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Single‐molecule immunoassay and DNA diagnosis
Author(s) -
Ma Yinfa,
Shortreed Michael R.,
Li Hanlin,
Huang Weihua,
Yeung Edward S.
Publication year - 2001
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(200102)22:3<421::aid-elps421>3.0.co;2-w
Subject(s) - capillary electrophoresis , electrophoresis , gel electrophoresis , microbiology and biotechnology , dna , mitochondrial dna , gel electrophoresis of nucleic acids , immunoassay , polymerase chain reaction , dna sequencer , digoxigenin , chemistry , biology , chromatography , biochemistry , genetics , dna sequencing , gene , antibody , in situ hybridization , gene expression
Many assays relevant to disease diagnosis are based on electrophoresis, where the migration velocity is used for distinguishing molecules of different size or charge. However, standard gel electrophoresis is not only slow but also insensitive. We describe a single‐molecule imaging procedure to measure the electrophoretic mobilities of up to 100 000 distinct molecules every second. The results correlate well with capillary electrophoresis (CE) experiments and afford confident discrimination between normal (16.5 kbp) and abnormal (6.1 kbp) mitochondrial DNA fragments, or β‐phycoerythrin‐labeled digoxigenin (BP‐D) and its immunocomplex (anti‐D‐BP‐D). This demonstrates that virtually all electrophoresis diagnostic protocols from slab gels to CE should be adaptable to single‐molecule detection. This opens up the prossibility of screening single copies of DNA or proteins within single biological cells for disease markers without performing polymerase chain reaction (PCR) or other biological amplification.