Electrocatalytic behaviors of poly acridine orange/multi-walled carbon nanotube modified electrode

In this work, noncovalent functionalization of multiwalled carbon nanotube （MWNT） with acridine orange （AO） by electropolymerization is studied. The obtained composite film is a viable alternate electrode material, non-toxic, chemical inert, not volatile, using to construct modified electrode. The new type modified electrode has both of unique properties of MWNT and poly acridine orange （POAO）, can provide good sensitivity, low limits of detection, good response precision, and superb response stability.

On-line HPLC-DAD coupled with ESI-IT-TOF-MS and fluorescence detection to identify DNA-binding compounds from Lithospermum erythrorhizon using acridine orange as the fluorescence probe

We have developed an on-line detection method using acridine orange as the fluorescence probe and applied this method to rapidly identify active compounds in herbal medicines. This on-line method was equipped with a high-performance liquid chromatography tandem diode array detector, electrospray ionization-ion-trap time-of-flight mass spectrometry and DNA- acridine orange fluorescence detection （HPLC-DAD-MSn-DNA-AO-FLD）. A large amount of information could be simultaneously obtained during one run, which included HPLC fingerprint, ultraviolet spectra, total ion chromatograms, MSn data of high-resolution mass spectrometry and activity profile of each compound binding with DNA. The method also provided information on structureactivity relationships and mechanism of interaction. We used this on-line method to identify five DNA-binding activity components from Lithospermum erythrorhizon sample for the first time. The result showed that the parent nucleus of shikonin derivatives could bind with DNA. The structure-activity relationship showed that the parent nucleus of shikonin derivatives plays a major role in DNA binding, not the carboxyl group on the side chain. This simple, rapid, high precision and good stability on-line method should be useful for compound separation, structural identification and screening of DNA-binding compounds in herbal medicines.

Fluorescence enhancement of acridine orange in a water solution by Au nanoparticles

The surface enhanced fluorescence effect of acridine orange fluorophore in the proximity of Au nanoparticles has been investigated experimentally in the system of aqueous solution.Significant enhancement of the fluorescence intensity was observed when the system was excited with 532 nm or 442 nm CW lasers.The influence of the distances between neighboring Au particles as well as that between the fluorophore molecules and the Au surface were explored experimentally.The results demonstrated that a compact distribution of metallic particles was able to produce stronger fluorescence enhancement.Proper separation between the fluorophore molecules and the metal surface was favorable for a better enhancement.

Spectrofluorimetric analysis of captopril based on its obstruction effect of the nanomaterial surface energy transfer between acridine orange and gold nanoparticles

A simple and sensitive method for detection of captopril was established based on its obstructive effect on nanomaterial sur- face energy transfer （NSET）. It was found that the acridine orange （AO） could be adsorbed onto the surface of citrated-gold nanoparticles （AuNPs） through electrostatic interaction. Incidentally, the fluorescence of AO was quenched owing to the dipole-dipole interaction of NSET between AO fluorophore and the AuNPs. However, captopril could obstruct the occurrence of NSET between AO and AuNPs effectively with the formation of Au-S covalent bonds between it and the AuNPs. Consequently, AO molecules were moved away from the surface of AuNPs leading to a decline of the energy transfer efficiency. Moreover, the fluorescence of AO could be gradually restored with the addition of captopril. Under the optimal conditions, the recovered fluorescence intensity correlated linearly with the concentration of captopril in the range of 400 nmol/L-2.0μmol/L with a detection limit of 71 μmol/L. Besides, the proposed method was successfully applied for the detection of captopril in troches with the recovery of 93%-102% and the RSD lower than 2.24%. The results were in good agreement with those obtained from the HPLC method,

Interferon-alpha-2b induces autophagy in hepatocellular carcinoma cells through Beclin1 pathway

Objeαive： To determine whether Interferon-alpha-2b （IFN-α2b） can modulate the autophagic response in hepatocellular carcinoma cells. Methods： Hepatocellular carcinoma cells were treated with IFN-α2b. Autophagy was assessed by acridine orange staining, GFP-LC3 dotted assay, transmission eleαron microscopy and immunoblotting. Results： Acridine orange staining showed that IFN-α2b triggered the accumulation of acidic vesicular and autolysosomes in HepG2 cells. The acridine orange HepG2 cell ratios were （4.3±1.0）%, （6.9±1.4）%, and （13.1±2.3）%, respeαively, after treatment with 100, 1,000, and 10,000 IU/mL IFN-α2b for 48 h. A markedly punαate pattern was observed in HepG2 cells treated with 10,000 IU/mL [FN-α2b for 48 h, but only diffuse and weakly fluorescent GFP-LC3 punαa was observed in control cells. HepG2 cells treated with 10,000 IU/mL IFN-α2b for 48 h developed autophagosome-like charaαeristics, including single- or double-membrane vacuoles containing intaα and degraded cellular debris. The Beclinl and LC3-II protein expression was up-regulated by IFN-α2b treatment. Conclusion： Autophagy can be induced in a dose-dependent manner by treatment with IFN-α2b in HepG2 cells, and the Beclinl signaling pathway was stimulated by IFN-α2b.

Correlation Analysis of the Results of Double Fluorescence(AO/PI) Staining and Clinical Outcomes

Objective To estimate the predictive value of double fluorescence [acridine orange （AO）/propidium iodide （PI）] staining results for fertilization rate and clinical outcomes and analyze the correlation between the results of AO/P1 staining and sperm apoptosis. Methods A prospective study was carried out, 235 infertile couples remedied using traditional in vitro fertilization （IVF） were included. Semen collected from 235 patients were stained by fluorescence dye, AO and PL at the same time the spermatozoa apoptosis rate was calculated by using flow cytometry to detect the rate of Annexin V＋/ PI- . The result of fluorescence was divided into 3 groups as green （G）, yellow （Y） and red （R） according to the color of fluorescence. The correlation between the percent of the 3 colors and clinical outcomes and spermatozoa apoptosis rate was evaluated. Results Significant negative correlation was observed between the percentage of Y and fertilization rate （r= -0.42, P=0.04）, no significant correlation was observed between the percentage of G, R and fertilization rate. The percentage of G, Y, R was not significantly different between pregnant patients and non-pregnant patients, respectiw,ly, while the percentage of Y was significant different between miscarriage patients and liveborn patients （r=0.6L P=0.01） and no significant difference exist in the percentage of G and R between liveborn patients and miscarriage patients. There was a significant positive correlation between the percentage of Y and the rate of Annexin V＋/ PI （r=0.53, P=0.04）, and no significant correlation was shown between the percentage of G, R and the rate of Annexin V＋/ PI-.Conclusion The percentage of yellow group of double fluorescence （AO/PI） staining will affect the fertilization rate and the miscarriage rate, and this group of spermatozoa may be connected with the spermatozoa apoptosis.