Phosphorescent porphyrin probes in biosensors and sensitive bioassays

2000 ◽  
Vol 28 (2) ◽  
pp. 74-77 ◽  
Author(s):  
D. B. Papkovsky ◽  
T. O'Riordan ◽  
A. Soini
Keyword(s):  
Oxygen Sensor ◽  
Spectral Characteristics ◽  
Screening Method ◽  
High Sensitivity ◽  
Water Soluble ◽  
Fluorescent Detection ◽  
Rapid Screening ◽  
Time Resolved ◽  
Phosphorescence Lifetime ◽  
Practical Applications

Platinum(II) and palladium(II) complexes of porphyrins and related tetrapyrrolic pigments emit strong phosphorescence at room temperatures, which is characterized by long lifetimes falling into the sub-millisecond range and long-wave spectral characteristics. These features make the dyes useful as probes for a number of bioanalytical applications, particularly those employing time-resolved fluorescent detection. They can provide high sensitivity and selectivity, together with rather simple instrumental set-up. A number of analytical systems are now under development that are based on the use of phosphorescent porphyrin probes. Experimental results are presented on the following systems: (i) fibre-optic phosphorescence lifetime-based oxygen sensor on the basis of hydrophobic platinum-porphyrins and development of advanced sensing materials and prototype instrumentation; (ii) practical applications of the optical oxygen sensor, including a sensitive immunosensor that employs glucose oxidase labels, a rapid screening method for cell viability in microtitre-plate format, non-destructive measurement of oxygen in packaged foods and reagentless biosensors for metabolites (glucose, lactate); and (iii) the use of water-soluble platinum- and palladium-porphyrins as labels for ultra-sensitive time-resolved phosphorescence immunoassays.

Determination of Chlorinated Pesticide Residues in Foods. I. Rapid Screening Method for Chlorinated Pesticides in Milk

1979 ◽  
Vol 62 (3) ◽  
pp. 681-684 ◽  
Author(s):  
Takashi Suzuki ◽  
Kiyoshi Ishikawa ◽  
Nobutoshi Sato ◽  
Kei-Ichi Sakai
Keyword(s):  
Pesticide Residues ◽  
Screening Method ◽  
Raw Milk ◽  
Water Soluble ◽  
Rapid Screening ◽  
Chlorinated Pesticides ◽  
Fortified Milk ◽  
Fat Extraction ◽  
System F ◽  
Ethanol System

Abstract A rapid analytical method for determining chlorinated pesticide residues in milk was developed. Thirteen pesticides were almost completely extracted. Ten mL samples of fortified milk were extracted 3 times with 20 mL portions of n-hexane as follows: (A) in the absence of water-soluble solvent; in the presence of (B) 1 mL acetonitrile; (C) 3 mL acetonitrile; (D) 5 mL acetonitrile; (E) 5 mL ethanol; (F) 5 mL acetonitrile and 1 mL ethanol. System F produced the highest pesticide recoveries but the lowest fat extraction, thus eliminating the necessity for liquid-liquid partitioning and minimizing Florisil column cleanup. Pesticide recoveries throughout the procedure were 94– 103%. It was noticed, however, that the fat in high fat-containing raw milk is more readily extracted than that in commercial milk. Although a number of rapid methods

scholarly journals Screening for Optimal Liposome Preparation Conditions by Using Dual Centrifugation and Time-Resolved Fluorescence Measurements

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2046
Author(s):  
Jonas K. Koehler ◽  
Johannes Schnur ◽  
Heiko Heerklotz ◽  
Ulrich Massing
Keyword(s):  
Lipid Composition ◽  
Screening Method ◽  
Water Soluble ◽  
Time Resolved Fluorescence ◽  
Screening Process ◽  
Lipid Film ◽  
Time Resolved ◽  
Lipid Mixture ◽  
Fluorescence Measurements ◽  
Liposome Preparation

Dual centrifugation (DC) is a novel in-vial homogenization technique for the preparation of liposomes in small batch sizes under gentle and sterile conditions which allows encapsulation efficiencies (EE) for water soluble compounds of >50%. Since liposome size, size distribution (PDI), and EE depend on the lipid concentration used in the DC process, a screening method to find optimal lipid concentrations for a defined lipid composition was developed. Four lipid mixtures consisting of cholesterol, hydrogenated or non-hydrogenated egg PC, and/or PEG-DSPE were screened and suitable concentration ranges could be identified for optimal DC homogenization. In addition to the very fast and parallel liposome preparation of up to 40 samples, the screening process was further accelerated by the finding that DC generates homogeneously mixed liposomes from a macroscopic lipid mixture without the need to initially prepare a molecularly mixed lipid film from an organic solution of all components. This much simpler procedure even works for cholesterol containing lipid blends, which could be explained by a nano-milling of the cholesterol crystals during DC homogenization. Furthermore, EE determination was performed by time-resolved fluorescence measurements of calcein-loaded liposomes without removing the non-entrapped calcein. The new strategy allows the rapid characterization of a certain lipid composition for the preparation of liposomes within a working day.

Rapid Screening for EGFR Inhibitor in Rhei Radix et Rhizoma by HTRF Assay Coupled with HPLC Peak Fractionation

Planta Medica ◽  
2020 ◽  
Author(s):  
Yu Fu ◽  
Zhishen Xie ◽  
Peng Zhao ◽  
Shuangshuang Lv ◽  
Suiqing Chen
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Screening Method ◽  
Growth Factor Receptor ◽  
Rapid Screening ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Hplc Peak ◽  
Epidermal Growth

AbstractIn this paper, an HPLC peak fractionation approach combined with homogeneous time-resolved fluorescence analysis is proposed for screening epidermal growth factor receptor inhibitors from Rhei Radix et Rhizoma. With this approach, the amount of sample used for a single HPLC run is sufficient for performing a multiple assay due to the miniaturization ability of the homogeneous time-resolved fluorescence technology. This allows for improving the stability and repeatability of the activity assay for each fraction. From a total of 26 fractions collected from the Rhei Radix et Rhizoma extract, 13 fractions exhibit inhibitory activity against the epidermal growth factor receptor. The structures of activity compounds were determined by HPLC-LTQ-Orbitrap MS, revealing the presence of gallic acid, rhein, and emodin with IC50 values of 21.5, 5.29, and 10.2 µM, respectively. The ligand epidermal growth factor receptor interactions were explored by molecular docking simulations, and the inhibitory effects of the three compounds on A549 cell growth were tested in vitro by an MTT assay. This study demonstrates the suitability of the present screening method for drug discovery in natural products.

Rapid Screening Method for Water-Soluble External D&C Red No. 15 in Foods

1962 ◽  
Vol 45 (2) ◽  
pp. 463-466
Author(s):  
Charles H Coleman ◽  
Donald W Ezerski ◽  
Ches Butnis ◽  
Thomas G Murnane
Keyword(s):  
Screening Method ◽  
Water Soluble ◽  
Rapid Screening ◽  
Rapid Screening Method

scholarly journals Effects of Crystal Morphology on the Hot-Carrier Dynamics in Mixed-Cation Hybrid Lead Halide Perovskites

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 708
Author(s):  
Daniele Catone ◽  
Giuseppe Ammirati ◽  
Patrick O’Keeffe ◽  
Faustino Martelli ◽  
Lorenzo Di Mario ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Carrier Dynamics ◽  
Large Area ◽  
Photovoltaic Properties ◽  
Time Resolved ◽  
Hot Carrier ◽  
Mixed Cation ◽  
Small Crystals ◽  
Characterization Of Materials ◽  
Lead Halide

Ultrafast pump-probe spectroscopies have proved to be an important tool for the investigation of charge carriers dynamics in perovskite materials providing crucial information on the dynamics of the excited carriers, and fundamental in the development of new devices with tailored photovoltaic properties. Fast transient absorbance spectroscopy on mixed-cation hybrid lead halide perovskite samples was used to investigate how the dimensions and the morphology of the perovskite crystals embedded in the capping (large crystals) and mesoporous (small crystals) layers affect the hot-carrier dynamics in the first hundreds of femtoseconds as a function of the excitation energy. The comparative study between samples with perovskite deposited on substrates with and without the mesoporous layer has shown how the small crystals preserve the temperature of the carriers for a longer period after the excitation than the large crystals. This study showed how the high sensitivity of the time-resolved spectroscopies in discriminating the transient response due to the different morphology of the crystals embedded in the layers of the same sample can be applied in the general characterization of materials to be used in solar cell devices and large area modules, providing further and valuable information for the optimization and enhancement of stability and efficiency in the power conversion of new perovskite-based devices.

Urinary gonadotropin measurements by enhanced luminometric assays (LIA) for the evaluation of pubertal development

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
And Demir ◽  
Adem Aydın ◽  
Atilla Büyükgebiz ◽  
Ulf-Håkan Stenman ◽  
Matti Hero
Keyword(s):  
Healthy Subjects ◽  
Reliable Method ◽  
Pubertal Development ◽  
High Sensitivity ◽  
Tanner Stage ◽  
Time Resolved ◽  
Stage 1 ◽  
Sensitive Detection Technique ◽  
Serum And Urine

Abstract Objectives Determination of LH in urine has proved to be a reliable method for evaluation of pubertal development. The human LH assay based on time-resolved immunofluorometric (IFMA) technology (AutoDELFIA, PerkinElmer, Wallac) has been found to be suitable for this purpose thanks to its high sensitivity but other assays have not been evaluated. We have analyzed our data obtained by another potentially sensitive detection technique, enhanced luminometric assay (LIA) with the objective of finding a viable alternative to IFMA since these may not be available in the future. Methods LIA was used to measure LH and FSH in serum and urine samples from 100 healthy subjects of each Tanner stage and both genders, whose pubertal development has been determined. Results Urinary gonodotropin concentrations measured by LIA correlated well with Tanner stage [(r=0.93 for girls, r=0.81 for boys; p<0.01 for LH) and (r=0.81 for girls, r=0.73 for boys; p<0.01 for FSH)]. LIA determinations revealed the increase in U-LH concentrations during the transition from Tanner stage 1–2 in both girls and boys (p<0.001), whereas U-FSH and S-LH were able to detect the increase from Tanner stage 1–2 only in boys or girls, respectively (both p<0.001). Conclusions Measurement of urinary gonadotropin concentrations by LIA may be useful for the evaluation of overall pubertal development and also in the detection of transition from prepuberty to puberty.

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