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For early detection and diagnosis of gastric cancer, a novel, highly sensitive detection of microRNA-378 was developed through rolling circle amplification and DNA-templated silver nanoclusters as a lable-free fluorescent probe. DNA-templated fluorescent silver nanoclusters (DNA/AgNCs) to make target signal cascade amplification were prepared and identified through their fluorescent spectrum. MiRNA-378 trigged rolling circle amplification to obtain the complementary sequence (cDNA) to combine with two DNA/AgNCs in the middle of a sandwich structure to induce the new fluorescent signal at a new wavelength. In the presence of microRNA-378, a large amount of RCA product cDNAs were hybridized with DNA/AgNCs as the fluorescence nanocluster beacon, resulting in fluorescence enhanced “turn-on” phenomenon. This study indicated that amplified fluorescence detection of microRNA-378 is a stable, low-cost, highly specific, and ultra-low as 1.07 fM detectability. The proposed approach of signal synergetic amplification facilitating the fluorescence detection microRNA shows great potential for potentially clinically diagnosis.

Interference-free determination of polycyclic aromatic hydrocarbons (PAHs) in water pollution is proposed based on third-order correction algorithms with quadrilinear component modeling applied to the constructed four way fluorescence excitation–emission-sample data array with higher accuracy and better predictive ability than second-order (three-dimension) correction. Alternating weighted residue constraint quadrilinear decomposition (AWRCQLD), quadrilinear parallel factor analysis (4-PARAFAC), alternate penalty quadrilinear decomposition (APQLD) and alternate penalty trilinear decomposition (APTLD) are applied to acenaphthene (ANA), naphthalene (NAP) and fluorene (FLU) respectively. Fulvic acid affects PAHs determination seriously in real-world situation, so it is simulated as an interfering agent. Excitation-emission fluorescence matrixes (EEMs) of PAHs are measured at different volumes of fulvic acid simulated different interference conditions, to construct a four-way data array. After the four-way spectra data is analyzed by AWRCQLD, 4-PARAFAC, and APQLD, three-way EEMs analyzed by APTLD, results show that, on the one hand, PAHs can be measured more accurately with four-way data combined with third-order calibration than lower-order. On the other hand, AWRCQLD algorithm can reflect the superiority of third-order advantage better with higher recovery rate and smaller root mean square error, than other third-order or second-order correction algorithms.

Cronobacter sakazakii is a typical food-borne bacterium that causes clinical symptoms including necrotizing enterocolitis, bacteremia, and meningitis with a mortality rate of 40 %–80 %. In this study, a pair of split G-rich DNA probes was assembled into the DNAzyme capable of mimicking peroxidase. The assembly was utilized to provide a simple, low-cost, highly specific, and sensitive method for rapid detection of viable C. sakazakii. In the absence of viable C. sakazakii, the two split G-rich DNA probes formed DNAzyme, mimicked the activity of peroxidase and displayed colorimetric signals to indicate detection results. In the presence of viable C. sakazakii, specific recognition by the aptamer results in the destruction of the DNAzyme-aptamer complex, and subsequently the colorimetric signal is “turned-off” due to the decrease in DNAzyme bioactivity. Under the optimal reaction conditions, there is a linear relationship between absorption intensity at 418 nm and logarithmic concentration of C. sakazakii in the range of 2–1200 CFU/mL (R2 = 0.9839), with a detection limit of 1.2 CFU/mL. This is the highest sensitivity ever reported for viable C. sakazakii detection. Artificially contaminated samples were assayed by this novel sensor, and numerous advantages were discovered, including ultra-low sensitivity, low-cost, simple operation, and good performance, compared to existing methods. We believe the DNAzyme shows great potential for food safety applications.

The potentiality of PGPR and biocontrol bacteria in agriculture is steadily increased as it offers an attractive way to replace the use of chemical fertilizers, pesticides and other supplements. This study aimed to investigate the effects and potential mechanism of inoculation with two Bacillus velezensis strains on the growth and quality improvement of Anoectochilus roxburghii (Wall.) Lindl. (MRH) and Anoectochilus formosanus (Wall.) Lindl. (YYB). The control treatment was non-inoculated (CK) and the coculture treatments were inoculated with Bacillus velezensis D2WM (D2), Bacillus velezensis ZJ-11 (ZJ-11), Bacillus velezensis D2WM and Bacillus velezensis ZJ-11 (D2+ZJ-11). The fresh weight, plant length, amount of active compounds, as well as chlorophyll content were significantly increased under D2, ZJ-11, and D2+ZJ-11 treatments compared with MRH and YYB plants in CK. In particular, D2+ZJ-11 treatment resulted in the greatest growth promotion. In MRH and YYB plants, the fresh weight increased by 82.6 % and 106.6 %, the kinsenoside content increased by 9.33 % and 21.65 % per gram, and the flavonoid content increased by 44.70 % and 21.07 % per gram, respectively. D2WM and ZJ-11 were capable of secreting siderophore, phytase, indole-3-acetic acid (IAA), and zeatin to promote plant nutrient assimilation and growth. Moreover, when D2WM and ZJ-11 were both inoculated with Anoectochilus roxburghii, the rhizosphere soil enzyme activities of urease, phosphatase, and invertase were significantly higher than control, thus helped to provide more nutrients to Anoectochilus. Further, the analysis of microbial community diversity indicated the increase of abundance of beneficial microorganisms, such as nitrogen-fixing bacteria, Basidiomycota and Ascomycota both of which are known to fuel their plant partners with mineral nutrients from the soil. Additionally, the abundance of pathogens belonging to Xanthobacteraceae as well as Cladophialophora and Penicillium were reduced. Hence, coculture with beneficial microorganisms can improve the growth and quality of Anoectochilus plants via promoting nutrient assimilation and regulating rhizosphere microbial community. This technique is of great application value in promoting the efficient cultivation and production of high-quality plant materials.

Combined photothermo-chemotherapy is a new cancer treatment modality that improves therapeutic outcome by synergistic actions of two different means. A reduction and pH dual sensitive polymeric vesicle encapsulating doxorubicin (DOX) was prepared and then decorated with a gold layer using a modified method of in situ gold seed growth. By tuning the compactness of gold layer, the gold nanoshell may possess a desirable light absorption peak for tumor photothermal therapy using near-infrared (NIR) laser irradiation, a method featuring high tissue penetrability essential for in vivo applications. The NIR light energy was converted into heat, which killed cancer cells in the vicinity and induced the rupture of nanoshell to release DOX inside tumor. Therefore, a combined photothermo-chemotherapy of tumor can be achieved precisely at tumor site. In addition, DOX released in the thermochemotherapeutic mode effectively penetrated tumor tissue, which is meaningful considering the intrinsic low tissue penetrability of nanomedicines. In nude mice bearing human Bel-7402 hepatoma, the photothermo-chemotherapy using DOX-loaded gold nanoshell appeared advantageous over a chemotherapy or a photothermal therapy alone.

A novel surface-plasmon-enhanced structure is proposed to improve the absorption efficiency of organic solar cells in this paper. The PEDOT:PSS-Ag light-trapping structure introduced allows light to be reflected multiple times between the multilayer films, increasing the optical path length of light in the device and the light absorption by the absorption layer. The Ag film in P3HT:PCBM absorption layer can induce surface plasmons, which can enhance the electromagnetic energy around Ag film, improving the light absorption ability of organic solar cells. Based on the finite element method, the COMSOL-RF module is used to simulate the designed structure, and the absorption efficiency, electric field mode distribution and total power loss density distribution at different structural parameters were obtained. The results reveal that the absorption efficiency is more than 80% in the wavelength range of 485 nm to 520 nm in TE mode and more than 85% in the wavelength range of 495 nm to 595 nm in TM mode, providing a reliable basis for the development of high-performance organic solar cells.