Liquid phase immunoassays utilizing magnetic markers and SQUID magnetometer
-
Hiroyuki Kuma
Abstract
Background: Immunoassays are one main detection system used in the field of clinical chemistry. Recent developments of a new detection method utilizing a magnetic marker and magnetic sensor have enabled rapid and sensitive immunoassay without the need for bound/free (BF) separation.
Methods: Newly-synthesized conjugated avidin was used as the magnetic marker for quantitative analysis of human interleukin-8 (hIL-8) and immunoglobulin E (hIgE) in several media. A superconducting quantum interference device sensor detected the magnetic fields from markers fixed to antigens by the sandwich method. Magnetic signals from unbound markers were nearly zero due to Brownian rotation.
Results: Our magnetic immunoassay could detect four attomoles of model proteins (hIL-8, hIgE) in phosphate buffer without BF separation. Using our standard curve, the range of protein detected ranged from 40 femtomoles to 4 attomoles, and we observed a strong association between protein amounts and magnetic signals from the bound markers. The homogeneous immunoassay could also quantify three hundred cells from the fungus Candida albicans in phosphate buffer.
Conclusions: The present study demonstrates the ability of magnetic markers for measuring biological targets without BF separation. This detection system has great potential for use as the next generation's analytical system.
Clin Chem Lab Med 2010;48:1263–9.
©2010 by Walter de Gruyter Berlin New York
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- Congress Abstracts
- Congress of Clinical Chemistry and Laboratory Medicine 7th Annual Conference of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL) Mannheim, Germany, 29th September – 02nd October, 2010
- 9th National Congress of the Greek Society of Clinical Chemistry Athens, Greece, October 7 – 9, 2010
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Articles in the same Issue
- Editorial
- Lost in translation…wallowing in transformation?
- Reviews
- Coeliac disease – a diagnostic and therapeutic challenge
- Advancements in anemias related to chronic conditions
- Opinion Paper
- Translations of the “Evidence-Based Medicine” concept in different languages: is it time for international standardisation?
- Genetics and Molecular Diagnostics
- Rapid detection of glycogen storage disease type Ia by DNA microarray
- Transfer of myxovirus-protein-A mRNA assay for interferon-β bioactivity measurement in multiple sclerosis patients to routine laboratory practice. A 4-year experience
- General Clinical Chemistry and Laboratory Medicine
- Transferrin receptor expression on reticulocytes as a marker of iron status in dialyzed patients
- Quartz crystal microbalance-based biosensor for the detection of α-thalassemia 1 (SEA deletion)
- Retrospective analysis of 88,429 serum and urine glucose EQA results obtained from professional laboratories and medical offices participating in surveys organized by three European EQA centers between 1996 and 2007
- Liquid phase immunoassays utilizing magnetic markers and SQUID magnetometer
- L-Phenylalanine concentration in blood of phenylketonuria patients: a modified enzyme colorimetric assay compared with amino acid analysis, tandem mass spectrometry, and HPLC methods
- Amniotic fluid α-fetoprotein microheterogeneity in the prenatal diagnosis of congenital disorders of glycosylation type Ia
- Minor histocompatibility antigen HA-1 and HA-2 polymorphisms in Taiwan: frequency and application in hematopoietic stem cell transplantation
- Reference Values and Biological Variations
- Blood cell and iron status analytes of preterm and full-term infants from 20 weeks onwards during the first year of life
- Cancer Diagnostics
- Quantitative denaturing high performance liquid chromatography (Q-dHPLC) detection of APC long DNA in faeces from patients with colorectal cancer
- Rapid intraoperative parathyroid hormone assay in fine needle aspiration for differential diagnosis in thyroid and parathyroid surgery
- Serum albumin-bound proteomic signature for early detection and staging of hepatocarcinoma: sample variability and data classification
- Prevalence of atrophic gastritis in dyspeptic patients in Piedmont. A survey using the GastroPanel test
- Cardiovascular Diseses
- Diagnostic accuracy of B-type natriuretic hormone for congenital heart disease in the first month of life
- Carcinoembryonic antigen concentrations in patients with acute coronary syndrome
- Evolution of vitamin D binding protein concentration in sera from cardiac surgery patients is determined by triglyceridemia
- Letters to the Editor
- Effect of storage temperature or collection tube type on blood methylmalonic acid concentrations measured by gas chromatography-mass spectrometry
- Acute porphyrias may be overlooked in patients taking methenamine hippurate
- Reduced plasma apolipoprotein A-V concentrations in two lecithin:cholesterol acyltransferase deficient patients
- Salivary calcium: a risk indicator in periodontal disease
- S100B protein increases in human blood and urine during stressful activity
- Congress Abstracts
- Congress of Clinical Chemistry and Laboratory Medicine 7th Annual Conference of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL) Mannheim, Germany, 29th September – 02nd October, 2010
- 9th National Congress of the Greek Society of Clinical Chemistry Athens, Greece, October 7 – 9, 2010
- 42nd National Congress of the Italian Society of Clinical Biochemistry and Clinical Molecular Biology ROME MARRIOTT PARK HOTEL, Rome (Italy), 5 – 8 October 2010