One-Pot, Solid-Phase Immunosensing Platform Consisting of a Nanometer-Thick Au/TiO2 Photocatalytic Film and Cy5/Capture Antibody/Gold Nanorod Conjugates

Author(s):  
Kihyeun Kim ◽  
Eun-Jung Jo ◽  
Donggu Hong ◽  
Hyun-Kyung Oh ◽  
Ki Joong Lee ◽  
...  
2004 ◽  
Vol 50 (9) ◽  
pp. 1607-1617 ◽  
Author(s):  
Ville Väisänen ◽  
Susann Eriksson ◽  
Kaisa K Ivaska ◽  
Hans Lilja ◽  
Martti Nurmi ◽  
...  

Abstract Background: Free and total human kallikrein 2 (hK2) might improve the discrimination between prostate cancer and benign prostatic hyperplasia. Concentrations of hK2 are 100-fold lower than concentrations of prostate-specific antigen (PSA); therefore, an hK2 assay must have a low detection limit and good specificity. Methods: PSA- and hK2-specific monoclonal antibodies were used in solid-phase, two-site immunofluorometric assays to detect free and total hK2. The total hK2 assay used PSA-specific antibodies to block nonspecific signal. The capture antibody of the free hK2 assay did not cross-react with PSA. To determine the hK2 concentrations in the male bloodstream, total hK2 was measured in a control group consisting of 426 noncharacterized serum samples. Free and total hK2 were measured in plasma from 103 patients with confirmed prostate cancer. Results: All 426 males in the control group had a total hK2 concentration above the detection limit of 0.0008 μg/L. The median total hK2 concentration was 0.022 μg/L (range, 0.0015–0.37 μg/L). hK2 concentrations were 0.1–58% of total PSA (median, 3.6%). hK2 concentrations were similar in men 41–50 and 51–60 years of age. The ratio of hK2 to PSA steadily decreased from 5–30% at PSA <1 μg/L to 1–2% at higher PSA concentrations. In 103 patients with prostate cancer, the median hK2 concentration in plasma was 0.079 μg/L (range, 0.0015–16.2 μg/L). The median free hK2 concentration was 0.070 (range, 0.005–12.2) μg/L. The proportion of free to total hK2 varied from 17% to 131% (mean, 85%). Conclusions: The wide variation in the free-to-total hK2 ratio suggests that hK2 in blood plasma is not consistently in the free, noncomplexed form in patients with prostate cancer. The new assay is sufficiently sensitive to be used to study the diagnostic accuracies of free and total hK2 for prostate cancer.


Tetrahedron ◽  
2005 ◽  
Vol 61 (1) ◽  
pp. 205-211 ◽  
Author(s):  
Michael Sax ◽  
Stefanie Berning ◽  
Bernhard Wünsch

Biomedicines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 99 ◽  
Author(s):  
Klaas Decoene ◽  
Willem Vannecke ◽  
Toby Passioura ◽  
Hiroaki Suga ◽  
Annemieke Madder

Flexible in vitro translation (FIT) was used as a screening method to uncover a new methodology for peptide constraining based on the attack of a nucleophilic side-chain functionality onto an oxidized furylalanine side chain. A set of template peptides, each containing furylalanine as furan-modified amino acid and a nucleophilic residue (Cys, His, Lys, Arg, Ser, or Tyr), was produced through FIT. The translation mixtures were treated with N-bromosuccinimide (NBS) to achieve selective furan oxidation and subsequent MALDI analysis demonstrated Lys and Ser as promising residues for cyclisation. Solid-phase peptide synthesis (SPPS) was used to synthesize suitable amounts of material for further in-depth analysis and characterisation. It was found that in the case of the peptide containing lysine next to a furylalanine residue, a one-pot oxidation and reduction reaction leads to the generation of a cyclic peptide featuring a pyrrole moiety as cyclisation motif, resulting from the attack of the lysine side chain onto the oxidized furylalanine side chain. Structural evidence was provided via NMR and the generality of the methodology was explored. We hereby expand the scope of our previously developed furan-based peptide labeling and crosslinking strategy.


2014 ◽  
Vol 21 (12) ◽  
pp. 1257-1264
Author(s):  
Stevenson Flemer

A proof-of-principle methodology is presented in which all commercially-available cysteine (Cys) and selenocysteine (Sec) solid phase peptide synthesis (SPPS) derivatives are synthesized in high yield from easily prepared protected dichalcogenide precursors. A Zn-mediated biphasic reduction process applied to a series of four bis-Nα-protected dichalcogenide compounds allows facile conversion to their corresponding thiol and selenol intermediates followed by insitu S- or Se-alkylation with various electrophiles to directly access twenty one known Cys and Sec SPPS derivatives. Most of these derivatives were able to be precipitated in crude form out of petroleum ether in sufficient purity for direct use as peptide building blocks. Subsequent incorporation of these derivatives into peptide models nicely illustrates their viability and applicability toward SPPS.


Author(s):  
Katharina Habler ◽  
Bernhard Koeppl ◽  
Franz Bracher ◽  
Michael Vogeser

Abstract Objectives Bile acids serve as biomarkers for liver function and are indicators for cholestatic and hepatobiliary diseases like hepatitis, cirrhosis, and intrahepatic cholestasis of pregnancy (ICP). Sulfation and renal excretion of bile acids are important elimination steps. The power of ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) allows specific profiling of primary and secondary bile acids as well as their sulfated counterparts. Methods Twenty-four sulfated and non-sulfated primary and secondary bile acids were quantified in urine with 15 corresponding stable isotope labeled internal standards by using two-dimensional UHPLC-MS/MS. The sample preparation was based on a simple dilution with a methanolic zinc sulfate solution followed by an automated online solid phase extraction clean up. Results The validation results of the method fulfilled the criteria of the European Medicine Agency (EMA) “Guideline on bioanalytical method validation”. To verify fitness for purpose, 40 urine samples were analyzed which showed an average of 86% sulfation, 9.1% taurine-conjugation, 14% non-conjugation, and 77% glycine-conjugation rates. Conclusions Lossless one-pot sample preparation, automated sample purification, and high number of internal standards are major innovations of the presented profiling method, which may allow diagnostic application of BA profiling in the future.


1988 ◽  
Vol 34 (8) ◽  
pp. 1640-1644 ◽  
Author(s):  
M J Khosravi ◽  
R C Morton ◽  
E P Diamandis

Abstract In this new immunofluorometric method for quantification of lutropin in serum, the "sandwich" principle is combined with time-resolved fluorescence measurements, with the europium chelate 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA) used as label. A monoclonal antibody to the alpha-subunit of lutropin is adsorbed onto the walls of white-opaque microtiter wells to form the solid-phase capture antibody, and a biotin-labeled soluble monoclonal antibody is used for antigen quantification. The detection system is completed with streptavidin, which has been linked to a protein bulking agent labeled with multiple BCPDA residues. In the presence of excess europium, the fluorescence of the final complex attached to captured lutropin molecules is measured on the dried solid phasse with an automated time-resolved fluorometer. The assay can be performed as a rapid (less than 60 min incubation) or regular (150 min incubation) procedure. The rapid assay is well-suited for routine daily monitoring of increasing or ovulatory lutropin concentrations; the regular assay, with its greater sensitivity (0.5 int. unit/L), is a practical procedure for lutropin measurements in hyposecretory states. The assay measures up to 240 int. units/L, and results compare well with those by a commercially available radioimmunoassay, an immunoradiometric assay, and another time-resolved immunofluorometric procedure.


1987 ◽  
Vol 33 (9) ◽  
pp. 1509-1516 ◽  
Author(s):  
K Auditore-Hargreaves ◽  
R L Houghton ◽  
N Monji ◽  
J H Priest ◽  
A S Hoffman ◽  
...  

Abstract Solid-phase-based immunoassays have traditionally been plagued by nonspecific binding to the solid phase and by slow reaction kinetics relative to reactants that are free to diffuse in solution. We have developed two novel immunoassays in which the solid phase is generated in situ after the specific binding reaction has occurred, thereby enhancing reaction kinetics and minimizing the opportunities for non-specific binding. In the first system, the capture antibody is conjugated to an organic monomer, polymerization of which to form insoluble polymer particles is initiated by a reaction involving free radicals. The amount of signal-labeled antibody incorporated into the resulting particles is directly proportional to the concentration of antigen. The principle is illustrated for the simultaneous assay of IgG and IgM in a single sample. In the second system, capture antibody is conjugated to a polymer, the solubility of which is a function of temperature. Specific binding is conducted below the critical solution temperature of the polymer, which is then separated from solution by increasing the temperature above the critical temperature. The incorporation of signal-labeled antibody into the precipitated polymer is directly proportional to the concentration of antigen. This principle is illustrated for the assay of hepatitis B surface antigen and Chlamydia trachomatis.


Tetrahedron ◽  
2000 ◽  
Vol 56 (45) ◽  
pp. 8867-8875 ◽  
Author(s):  
Wen-Ren Li ◽  
Ying-Chih Yo ◽  
Yu-Sheng Lin

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