Evaluation of the microstructure, chemical composition, and image quality of different PSP receptors

Abstract This study aimed to assess the microstructure, chemical composition, and image quality of different photostimulable phosphor plates (PSP). Four PSP systems, Express®, Digora®, VistaScan®, and Apixia,® were assessed. Five radiographs of a homogeneous acrylic phantom were obtained with the PSP of each system, to acquire a total of 20 images. The images were objectively evaluated for uniformity using mean grey and standard deviation (SD) of their grey values. PSP receptors were analyzed using scanning electron microscopy (SEM) to determine the thickness of the granule layer and the size of the granules. The chemical composition of the PSP receptors was analyzed using total reflection X-ray fluorescence (TXRF). VistaScan showed more uniform and higher density images than the other tested systems (p < 0.05), as well as the lowest SD of grey values (p < 0.05). Regarding the microstructure of the receptors, Digora and VistaScan had thicker granule layers than Express and Apixia, and VistaScan had smaller granules than Digora and Express (p < 0.05). Fourteen chemical elements were detected in the receptors, with barium being the element with the highest concentration in all PSP systems. The microstructure, chemical composition, and image quality varied among all four PSP receptors studied. VistaScan receptors showed the smallest variation in granule size, one of the thickest granule layers, and the most uniform and least noisy images.

Establishment of Eu3+ / Sm3+ dual?label time?resolved fluoroimmunoassay for measurement of anti?bodies to hepatitis C virus and its clinical application / 中华核医学与分子影像杂志

Objective To establish a time-resolved fluoroimmunoassay (TRFIA) system for simul-taneous measurement of immunoglobulin (Ig)M and IgG antibodies to HCV. Methods Recombinant HCV antigen was fixed on microtiter plates to detect serum HCV antibodies. Eu3+-labeled anti-human IgM and Sm3+-labeled anti-human IgG were prepared. HCV-IgM and HCV-IgG TRFIA were established using indirect assay and further optimized and evaluated. The one-sided 95th-percentile was used to calculate the cut-off (CO) values. Results Defining 1 sample/ CO (S/ CO) as measuring unit, the detection limit was 0.06 S/ CO for HCV-IgM and 0.15 S/ CO for HCV-IgG. When diluted a strong-positive specimen from 1 :12.5 to 1 :51200, there was a good liner range within 1 :12.5 to 1 :12800 for HCV-IgM and 1 :25 to 1 :6400 for HCV-IgG. The average intra-assay CV of HCV-IgM and HCV-IgG were 3.37％ and 3.66％, respectively, and the aver-age inter-assay CV were 6.52％ and 6.75％, respectively. Compared with enzyme-linked immunosorbent as-say (ELISA) kits, the positive conformity rate, the negative conformity rate and total conformity rate were 100.0％(20/ 20), 90.0％(18/ 20), 95.0％(38/ 40) for HCV-IgM TRFIA, and were 100.0％ (20/ 20), 95. 0％(19/ 20), 97.5％(39/ 40) for HCV-IgG TRFIA, respectively. Additionally, the established HCV-IgM and HCV-IgG assay kits presented good stability with a decline in the value of fluorescence of 11.1％and 9.5％ respectively after being stored at 37 ℃ for 7 d. Conclusions The established HCV-IgM and HCV-IgG TRFIA could simultaneously measure HCV-IgM and HCV-IgG antibodies at one step. The method has wider detectable range and may be a more sensitive, stable, and reliable method for diagnosing HCV in-fection.

Development of Immunochromatographic Strips Based on Covalently Conjugated BHHCT-Eu3+@SiO2 for Rapid and Quantitative Detection of Kanamycin / 分析化学

As a kind of fluorescent nanoprobe, BHHCT-Eu3+ @ SiO2 fluorescent nanoparticles were synthesized using microwave irradiation. Transmission electron microscopy characterization showed that the nanoparticles were in spherical shape with particle size of about 36 nm. The BHHCT-Eu3+@SiO2 exhibited good fluorescence property, with a maximal excitation wavelength of 343 nm and an maximal emission wavelength of 615 nm. The fluorescence lateral flow immunoassay ( LFIA ) was established for rapid and quantitative detection of kanamycin ( Kana) in milk after BHHCT-Eu3+@SiO2 fluorescent nanoparticles were conjugated with Kana antibody, with dextran as a linker. The limit of detection of Kana with the LFIA method was 0. 85 ng/mL with IC50 of 12. 76 ng/mL, and the detection range was from 3. 0 ng/m to 76 ng/mL. The recoveries of Kana in milk were between 93 . 7% and 97 . 4% with RSD of 3 . 1%-4 . 6%, and cross-reactivity of the fluorescence immunoassay strip for Kana determination was<1%. The detection results of kana in milk samples between the LFIA and traditional ELISA method showed good correlation.

Development of Immunochromatographic Strips Based on Covalently Conjugated BHHCT-Eu3+@SiO2 for Rapid and Quantitative Detection of Kanamycin / 分析化学

As a kind of fluorescent nanoprobe, BHHCT-Eu3+ @ SiO2 fluorescent nanoparticles were synthesized using microwave irradiation. Transmission electron microscopy characterization showed that the nanoparticles were in spherical shape with particle size of about 36 nm. The BHHCT-Eu3+@SiO2 exhibited good fluorescence property, with a maximal excitation wavelength of 343 nm and an maximal emission wavelength of 615 nm. The fluorescence lateral flow immunoassay ( LFIA ) was established for rapid and quantitative detection of kanamycin ( Kana) in milk after BHHCT-Eu3+@SiO2 fluorescent nanoparticles were conjugated with Kana antibody, with dextran as a linker. The limit of detection of Kana with the LFIA method was 0. 85 ng/mL with IC50 of 12. 76 ng/mL, and the detection range was from 3. 0 ng/m to 76 ng/mL. The recoveries of Kana in milk were between 93 . 7% and 97 . 4% with RSD of 3 . 1%-4 . 6%, and cross-reactivity of the fluorescence immunoassay strip for Kana determination was<1%. The detection results of kana in milk samples between the LFIA and traditional ELISA method showed good correlation.

Determination of Tryptophan Based on Inner Filter Effect of FluorescentYttrium Vanadate: Europium Nanoprobes / 分析化学

Yttrium vanadate:europium nanoprobes (YVO4∶Eu NPs) with good fluorescence properties and water solubility were synthesized by solvent thermal method.Due to the overlapping of the excitation spectrum of YVO4∶Eu NPs and the absorption spectrum of tryptophan, fluorescent internal filter effect (IFE) occurred, in which YVO4∶Eu NPs were the fluorophore and tryptophan was the absorber, leading the fluorescence of YVO4∶Eu NPs was quenched.Therefore, a new method for the determination of tryptophan was established by using fluorescent YVO4∶Eu as nanoprobes based on IFE.Some experimental parameters, such as the adding amount of YVO4∶Eu NPs, pH value of the reacting solution, and reacting time, were investigated.Under the optimum reaction conditions, the linear range of the method was 4.0×10-6-4.0×104 mol/L and the detection limit was 1.0×10-6 mol/L (3σ).The content of tryptophan in the soy sauce was determined with the recovery of 95.2% and 97.3%.This method is simple, rapid, sensitive and accurate.

Development of time resolved fluorescence microparticle-conjugated anti-human procalcitonin antibody for homogeneous immunoassay / 军事医学

Objective To develop europium (Ⅲ) [Eu (Ⅲ)] chelated microparticles for homogeneous immunoassay.Methods Anti-human PCT antibodies were labeled with Eu (Ⅲ) chelated nanoscale microparticles as the detection antibody,and another anti-human PCT antibody was labeled with biotin as the solid-phase antibody.Magnetic microspheres labeled with streptavidin were used to separate the complexes of Eu-IgM-PCT-IgM-Biotin.Results In the homogeneous immunoassay,the standard curve fit was not linear.The quadratic curve was Y =19170.12 + 75493.74X-26.00X2(r =0.9986).According to the standard curve,the limit of detection for PCT was 0.04 ng/ml.Conclusion The homogeneous immunoassay which uses Eu (Ⅲ) chelated microparticles is highly sensitive for detection of PCT recombinant antigens and may serve as a promising method to measure serum PCT levels in the future.

Application of Time-resolved Fluroimmunoassay for Determination of Furaltadone Metabolite 3-Amino-5-morpholinomethyl-2-oxazolidinone / 分析化学

To detect furaltadone metabolite 3-amino-5-morpholinomethyl-2-oxazolidinone ( AMOZ ) in fish sample, an Eu3+ labeling time-resolved fluoroimmunoassay ( TRFIA ) was developed. The effects of experimental conditions including AMOZA-OVA concentration, dilution of antibody, and reaction time on the sensitivity of TRFIA were explored. The results showed that the optimized assay conditions were as follows:the AMOZA-OVA concentration was 0. 25 μg/mL; the antibody was diluted 5í104 folds, and the competitive reaction time was 50 min. Under optimal conditions, the method showed a detection limit of 0. 01 ng/mL, an IC50 of 0. 26 ng/mL and a linear range (IC20-IC80) of 0. 025-2. 83 ng/mL. The recoveries of AMOZ in fish at three spiked levels ranged from 78 . 0% to 86 . 0%, and the relative standard deviations were less than 15%. Good correlation between the ic-TRFIA and high performance liquid chromatography-tandem mass spectrometry was obtained for spiked food samples. The proposed ic-TRFIA method was suited for the determination of AMOZ residue in food samples.

Highly Sensitive and Novel Point-of-Care System, aQcare Chlamydia TRF Kit for Detecting Chlamydia trachomatis by Using Europium (Eu) (III) Chelated Nanoparticles

BACKGROUND: The bacterium Chlamydia trachomatis is one of the leading causes of sexually transmitted diseases worldwide. Since no simple and effective tool exists to diagnose C. trachomatis infections, we evaluated a novel point-of-care (POC) test, aQcare Chlamydia TRF kit, which uses europium-chelated nanoparticles and a time-resolved fluorescence reader. METHODS: The test performance was evaluated by comparing the results obtained using the novel POC testing kit with those obtained using a nucleic acid amplification test (NAAT), using 114 NAAT-positive and 327 NAAT-negative samples. RESULTS: The cut-off value of the novel test was 20.8 with a detection limit of 0.27 ng/mL. No interference or cross-reactivity was observed. Diagnostic accuracy showed an overall sensitivity of 93.0% (106/114), specificity of 96.3% (315/327), positive predictive value (PPV) of 89.8% (106/118), and negative predictive value (NPV) of 97.5% (315/323). The sensitivity of the novel test was much higher than that of currently available POC tests. Furthermore, the relative ease and short turnaround time (30 min) of this assay enables C. trachomatis-infected individuals to be treated without a diagnostic delay. CONCLUSIONS: This simple and novel test is a potential tool to screen a larger population, especially those in areas with limited resources.

Determination of Trace Carbaryl in Water by Europium-Diallyl Phthalate Fluorescent Probe / 分析化学

A rapid and sensitive method for the determination of trace carbaryl in water by using diallyl phthalate-europium ( Eu3+) as fluorescent probes was developed. The interaction between Eu3+ and diallyl phthalate and carbaryl was studied by high resolution mass spectrum, and the fluorescence spectra change of complexes before/after binding with carbaryl was also investigated. The influence factors of fluorescence intensity including solution pH and interferent were studied. The results showed that two diallyl phthalate molecules were complexed with one Eu3+to form stable complexes. Carbaryl could also interact with the probe to form multiple complexes, which significantly increased the fluorescent efficiency of the probe. At pH 9. 0 of solution and by using 245/615 nm as excitation/emission wavelength, the fluorescence intensity showed good linear relationship with the carbaryl concentration ranged from 6. 25í10-8 mol/L to 2. 50í10-6 mol/L, and the linear correlation coefficient was 0. 9968. The detection limit of the method was 9. 6í10-9 mol/L. Water samples were extracted by acetonitrile, and then detected by europium ( Eu3+)-diallyl phthalate fluorescent probe. The recovery of the method was 91. 8%-94. 5%, while RSD was within 6. 1%. The method is suitable for the rapid determination of carbaryl in water samples.

Establishment and evaluation of time resolved fluoroimmuno assay for quantification of total immuno globulin E / 重庆医学

Objective To establish a method for quantitative detection of total immunoglobulin E(TIgE) by Time resolved Flu‐oroimmunoassay(TRFIA ) .Methods The method for quantitative detection of TIgE by TRFIA was established on the basis of solidphase double sandwich enzyme linked immunosorbent assay(ELISA) .The methodology was evaluated .Results The TIgE TR‐FIA intra assay and inter assay coefficients of variation (CV) were 1 .59% -1 .68% and 5 .23% -7 .33% ,respectively .The lower limit of detection was 0 .25 IU/mL .The linear range was 1 .47-1 510 .00 IU/mL .The accuracy was within the allowable deviation ( ± 10% ) .The recovery rate was 97 .00% -106 .75% .The cross reaction test and interference experiment could meet the testing requirements .The TIgE TRFIA showed no HOOK effect at least up to 15 000 IU/mL TIgE ,compared with EUROIMMUN ELISA ,the correlation coefficient(r) was 0 .999 2(P<0 .01)for 40 blood specimens in the range of 14 .43-518 .81 IU/mL ,and the expected bias was in the range of acceptable bias (± 12 .50% ) .The reference value 100 IU/mL could be used for a normal ,allergy free adult sample TIgE level detected by TRFIA .Conclusion The established TRFIA for TIgE detection meets the demand of clini‐cal application with good precision ,high sensitivity ,wide linear range ,high accuracy ,specificity and other advantages .

Study of Eu-metacycline complex fluorescent probe and its analytical application / 中国药学杂志

OBJECTIVE: To study the luminescence effect of Eu3+-Metacycline (MTC)-cetyltrimethyl ammonium bromide (CTMAB) system and the luminescence mechanism of the system. METHODS: Based on the luminescence effect, a fluorescent method for the determination of MTC was proposed. Fluorescence characteristics of the complex of metacycline (MTC) with Eu3+ in a micellar system was studied, and the effect of different concentrations of MTC and MTC complexes on Escherichia coli and the Staphylococcus aureus in optimum experimental conditions was investigated. RESULTS: The experiments indicated that in pH 9.0-10.5 Na2B4O7-NaOH buffer solution, both MTC and cationic surfactant (CTMAB) could enhance greatly the fluorescence intensity of Eu3+. The fluorescence intensity was linearly related to the fleroxacin concentration in the range of 0.45-12 μg · mL-1. CONCLUSION: A new fluorescent method has been developed for the determination of MTC in pharmaceutical preparations. The detection limit was 0.015 3 μg · mL-1 and the RSD was 1.03%. The complexes of different concentrations of MTC and MTC have good antibacterial effect against Escherichia coli, and the antibacterial effect is the best when the MTC's concentration is 1 × 10-3 mol · L-1 against escherichia colon.

Rapid europium-sensitized fluorescent determination of ulifloxacin, the active metabolite of prulifloxacin, in human serum and urine / 药物分析学报

A new fluorescent method was developed based on the ulifloxacin-europium (Ⅲ)-sodium dodecylbenzene sulfonate system for the determination of ulifloxacin,the active metabolite of prulifloxacin.Sodium dodecylbenzene sulfonate formed a ternary complex with ulifloxacin-europium (Ⅲ) and significantly enhanced the characteristic fluorescence of europium (Ⅲ).The enhanced fluorescence intensity showed a good linear relationship with the concentration of ulifloxacin in the range of 5.0× 10 8 -2.0× 10-6M with a detection limit of 2.0× 10-10 M (3σ).This method is rapid and sensitive,and has been successfully applied to the determination of ulifloxacin in human urine and serum samples.

Rapid europium-sensitized fluorescent determination of ulifloxacin,the active metabolite of prulifloxacin,in human serum and urine / 药物分析学报

A new fluorescent method was developed based on the ulifloxacin-europium（Ⅲ）-sodium dodecylbenzene sulfonate system for the determination of ulifloxacin,the active metabolite of prulifloxacin.Sodium dodecylbenzene sulfonate formed a ternary complex with ulifloxacin-europium（Ⅲ）and significantly enhanced the characteristic fluorescence of europium（Ⅲ）.The enhanced fluorescence intensity showed a good linear relationship with the concentration of ulifloxacin in the range of 5.0×10

Europium (II) triflate catalyzed ring opening of oxiranes: an improved method for the synthesis of Β-amino alcohols.

Epoxides undergo rapidly ring-opening reaction with various amine nucleophiles in the presence of Europium triflate. The catalyst was very active and used in 10% mole only. All the reactions were carried out at room temperature in methylene dichloride to afford the corresponding b-amino alcohols in very good yields.

Semi-quantitative measurement of HCV RNA by Europium-labeled gene probe / 中华检验医学杂志

Objective To establish a semi-quantitative method for measurement of HCV RNA by use of primers and probe, which was sensitive and designed by ourselves, a new europium fluorescent chelate BHHCT. Methods 44 serum samples of HCV infected patients and 20 samples of the healthy people were collected. HCV RNA in serum sample was extracted by HCV fluorescence PCR diagnostic kit produced by Zhongshan University DAAN Gene Co Ltd, and amplified by RT-PCR in which one PCR primer was pre-labeled with biotin. The amplified products were hybridized with capture probes pre-fixed on the microplate. The biotin in the amplified products was conjugated with europium labeled streptavidin. So europium was linked to the target DNA. Then the fluorescent of europium was measured. Results The linear range of this assay was 10 - 10 copies/ml. Both sensitivity and specificity were 100%. Conclusion Europium labeled RT-PCR assay is a sensitive, specific, fast and non-radioactive contaminant method for the measurement of HCV RNA.

Genetic Toxicity of Europium Nitrate to Vicia faba Root Tip Cells / 环境与健康杂志

Objective To evaluate the genotoxicity of europium nitrate to the Vicia faba L root-tip cells. Methods The primary roots of Vicia faba L were cultured for 6 hours in the solution of Eu series(64,32,16,8,4,2,1 ?g/ml) at 25℃.And then the roots were repair-cultured in double distilled water for 24 h. The root tips of Vicia faba L were dissected and fixed,stained and the micronucleus rate,mitotic index and the rate of chromosomal aberrations were determined. Results From 1 ?g/ml to 32 ?g/ml,the rate of micronucleus increased with the increasing of the europium nitrate dosage(D),presented a dosage-effect relationship(r=0.949). From 2 ?g/ml to 64 ?g/ml,mitotic index decreased with the increasing of the europium nitrate dosage,presented a dosage-effect relationship(r=-0.852). From 1 ?g/ml to 64 ?g/ml,chromosome fragments(CF) and frequency of chromosomal aberrations(FCA) increased with the increasing of the europium nitrate dosage with a dosage-effect relationship significantly(rD-CF=0.915,rD-FCA=0.872). Conclusion Europium nitrate has the certain genetic toxicity to the Vicia faba L root-tip cells. The chromosome fragments may be one of the reasons to produce micronucleus.