Determination of methylene blue release in plasma virus inactivation bag by fluorescence energy transfer method / 中国输血杂志

【Objective】 To establish a simple, economical and rapid method for the determination of methylene blue (MB) release in virus inactivation bag. 【Methods】 Based on the fluorescence energy transfer between MB and BSA-stabilized gold nanoclusters (BSA-AuNCs), the standard curve of MB determination was established by measuring the fluorescence quenching degree of MB to BSA-AuNCs in different concentrations to conduct the determination of MB release in virus inactivation bag. 【Results】 There was a good linear relationship between the MB concentration (cMB) and the fluorescence quenching degree of BSA-AuNCs[ (I0-I)/I0=0.018cMB+ 0.021(r=0.996)] when the fluorescence emission wavelength was about 620 nm and the cMB was in the range of (0.9-36) μmoL/L. The recovery of MB was 98.00% -101.95 % when applied to determine MB at high, medium, and low concentrations, the obtained intra-day variation coefficients were 0.73%, 0.81% and 0.77% respectively, and the obtained inter-day variation coefficients were 3.92%, 3.81%, and 4.73% respectively. There was no significant difference between the results measured by this method and those measured by combination of solid-phase extraction and spectrophotometry(P>0.05). 【Conclusion】 The fluorescence energy transfer method could achieve simple and rapid determination of MB release in virus inactivation bag with accurate and reliable results.

Research progress in gold nanoclusters for radiosensitization / 中华放射医学与防护杂志

Radiotherapy still fails to achieve satisfactory efficacy in the treatment of malignant tumors, and applying radiotherapy sensitizers is an effective method to improve the efficacy of radiotherapy. Gold nanomaterials can effectively increase the sensitivity of tumor cells to radiotherapy due to their high atomic numbers. Gold nanoclusters have more excellent radiobiological and radiophysical properties due to their smaller size. This paper reviews the special radiobiological and radiophysical properties of gold nanoclusters and describes in detail their sensitizing effects in external radiation radiotherapy, radionuclide therapy, and X-ray induced photodynamic therapy.

Synthesis and Application of Gold Nanoclusters for Detection of Heavy Metal Mercury Ions / 分析化学

A colorimetric method was developed for detection of mercury based on the inhibition of oxidation of peroxidase substrates. The as-prepared gold nanoclusters ( Au NCs), which has been stabilized and reduced by Glutathione (GSH), can effectively catalyze the H2 O2-TMB to generate a blue color signal. It is interestingly that Hg2+ can inhibit the oxidation of peroxidase substrates, thus causing a color diminished. Taking advantage of the inhibitive effect of Hg2+, a novel Hg2+ sensor has been developed. In this system, sensing conditions, including pH of the buffer solution, substrate concentration and time, were optimized. Under the optimal conditions, the probe showed a linear range of 10 - 300 nmol/ L ( R2 = 0. 997) with a detection limit of 6. 26 nmol/ L. In addition, this sensor exhibited good selectivity and sensitivity for Hg2+against other common environmental mental ions, providing a new method for water analysis.

Preparation of Protein Hybrid Fluorescence Nanoclusters for Rapid Detection of Mercury Ion / 分析化学

One-step green synthetic approach,with bovine serum albumin(BSA) as stabilizer and reductant, was developed for preparation of BSA hybrid fluorescence gold nanoclusters (AuNCs@BSA). The prepared AuNCs@BSA exhibited strong red fluorescence under UV light illumination. Upon excited at 360 nm, the fluorescence spectrum of AuNCs@ BSA exhibited maximum emission peak at 635 nm. AuNCs@ BSA was presented as uniform spherical morphology with diameter at (2.0 ±0.05) nm. The fluorescence of AuNCs@BSA could be quenched by Hg2+because of its metallophilic reaction. Based on the fluorescent spectrometry, a rapid detection system was developed for Hg2+detection in tap water. The AuNCs@BSA amount, pH and buffer system were optimized in this study. According to optimization results, ultrapure water (pH 5.0) was selected to dilute the AuNCs@BSA by 100 times, and 50 μL/well of AuNCs@BSA dilution was applied to detect mercury ion in tap water. Under the optimized conditions, the detection could be completed within 3 min,the fluorescence intensity of the system was linearly proportional to the concentration of mercury ion in the range of 0.5–900 μg/L with linear equations y=-26.76lgx+803.1(0.5-75 μg/L,R2=0.9951) and y=-0.27x+762.02 (75-900 μg/L,R2=0.9959). The limit of detection was 0.14 μg/L(3σ). The average recoveries in spiked tape water samples ranged from 86.8%-113.4% with relative standard deviation of less than 15%. The result implied that the developed method was able to apply to detect mercury ion rapidly, sensitively and conveniently.

Highly Sensitive Detection of Spermine Based on Fluorescence Quenching of Gold Nanoclusters / 分析化学

A new type of fluorescent gold nanoclusters (MU-Au NCs) was prepared by hydrothermal synthesis method using ammonium benzoate murexide (MU) as reducing agent and protecting agent.The synthesis method was simple and rapid.Based on the fluorescence quenching ability of spermine, a turn off type fluorescence analysis method was established for rapid and ultra sensitive detection of spermine.The linear range for detection of spermine was 0.003-300 μmol/L and the detection limit was 1 nmol/L (S/N=3).The established analytical method of spermine provided theoretical basis and reference for construction of spermine biosensor and actual sample detection.

Study of glutathione protected gold nanoclusters on HeLa cytotoxicity / 国际生物医学工程杂志

Objective To investigate the effects of glutathione protected gold nanoclusters (GSH-Au NCs) on HeLa cytotoxity.Methods Fluorescence intensity were measured on GSH-Au NCs containing medium treated cells using fluorescence spectrophotometer at different time points.GSH-Au NCs uptake by HeLa cells at 1,2,6,12 and 24 h were investigated through fluorescent spectrophotometer.In vivo tumor uptake was also investigated on BALB/c tumor-bearing mice through inductively coupled plasma mass spectrometry (ICP-MS) at 24 h after intraperitoneal injection of 0.2 ml GSH-Au NCs (3 mmol/L) and distilled water (control group) respectively.The cytotoxicity of GSH-Au NCs at different doses (0.003-0.3 mmol/L) was tested at 24 and 48 h using MTT assay after interaction with HeLa cells.Results The uptake efficiency of GSH-Au NCs by HeLa cells kept increasing and reached maximum of 73.13％ at 24 h.The results of tumor-bearing mice indicated that the tumor tissue had higher uptake efficiency after 24 h (320±15) ng/g than that of control group (intraperitoneal injection of distilled water),and the difference was stastically significant (P＜0.05).HeLa cells were treated with different concentrations of GSH-Au NCs for 24 h,and GSHAu NCs had a slight effect on cell viability.With the increase of GSH-Au NCs dose,the inhibition effects on growth of HeLa cells enhanced.The cell activity of HeLa cells treated with 0.3 mmol/L GSH-Au NCs for 24 h reduced to 86％compared with that of control group (the concentration of GSH-Au NCs was 0) (P＜0.05),while there was no significant difference between the survival rate of different concentrations of GSH-Au NCs group and the control group for 48 h.Conclusions GSH-Au NCs have neglectable cytotoxity on HeLa cells even though both in vitro and in vivo uptake are high.GSH-Au NCs are suitable for biomedical application such as imaging,drug loading and targeted drug delivery.