Alkyne-functionalized superstable graphitic silver nanoparticles for Raman imaging.

Noble metals, especially gold, have been widely used in plasmon resonance applications. Although silver has a larger optical cross section and lower cost than gold, it has attracted much less attention because of its easy corrosion, thereby degrading plasmonic signals and limiting its applications. To circumvent this problem, we report the facile synthesis of superstable AgCu@graphene (ACG) nanoparticles (NPs). The growth of several layers of graphene onto the surface of AgCu alloy NPs effectively protects the Ag surface from contamination, even in the presence of hydrogen peroxide, hydrogen sulfide, and nitric acid. The ACG NPs have been utilized to enhance the unique Raman signals from the graphitic shell, making ACG an ideal candidate for cell labeling, rapid Raman imaging, and SERS detection. ACG is further functionalized with alkyne-polyethylene glycol, which has strong Raman vibrations in the Raman-silent region of the cell, leading to more accurate colocalization inside cells. In sum, this work provides a simple approach to fabricate corrosion-resistant, water-soluble, and graphene-protected AgCu NPs having a strong surface plasmon resonance effect suitable for sensing and imaging.

Bispyrene-fluorescein hybrid based FRET cassette: a convenient platform toward ratiometric time-resolved probe for bioanalytical applications.

Pyrene excimer possesses a large Stokes shift and long fluorescence lifetime and has been widely applied in developing time-resolved biosensing systems to solve the autofluorescence interference problems in biological samples. However, only a few of pyrene excimer-based small molecular probes have been reported so far. Ratiometric probes, on the other hand, can eliminate interferences from environmental factors such as instrumental efficiency and environmental conditions by a built-in correction of the dual emission bands but are ineffective for endogenous autofluorescence in biosystems. In this work, by combining the advantages of time-resolved fluorescence technique with ratiometric probe, we reported a bispyrene-fluorescein hybrid FRET cassette (PF) as a novel ratiometric time-resolved sensing platform for bioanalytical applications, with pH chosen as a biorelated target. The probe PF showed a fast, highly selective, and reversible ratiometric fluorescence response to pH in a wide range from 3.0 to 10.0 in buffered solution. By employing time-resolved fluorescence technique, the pH-induced fluorescence signal of probe PF can be well-discriminated from biological autofluorescence background, which enables us to detect pH in a range of 4.0-8.0 in cell media within a few seconds. It has also been preliminarily applied for ratiometric quantitative monitoring of pH changes in living cells with satisfying results. Since many fluorescein-based fluorescence probes have been developed, our strategy might find wide applications in design ratiometric time-resolved probes for detection of various biorelated targets.

Naphthalimide-based a highly selective two-photon fluorescent probe for imaging of hydrogen sulfide in living cells and inflamed tissue of mouse model.

Hydrogen sulfide (H2S) is a very important third endogenously generated gaseous signaling molecule and plays a key role in physiological and pathological regulation processes of living biosystems. Although a lot of H2S fluorescent probes have been reported, the relationship between the physiology and pathology of H2S in inflamed tissues remains unclear. Herein, by adopting a donor-π-acceptor (D-π-A)-structured naphthalimide derivative as the two-photon (TP) fluorophore and a 4-dinitrobenzene-ether (DNB) with a strong intramolecular charge transfer (ICT) effect as the recognition moiety, we reported a novel TP bioimaging probe NP-H2S for H2S with improved sensitivity. The NP-H2S exhibits very low background fluorescence in the absence of H2S, and a significant 258-fold fluorescence intensity enhancement was observed in the presence of H2S, resulting in a high sensitivity and selectivity to H2S in aqueous solutions with a detection limit of 18.8 nM observed. The probe also shows a wide linear response concentration range (0-10.0 µM) to H2S with high selectivity. All these features are favorable for direct monitoring of H2S in complex biological samples. It was then applied for direct TP imaging of H2S in tissues of inflammation model with satisfactory sensitivity, indicating it has the latent capability in further biological applications for investigation of the interaction H2S with inflammation.

Down-regulation of microRNA-200b is a potential prognostic marker of lung cancer in southern-central Chinese population.

MicroRNAs (miRNAs) may regulate diverse biological processes and play an important role in cancer. And MiRNAs have been proposed as a useful tool for lung cancer diagnosis and therapeutics in cancer. The purpose of the present study was to investigate the association among the expression level of mature miR-200b-5p in peripheral blood and the risk of lung cancer and clinic pathological characteristics. This case-control study included 24 patients with lung cancer and 12 healthy controls. MiR-200b expression was deleted using real-time PCR. and the miR-200b expression of normal controls was significantly higher than that in lung cancer patients (1732.13 pg/mL vs 881.67 pg/mL, P < 0.05), no difference with age, sex, tissue type and clinical stage of lung cancer patients (P > 0.05). Furthermore, miR-200b expression level fluctuated with tumor progression in lung cancer, and there was highly significant for clinical stage II compared with the clinical stage III (P < 0.05). In addition, the down-regulation of miR-200b showed a highly discriminative receiver operating characteristic (ROC) curve profile, clearly distinguishing cancer patients from cancer-free subjects with an area under the ROC curve (AUROC) of 0.87. The detection of miR-200b expression yielded 83.30% sensitivity and 100.00% specificity in the diagnosis of lung cancer. Therefore, these findings suggested that miR-200b may be used as a marker for the detection and diagnosis of lung cancer in peripheral blood.

Isolation, genetic identification and degradation characteristics of COD-degrading bacterial strain in slaughter wastewater.

Contamination of water by meat production is an important and extensive environmental problem and even threat to human health. Biodegradation is a major mechanism which removes the pollutants from the environment. Therefore, the present study aimed to isolate and characterize a COD degrading bacteria which can effectively degrade slaughter wastewater. Six COD degrading bacteria were isolated from slaughtering waste water and sludge in Hunan a meat product Co., Ltd. And the COD degradation rate of each strain was determined by potassium permanganate method. Through observing morphologically and analyzing sequence to 16S rDNA, the highest COD degradation strain was Bacillus velezensis by preliminarily identified and classified, reaching 11.80%. The suitable conditions of the growth of Bacillus velezensis strain were 37 °C, pH 7.0, the peptone concentration 1.5%, and the yeast extract concentration 0.8%.

Ag2CO3/CA-AA-AmidPhos Multifunctional Catalysis in the Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylides.

The new Ag2CO3/CA-AA-amidphos complexes have been demonstrated as highly efficient multifunctional catalysts in the asymmetric 1,3-dipolar cycloaddition of azomethine ylides. Under optimal conditions, highly functionalized endo-4 pyrrolidines were obtained with excellent yields (up to 99% yield) and enantioselectivities (up to 96% ee).

A highly sensitive and reductant-resistant fluorescent probe for nitroxyl in aqueous solution and serum.

A novel coumarin-based fluorescent probe, P-CM, for quantitative detection of nitroxyl (HNO) was developed. P-CM exhibits a selective response to HNO over other biological reductants and was also applied for quantitative detection of HNO in bovine serum with satisfactory results.

Rhodamine-based fluorescent probe for direct bio-imaging of lysosomal pH changes.

Intracellular pH plays a pivotal role in various biological processes. In eukaryotic cells, lysosomes contain numerous enzymes and proteins exhibiting a variety of activities and functions at acidic pH (4.5-5.5), and abnormal variation in the lysosomal pH causes defects in lysosomal function. Thus, it is important to investigate lysosomal pH in living cells to understand its physiological and pathological processes. In this work, we designed a one-step synthesized rhodamine derivative (RM) with morpholine as a lysosomes tracker, to detect lysosomal pH changes with high sensitivity, high selectivity, high photostability and low cytotoxicity. The probe RM shows a 140-fold fluorescence enhancement over a pH range from 7.4 to 4.5 with a pKa value of 5.23. Importantly, RM can detect the chloroquine-induced lysosomal pH increase and monitor the dexamethasone-induced lysosomal pH changes during apoptosis in live cells. All these features demonstrate its value of practical application in biological systems.

A rhodamine-appended water-soluble conjugated polymer: an efficient ratiometric fluorescence sensing platform for intracellular metal-ion probing.

Thewater-soluble CP was conjugatedwith a rhodamine spirolactam for the first time to develop a new FRET-based ratiometric fluorescence sensing platform(CP 1) for intracellular metal-ion probing. CP 1 exhibits excellent water-solubility with twowell-resolved emission peaks, which benefit ratiometric intracellular imaging applications.