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A low operating temperature and short response/recovery time are essential factors for sensors. Hence, it is necessary to create a sensor that can quickly detect target gas at a relatively low temperature. In this work, Co3O4 microtube based sensors were fabricated by a bio-template method using absorbent cotton. Co3O4 microtube sensors prepared in different concentrations of a salt solution displayed different sensitivities to triethylamine (TEA). The Co3O4-0.10 microtube sensor exhibited excellent sensitivity to TEA at 160 °C. The response of the Co3O4-0.10 sensor to 100 ppm TEA gas was 31.27 and the detection limit of TEA was 50 ppb. Meanwhile, the Co3O4-0.10 sensor also showed a short response/recovery time, such as 95 s/38 s to 100 ppm TEA, high selectivity, a good linear relationship (R2 = 0.994 for 1–100 ppm TEA and R2 = 0.991 for 50–1000 ppb TEA gas), fine repeatability and long-term stability, and strong humidity resistance. Thus, Co3O4 microtube based sensors prepared using a bio-template method have potential application prospects for the detection of TEA gas. [ABSTRACT FROM AUTHOR]

A system for the rapid and ultra-sensitive detection of Staphylococcus aureus (S. aureus), a prevalent foodborne pathogen is introduced. Limitations of typical electrochemical sensing, often subjected to interference from non-specific protein adsorption are addressed. A dual-aptamer-based sandwich immunobiosensor is shown for its benefits regarding specificity and anti-fouling capacity, endowed by a sulfonated polyaniline layer combined with signal amplification via highly conductive gold nanoparticles. EIS spectra (Nyquist plots) were recorded at pH 7.4 PBS containing 5 mM Fe(CN)63−/Fe(CN)64−, in order to verify the possibility of the electrochemical sensing for detection of S. aureus. Results demonstrated that the constructed immunobiosensor presents an extended detection range (1 × 101 to 1 × 105 CFU/mL) and detection limit as low as 2 CFU/mL. The resistance values of the immunobiosensor developed maintain at a stable value during 2 weeks. Besides, the specificity of the system is highlighted by testing raw milk, and the results of which demonstrate the excellent prospects of the system for monitoring foodborne pathogens. [ABSTRACT FROM AUTHOR]

ZnO/ZnCo 2 O 4 hollow tube clusters are fabricated by a one-step method using aster novi-belgii fluffs as bio-template, followed by calcination treatment at 500, 600 and 700 °C. The sensors fabricated with the ZnO/ZnCo 2 O 4 hollow tube clusters display fine sensitivity to H 2 S. Herein, ZZCO-600 sensor presents high response value of 65.38–100 ppm H 2 S at 160 °C with the low detection limit of 30 ppb. Meanwhile, ZZCO-600 sensor also displays fast recover time (94 s for 10 ppm H 2 S), high selectivity, fitting linear relationship (R2 =0.997 for 1–100 ppm H 2 S and R2 =0.995 for 30–1000 ppb H 2 S), great repeatability and long-term stability. These superb performances of ZZCO-600 sensor are conducive to real-time and chronical monitoring in practical applications. Additionally, the XPS analysis is used to speculate the possible gas-sensing mechanism of ZZCO-600 towards H 2 S. Therefore, this work provides the structure design of ZnO/ZnCo 2 O 4 hollow tube clusters for H 2 S detection and investigates their potential practical applications for high-sensitive gas sensors. • ZnO/ZnCo 2 O 4 was synthesized by an eco-friendly method sacrificing aster novi-belgii fluffs as bio-template. • The ZZCO-600 sensor has superb sensitivity to H 2 S at operating temperature of 160 ℃ with detection limit of 30 ppb. • The ZZCO-600 sensor reveals fast recovery time. [ABSTRACT FROM AUTHOR]

A novel fluorescent probe CuNI was synthesized and exhibited highly effective fluorescence detection ability for Cu2+ in aqueous solution (HOAc–NaOAc buffer, 10 mM, pH 5.0). CuNI was obtained by a simple condensation reaction between the aldehyde (MFNI, bearing the naphthalimide fluorescence group) and the 2-picolinyl hydrazide, which bears the Cu2+ recognized group. Under acidic conditions, CuNI showed turn-on fluorescence recognition of Cu2+ which could be readily distinguished with the naked eye under a 365 nm UV lamp and the detection limit is as low as 19.40 nM. It has been further demonstrated that CuNI was hydrolyzed under the action of Cu2+ and the significant increase of fluorescence is due to the obvious AIE effect of the hydrolysate MFNI. The application of the probe CuNI in imaging lysosomal Cu2+ in HepG2 cells has also been demonstrated. [ABSTRACT FROM AUTHOR]

An electrochemical sensor for Pb(II) is described that exploits (a) the outstanding adsorption ability of chitosan modified with quaternary ammonium groups (CQAS; cationic) and of lignosulfonate (LSN; anionic), and (b) the good electrical conductivity of polypyrrole nanoparticles (PPy NPs). A glassy carbon electrode (GCE) was modified with PPy NPs and polydopamine, and CQAS and LSN are used as dispersants in PPy. The modified GCE exhibits high selectivity and sensitivity for Pb(II) in the 0.1 to 50 μM concentration range, with a 55 nM detection limit (3σ method). The redox potentials for Pb(II) is around −0.55 V, and the sensor is not interfered by the presence of Hg(II) and Cu(II). The time dependent stability test showed that this sensor can maintain good reproducibility for one month. This sensor was applied to the determination of Pb(II) in wastewater samples. [ABSTRACT FROM AUTHOR]

It is extremely necessary to detect Hydrogen sulfide (H 2 S) due to the hazardous nature. Thus, it is required to design a material which can detect H 2 S gas at low temperature. In this work, ZnCo 2 O 4 microtubes are prepared by using absorbent cotton as template, combining immersion method in metal salt solution (Zn:Co=1:2) with calcination treatment in air. The influence of calcination temperature on the particle size and sensing property was also discussed. The diameter of particles on the ZnCo 2 O 4 microtubes increases with increasing calcination temperature. The hollow microtubes of ZnCo 2 O 4 materials calcined at 600 °C (ZCO-600) exhibit superb sensing performance to H 2 S at 90 °C with the lowest detection limit of 50 ppb. The optimum operating temperature (90 °C) was lower than the other reported ZnCo 2 O 4 sensors. ZCO-600 sensor also shows excellent selectivity, repeatability, stability, humidity resistance and the good linear relationship in ppb and ppm level H 2 S. In addition, the feasible sensing mechanism of ZCO-600 to H 2 S is explored on the basis of XPS analysis. Thus, ZnCo 2 O 4 as a sensing material possesses widespread application prospects for the detection of trace H 2 S gas. [Display omitted] • ZnCo 2 O 4 was synthesized by a simple method employing absorbent cotton. • The ZCO-600 sensor has superb sensitivity to H 2 S at low temperature of 90 ℃. • The ZCO-600 sensor could realize detection of H 2 S gas at ppb-level. [ABSTRACT FROM AUTHOR]

• A sensor with PANI/Hep/MTA/MGCE for detection of Cr(VI) in whole blood was obtained. • The sensor exhibited outstanding electrochemical performance for Cr(VI) detection. • The sensor can detect Cr(VI) in whole blood due to its antibiofouling property. Fast and accurate test Cr(VI) in the whole blood is particularly critical for the treatment and prevention of Cr(VI) poisoning. Here, a blood compatible, high-efficient sensor based on the magnetic glassy carbon electrode (MGCE) that modified by conductive polyaniline (PANI), heparin and tannin modified Fe 3 O 4 nanoparticles (magnetic tannin-modified adsorbent, MTA) with high adsorption ability toward Cr(VI) ions was developed. Results indicated the designed PANI/Hep/MTA/MGCE exhibited high sensitivity for Cr(VI) in the concentration range of 10 − 7 to 10−4 ppm with a 0.87 μM detection limit (3σ method). In particular, this prepared sensor not only exhibited outstanding electrochemical performance for Cr(VI) detection, but also possessed good antibiofouling characteristics due to the existence of heparin, which can provide guarantee for direct detection of Cr(VI) in the whole blood. [ABSTRACT FROM AUTHOR]

Fast and accurate detection of S. aureus and effectively kill S. aureus in the bloodstream in low doses acted as key roles in medicine and microbiology studies. In this work, sufonated-hyaluronic acid (S-HA) terminated magnetic mesoporous silica nanoparticles (MMSNs) loaded with vancomycin was successfully prepared, and S. aureus antibody was further modified on the surface of MMSNs (Ab@S-HA@MMSNs) by amidation reaction. The result showed that Ab@S-HA@MMSNs were 240 nm-sized spheres with worm-like mesoporous channels. With the aid of magnetic interaction, Ab@S-HA@MMSNs were modified on the surface of magnetic glassy carbon electrode (MGCE). This prepared immunosensor exhibited an excellent detection limit and linear range, and possessed good selectivity, stability and reproducibility. Besides, since the S-HA terminated MMSNs have anticoagulant property, the Ab@S-HA@MMSNs/MGCE showed antiadhesion property, which ensure that it can be directly applied to detect the amount of S. aureus in whole blood. What's more, with an increasing amount of S. aureus arriving at MGCE, the capping Ab@S-HA@MMSNs were degraded by Hyal which was secreted by S. aureus , and the packaged vancomycin was subsequently released. Ultimately, S. aureus can be effectively killed. Therefore, this integrated platform would be a promising multifunctional platform for achieving accurate diagnosis and efficient treatment of S. aureus bloodstream infection. • Since the S-HA terminated MMSNs have anticoagulant property, this prepared immunosensor not only exhibited an excellent detection limit and linear range, possessed good selectivity, stability and reproducibility, but also could be directly applied to detect the amount of S. aureus in whole blood. • With the increase of amount of S. aureus arriving at MGCE, the capping Ab@S-HA@MMSNs were degraded by Hyal which was secreted by S. aureus , and the packaged vancomycin was subsequently released, which ensure that S. aureus can be effectively killed. • This integrated platform would be a promising multifunctional platform for achieving accurate diagnosis and efficient treatment of S. aureus bloodstream infection. [ABSTRACT FROM AUTHOR]

Covert mortality nodavirus (CMNV), the pathogen of viral covert mortality disease (VCMD), has caused serious economic losses of shrimp aquaculture in Southeast Asian countries and China in the past decade. In view of that the rapid and accurate laboratory detection of CMNV plays a major role in the effective control of the spread of VCMD. The national proficiency test (NPT) for the detection of covert mortality nodavirus (CMNV) started in China from 2021. In this study, a novel TaqMan real-time reverse transcription quantitative PCR (RT-qPCR) detection method for CMNV with higher sensitivity than previous reports was established based on specific primers and probe designing from the conserved regions of the CMNV coat protein gene for using molecular detection of CMNV in NPT. The optimized RT-qPCR reaction program was determined as reverse transcription at 54.9 °C for 15 min and denaturation at 95 °C for 1 min, followed by 40 cycles including denaturation at 95 °C for 10 s, and annealing and extension at 54.9 °C for 25 s. The detection limit of the newly developed RT-qPCR method was determined to be as low as 2.15 copies of CMNV plasmids template per reaction, with the correlation coefficient (R2) at above 0.99. The new method showed no cross reaction with the six common aquatic animal pathogens and could be finished in one hour, which represents a rapid detection method that can save 50% detection time versus the previously reported assay. The CMNV TaqMan probe based RT-qPCR method developed in present study supplies a novel sensitive and specific tool for both the rapid diagnosing and quantitating of CMNV in NPT activities and in the farmed crustaceans, and will help practitioners in the aquaculture industry to prevent and control VCMD effectively. [ABSTRACT FROM AUTHOR]

High‐sensitive detection of NO is very important to protect environment and human health. In this study, the composites of ZnO nanorods and CsPbBr3/Cs4PbBr6 particles are synthesized successfully and used as sensing materials for detection of NO, in which the as‐prepared samples exhibit ultra‐high response and excellent selectivity to NO at 50 °C. Toward 100 ppm NO, the response is up to about 2296. The samples can high‐sensitively detect 1 ppm NO with response of about 6, demonstrating a low detection limit. The high response of CsPbBr3/Cs4PbBr6/ZnO could be attributed to the multiple heterojunctions formed among three materials. The results demonstrated that the composites of CsPbBr3/Cs4PbBr6 and ZnO should be a promising material for preparing the high‐sensitive NO sensors at low temperature. [ABSTRACT FROM AUTHOR]