Dual-Lanthanide-Chelated Silica Nanoparticles as Labels for Highly Sensitive Time-Resolved Fluorometry

2007 ◽  
Vol 19 (24) ◽  
pp. 5875-5881 ◽  
Author(s):  
Heng Zhang ◽  
Ye Xu ◽  
Wei Yang ◽  
Qingge Li
Keyword(s):  
Silica Nanoparticles ◽  
Time Resolved ◽  
Highly Sensitive

scholarly journals Multiple Fluorescent Labeling of Silica Nanoparticles with Lanthanide Chelates for Highly Sensitive Time-Resolved Immunofluorometric Assays

2007 ◽  
Vol 53 (8) ◽  
pp. 1503-1510 ◽  
Author(s):  
Ye Xu ◽  
Qingge Li
Keyword(s):  
Detection Limit ◽  
Hepatitis B ◽  
Silica Nanoparticles ◽  
Fluorescent Labeling ◽  
Time Resolved ◽  
Robust Detection ◽  
Lower Detection Limit ◽  
Lanthanide Chelates ◽  
Highly Sensitive ◽  
Lower Detection

Abstract Background: Time-resolved immunofluorometric assays (TrIFA) using lanthanide-labeled nanoparticles have greatly increased the sensitivity of immunoassays. Current labeling strategies, however, use either physical doping of lanthanide chelates into preformed nanoparticles or covalent linking of lanthanide chelates to precursors used for making nanoparticles; both these strategies have drawbacks. Methods: Luminescent Eu(III) and Tb(III) chelates were covalently coated on the surface of preformed silica nanoparticles to which detection antibodies or bridging proteins for antibody binding were conjugated. We used the resulting conjugates in TrIFA for detection of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg), both individually and simultaneously. We compared the results of the newly established method with results of an ELISA for serum samples. Positive samples identified by TrIFA but not by ELISA were confirmed by additional assays, including real-time PCR detection of viral DNA. Results: The prepared nanoparticle conjugates were homogeneous in size, at ∼55 (5) nm in diameter [mean (SD)], were stable for long-time storage (>2 years), and contained more chelates [6.86 × 105 for Eu(III), 4.73 × 104 for Tb(III)] per nanoparticle than particles made as previously reported. The TrIFA established for HBsAg had a comparable or lower detection limit (0.0092 μg/L) than existing nanoparticle-based TrIFA or ELISA. The TrIFA for HBeAg had a much lower detection limit [10.0 National Centre Unit (NCU)/L] than ELISA and detected HBeAg in 5 samples missed by the ELISA method. Simultaneous TrIFA for both HBsAg and HBeAg was achieved with detection limits (0.033 μg/L for HBsAg and 27.0 NCU/L for HBeAg) close to those of the individual assays. Conclusions: Covalent surface labeling of silica nanoparticles with lanthanide chelates provides good fluorescent labels that can be used in TrIFA for highly sensitive and robust detection of clinical targets.

Establishment and clinical application of a highly sensitive TAT-2 time-resolved fluorescence immunoassay detection

2021 ◽  
Author(s):  
Xindong Chen ◽  
Jianfeng Hong ◽  
Han Zhao ◽  
Zhongyi Xiang ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Nasopharyngeal Cancer ◽  
Reaction Rates ◽  
Measurement Range ◽  
Fluorescence Immunoassay ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Combined Use ◽  
Highly Sensitive ◽  
Positive Rate

Abstract Background: A rapid and highly sensitive assay for tumor-associated trypsinogen-2 (TAT-2) based on the time-resolved fluorescence immunoassay (TRFIA) detection technique was developed for the determination of serum TAT-2 levels in cancers. Results: The measurement range of TAT-2-TRFIA was 1.53-300 ng/mL. The within-run and between-run coefficients of variation of TAT-2-TRFIA were 4.38% and 7.82%, respectively. The recovery rate of TAT-2-TRFIA was 103.0%. The cross-reaction rates of trypsin and T-cell immunoglobulin mucin 3 were 0.02% and 0.82%, respectively. The TAT-2-positive rates in lung cancer, liver cancer, nasopharyngeal cancer, cholangiocarcinoma, brain cancer, and pancreatic cancer were 45.9%, 50.0%, 45.0%, 64.3%, 50.0%, and 41.7%, respectively, with the areas under ROC curves of 0.788, 0.734, 0.862, 0.720, 0.887, and 0.585, respectively. In patients with lung cancer, the positive rate of the single indicator CEA was 28.4%, which increased to 60.6% after combined use with TAT-2. In patients with cholangiocarcinoma, the positive rate of CA-199 was 35.7%, which increased to 71.4% after combined use with TAT-2. Conclusions: TAT-2 is expected to be used as an auxiliary diagnostic indicator for the combined use of tumor markers to improve the positive rate and accuracy of detection.

Prostate-specific antigen in milk of lactating women

1995 ◽  
Vol 41 (1) ◽  
pp. 54-58 ◽  
Author(s):  
H Yu ◽  
E P Diamandis
Keyword(s):  
Breast Milk ◽  
Prostate Specific Antigen ◽  
Specific Antigen ◽  
Normal Breast ◽  
Specific Marker ◽  
Time Resolved ◽  
Lactating Women ◽  
Highly Sensitive ◽  
Mother’S Age ◽  
Total Psa

Abstract Prostate-specific antigen (PSA) is believed to be a highly specific marker for normal and cancerous prostatic tissue. We recently found that 30-40% of breast tumors produce PSA. Other data from our group suggest that normal breast can also produce PSA under conditions of stimulation by steroid hormones. In addition, we detected PSA in amniotic fluid. Here we report the presence of PSA in breast milk of lactating women. PSA concentrations in breast milk were quite variable, ranging from < 0.01 microgram/L in 4 of 38 milks to 350 micrograms/L; the median was 0.47 microgram/L. PSA concentration in breast milk was not correlated with mother's age or the sex of the newborn. It did tend to decrease with increasing time postdelivery, but was still detectable 2 weeks postdelivery. PSA in milk was equally measurable by a highly sensitive PSA assay based on time-resolved fluorometry and by the IMx automated PSA method. As confirmed by Western blot analysis, PSA in milk was present predominantly in its 33-kDa form; the PSA-alpha 1-antichymotrypsin complex (100 kDa) was also present but its concentration was < 25% of total PSA. We conclude that the female breast can produce PSA and that PSA is secreted into the milk during lactation; however, the biological role of PSA in milk is unknown. These and other data presented by our group suggest that PSA, a serine protease, may play a role in control of growth in mammary and other tissues through regulation of growth factors, cytokines, and growth-factor-binding proteins.

scholarly journals Phospholipase A2 Receptor Antibody IgG4 Subclass Improves Sensitivity and Specificity in the Diagnosis of Idiopathic Membranous Nephropathy

2019 ◽  
Vol 44 (4) ◽  
pp. 848-857 ◽  
Author(s):  
Biao Huang ◽  
Yi Zhang ◽  
Liang Wang ◽  
Wenwei Xu ◽  
Jue Zhang ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Sensitivity And Specificity ◽  
Membranous Nephropathy ◽  
Kidney Diseases ◽  
Measurement Range ◽  
Idiopathic Membranous Nephropathy ◽  
Time Resolved ◽  
Specificity And Sensitivity ◽  
Phospholipase A2 Receptor ◽  
Highly Sensitive

Aims: The aim of this study was to develop a new method for detecting anti-phospholipase A2 receptor-IgG4 to improve the sensitivity and specificity in the diagnosis of idiopathic membranous nephropathy (IMN). Methods: A highly sensitive quantitative assay was developed for the detection of serum anti-phospholipase A2 receptor-IgG4 with europium chelation by time-resolved fluoroimmunoassay (TRFIA), and a mouse anti-human IgG4 tracer was prepared using europium chelation for detection. The specificity and sensitivity of anti-phospholipase A2 receptor-IgG4 in the diagnosis of IMN were further assessed in patients with different kidney diseases. Results: The detection limit of anti-PLA2R-IgG4 was 0.69 ng/mL. The measurement range of anti-PLA2R-IgG4 TRFIA was 0.69–2,500 ng/mL. Mean serum anti-PLA2R-IgG4 was 21.27 ± 15.15 ng/mL in 45 healthy volunteers, 31.08 ± 18.17 ng/mL in 29 IgA nephropathy patients, 49.10 ± 34.32 ng/mL in 8 lupus nephropathy patients, and 10,324.11 ± 17,030.40 ng/mL in 30 IMN patients. The anti-PLA2R-IgG4 cutoff concentration was >161.2 ng/mL with the sensitivity of 90.0% and specificity of 100% in the diagnosis of IMN. However, the cutoff for other kidney diseases was lower than 161.2 ng/mL. Conclusion: The serum anti-phospholipase A2 receptor IgG4 detected with the method developed in this study has higher sensitivity and higher specificity than total IgG in the diagnosis of IMN.

Sign in / Sign up

Export Citation Format

Share Document