Label-free biosensors provide an important platform for detecting chemical and biological substances without needing extra labeling agents. Unlike surface-based techniques such as surface plasmon ...resonance (SPR), interference, and ellipsometry, surface-enhanced Raman spectroscopy (SERS) possesses the advantage of monitoring analytes both on surfaces and in solutions. Increasing the SERS enhancement is crucial to preparing high-quality substrates without quickly losing their stability, sensitivity, and repeatability. However, fabrication methods based on wet chemistry, nanoimprint lithography, spark discharge, and laser ablation have drawbacks of waste of time, complicated processes, or nonreproducibility in surface topography. This study reports the preparation of recyclable TiOsub.2/Ag nanoparticle (AgNP) substrates by using simple arc ion plating and direct-current (dc) magnetron sputtering technologies. The deposited anatase-phased TiOsub.2 ensured the photocatalytic degradation of analytes. By measuring the Raman spectra of rhodamine 6G (R6G) in titrated concentrations, a limit of detection (LOD) of 10sup.−8 M and a SERS enhancement factor (EF) of 1.01 × 10sup.9 were attained. Self-cleaning was performed via UV irradiation, and recyclability was achieved after at least five cycles of detection and degradation. The proposed TiOsub.2/AgNP substrates have the potential to serve as eco-friendly SERS enhancers for label-free detection of various chemical and biological substances.
Surface-enhanced Raman scattering (SERS) is a promising technique for sensitive detection. The design and optimization of plasma-enhanced structures for SERS applications is an interesting challenge. ...In this study, we found that the SERS activity of MXene (Tisub.3Csub.2Tsub.x) can be improved by adding Au nanoparticles (NPs) in a simple photoreduction process. Fluoride-salt-etched MXene was deposited by drop-casting on a glass slide, and Au NPs were formed by the photocatalytic growth of gold(III) chloride trihydrate solutions under ultraviolet (UV) irradiation. The Au–MXene substrate formed by Au NPs anchored on the Tisub.3Csub.2Tsub.x sheet produced significant SERS through the synergistic effect of chemical and electromagnetic mechanisms. The structure and size of the Au-decorated MXene depended on the reaction time. When the MXene films were irradiated with a large number of UV photons, the size of the Au NPs increased. Hot spots were formed in the nanoscale gaps between the Au NPs, and the abundant surface functional groups of the MXene effectively adsorbed and interacted with the probe molecules. Simultaneously, as a SERS substrate, the proposed Au–MXene composite exhibited a wider linear range of 10sup.−4–10sup.−9 mol/L for detecting carbendazim. In addition, the enhancement factor of the optimized SERS substrate Au–MXene was 1.39 × 10sup.6, and its relative standard deviation was less than 13%. This study provides a new concept for extending experimental strategies to further improve the performance of SERS.
Tribolium castaneum is a damaging pest of stored grains, causing significant losses and secreting lethal quinones, which render the grains unfit for human consumption. Chemical insecticides are the ...most commonly used approach for control; however, they create insecticide resistance and affect the health of humans, animals, and the environment. As a result, it is critical to find an environmentally friendly pest-management strategy. In this study, two naturally occurring chemicals, benzyl alcohol (BA) and benzoyl benzoate (BB), were investigated for insecticidal activity against T. castaneum using different assays (impregnated-paper, contact toxicity, fumigant, and repellency assays). The results showed that BA had a significant insecticidal effect, with the LCsub.50 achieved at a lower concentration in the direct-contact toxicity test (1.77%) than in the impregnated-paper assay (2.63%). BB showed significant effects in the direct-contact toxicity test, with an LCsub.50 of 3.114%, and a lower toxicity in the impregnated-paper assay, with an LCsub.50 of 11.75%. Furthermore, BA exhibited significant fumigant toxicity against T. castaneum, with an LCsub.50 of 6.72 µL/L, whereas BB exhibited modest fumigant toxicity, with an LCsub.50 of 464 µL/L. Additionally, at different concentrations (0.18, 0.09, 0.045, and 0.0225 µL/cmsup.2), BA and BB both showed a notable and potent repelling effect. BA and BB significantly inhibited acetylcholinesterase, reduced glutathione (GSH), and increased malondialdehyde (MDA) in treated T. castaneum. This is the first report of BA insecticidal activity against the red flour beetle. Also, the outcomes of various assays demonstrated that the application of BA induces a potent bio-insecticidal effect. BA may be a promising eco-friendly alternative to control T. castaneum due to its safety and authorization by the EFSA (European Food Safety Authority).
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•Recent advances in ultrasound-assisted extraction (UAE) are detailed.•Ultrasound extraction enhances extraction yield, economy and green impacts.•Ultrasound acts directly in the ...plant cell to release metabolites.•Ultrasound-assisted extraction acts through single or combined mechanisms.•Ultrasound-assisted extraction is an efficient tool for plant-based chemistry.
This review presents a complete picture of current knowledge on ultrasound-assisted extraction (UAE) in food ingredients and products, nutraceutics, cosmetic, pharmaceutical and bioenergy applications. It provides the necessary theoretical background and some details about extraction by ultrasound, the techniques and their combinations, the mechanisms (fragmentation, erosion, capillarity, detexturation, and sonoporation), applications from laboratory to industry, security, and environmental impacts. In addition, the ultrasound extraction procedures and the important parameters influencing its performance are also included, together with the advantages and the drawbacks of each UAE techniques. Ultrasound-assisted extraction is a research topic, which affects several fields of modern plant-based chemistry. All the reported applications have shown that ultrasound-assisted extraction is a green and economically viable alternative to conventional techniques for food and natural products. The main benefits are decrease of extraction and processing time, the amount of energy and solvents used, unit operations, and CO2 emissions.
ReSsub.2, as a new member of transition metal dichalcogenides (TMDCs), has emerged as a promising substrate for semiconductor surface-enhanced Raman spectroscopy (SERS) due to its unique ...optoelectronic properties. Nevertheless, the sensitivity of the ReSsub.2 SERS substrate poses a significant challenge to its widespread application in trace detection. In this work, we present a reliable approach for constructing a novel ReSsub.2/AuNPs SERS composite substrate, enabling ultrasensitive detection of trace amounts of organic pesticides. We demonstrate that the porous structures of ReSsub.2 nanoflowers can effectively confine the growth of AuNPs. By precisely controlling the size and distribution of AuNPs, numerous efficient and densely packed "hot spots" were created on the surface of ReSsub.2 nanoflowers. As a result of the synergistic enhancement of the chemical and electromagnetic mechanisms, the ReSsub.2/AuNPs SERS substrate demonstrates high sensitivity, good reproducibility, and superior stability in detecting typical organic dyes such as rhodamine 6G and crystalline violet. The ReSsub.2/AuNPs SERS substrate shows an ultralow detection limit of 10sup.−10 M and a linear detection of organic pesticide molecules within 10sup.−6-10sup.−10 M, which is significantly lower than the EU Environmental Protection Agency regulation standards. The strategy of constructing ReSsub.2/AuNPs composites would contribute to the development of highly sensitive and reliable SERS sensing platforms for food safety monitoring.
Fumonisin FB is produced by Fusarium moniliforme Sheld, of which FBsub.1 is the most common and the most toxic. The establishment of a rapid detection method is an important means to prevent and ...control FBsub.1 pollution. A highly sensitive fluorescent sensor based on an aptamer for the rapid detection of fumonisin Bsub.1 (FBsub.1) in corn was established. In this study, 5-carboxyfluorescein (FAM) was labeled on the aptamer of FBsub.1 (F10). F10 was adsorbed on the surface of graphene oxide (GO) by π-π stacking. The FAM fluorescence signal could be quenched by fluorescence resonance energy transfer between fluorescent molecules and graphene oxide (GO). In the presence of FBsub.1, the binding efficiency of the aptamer to GO was reduced. Therefore, the content of FBsub.1 in corn samples was determined by fluorescence measurements of mixed FAM-labeled F10, GO and corn samples. This method had a good linear relationship in an FBsub.1 concentration range of 0-3000 ng/mL. The equation was y = 0.2576x + 10.98, Rsup.2 = 0.9936. The limit of detection was 14.42 ng/mL, and the limit of quantification was 43.70 ng/mL. The recovery of a spiked standard in the corn sample was 89.13-102.08%, and the time of detection was 30 min.
The important role of Lactiplantibacillus plantarum strains in improving the human mucosal and systemic immunity, preventing non-steroidal anti-provocative drug-induced reduction in T-regulatory ...cells, and as probiotic starter cultures in food processing has motivated in-depth molecular and genomic research of these strains. The current study, building on this research concept, reveals the importance of Lactiplantibacillus plantarum 13-3 as a potential probiotic and bacteriocin-producing strain that helps in improving the condition of the human digestive system and thus enhances the immunity of the living beings via various extracellular proteins and exopolysaccharides. We have assessed the stability and quality of the L. plantarum 13-3 genome through de novo assembly and annotation through FAST-QC and RAST, respectively. The probiotic-producing components, secondary metabolites, phage prediction sites, pathogenicity and carbohydrate-producing enzymes in the genome of L. plantarum 13-3 have also been analyzed computationally. This study reveals that L. plantarum 13-3 is nonpathogenic with 218 subsystems and 32,918 qualities and five classes of sugars with several important functions. Two phage hit sites have been identified in the strain. Cyclic lactone autoinducer, terpenes, T3PKS, and RiPP-like gene clusters have also been identified in the strain evidencing its role in food processing. Combined, the non-pathogenicity and the food-processing ability of this strain have rendered this strain industrially important. The subsystem and qualities characterization provides a starting point to investigate the strain's healthcare-related applications as well.
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