A facile and eco-friendly approach for the synthesis of water-soluble WS2 quantum dots (QDs) was developed via ultrasonication and a hydrothermal process from bulk WS2. In this strategy, the dispersity of bulk WS2 in aqueous phase was improved with the aid of a surfactant (hexadecyltrimethylammonium bromide, CTAB), which could shorten the exfoliation time and improve the exfoliation efficiency to form layered WS2 nanosheets. Through hydrothermal treatment, the nanosheets were further scissored into QDs with high quality. The QDs show excellent features with narrow size distribution, good water solubility, and stable fluorescence. We find that the fluorescence of WS2 QDs can be quenched by Fe3+ through photoinduced electron transfer, and a wide detection linear range for Fe3+ is acquired. It indicates that WS2 QD can be used as a “turn-off” probe for Fe3+. In the presence of lipoic acid (LA), the fluorescence was recovered due to the stronger interaction between LA and Fe3+ than WS2 QDs. A “turn-on” sensor for LA was developed with a linear range from 1 to 10 μM and a detection limit of 0.59 μM. The strategy might be suitable for the facile synthesis of other water-soluble transition metal dichalcogenide QDs. It is expected that the water-soluble QDs have great potential applications in biological system.

Ischemia/reperfusion (I/R)‑associated acute kidney injury is a major clinical problem in both native and transplanted kidneys. Renal I/R, and subsequent renal injury, may be attributed to oxidative stress, inflammation, and apoptosis. Oleanolic acid (OA) is a natural product, which possesses antioxidant, anti‑inflammatory, and anti‑apoptotic activities. The present study aimed to examine the effects of OA preconditioning on renal I/R and the possible underlying mechanisms. In a renal I/R model, rats were administered OA (12.5, 25 and 50 mg/kg) for 15 consecutive days prior to bilateral renal I/R induction. Serum samples and kidneys were then collected and stored for subsequent determination. The results of the present study demonstrated that OA significantly and dose‑dependently attenuated I/R‑induced renal damage. OA prevented renal I/R injury, as evidenced by decreased levels of blood urea nitrogen, creatinine, kidney injury molecule‑1 and lactate dehydrogenase. In addition, OA defended against oxidative stress, as reflected by decreased levels of methane dicarboxylic aldehyde, increased activities of superoxide dismutase, catalase and glutathione peroxidase, and increased glutathione (GSH) levels. Levels of proinflammatory cytokines, interferon‑γ, interleukin (IL)‑6) and myeloperoxidase, were also reduced by OA, whereas the anti‑inflammatory cytokine IL‑10 was increased. Furthermore, OA prevented I/R‑induced apoptotic cell death, and prevented decreases in the mRNA expression levels of nuclear factor erythroid 2‑related factor 2 (Nrf2) and γ‑glutamylcysteine ligase (GCLc). Conversely, buthionine sulphoximine attenuated the protective effects of OA on renal I/R injury. These results indicated that OA preconditioning may prevent I/R‑induced renal damage via antioxidant, anti‑inflammatory, and anti‑apoptotic activities. Stabilization of Nrf2/GCLc signaling and subsequent maintenance of the GSH pool is critical for the protective effects of OA against renal I/R injury. The present study reported a novel therapeutic strategy for the treatment of renal I/R injury.

Osteopenia, a preclinical state of osteoporosis, restricts the application of adult orthodontic implant anchorage and tooth implantation. Strontium (Sr) is able to promote bone formation and inhibit bone absorption. The aim of the present study was to evaluate a new method for improving the success rate of dental implantation. In this study, an electrochemical deposition (ECD) method was used to prepare a Sr coating on a titanium implant. The coating composition was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction, and the surface morphology of the coating was studied using scanning electron microscopy. A total of 24 Sprague-Dawley rats received bilateral ovariectomy (OVX) and an additional 12 rats underwent a sham surgery. All rats were then implanted in the bilateral tibiae with titanium mini-implants with or without a Sr coating. The results of histological examination and a fluorescence double labeling assay showed strong new bone formation with a wider zone between the double labels, a higher rate of bone mineralization and better osseointegration in the OVX rats that received Sr-coated implants compared with the OVX rats that received uncoated implants. The study indicates that Sr coatings are easily applied by an ECD method, and that Sr coatings have a promoting effect on implant osseointegration in animals with osteopenia.

F4 (K88) and F18 fimbriaed enterotoxigenic Escherichia coli (ETEC) are the predominant causes of porcine postweaning diarrhea (PWD), and vaccines are considered the most effective preventive approach against PWD. Since heterologous DNA integrated into bacterial chromosomes could be effectively expressed with stable inheritance, we chose probiotic EcNc (E. coli Nissle 1917 prototype cured of cryptic plasmids) as a delivery vector to express the heterologous F4 or both F4 and F18 fimbriae and sequentially assessed their immune efficacy of anti-F4 and F18 fimbriae in both murine and piglet models. Employing the CRISPR-cas9 technology, yjcS, pcadA, lacZ, yieN/trkD, maeB, and nth/tppB sites in the chromosome of an EcNc strain were targeted as integration sites to integrate F4 or F18 fimbriae cluster genes under the Ptet promotor to construct two recombinant integration probiotic strains (RIPSs), i.e., nth integration strain (EcNcΔnth/tppB::PtetF4) and multiple integration strain (EcNc::PtetF18x4::PtetF4x2). Expression of F4, both F4 and F18 fimbriae on the surfaces of two RIPSs, was verified with combined methods of agglutination assay, Western blot, and immunofluorescence microscopy. The recombinant strains have improved adherence to porcine intestinal epithelial cell lines. Mice and piglets immunized with the nth integration strain and multiple integration strain through gavage developed anti-F4 and both anti-F4 and anti-F18 IgG immune responses. Moreover, the serum antibodies from the immunized mice and piglets significantly inhibited the adherence of F4+ or both F4+ and F18+ ETEC wild-type strains to porcine intestinal cell lines in vitro, indicating the potential of RIPSs as promising probiotic strains plus vaccine candidates against F4+/F18+ ETEC infection.

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