under mild conditions has broad prospects for green and sustainable NH3 production. In this work, bimetallic RhRu nanoalloys (NAs) with cross-linked curly nanosheets were successfully prepared and exhibited exciting results in the eNRR process. Furthermore, the composition effect of RhRu NAs on eNRR activity was studied systematically, and the results showed that Rh0.6Ru0.4 NAs/CP exhibited the highest NH3 yield rate of 57.75 μg h−1 mgcat.−1 and faradaic efficiency of 3.39%. As an eNRR catalyst with great potential, Rh0.6Ru0.4 NAs extend the possibility of alloy-nanomaterials in the eNRR field and further provide an idea for the precise structure of more effective and stable electrocatalysts.

The development of photocatalysts with high catalytic activity that are capable of full utilization of solar energy is a challenge in the field of photocatalysis. Accordingly, in the present study, an efficient Z-scheme cage-structured Co9S8/g-C3N4 (c-CSCN) photocatalyst was constructed for the degradation of tetracycline antibiotics under visible-light irradiation. The Z-scheme charge-transfer mechanism accelerates the separation of photogenerated charge carriers and effectively improves photocatalytic activity. Moreover, c-CSCN has a hollow structure, allowing light to be reflected multiple times inside the cavity, thereby effectively improving the utilisation efficiency of solar energy. As a result, the photocatalytic activity of c-CSCN is 1.5-, 2.5-, and 5.8-times higher than those of sheet-type Co9S8/g-C3N4 (s-CSCN), c-Co9S8, and g-C3N4, respectively, for the degradation of tetracycline. c-CSCN maintains favourable photocatalytic activity over five consecutive degradation cycles, demonstrating its excellent stability. In addition, c-CSCN performs efficient tetracycline removal in different water substrates. Moreover, c-CSCN exhibits excellent ability to remove tetracycline under direct natural sunlight. This work fully demonstrates that c-CSCN has high catalytic activity and the potential for practical application as a wastewater treatment material.

In comparison with the traditional Haber–Bosch process, the electrocatalytic nitrogen reduction reaction (NRR) with high purity and sustainability became a popular process to satisfy the demand of ammonia. However, the strong competing reaction (hydrogen evolution reaction, HER) and low reaction efficiency hinder the practical applications of NRR. Thus, the development of advanced NRR catalysts by regulating the electronic structure and the activity of single active sites is urgent. Here, in our study, vanadium-doped NiS2 (V–NiS2) nanospheres with abundant active sites were first proposed in the NRR field, which exhibited excellent catalytic activity with a high NH3 yield (47.63 μg h−1 mg−1cat., at −0.45 V) and good faradaic efficiency (FE) (9.37% at −0.35 V) in a 0.1 M HCl solution. Moreover, V–NiS2 also performed desired selectivity and stability. This study provides a pathway to design advanced NRR catalysts for practical applications.

The industrial-scale NH3 production still heavily depends on the Haber–Bosch process, which not only demands high energy consumption but also emits a large amount of CO2. The electrochemical fixation of N2 to NH3 under ambient conditions is regarded as an eco-friendly and sustainable approach, but stable and efficient electrocatalysts are demanded for the N2 reduction reaction under ambient conditions. In this communication, ReS2 nanosheet array on carbon cloth (ReS2/CC) is first utilized in NRR. This ReS2/CC exhibits high catalytic activity and strong long-term electrochemical durability. The Faraday efficiency of ReS2/CC is 0.78% and the NH3 yield of ReS2/CC is 3.61 × 10−10 mol s−1 cm−2 at −0.4 V versus reversible hydrogen electrode in 0.1 M HCl.

Electrocatalytic nitrogen reduction reaction (NRR), as a green and sustainable method for ammonia synthesis, has become one of the candidates to substitute industrial Haber-Bosch ammonia synthesis in the near future. In this work, gold nanoparticles (Au NPs) were successfully anchored on bismuth sulfide nanorods (Bi

Two novel two-dimensional metal-organic frameworks (2D MOFs), 2D-M2 TCPE (M=Co or Ni, TCPE=1,1,2,2-tetra(4-carboxylphenyl)ethylene), which are composed of staggered (4,4)-grid layers based on paddlewheel-shaped dimers, serve as heterogeneous photocatalysts for efficient reduction of CO2 to CO. During the visible-light-driven catalysis, these structures undergo in situ exfoliation to form nanosheets, which exhibit excellent stability and improved catalytic activity. The exfoliated 2D-M2 TCPE nanosheets display a high CO evolution rate of 4174 μmol g-1 h-1 and high selectivity of 97.3 % for M=Co and Ni, and thus are superior to most reported MOFs. The performance differences and photocatalytic mechanisms have been studied with theoretical calculations and photoelectric experiments. This study provides new insight for the controllable synthesis of effective crystalline photocatalysts based on structural and morphological coregulation.

Photoanode sensing platforms with remarkable photoelectrochemical (PEC) response and satisfying visible-light absorption have become the most promising detection systems. Nevertheless, their inevitable electrophilic character limits their expansion in the bioassay because of reductive substances in serum or other body fluids that can severely interfere with the photocurrent to be read. To solve it, a PEC platform-assembled dual-active electrode is designed to realize the separation of biological monitoring from the photoanode. The ferricyanide ([Fe(CN)6]3-)-mediated redox cycle is first proposed to meet the gain and loss electron requirements of the PEC system. It can avoid the self-reaction in the electrolyte caused by the addition of a traditional electron donor and acceptor, for instance, ascorbic acid and hydrogen peroxide. As a consequence, the traditional counter electrode (Pt wire) is replaced by Fe2O3/AgInS2 heterojunction, which can amplify the PEC response of the cathode to meet the requirement of trace analysis. An aptasensor fabricated by the above strategies exhibits convincing data for 17β-estradiol (E2) detection from which a wide detection range is obtained in 10 fg/mL to 1 μg/mL with a detection limit of 2.74 fg/mL (S/N = 3). These advanced elements show a rosy prospect for environmental monitoring and point-of-care biomarker diagnosis.

The transient gene expression of protoplasts in plant is a considerable tool for gene functional research that has been widely used in gene analysis and functional characterization. Therefore, the objectives of this study were to develop a protocol for the isolation and purification of sugarcane protoplasts (Saccharum spp. hybrids), conduct transient PEG-mediated protoplast transfection with D27, and localize the D27 protein in sugarcane protoplasts. Total yield and viability of protoplasts were optimized for enzyme combination, mannitol concentration, and duration and temperature of enzymatic hydrolysis. High production of intact protoplasts (10.94 × 106 protoplasts g−1 FW) and a survival rate of > 80.0% was achieved through enzymatic hydrolysis at constant temperature of 28 °C, 60–70 rpm min−1 for 8 h in a solution containing 2.0% cellulase R-10, 0.5% macerozyme R-10, 0.6% pectolyase Y-23, 20 mM 2-(N-morpholine) ethanesulfonic acid (MES), 20 mM KCl, and 400 mM mannitol (pH 5.7). Using GFP as the reporter gene, the protoplasts were transformed most efficiently with 25% PEG 4000 for 25 min and the ScD27 protein was localized in the chloroplasts. The localization of ScD27 protein in sugarcane protoplast demonstrated that the newly developed protocol was functionally effective. This optimized sugarcane protoplast isolation, purification, and transient expression protocol lays a foundation for future molecular biology research in sugarcane.

This work outlines an electrochemiluminescence (ECL) platform with versatile and high-performance, which using the complex luminescent molecules [Ru(Ⅱ) complex] formed by carbohydrazide (...

An ultrasensitive controlled release system electrochemical aptasensor (CRSEA) has been developed for supersensitive determination of mercury ions (Hg2+), using gold nanoparticle-linked specific single-stranded DNA (Au NPs-ssDNA) as a molecular gate and mesoporous silica nanocontainers (MSNs) as containers. MSNs have a rich porous structure, thus entrapping the toluidine blue (TB) molecules inside. It is worth noting that Hg2+ binds to the ssDNA with multiple thymine (T) and induces the ssDNA to form a hairpin structure, which makes the separation of the Au NPs-ssDNA from the MSNs. Eventually, the stored TB molecules were released from MSNs. The electron transfer signals of TB were detected stably by a differential pulse voltammetry (DPV) detection method, which are correlated with the concentration of Hg2+. Therefore, the wide linear range (10 pM-100 μM) and low limit of detection (2.9 pM) were obtained, and the system also displayed an apparent electrochemical signal response in real sample detection and showed a promising possibility in actual monitoring.

A novel luminol electrochemiluminescence (ECL) sensing platform was developed based on the closed indium tin oxide bipolar electrode (ITO BPE) for detecting the biomarkers of squamous cell carcinomas named cytokeratin 19 fragments (CYFRA 21-1). A strategy of in situ-generated coreactant H2O2 and O2 was proposed to enhance luminol ECL intensity. CaO2, possessing a high capacity of self-supplying H2O2 and O2, was encapsulated by ZIF-67, glucose oxidase, and horseradish peroxidase (GOD/HRP-loaded ZIF-67@CaO2). In the presence of glucose, gluconic acid and H2O2 were generated via the catalytic effect of GOD; then, gluconic acid induced the degradation of ZIF-67, leading to the hydrolysis of the unprotected CaO2 to produce both O2 and H2O2. Therefore, the generated coreactants O2 and H2O2, via the oxidation of glucose and the hydrolysis of CaO2, can effectively enhance the luminol ECL behavior. According to the luminol ECL reaction occurring on the anode surface of the ITO BPE, a sandwich immunosensor was fabricated on the anodic ITO BPE and GOD/HRP-loaded ZIF-67@CaO2 as labels incubated with secondary antibodies. Owing to the cathodic reaction rate influencing the anodic reaction rate, Au nanoparticles were electrodeposited on the cathode surface of the ITO BPE, which not only meliorated oxygen reduction but also further enhanced the ECL intensity of luminol. Under optimal experiments, an ECL immunosensor for detecting CYFRA 21-1 with a wider linear range from 0.0075 to 50 ng mL-1 and a detection limit of 1.89 pg mL-1 (S/N = 3) was obtained.

Oxygen vacancies (OVs) enhanced electrochemiluminescence (ECL) biosensing strategy using luminol thermally encapsulated in apoferritin (Lum@apoFt) as an efficient transducer was investigated for ultrasensitive biomarker detection. By applying the oxygen-defect engineering (ODE) strategy, the OVs enriched cobalt-iron oxide (r-CoFe2O4) was fabricated as the sensing substrate to boost the electron mobility and catalyze the generation of superoxide anion radical (O2•-) for signal amplification. It should be noted that r-CoFe2O4 with higher OVs density dramatically accelerated the ECL reaction between O2•- and luminol anionic radicals, achieving 6.5-fold stronger ECL output than CoFe2O4 with no or low OVs density. Moreover, facile encapsulation of approximate 412 luminol molecules in a single apoFt cavity was first realized by an efficient thermal-induction method. The obtained Lum@apoFt complexes exhibited well-maintained ECL efficiency and excellent biocompatibility for biological modifications. On this basis, a biosensor was developed for early diagnostics of squamous cell carcinomas by detecting its representative biomarker named cytokeratin 19 fragment 21-1 (CYFRA 21-1), from which excellent linearity was achieved in 0.5 pg/mL to 50 ng/mL with a detection limit of 0.14 pg/mL. This work not only put forward a novel idea of creating OVs enriched sensing interface with excellent signal-amplification function but also proposes a facile and robust methodology to design apoFt-based transducers for developing more practical nanoscale biosensors in early diagnostics of diseases.

A three-dimensional viscous inverse design method is improved and extended to multirow blades environment. The inverse method takes load distribution as optimization objective and is implemented into the time-marching finite-volume Reynolds-averaged Navier–Stokes solver. The camber line of rotor blade is updated by virtual displacement, which is calculated by characteristic compatibility relations according to the difference between target and actual load so as to control the location and intensity of shock wave, and realize the optimization of flow structure and reduction flow separation. The inlet and outlet geometry angles of stator blade are adjusted in real time according to the inlet and outlet flow angles. Thus, it is computationally ensured that the blade row interactions are accounted and optimization process is carried out under the design condition. To preserve the robustness of calculation, the maximum virtual displacement is limited by Y+

Anisotropic magnetic exchange is of great value for the design of high performance molecular nanomagnets. In the present work, enhanced single-chain magnet (SCM) behavior is observed for a MoIII -MnII chain that exhibits anisotropic magnetic exchange. Self-assembly of the pentagonal bipyramidal [Mo(CN)7 ]4- anion and the MnII unit with a tridentate ligand results in a neutral double zigzag 2,4-ribbon structure which exhibits SCM behavior with a high relaxation barrier of 178(4) K. Open magnetic hysteresis loops are observed below 5.2 K, with a coercive field of 1.5 T at 2 K. Interestingly, this SCM can be considered to be a result of a step-wise process based on our previously reported Mn2 Mo single-molecule magnets (SMMs).

The carbon layer with good electrical conductivity and outstanding mechanical stability are essential in designing high-performance silicon/carbon (Si/C) anodes to replace the commercial graphite in lithium-ion batteries (LIBs). In terms of solving the two inherent defects of poor conductivity and big volume change of silicon, we fabricate a spongy carbon matrix derived from ZIF-8 to anchor saclike silicon synthesized by molten salt magnesiothermic reduction method. This spongy matrix can anchor saclike silicon to provide a stable reaction interface and support fast electronic transmission. At the same time, buffer space in saclike Si nanoparticles and spongy matrix can synergistically accommodate the volume change of Si to maintain the integrity of the electrode. The resulting composite with a high Si content of 77.58% exhibits good capacities of 1448 mAh g−1 at 2 A g−1 and 848 mAh g−1 at 4 A g−1 after 500 cycles. High initial coulombic efficiency of 84% at 0.2 A g−1 is also exhibited in the first three activation cycles. Therefore, this novel multifunctional N-doped spongy matrix can supply multifaceted benefits in accommodation of volumetric variation, enhancement of conductivity, and integrity of structure during cycling.

This study proposes a competitive photoelectrochemical (PEC) immunosensor for detecting diethylstilbestrol (DES). The PEC sensing platform uses a zinc and molybdenum codoped BiVO4 nanoarray ((Zn,Mo):BiVO4) as the photoactive matrix and manganese hexacyanoferrate hydrate loading silicon dioxide layer composite nanocubes (MHCF@SiO2 NCs) as the signal quencher. The (Zn,Mo):BiVO4 nanoarray demonstrated brilliant PEC behavior, by virtue of the local electric field formed by the codoped Zn and Mo. This doping accelerated the electron transfer and improved the photoelectric conversion efficiency in BiVO4 nanoarray under visible light. Furthermore, the nanoarray structure with its large surface area provided abundant binding sites for the immune response. As the MHCF@SiO2 NCs-anti-DES competitively bonded with either free DES or bovine serum albumin conjugated DES (BSA-DES), hydrogen peroxide (H2O2) as electron donor was competitively consumed and meanwhile steric resistance blocked electrons transfer. For the above reasons, the photocurrent signal was reduced. Thus, the standard sample free DES was accurately detected, and the fabricated PEC immunosensor displayed an outstanding photocurrent response from 0.1 pg/mL to 50 ng/mL with a detection limit of 0.05 pg/mL. Simultaneously, the acceptable stability, selectivity, and reproducibility of the designed dual-competitive sensing platform suggest its applicability to small molecule detection.

An original dual signal amplification immunoassay for N-Terminal pro-brain natriuretic peptide (NT-proBNP) detection is developed based on Au NPs and Zn doped CdS nanoparticles (Zn0.02Cd0.98S) co-sensitized Bi2MoO6 nanosheet photoelectrochemical (PEC) platform, the target is a good myocardial marker for diagnosing heart failure (HF). Bi2MoO6 as an outstanding photocatalysis material is successfully used in PEC analysis in this work, and the nanosheet structure provide a preponderance to capture superior Zn0.02Cd0.98S in order to achieve anticipant PEC response. The doping of Zn makes the energy band of CdS matched more compatible with Bi2MoO6, and improves the narrow band gap of CdS, making the surface plasma resonance (SPR) effect of Au NPs more significant, thus further improving the PEC response, as well as elevated the detection sensitivity of biological targets. The constructed PEC platform for NT-proBNP provides a wide detection range of 0.0001–1000 ng mL−1 and gives the minimum detection value of 0.037 pg mL−1. Great stability, high selectivity, and good reproducibility are also achieved. The proposed PEC immunoassay provides more possibilities for other protein ultra-sensitivity detection.

Dual-functional NiCo2S4 polyhedral architectures with outstanding electrochemical performance for supercapacitors and lithium-ion batteries (LIBs) have been rationally designed and successfully synthesized by a hydrothermal method. The as-synthesized NiCo2S4 electrode for supercapacitor exhibits an outstanding specific capacitance of 1298 F g−1 at 1 A g−1 and an excellent rate capability of ~80.4% at 20 A g−1. Besides, capacitance retention of 90.44% is realized after 8000 cycles. In addition, the NiCo2S4 as anode in LIBs delivers high initial charge/discharge capacities of 807.6 and 972.8 mAh g−1 at 0.5 C as well as good rate capability. In view of these points, this work provides a feasible pathway for assembling electrodes and devices with excellent electrochemical properties in the next generation energy storage applications.

In this work, a triple-amplified biosensor with a bioactivity-maintained peculiarity was constructed for quantitative procalcitonin (PCT) detection. As everyone knows, a strong electrochemiluminescence (ECL) signal is the premise to ensure high sensitivity for trace target detection. Hence, a valid tactic was developed to achieve signal amplification of luminophor by using Co2+-based metal-organic frameworks (ZIF-67) and silver-cysteine (AgCys). The ZIF-67 particles, which have more atomically dispersed Co2+, could play the role of a co-reaction accelerator to catalyze S2O82- to generate abundant Co3+ and sulfate radical anions (SO4•-). Afterward, a mass of Co3+ was reduced to more hydroxyl radicals (OH•) by H2O, thus ulteriorly reducing S2O82- to generate more SO4•-. Remarkably, S2O82- was reduced to SO4•- continuously with the recycling of Co2+ and Co3+, which realized an effective signal amplification. Meanwhile, the AgCys complex with superior catalysis and biocompatibility was prepared to further improve the ECL signal and maintain the bioactivity of the biomolecule. Furthermore, HWRGWVC, a heptapeptide that was used for combining the Fc fragments of an antibody by Au-S bonding to achieve the fixed point fixation, could not only maintain bioactivity of an antibody but also improved its incubation efficiency, thus further enhancing biosensor sensitivity. Under optimum conditions, the proposed biosensor realized highly sensitive assay for PCT with a wide dynamic range from 10 fg/mL to 100 ng/mL and a detection limit as low as 3.67 fg/mL. With superior stability, selectivity, and repeatability, the prepared biosensor revealed immense potential application of ultrasensitive assay for PCT in human serum.

Thrombin is a marker of blood-related diseases, and its detection is of great significance in the fields of medical and biological research. Herein, a novel chemiluminescence (CL) sensor for thrombin detection was prepared based on dual-aptamer biorecognition and mesoporous silica encapsulated with iron porphyrin. Mesoporous silica encapsulated with hematin by aptamer1 (Apt1/hematin/M-SiO2) and magnetic microspheres modified with aptamer2 (Apt2/NH2-MS) were successfully prepared, and the two materials were used to construct a CL sensor to detect thrombin. Primarily, Apt2/NH2-MS is used for pretreatment separation of thrombin samples by the biorecognition effect between the aptamer (Apt2) and target (thrombin). Then, thrombin/Apt2/NH2-MS is again recognized with Apt1 on the surface of Apt1/hematin/M-SiO2 and Apt1/thrombin/Apt2/NH2-MS is formed, so dual-aptamer biorecognition is realized. Meanwhile, the generated Apt1/thrombin/Apt2/NH2-MS makes Apt1 shed off the surface of M-SiO2 and release hematin. The released hematin can catalyze the luminol-H2O2 CL reaction. Therefore, a sandwich-type CL sensor was constructed based on dual-aptamer biorecognition and hematin catalysis for the detection of thrombin. The sensor has a linear range of 7.5 × 10-15 to 2.5 × 10-10 mol·L-1 and a detection limit of 2.2 × 10-15 mol·L-1 and also exhibits excellent selectivity, reproducibility, and stability. The sensor was successfully used for the detection of thrombin in serum samples, which makes it possible to apply the sensor in the detection of thrombin in actual samples.

A label-free photoelectrochemical (PEC) immunoassay system based on the one-step synthesis of SnS2/CdS nanocomposites is successfully constructed for sensitively analyzing procalcitonin (PCT). The one-step synthesis of SnS2/CdS enables the rapid construction of an immunoassay system and avoids the waste of energy. In the constructed immunoassay system, CdS as a sensitizer for PCT analysis not only enhances the light absorption of SnS2 as a photocurrent generator but also can accelerate the separation of photosensitive electrons and holes by forming a heterostructure. Under optimum conditions, the energy-saving assay platform based on the enhancement photocurrent response of SnS2/CdS nanocomposites exhibited an excellent performance in analyzing a series of PCTs with different concentrations in a wide linear range of 0.5 pg mL−1 to 100 ng mL−1 and the detection limit was 0.17 pg mL−1. In view of the advantages of good selectivity, high sensitivity, and facile preparation procedure, the PEC immunoassay is expected to be a promising analytical platform for rapid analysis of PCT and other biomarkers in clinical medical samples.

A new strategy for the highly sensitive electrochemiluminescence (ECL) detection of insulin was developed based on curcumin-conjugated Au nanoparticles wrapped in zeolitic Zn2+-imidazolate cross-linked framework nanoparticles (Au-Cur/ZIF-8) quenching the ECL of CdS-decorated TiO2 nanobelts (CdS@TiO2). Curcumin-conjugated Au nanoparticles were embedded in ZIF-8 through epitaxial growth or nucleus coalescence. Herein, dual coreactants H2O2 and K2S2O8 were employed to enhance the ECL emission of CdS@TiO2, and the enhancing mechanism may be due to the electrogenerated hydroxyl radical (OH˙) strengthening the amount of sulfate radical anion (SO4˙-), which was the main species of generating ECL signals. In order to sensitively detect insulin, Au-Cur/ZIF-8 labels were used to anchor secondary antibodies via amidation reaction and inhibit the ECL intensity of CdS@TiO2. Moreover, the possible mechanism of quenching between Au-Cur/ZIF-8 and CdS@TiO2 was ascribed to the poor conductivity of ZIF-8, the consumption of OH˙ and the ECL resonance energy transfer between CdS@TiO2 and Au-Cur. Under optimal conditions, a sandwich immunosensor was prepared to determine insulin with a good linear range from 0.3 pg mL-1 to 20 ng mL-1 and a low detection limit of 0.09 pg mL-1 (S/N = 3).

Developing dopant-free hole transporting materials (HTMs) and passivating defects in perovskite films are two significant themes to realize efficient and stable perovskite solar cells (PSCs). Compared to various individual endeavors for either of them, enabling both via a single material is more interesting but certainly challenging. In this report, we develop dopant-free polymer HTMs bearing amino pendants as passivating groups for improved efficiency and stability of PSCs. The bifunctional polymers present simultaneous main-chain (donor–acceptor conjugated backbone) hole extraction/transport and side-chain (amino group) defect passivation at the perovskite/HTM interface. Moreover, with an increased content of amino pendants, the polymers exhibit enhanced hole mobility and defect passivation ability, advancing device efficiency and stability. As a result, PSCs using the dopant-free polymer HTM achieve an efficiency approaching 19%, with impressive stability when testing at a relative humidity of 85%, by heat at 80 °C, or under continuous light illumination. This work demonstrates that amino functionalization at the side chain of polymers is a promising method to develop dopant-free HTMs accompanied by defect passivation effects for high-performance and durable PSCs.

In this work, a photoelectrochemical (PEC) aptasensor for the detection of 17β-estradiol (E2) based on an In2S3 and CdS co-sensitized cerium (Ce) doped TiO2 (Ce:TiO2) electrode was constructed successfully. In2S3 with superior properties, such as narrow band gap, attractive photoelectric conversion efficiency, hypotoxicity and low pollution, could act as a promising material in the PEC sensing detection field. Here, a PEC aptasensor based on In2S3 was fabricated for the detection of E2. Besides, Ce doped into TiO2 introduced a new intrinsic energy band into TiO2, which created an easier electron transfer path. In2S3 and CdS co-loaded on Ce:TiO2 not only improved the photocurrent response but also expanded the light absorption range. Meanwhile, an aptamer with a specific sequence, serving as a recognition unit, was used to specifically bind with E2 to enable detection. Under optimal conditions, the as-prepared aptasensor exhibited a linearity range of 10−5–100 ng mL−1 with a detection limit of 4.0 fg mL−1. The aptasensor also showed satisfactory selectivity, stability and acceptable reproducibility.

For the first time, we report the formation of a chiral MOF-based helical nanomaterial (h-HDGA@ZIF-67) through arranging zeolitic imidazolate framework (ZIF-67) nanocrystals on helical l-glutamic acid terminated bolaamphiphile (h-HDGA) via a facile process at room temperature. The self-assembly leads to the chiral function of the ZIF-67 from an achiral ligand. The h-HDGA@ZIF-67 served as a new type of electrochemical sensing interface for recognizing and quantifying Pen enantiomers that realize significant enantioselectivity, satisfactory stability, and reproducibility. The synergetic effect from ZIF-67 nanocrystals on h-HDGA and stereoselectivity of h-HDGA@ZIF-67 lead to the excellent enantioselectivity. The present strategy showed the first example of a chiral MOF-based supramolecule helical nanomaterial, presenting high enantioselectivity for electrochemical enantiomeric determination.

A novel, highly selective and sensitive chemiluminescence (CL) biosensor for insulin (INS) detection was proposed based on aptamer and oligonucleotide-gold nanoparticles functionalized nanosilica @ graphene oxide aerogel. Initially, nanosilica functionalized graphene oxide aerogel (SiO2@GOAG) was successfully prepared and the composite showed rich pore distribution, large specific surface area and good biocompatibility. Insulin aptamer (IGA3) was used as a biorecognition element and oligonucleotide functionalized gold nanoparticles (ssDNA-AuNPs) was used as CL signal amplification materials, which were functionalized on the surface of SiO2@GOAG. The multi-functionalized composite - ssDNA-AuNPs/IGA3/SiO2@ GOAG was obtained and used to construct the CL biosensor for insulin detection. When insulin is present in a sample, the insulin will bind to the IGA3, which will result in the release of ssDNA-AuNPs. The released ssDNA-AuNPs would catalyze the luminescence of luminol and H2O2. The linear range of the CL biosensor for insulin detection was 7.5 × 10−12 to 5.0 × 10−9 moL/L and the detection limit was 1.6 × 10−12 moL/L (S/N = 3). The selectivity and stability of the CL biosensor were also studied and the results showed that the biosensor exhibited high selectivity and good stability due to the introduction of ssDNA-AuNPs/IGA3/SiO2@GOAG. The CL biosensor was finally used for recombinant human insulin detection in recombinant human insulin injection and the results were satisfactory.

Electrocheluminescence (ECL) immunoassay amplified by coreaction accelerators has experienced major breakthroughs in ultrasensitive detection of biomarkers. Herein, CeO2/SnS2 heterostructures were synthesized and applied as a novel coreaction accelerator to enhance the ECL efficiency of the luminol-dissolved O2 system for the first time. Benefiting from the well-matched lattice spacing, ultrafine CeO2 nanoparticles (NPs) were grown in situ on layered SnS2 nanosheets (NSs) with improved dispersion. CeO2/SnS2 as an electroactive substrate can remarkably accelerate the generation of abundant superoxide anion radicals (O2•-) to react with luminol anion radical (L•-), achieving about 2-fold stronger ECL intensity than that of pure CeO2 NPs. To avoid harsh chemical synthesis of conventional ECL labels and simplify the antibody conjugation process, ferritin (Ft) was served as a natural nanocarrier to immobilize luminol molecules (Lum@Ft) via a one-step linkage, whose protein nanocage can easily connect with the detection antibody. Moreover, a robust site-oriented immobilization strategy using HWRGWVC heptapeptide as specific capturer was further adopted to maintain the bioactivity of the capture antibody on the amine-functionalized CeO2/SnS2 surface, which promoted the incubation efficiency markedly. On account of this advanced sensing strategy, a brand new biosensor was constructed for the accurate detection of heart failure biomarkers, which performed with favorable linearity in the range of 0.0001-50 ng/mL and achieved the detection limit of 36 fg/mL.

Nowadays, the electrochemiluminescence (ECL) immunosensor with the unique superiority of tunable luminescence and ultrahigh sensitivity has become one of the most promising immunoassay techniques, especially for low-abundance biomarkers analysis. However, the use of signal probes with high excited potential and applied emitters which owned good intensity but biotoxicity limited its application. Herein, an ECL resonance energy transfer strategy was developed based on protein bioactivity protection utilizing europium-doped phosphoric acid gadolinium (GdPO4:Eu) as novel low-potential luminophor (donor) and Pd@Cu2O as the quenching probe (acceptor). Specifically, GdPO4:Eu was first prepared by using the hydrothermal synthesis method to apply in ECL, and when it coexisted with K2S2O8, cathode, a strong ECL signal would be generated at a low potential of -1.15 V (vs Ag/AgCl), where the immunocompetence of antigens and antibodies can be maintained well. Electrical pair Eu3+/Eu2+, as the coreactant promoter, produced by potential excitation could produce more SO4•- to accelerate the oxidation process of GdPO4:Eu. Meanwhile, Cu2O coated onto Pd (Pd@Cu2O), as a dual-quencher, enhanced the quenching effect of Pd alone and controlled the ECL intensity of the "signal on" state within a reasonable range. As a result, the proposed biosensor for detection of trace procalcitonin, a biomarker of systemic inflammatory response syndrome, exhibited a far low detection limit, 0.402 fg/mL (S/N = 3). Importantly, this work not only utilized a promising ECL emitter for biosensing platform construction but also had momentous potential in biomarker detection of disease diagnosis and clinical analysis.

This research put forward a novel split-type electrochemical (EC) immunosensor which integrated the controlled-release strategy with EC detection for application in the field of biosensing. Concretely, ascorbic acid (AA) was packaged in a cadmium sulfide (CdS)-capped spherical mesoporous bioactive glass (SBG) nanocarrier (SBGCdS) on account of encapsulation technology. To reduce the complexity of the bioanalysis, the detection antibody-labeled SBGCdS-AA bioconjugate was applied in a 96-well microplate for the immunoreaction process, which is independent of the EC determination procedure. Thus, the immune interference and steric hindrance caused by the accumulation of nanomaterials on the electrode could be minimized. Subsequently, AA was released efficiently via the destruction effect of dithiothreitol on the disulfide bond. In addition, for the as-prepared FcAI/l-Cys/gold nanoparticles (GNPs)/porous BiVO4 (p-BVO)/ITO EC sensing platform in the detection solution, the synergetic catalysis of Fc and GNPs/p-BVO toward the oxidation of the released AA could be realized, which triggered AA-mediated significant signal magnification throughout this study. In particular, p-BVO with an ordered nanoarray structure could accelerate the electron transfer to assist in sensitivity improvement of this system. This novel biosensor was capable of assaying the neuron-specific enolase (NSE) biomarker sensitively, from which a linear range of 0.001-100 ng/mL was derived along with a low detection limit of 1.08 pg/mL. An innovative way could be paved in the bioanalysis of NSE and other biomarkers.

The design and synthesis of highly efficient and durable non-noble metal electrocatalysts have become a top priority for the hydrogen evolution reaction (HER). Thus, this study describes a straightforward synthesis of nickel-doped cobalt phosphide nanowire clusters on carbon cloth (Ni-CoP/CC) via a simple hydrothermal-phosphating process. Owing to the unique nanowire cluster structure together with the use of current collector, such binder-free three-dimensional electrode of Ni-CoP/CC displays efficient HER activity, achieving the low overpotential of 53 mV at a geometric current density of 10 mA cm−2, with a Tafel slope of 57 mV dec−1 and superior stability (100 h) in 1.0 M KOH.

There dimensional (3D) metallic nanohybrids have attracted attentions for the applications in nanophotonic devices, catalysis and biosensor. Here, the 3D suspended Ag nanoparticles/Carbon nanotubes (AgNPs/CNTs) nanohybrids, obtained by self-aggregating AgNPs onto the suspended CNT networks, are synthesized and used for the SERS application. The electric field distribution with the near-field and far-field coupling can be obtained by the optimization of the nanogaps of the AgNPs. Such suspended AgNPs/CNTs nanohybrids are studied to be used as the ultra-sensitive SERS biosensor, benefiting from the bio-compatibility and chemical absorption of the CNT networks and the EM enhancement of the 3D denser “hotspots”. R6G molecules with a concentration as low as 10−15 M can be clearly detected, demonstrating their excellent Raman enhancement.

Silicon (Si) has been regarded as one of the next-generation anode materials due to its ultrahigh theoretical capacity, low equilibrium potential, abundant resources and superior safety performance. Herein, we fabricated a novel honeycomb Si composed of many Si nanoparticles (NPs), which can be refined from the urchin-like crude product obtained through the magnesiothermic reduction process. Via the electrostatic attraction, rapid freeze-drying process and further thermal treatment, the honeycomb Si can be tightly encapsulated in a thin layer composed of reduced graphene oxide and carbon nanotube (indicating as Si-rGO/CNT) to avoid direct exposure to the electrolyte. Si NPs with the wrinkled rGO/CNT wrapping layer containing mesopores can not only shorten the pathway of Li+ ions and electrons but also accommodate the unavoidable expansion/contraction and buffer the excessive stress. Meanwhile, the CNT intertwined throughout the electrode can effectively repair those areas that lost conductivity during long-term cycling. Therefore, the self-supported Si-rGO/CNT electrode having a high Si content of 76 wt% exhibits capacities of 1304 mAh g−1 at 2 A g−1 and 1053 mAh g−1 at 5 A g−1 in rate performance, and maintain a capacities of 1899 mAh g−1 at 0.5 A g−1 after 250 cycles and 1003 mAh g−1 at 4 A g−1 after 1000 cycles accompanying with a stable coulombic efficiency (CE) up to 99.5%.

Reversible controlling and switching of magnetic bistability remains relatively difficult. Here, reversible on–off switching of a hysteretic spin transition in a CoII complex via a single-crystal t...

Colloidal nanocrystal clusters constructed of abundant nanocrystal subunits possess immense potential for catalysis in fuel cells due to their collective properties and novel functionalities deriving from the ensemble. Nevertheless, the effects of electronic structure and boundary density of subunits on their electrocatalytic properties are rarely reported. Herein, we report a facile synthesis of PtNi colloidal nanocrystal clusters with tunable electronic structure and boundary density through a one-step solvothermal approach. With the increase of Ni/Pt molar ratio, more grain boundary and interspace are generated in PtNi colloidal nanocrystal clusters, which result in more active sites and high electrochemical surface area for the electrooxidation reactions of methanol and formic acid. Specifically, the PtNi3 exhibit approximately 11.5 (9.6) times higher specific activity and 1.8 (1.5) times higher mass activity than those of benchmark Pt/C for methanol (formic acid) oxidation. The PtNi3 CNCs also possess more excellent diffusion ability for MOR (0.038) and FAOR (0.0082) compared with other PtNi CNCs and Pt/C. Combination of experiments and density functional theory calculation reveals the enhanced activity derives from the optimization of boundary density, d-band center and further OH adsorption ability. This approach provides a strategy to design other colloidal nanocrystal clusters with excellent electronic and surface structure for direct fuel cell applications.

Chrysanthemum is one of the most important ornamental flowers in the world. In general, abnormal morphology of Chrysanthemum flowers is developed during~35–40 °C, which significantly damages incomes of flower gardener. Therefore, to select Chrysanthemum lines of high temperature tolerance is of vital importance. In this study, transgenic calluses with eIF5B1, a regulatory gene of high temperature tolerance, were generated, and the presence of the transgene and its stable expression were confirmed through PCR, GUS assay and Western blotting. These transgenic calluses with plantlets were also observed by both electron and optical microscope. Findings indicate these lines contain more starch granules, which are a marker of high temperature tolerance. We expect that the efficient protocol developed in this study will facilitate the genetic transformation of the genes of interest and that these regulatory genes will help in keeping the flower morphology of Chrysanthemum under high temperature stress.

The shuttle effect from the dissoluble polyselenide intermediates in lithium-selenium (Li-Se) battery is a critical problem. In order to explore the effective solution, a specific composite ceramic separator including a covalent organic framework prepared by the polymerization of 2,5-Dimethoxy-1,4-Dicarboxaldehyde and Tetrakis(4-aminophenyl)ethane (DMTA-COF) was used to enhance electrochemical performance of Li-Se battery for the first time. It should be noted that the cathode with pure selenium of 80% by weight leads to a high selenium loading of ∼3 mg/cm2 for the simply-made cells. Due to the small pore channel of the DMTA-COF-coated separator, the dissolution of the polyselenide LiSen (n > 4) can be effectively restrained. As a consequence, the cells delivered a long cycling performance of up to 700 cycles with high capacity of 126 mA h/g at 6 C and good capacity of 51 mA h/g at 20 C. Obviously, our study elucidates the COF-integrated separator is a promising pathway to improve the capacity and stability of the lithium-selenium battery.

In this work, a “luminophore/coreactant/co-reaction accelerator” ternary electrochemiluminescence (ECL) system is proposed by using N-(aminobutyl)-N-(ethylisoluminol) (ABEI) functionalized cobalt-based MOFs (Co-MOFs/ABEI) with superior peroxidase-like activities as the luminophore. ABEI, the derivative of luminol, is used as the reductant and organic ligand to synthesize flower-like Co-MOFs/ABEI. The as-synthesized Co-MOFs/ABEI not only function as desirable nano-carriers for the enrichment of ABEI, but also act as co-reaction accelerators for the catalysis of H2O2 decomposition. Furthermore, Au nanoparticles are decorated on Co-MOFs/ABEI via electrostatics attraction, endowing it with favorable biocompatibility and electrocatalytic property to bond with detection antibodies and generate more excited state ABEI*. Besides, with the advantages of large specific surface area and easy preparation, Au nanoparticles functionalized Fe3O4@polypyrrole is utilized to anchor the capture antibodies for immunoaction with target analyte. Amyloid-β protein (Aβ42), a principal hallmark of Alzheimer’s disease, is chosen as the target analyte. The proposed Aβ42 immunosensor performs with a broad linear range from 10 fg mL−1 to 100 ng mL−1 and a detection limit down to 3 fg mL−1, opens up new prospects for clinical analysis of Aβ42 and provides promising approaches to synthesize luminophore-functionalized MOFs with high luminous efficiency for ECL bioanalysis.

Distributed block clamps are widely used in hydraulic piping systems. However, due to wear and tear over time, the clamps may loosen, and if not detected in the early stages, it can lead to the catastrophic results. The common methods to detect the clamp looseness are based on the monitoring the pre-load of the connected bolts. The Fiber Bragg Grating (FBG) sensors, as the emerging sensing technology with anti-electromagnetic interference, small size and lightweight, easy to install, corrosion resistant, durable, cost effective and multiplexed properties has been used to design smart bolts and smart washers in the existed literatures recently. However, the distributed features of the smart bolts are limited to the through-hole structures and the smart washer can only be used to the bolted connections with big-diameter bolts, which makes the smart bolts and washers difficult to apply to distributed clamp bolted with small-diameter bolts. Therefore, an FBG based smart clamp is presented for the first time in this paper. The theoretical models, i.e. the analytical model and Finite Element Model (FEM) are developed to derive the measurement principle and optimize the structure of the clamp. The calibration experiments of the smart clamp are conducted to obtain the sensitivity of the smart clamp. Subsequently, a practical application, i.e. clamp looseness detection, is given in an industrial piping system which shows that the smart clamp is high sensitive to the incipient looseness of the clamp.

The expansion of electrochemiluminescence (ECL) technology to immunoassay at the core of care emphasizes all immune molecules will not be inactivated in the analysis process. That poses a major challenge to ECL-based biosensors due to the deoxynucleotide sequences of an antigen or antibody could be oxidized through a route of excessive cyclic potential. Herein, an ultrasensitive ECL biosensor was developed based on a novel bioactivity-protected sensing strategy utilizing Au nanoclusters (Au NCs) as low-potential luminophor for detection of procalcitonin (PCT). Bovine serum albumin (BSA)-templated Au NCs exhibited a low-potential anodic ECL signal in triethylamine (TEA) solution at 0.87 V, where it is suitable for the survival of immune molecules. Taking advantage of good conductivity and high surface area, a Cu2S snowflake not only functions as a satisfying substrate for connecting immune molecules but also acts as co-reaction accelerator to produce more cationic radicals TEA•+, which could improve the ECL intensity needed to meet the requirements of trace analysis. Otherwise, HWRGWVC (HC-7) heptapeptide as specific antibody immobilizer for site-oriented fixation was introduced to further maintain the bioactivity of an antibody. In view of the preceding discussion, the obtained biosensor exhibited ultrahigh immune recognition to targets so that the detection limit was as low as an unprecedented value of 2.36 fg/mL, which will be of great significance to the application and development of a biosensor in the future.

The serum level of soluble CD44 is directly associated with several clinicopathological parameters of malignant diseases. There is a great need for the development of an easy and cost-effective detection method for soluble CD44 for both the diagnosis and the treatment of cancers. In this work, a simple photoelectrochemical (PEC) method for the sensitive detection of serum-soluble CD44 is proposed based on the construction of a hybrid antifouling coating on the TiO2 substrate. Hyaluronic acid (HA) and poly(ethylene glycol) (PEG) are co-immobilized using a biomimetic one-step surface functionalization approach. The immobilized HA shows strong recognition abilities toward soluble CD44, and the synergistic antifouling effect achieved by the combination of PEG and HA improves the sensing specificity. Based on the inhibitory effect of CD44 recognition on the PEC signal of the TiO2 substrate, a PEC biosensor is developed with a wide response range and a low detection limit. The development of antibody-free biosensors may promote the application of soluble CD44 as a biomarker for the diagnosis and treatment of malignant diseases.

It is essential to develop a highly efficient detection platform for tetracycline (Tc). Herein, based on well-designed hierarchical MIL-68(In)-NH2/MWCNT/CdS composites as a highly efficient transducer, a label-free visible light driven photoelectrochemical (PEC) aptasensor was systematically fabricated. Characterization results indicate that the forming of MIL-68(In)-NH2/CdS heterojunction remarkable facilitated the transfer and inhibited the recombination of charge carriers. Moreover, the transfer properties of multiwalled carbon nanotubes (MWCNTs) further improved the photoelectric conversion efficiency by adjusting electron transport routes. The aptamer as a biorecognition unit was grafted on the modified electrode by chemical bonding effect, and Tc molecules could be captured through the specific interaction of aptamer and Tc in solution. The concentration of Tc was detected by observing the fluctuation of photocurrent signals. Under optimized conditions, the proposed aptasensor showed the broad linear range from 0.1 nmol L−1 to 1 μmol L−1 with a low detection limit (LOD) of 0.015 nmol L−1. Furthermore, the high sensitivity, excellent reproducibility and favorable stability of the PEC sensing platform indicated the potential applications for antibiotic residues detecting in environmental media.

Considering the parametric uncertainties, the model of a rotor system with transverse crack is investigated. Polynomial Chaos Expansion is used to describe the uncertainties. The Harmonic Balance method is employed to solve the dynamic equations of cracked uncertain hollow-shaft system. The application of the PCE in hollow shaft structures will be tested and the results can provide practical reference for engineering context. Validation of present method is verified by comparing with Monte Carlo simulations. From the simulation results, the multi-vibration peaks near the first critical speed and the sub-critical speeds are sensitive to the uncertain parameters. When considering the uncertain parameters, the non-linear responses in harmonic components of the rotor system are key indicators for the detection of transverse crack.

A novel visible light photoelectrochemical immunosensor based on BiOBr/Bi2S3 heterostructures was fabricated to detect squamous cell carcinoma antigen (SCCA). Bi2S3 nanoparticles formed on the BiOBr microflowers by the self-sacrificial synthesis method based on the facile reaction between BiOBr and S2- ions. The BiOBr/Bi2S3 composites exhibited excellent visible light photoelectrochemical activity, when ascorbic acid (AA) was employed as a perfect electron donor. The photocurrent intensity of BiOBr/Bi2S3 modified ITO electrode arrived at around 20 µA, which was approximately 30 times than that of pure BiOBr. Dopamine formed easily polydopamine film via self-polymerization on the surface of BiOBr/Bi2S3 composites to immobilize SCCA antibody. Under the optimal condition, this photoelectrochemical immunosensor realized the ultrasensitive determination of SCCA. With the logarithm of SCCA concentration in the range of 0.001–75 ng mL−1, the specific binding between SCCA and antibody led to the linearly decrease of photocurrent signal with a low detection limit of 0.3 pg mL−1 (S/N = 3). This facilely constructed photoelectrochemical immunosensor maybe have promising practical application in photocatalysis, analytical detection and biosensor, etc.

Ultrafine Ni2P/Co2P nanoparticles encapsulated in hollow porous N-doped carbon nanospheres are synthesized through a facile two-step access. Firstly, metallic Ni and Co coated by hollow N-doped spheres as precursors are obtained through a high temperature calcination route of organic polymer and inorganic Ni and Co salts. Then bimetal Ni2P/Co2P supported on N-doped carbon nanospheres are acquired by a facile phosphorization process. It is worth to note that aniline-pyrrole polymer can prevent fast growth and severe aggregation of Ni2P/Co2P, which implies more exposed active sites. Moreover, the calcination of hollow polymer spheres lead to the formation of ultrathin NC shell on the surface of Ni2P/Co2P hybrids, which can tune electronic structures, improve the conductivity and protect active sites from corrosion in harsh conditions. When used as HER catalyst, it displays remarkable catalytic activity in both acidic and alkaline solutions, which needs an onset potential of only 164 mV and 168 mV, respectively. Therefore, this work may propose a new strategy to design unique inorganic-organic heterostructures to combine ultrafine metal phosphides with porous carbon for efficient HER.