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Polystyrene (PS), a polymer material renowned for its notable optical and mechanical properties, as well as low cost and ease of processing, stands as one of optimal candidate for flexible electrode substrate materials. However, prevalent modification techniques such as lithography, electron beam evaporation, and plasma etching all entail the requirement for specialized equipment and precise operation, thereby significantly elevating the technical barrier. In this study, we introduce a chemical plating method to fabricate a gold film electrode, coupled with prussian blue (PB) and glucose oxidase (GOx), for the development of a glucose electrochemical biosensor. This process offers simplicity, cost‐effectiveness, and feasibility under regular experimental conditions. The electrode surface is covered with numerous gold nanoparticles, effectively augmenting the actual electrode area and enhancing electron transfer efficiency. Remarkably, without the addition of sensitizing agents, the biosensor achieves highly sensitive glucose detection. The proposed biosensor exhibits a broad linear relationship in the concentration range of 0.005–1 mM, with a detection limit of 4.4 μM. Moreover, it exhibits favorable performance in detecting glucose levels in sweat samples, showcasing promising prospects for personal healthcare diagnostics. [ABSTRACT FROM AUTHOR]

Surface vegetations are one of the key factors affecting the spread of green space fires. To explore the combustibility of commonly used local surface layer herbaceous species in Beijing, and to provide a reference for the construction and management of urban green space, we comprehensively evaluated the combustibility of Carex giral- diana, Carex breviculis, Liriope spicata, Iris lactea, Iris tectorum, and Buffaloe dactyloides, with the entropy weight method and K-mean cluster analysis based on the principal component analysis method. We measured the combustion characteristics indicators (blade ignition point, combustion time and heat release rate), physical and chemical indicators (leaf moisture content and crude fat content), and biological characteristics indicators ( blade thickness and unit load) during the key period of fire prevention. The results showed that blade thickness and ignition point got the highest weight and affected the overall combustibility most. Peak heat release rate and ignition time had the lowest weight and minimal impact on the overall combustibility. The combustibility of the six species followed an order of B. dactyloides > C. breviculmis > L. spicata > C. giraldiana > I. lactea > I. tectorum. Results of the cluste-ring analysis showed that the combustion ability of B. dactyloides, C. breviculmis, and L. spicata were in class I, with the strongest combustion ability; C. giraldiana was in class H ; I. lactea and I. tectorum were in class M, with the lowest flammability. As widely used surface vegetations, critical attention should be paid on B. dactyloides, C. breviculmis and L. spicata for fire prevention in winter and spring. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The development of accurate, rapid and practical electrochemical sensing technology for antibiotic detection has an important application prospect in many fields such as food safety, environmental monitoring, medical and health care. In this research, kanamycin specific DNA aptamer and its partially complementary short chain were self‐assembled onto the surface of an integrated portable plastic gold electrode (PGE) by Au—S bond, and a simple kanamycin electrochemical biosensor interface was constructed. At the same time, the epoxy resin channel layer was designed, and the auxiliary instrument was set up independently in the laboratory, which could help to measure and analyze eight groups of samples automatically in turn. The quantitative analysis results showed that in 20 min, the sensor had a good linear relationship between the peak current change of square wave voltammetry and the negative logarithm of kanamycin concentration when kanamycin concentration was in the range of 1—1000 μmol/L, and the detection limit could reach 0.40 μmol/L. In addition, the discrimination could be achieved within 5 min in the real‐time analysis mode. The sensor had a simple construction method, good selectivity and stability, and could be used for rapid or real‐time detection of kanamycin residues in actual water samples, which provided a new direction for the practical detection of kanamycin in environmental water samples. [ABSTRACT FROM AUTHOR]

Nanopore sensing is highly promising in single molecular analysis but their broad applications have been challenged by the limited strategies that can transduce a target‐of‐interest into a specific and anti‐false/inference signal, especially for solid‐state nanopores with relatively lower resolution and higher noise. Here we report a high‐resolution signal‐production concept named target‐induced duplex polymerization strategy (DPS). Through linking the same or different duplex substrates (DSs) with a special linker (L) and an optional structure tag (ST), the DPS can generate target‐specific DS polymers with highly controllable duration times, duration intervals and even distinguished secondary tagging currents. Experimentally, DPS mono‐polymerization of single DS and co‐polymerization of multiple DSs has verified the duration time of a DPS product is the sum of those for each DS monomer. Tetrahedron‐DNA structures with different sizes are used as the STs to provide needle‐like secondary peaks for further resolution enhancement and multiplex assay. With these examples DPS represents a general, programmable and advanced strategy that may simultaneously provide size‐amplification, concentration amplification, and signal‐specificity for molecular recognition. It is also promisingly in various applications regarding to single molecular investigation, such as polymerization degree, structure/side chain conformation, programmable multiplex decoding and information index. [ABSTRACT FROM AUTHOR]

Aptamers, which are artificial oligonucleotides selected in vitro, have been employed to design novel biosensers (i.e., aptasensers). In this work, we first constructed a label-free electrochemical aptasenser introducing a probe immobilization technique by the use of a layer-by-layer (LBL) self-assembled multilayer with ferrocene--appended poly(ethyleneimine) (Fc-PEI) on an indium tin oxide (ITO) array electrode for detection of cocaine. The Fc-PEI and gold nanoparticles (AuNPs) were LBL assembled on the electrode surface via electrostatic interaction. Then, cocaine aptamer fragments, SH-C2, were covalently labeled onto the outermost AuNP layer. When the target cocaine and cocaine aptamer C1 were present simultaneously, the SH-C2 layer hybridized partly with C1 to bind the cocaine, which led to a decreased differential pulse voltammetry (DPV) signal of Fc-PEI. This DPV signal change could be used to sensitively detect cocaine with the lowest detectable concentration down to 0.1 [micro]M and the detection range up to 38.8 [micro]M, which falls in the the expected range for medical use of detecting drug abuse involving cocaine. Meanwhile, the sensor was specific to cocaine in complex biologic fluids such as human plasma, human saliva, etc. The sensing strategy had general applicability, and the detection of thrombin could also be realized, displayed a low detection limit, and exhibited worthiness to other analytes. The aptasensor based on the array electrode held promising potential for integration of the sensing ability in multianalysis for simultaneous detection. 10.1021/ac902566u

Here, a fluorescent switch is constructed combining hemin, hemin aptamer, and a newly synthesized anionic conjugated polymer (ACP), poly(9,9-bis(6'-phosphatehexyl) fluorenealt-1,4-phenylene) sodium salt (PFHPNa/ PFP). In the 'off-state', the fluorescence of PFP is sensitively quenched by hemin, with a high [K.sub.sv] value of [10.sup.7]. While in the 'on-state', the formation of the aptamer/hemin complex recovers the fluorescence intensity. The fluorescent switch is sensitive and selective to hemin. To testify the universality and practicality of the fluorescent switch, a series of label-free DNA-related sensing platforms are developed, containing three DNA sensing strategies and one ATP recognition strategy. The fluorescent switch developed is simple, sensitive, and universal, which extends applications of the anionic conjugated polymers.

Aptamers, which are in vitro selected functional oligonucleotides, have been employed to design novel biosensors (i.e., aptasensors) due to their inherent selectivity, affinity, and their multifarious advantages over traditional recognition elements. In this work, we reported a multifunctional reusable label-free electrochemical biosensor based on an integrated aptamer for parallel detection of adenosine triphosphate (ATP) and [alpha]-thrombin, by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A Au electrode as the sensing surface was modified with a part DNA duplex which contained a 5'-thiolated partly complementary strand (PCS) and a mixed aptamer (MBA). The unimolecular MBA contained small-molecule ATP binding aptamer (ABA) and also protein [alpha]-thrombin binding aptamer (TBA). Thus, the aptasensor could be used for detection of ATP and [alpha]-thrombin both. The detection limit of ATP was 1 x [10.sup.-8] M, and its detection range could extend up to [10.sup.-4] M, whereas the detection limit of [alpha]-thrombin was 1 x [10.sup.-11] M, and its detection range was from 1 x [10.sup.-11] to 1 x [10.sup.-7] M. Meanwhile, after detecting [alpha]-thrombin, the sensing interface could be used for ATP recognition as well. The aptasensor regeneration could be realized by rehybridizing of the MBA strand with the partly complementary strand immobilized on the Au surface after ATP detection or by treating with a large amount of ATP and then rehybridizing the MBA strand with the partly complementary strand immobilized on the Au surface after [alpha]-thrombin detection. The aptasensor fabricated exhibited several advantages such as label-free detection, high sensitivity, regeneration, and mulfifunctional recognition. It also showed the detectability in biological fluid. Therein it held promising potential for integration of the sensing ability such as the simultaneous detection for multianalysis in the future.