Detection of organic dyes using Ag NPAs/SMP SERS substrate produced via sandpaper template-assisted lithography and liquid-liquid interface self-assembly

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive and reliable fingerprinting technique. However, its analytical capability is closely related to the quality of a SERS substrate used for the analysis. In particular, conventional colloidal substrates possess disadvantages in terms of controllability, stability, and reproducibility, which limit their application. In order to address these issues, a simple, cost-effective, and efficient SERS substrate based on silver nanoparticle arrays (Ag NPAs) and sandpaper-molded polydimethylsiloxane (SMP) was proposed in this work. Successfully prepared via template lithography and liquid-liquid interface self-assembly (LLISA), the substrate can be applied to the specific detection of organic dyes in the environment. The substrate exhibited good SERS performance, and the limit of detection (LOD) of rhodamine 6G (R6G) was shown to be 10-7 M under the optimal conditions (1000 grit sandpaper) with a relative standard deviation (RSD) of 7.76%. Moreover, the SERS signal intensity was maintained at 60% of the initial intensity after the substrate was stored for 30 days. In addition, the Ag NPAs/SMP SERS substrate was also employed to detect crystal violet (CV) and methylene blue (MB) with the LODs of 10-6 M and 10-7 M, respectively. In summary, the Ag NPAs/SMP SERS substrate prepared in this study has great potential for the detection of organic dyes in ecological environments.

IL-9 promotes methicillin-resistant Staphylococcus aureus pneumonia by regulating the polarization and phagocytosis of macrophages

In this study, we examined the effect of Il9 deletion on macrophages in methicillin-resistant Staphylococcus aureus (MRSA) infection. MRSA-infected mice were employed for the in vivo experiments, and RAW264.7 cells were stimulated with MRSA for the in vitro experiments. Macrophage polarization was determined by flow cytometry and quantitative real-time PCR; macrophage phagocytosis was assessed by flow cytometry and laser scanning confocal microscopy; cell apoptosis was assessed by flow cytometry and western blotting. Il9 deletion markedly elevated macrophage phagocytosis and M2 macrophages in MRSA infection, which was accompanied by elevated expression of Il10 and Arg1 and reduced expression of Inos, tumor necrosis factor-α (Tnfα), and Il6. Il9 deletion also inhibited macrophage apoptosis in MRSA infection, which was manifested by elevated B-cell lymphoma 2 (BCL-2) protein level and reduced protein levels of cleaved cysteine protease 3 (CASPASE-3) and BCL2-Associated X (BAX). Both the in vivo and in vitro experiments further showed the activation of phosphoinositide 3-kinase (PI3K)/AKT (also known as protein kinase B, PKB) signaling pathway in MRSA infection and that the regulation of Il9 expression may be dependent on Toll-like receptor (TLR) 2/PI3K pathway. The above results showed that Il9 deletion exhibited a protective role against MRSA infection by promoting M2 polarization and phagocytosis of macrophages and the regulation of Il9 partly owing to the activation of TLR2/PI3K pathway, proposing a novel therapeutic strategy for MRSA-infected pneumonia.

Electrodeposition Synthesis of Coral-like MnCo Selenide Binder-Free Electrodes for Aqueous Asymmetric Supercapacitors

Bimetallic selenide compounds show great potential as supercapacitor electrode materials in energy storage and conversion applications. In this work, a coral-like MnCo selenide was grown on nickel foam using a facile electrodeposition method to prepare binder-free supercapacitor electrodes. The heating temperature was varied to tune the morphology and crystal phase of these electrodes. Excellent electrochemical performance was achieved due to the unique coral-like, dendritic- dispersed structure and a bimetallic synergistic effect, including high specific capacitance (509 C g-1 at 1 A g-1) and outstanding cycling stability (94.3% capacity retention after 5000 cycles). Furthermore, an asymmetric supercapacitor assembled with MnCo selenide as the anode and active carbon as the cathode achieved a high specific energy of 46.2 Wh kg-1 at 800 W kg-1. The work demonstrates that the prepared coral-like MnCo selenide is a highly promising energy storage material.

Fabrication of Micro-Cantilever Sensor Based on Clay Minerals for Humidity Detection

In this paper, novel humidity sensors based on montmorillonite, kaolinite, and composite films coated on micro-cantilevers were prepared to measure the relative humidity (RH) values by the deflection of a micro-cantilever (MC) at room temperature. The humidity-sensing properties, such as response and recovery, sensitivity, repeatability, humidity hysteresis, and long-term stability, were investigated in the range of working humidity (10-80% RH). The humidity response in the close humidity range of 10% RH to 80% RH revealed a linear increase in water absorption of montmorillonite, kaolinite, and montmorillonite/kaolinite mixed dispersant (1:1) as a function of RH with linear correlation factors between the humidity change and deflection estimated to be 0.994, 0.991, and 0.946, respectively. Montmorillonite's sensitivity was better than kaolinite's, with the mixed-clay mineral film's response falling somewhere in between. This research provides a feasible and effective approach to constructing high-performance MC humidity sensors that can be operated at room temperature based on clay minerals.

Ulothrix-Derived Sulfur-Doped Porous Carbon for High-Performance Symmetric Supercapacitors

With the demand for carbon dioxide emission reduction, the sustainable conversion of useless biomass into high-value energy storage devices has received excellent scientific and technological attention. The high synthesis cost and low specific capacitance limited the supercapacitor application. Therefore, biomass-derived sulfur-doping porous carbon (SPC) has been synthesized from ulothrix using simple pyrolysis and chemical activation methods. The unique activated carbon material exhibits a high specific surface area (2490 m² g^-1), and the effect of the activator addition ratio was systematically investigated. The optimized SPC-2 displayed a high specific capacitance (324 F g^-1 at 1 A g^-1) and excellent cycling stability (90.6% retention after 50 000 cycles). Furthermore, a symmetric supercapacitor (SSC) based on SPC-2 demonstrated a high energy density (12.9 Wh kg^-1) at an 800 W kg^-1 power density. This work offers a simple, economical, and ecofriendly synthetic strategy of converting widespread, useless biomass waste into high-performance supercapacitor applications.