Silicon quantum dot has become an attractive nanomaterial due to their excellent biocompatibility and optical performance. However, poor water-solubility of the traditional silicon quantum dot limits its wide application. In this study, we reported the synthesis of water-soluble silicon quantum dots with imidazole groups by using hydrothermal method, in which N-trimethysilylimidazole was used as a precursor of silicon. Compared with sodium borohydride, ascorbic acid, bovine serum protein, cysteine and citric acid, the as-prepared silicon quantum dots offered the strongest fluorescence intensity when sodium citrate was used as the reducing agent and stabilizer for the synthesis. The reaction could complete within 2 h at 220℃. The obtained silicon quantum dots showed good water-solubility with an average particle size of 2. 6 nm, and the result of infrared spectroscopic analysis verified the existence of free imidazole groups on the surface. By means of the investigation of the fluorescence quenching behavior of copper ions towards the silicon quantum dots at different temperatures, we found that the degree of fluorescence quenching increased with the increase of temperature. There results proved that the fluorescence decrease belongs to static quenching. Namely, the interaction of Cu2+ with imidazole groups on the surface of silicon quantum dots formed stable complex. In addition, the resonance light scattering analysis also showed that the fluorescence quenching process was accompanied by the agglomeration of particles. Based on the fluorescence quenching behavior of silicon quantum dots, we established a method for the fluorescent detection of Cu2+. When the concentration of Cu2+was in the range of 0. 04-2400 μmol/L, the fluorescence intensity would linearly decrease with the increase of Cu2+ concentration, and the detection limit (S/N=3) reached 1. 29×10-8 mol/L. The method provided high sensitivity, selectivity and reproducibility, and was successfully applied to the determination of trace copper in fruits and vegetables.

In the presence of hydrochloric acid, tetraethoxysilicane was hydrolyzed and formed silica sol. Non-labeled immunosensor was fabricated by droping the mixture solution of the silica sol and antibody of aflatoxin B_1 on the surface of glassy carbon electrode. In this work, a Fe(CN)_6~(3-/4-) phosphate buffer solution) was employed as base solution for investigating cyclic voltammetry(CV) and electrochemical impedance spectroscopic(EIS) performances of the sensor, respectively. The experimental results t indicated that because of the complex formed by the immunoreaction hindered the diffusion of Fe(CN)_6~(3-/4-) on the electrode surface, the redox peak current of the immunosensor in CV obviously decreased, and its electron transfer impedance linearly) increased with increasing the concentration of aflantoxin B_1(AFB). When the medium acidit and incubation) time were pH 6.5 and 20 min, respectively, the biggest electron transfer impedance changed value before and after the immunoreaction was obtained. Under the optimal conditions, a linear range to concentration of aflatoxin B_1 was 1-10 μg/L with a detection limit of 0.1 μg/L(S/N=3). Proposed method is of high sensitivity and stability, it has been successfully applied to determine AFB_1 in maize, rice and peanut.

Purpose To explore the accuracy of ALK fused gene expression by immunohistochemistry ( IHC) in non-small cell lung cancer ( NSCLC) patients, and to investigate the clinical and pathological features of ALK-positive NSCLC patients. Methods By u-sing rabbit monoclonal D5F3 antibody, ALK IHC was performed on 234 NSCLC patients. ALK positive cases were confirmed by reverse transcription-polymerase chain reaction ( RT-PCR) . Results The positive incidence of ALK by IHC in 234 NSCLC specimens was 8. 97% (21/234), the positive rate of ALK fused gene verificated by RT-PCR was 5. 98% (14/234). There was significant difference with histological type, age, stage (P<0. 05), but no significant difference with gender, smoking history, tumor differentiation. Of 21 cases of ALK-positive NSCLC patients, the consistency of IHC and RT-PCR was 0 when IHC was ( +) , however, when IHC was or immunohistochemical score was >120, the consistency rate was 100%. Conclusion Although immunohistochemical expres-sion of ALK fused gene may have a certain false positive, IHC or immunohistochemical score> 120 show very high value for ALK fused gene RT-PCR followed by ALK immunohistochemistry in lung cancer is a economical and feasible method for the valuation of ALK fused gene.

BACKGROUND:As a member of bone morphogenetic proteins,growth differentiation factor-5 shows promising potential in the application of cartilage and bone repair.The affinity of growth differentiation factor-5 onto bone tissue determines protein use efficiency,so it is of great significance to prepare growth differentiation factor-5 with bone targeting capability. OBJECTIVE:To modify growth differentiation factor-5 using bisphosphonates and investigate the effects of modified protein on the growth of preosteoblasts in mice. METHODS:Pamidronate disodium/growth differentiation factor-5 complex was prepared using chemical crosslinking to couple growth differentiation factor-5 with pamidronate disodium.The functional groups and structures of the complex were characterized using Fourier transform infrared spectroscopy and circular dichromatography.To determine the bone targeting in vitro,the binding of the modified growth differentiation factor-5 with calcium phosphate and in vitro release amount of growth differentiation factor-5 were measured with an ELISA kit.Growth differentiation factor-5(control group)and the pamidronate disodium/growth differentiation factor-5 complex(experimental group)were co-cultured with preosteoblasts MC3T3-E1.Individually cultured cells were blank controls.The effect of the complex on cell proliferation and differentiation was evaluated. RESULTS AND CONCLUSION:(1)The infrared spectroscopy and circular dichromatography results indicated that the bisphosphonate/growth differentiation factor-5 complex was successfully prepared without significant changes in the protein secondary structure.In vitro protein adsorption results showed that growth differentiation factor-5 adsorption on calcium phosphate was increased by about one time after coupling with a bisphosphonate.In the presence of cysteine,growth differentiation factor-5 could be released from the bisphosphonate/growth differentiation factor-5 complex.(2)CCK-8 assay results showed that the absorbance value of the experimental group cultured for 4 and 7 days was higher than that of the control group and blank control group(P<0.000 1).After 7 days of culture,the expression of alkaline phosphatase in the experimental group was significantly higher than that in the control group and blank control group(P<0.000 1).After 13 days of culture,the content of calcium nodules in the experimental group was significantly higher than that in the control group and the blank control group(P<0.000 1).The results of qRT-PCR showed that the mRNA expression of alkaline phosphatase,osteocalcin and Runx2 in the experimental group was higher than that in the control group and the blank control group after 7 days of culture(P<0.01,P<0.001,P<0.000 1).(3)These findings exhibit that bisphosphonate modification can enhance the binding capacity of growth differentiation factor-5 to calcium phosphate as well as improve its biological activity.