Streptavidin-Polyvinylamine Conjugates Labeled with a Europium Chelate: Applications in Immunoassay, Immunohistochemistry, and Microarrays
Bibliographic record
Abstract
BACKGROUND: The favorable properties of lanthanide chelates compared with conventional fluorescent probes have attracted considerable interest. A Eu(3+) chelator, 4,7-bis(chlorosulfophenyl)-1, 10-phenanthroline-2,9-dicarboxylic acid (BCPDA), has been synthesized previously. METHODS: We here describe immunoassay, immunohistochemistry, and microarray applications of a new streptavidin-based universal polyvinylamine (PVA) detection reagent that is multiply labeled with the europium chelate of BCPDA. Solid-phase time-resolved immunofluorometric assays for biotinylated mouse IgG and prostate-specific antigen (PSA) were developed using the new conjugate as a detection reagent. The new conjugate was also used for the immunohistochemical localization of PSA expression in paraffin-embedded prostatic tissues. A model microarray with spotted biotinylated antibody as target was also performed. RESULTS: Approximately 50-100 BCPDA moieties were covalently bound to PVA, which was then linked to streptavidin via biotin interaction. The macromolecular complex successfully recognized and bound biotinylated detection reagents, e.g., antibodies. The new reagent enabled measurement of solid phase-immobilized biotinylated mouse IgG with a detection limit of approximately 1 pg/assay and demonstrated excellent linearity. In an ELISA-type sandwich PSA assay that included two PSA monoclonal antibodies using the new conjugate as detection reagent, we detected 0.001 microg/L PSA ( approximately 100 fg or approximately 3 amol/assay). Serum samples analyzed for PSA by this method and a commercial assay gave highly correlated results. The new reagent enabled excellent immunohistochemical localization of PSA expression in prostate tissues. Using the new reagent in a model microarray experiment with biotinylated mouse IgG as target, we demonstrated excellent spatial resolution of 5- to 10-nL microspots. CONCLUSIONS: The new detection reagent may find important applications in biotechnology.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".