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Biofilms are primary causes of clinical bacterial infections. They are resistant to typical amounts of antibiotics, necessitating very high doses for elimination. Therefore, it is imperative to establish sensitive, rapid, and timely methods for the detection of Staphylococcus aureus (S. aureus) biofilm. The aim of this research was to develop an easy-to-use electrochemical sensor for sensing pathogenic S. aureus biofilms. We developed mesoporous Cu-doped BaTiO3-G-SiO2 (CBTGS)-based electrodes to investigate their electrochemical detection ability for S. aureus biofilms. Results revealed that mesoporous CBTGS electrode in biosensing devices provided high sensitivity and stability for electrochemical detection of S. aureus biofilms. When the mesoporous morphology of CBTGS was compared to that of Cu-doped BaTiO3-G or Cu-doped BaTiO3, it showed a higher surface area with more active sites for attaching S. aureus biofilms, leading to its higher electron transfer resistance. As a result, it enabled rapid detection. A linear relationship between the increment in electron transfer resistance and the logarithmic value of S. aureus biofilm concentration was observed between 40 and 200 µL. The limit of detection was observed to be 5 µL. Finally, a good selectivity versus S. enterica (Salmonella enterica) and P. aeruginosa (Pseudomonas aeruginosa) was obtained for our developed mesoporous CBTGS, demonstrating its specificity towards only Staphylococcus aureus biofilms. [ABSTRACT FROM AUTHOR]

In this study, we present the development of a novel CaMn4O8–G–SiO2 (CaMnGS) sensor to detect the presence of Penicillium italicum mold. CaMnGS as ternary type nanocomposite was synthesized using a self-assembly technique. CaMnGS sample demonstrated outstanding stability, high selectivity, and notable characteristics for Penicillium italicum fungus detection. For Penicillium italicum fungus sensing, the CaMnGS displayed a large linear range of (50–100) μL, and a low detection limit of 0.50 μL. Significantly, the CaMnGS sensor was capable of swiftly detecting the Penicillium italicum fungus in wastewater. The CaMnGS has been proven to improve the selectivity for Penicillium italicum and had tremendous potential for Penicillium italicum fungal sensing. The mesoporous CaMnGS sensor may also detect the presence or absence of the fungus Penicillium italicum. This method might be used to identify the fungus Penicillium italicum. This is also the first attempt to discuss the fabrication of an electrochemical sensor employing a mesoporous CaMnGS nanoparticle composite as a platform for the selective detection of Penicillium italicum. Penicillium italicum sensing [ABSTRACT FROM AUTHOR]

This paper describes the development of a graphene-based mesoporous electrochemical biosensor for the quantitative detection of Escherichia coli (E. coli) O157:H7 based on biocompatible mesoporous Ca-doped MgAl2O3–G–SiO2 (CMAGS) nanomaterials. The nanocomposites were morphologically characterized using various techniques, such as XRD, SEM, BET, HRTEM, Raman, DRS, and XPS. In addition, the active materials for the sensing test were electrochemically characterized using cyclic voltammetry (CV). The uniform film for E. coli O157:H7 was successfully established through a self-assembly route. The target bacteria were directly sensed by the electrode, thus allowing E. coli O157:H7 to be selectively recognized; E. coli O157:H7 was detected using the cyclic voltammetry sensing system. Under optimal conditions, the linear relationships between E. coli O157:H7 concentrations were obtained from 101 CFU to 1010 CFU with a 101 CFU limit of detection (LOD). The biosensor was also successfully used in the detection of water samples. A mesoporous Ca-doped MgAl2O3–G–SiO2 (CMAGS)-based sensing method for E. coli O157:H7 was reported for the first time. The sensing system showed high selectivity to the target analyte and is expected to lead to new opportunities, such as speeding up disease diagnosis, treatment, and prevention with pathogens. [ABSTRACT FROM AUTHOR]

Azithromycin is one of the most concentrated antibiotics in wastewater, as conventional wastewater treatment facilities cannot eliminate this antibiotic from the environment. In this study, we proposed using a graphene-based mesoporous electrochemical sensor to take simultaneous voltammetric measurements of azithromycin. Because of its homogeneous pore structure, large surface area, quick electron transfer rate, and superior biocompatibility, magnesium-containing mesoporous silica is a promising resource for the immobilization of biomolecule matrix. Ca2+-doped MgAl2O3-G-SiO2 was used to build an amperometric biosensor through a self-assembly process. At room temperature in a buffer solution with a pH of 7.0, the modified electrode under ideal circumstances displayed good azithromycin sensing activity, a linear range of 1 to 5 µmolL−1, a detection limit of 0.5 µmolL−1, and a reaction time of less than 2 sec. An array of morphological analysis methods—including X-ray diffraction methos, scanning electron microscopy, Brunauer-Emmett-Teller method, high resolution tunneling electron microscopy, Raman, diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy—was used to examine the nanocomposite's crystalline structure. Cyclic voltammetry was used to determine the sensing effects in the mesoporous active nanomaterials. Finally, it was found that the electrochemical sensor performed as an ideal biosensor that was able to detect azithromycin in the presence of several interfering species with high stability, selectivity, and repeatability. [ABSTRACT FROM AUTHOR]

The development of CO2 into hydrocarbon fuels has emerged as a green method that could help mitigate global warning. The novel structured photocatalyst is a promising material for use in a photocatalytic and magneto-electrochemical method that fosters the reduction of CO2 by suppressing the recombination of electron—hole pairs and effectively transferring the electrons to the surface for the chemical reaction of CO2 reduction. In our study, we have developed a novel-structured AgCuZnS2—graphene—TiO2 to analyze its catalytic activity toward the selective evolution of CO2. The selectivity of each nanocomposite substantially enhanced the activity of the AgCuZnS2—graphene—TiO2 ternary nanocomposite due to the successful interaction, and the selectivity of the final product was improved to a value 3 times higher than that of the pure AgCuZnS2 and 2 times higher than those of AgCuZnS2—graphene and AgCuZnS2—TiO2 under ultraviolet (UV)-light (λ = 254 nm) irradiation in the photocatalytic process. The electrochemical CO2 reduction test was also conducted to analyze the efficacy of the AgCuZnS2—graphene—TiO2 when used as a working electrode in laboratory electrochemical cells. The electrochemical process was conducted under different experimental conditions, such as various scan rates (mV·s−1), under UV-light and with a 0.07 T magnetic-core. The evolution of CO2 substantially improved under UV-light (λ = 254 nm) and with 0.07 T magnetic-core treatment; these improvements were attributed to the facts that the UV-light activated the electron-transfer pathway and the magnetic core controlled the pathway of electron-transmission/prevention to protect it from chaotic electron movement. Among all tested nanocomposites, AgCuZnS2—graphene—TiO2 absorbed the CO2 most strongly and showed the best ability to transfer the electron to reduce the CO2 to methanol. We believe that our newly-modeled ternary nanocomposite opens up new opportunities for the evolution of CO2 to methanol through an electrochemical and photocatalytic process. [ABSTRACT FROM AUTHOR]