Detection of analytes by immunoassay using up-converting phosphor technology.
Up-Converting Phosphor Technology (UPT) is based on lanthanide-containing, submicrometer-sized, ceramic particles that can absorb infrared light and emit visible light. Biological matrices do not up-convert; hence, there is no contribution to test background from sample autofluorescence. Up-converting phosphors do not photobleach and are inert to common assay interferants such as hemoglobin. A reader called UPlink has been developed to interrogate lateral flow test strips that utilize UPT labels. The reader contains a miniaturized, 1-W, infrared laser with peak emission at 980 nm. Preliminary assays that use up-converting phosphor labels, including tests for a drugs of abuse panel and Escherichia coli O157:H7, have been developed. In a "sandwich" assay format, 10(3) org/mL E. coli O157:H7 organisms were detectable in a negative control background of 10(9) other organisms per milliliter of culture medium. Coefficients of variation in concentrations tested from 0 to 10(7) org/mL were all < or =10%. In a competitive inhibition assay format, a multiplexed test simultaneously detected amphetamine, methamphetamine, phencyclidine, and opiates in saliva. For all assays, the percent displacement at 10 ng/mL was > or =40% demonstrating performance comparable with lab-based, commercially available EIAs. All assays were complete in 10 min. The development of rapid tests using UPT creates new applications for on-site testing with sensitivity not available using other label technologies.
Niedbala
R S
RS
OraSure Technologies, Inc., 150 Webster Street, Bethlehem, Pennsylvania 18015-1389, USA. sniedbala@orasure.com
Feindt
H
H
Kardos
K
K
Vail
T
T
Burton
J
J
Bielska
B
B
Li
S
S
Milunic
D
D
Bourdelle
P
P
Vallejo
R
R
D019969:Amphetamine-Related Disorders / Q000378:metabolism; D000907:Antibodies, Bacterial / Q000276:immunology; D000697:Central Nervous System Stimulants / Q000378:metabolism; D003124:Colorimetry / Q000379:methods; D003429:Cross Reactions; D004791:Enzyme Inhibitors / Q000378:metabolism; D019453:Escherichia coli O157 / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques; D008081:Liposomes; D008163:Luminescent Measurements; D008694:Methamphetamine / Q000378:metabolism; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D009292:Narcotic Antagonists / Q000378:metabolism; D009294:Narcotics / Q000378:metabolism; D010622:Phencyclidine / Q000378:metabolism; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D000697:Central Nervous System Stimulants; D004791:Enzyme Inhibitors; D008081:Liposomes; D009292:Narcotic Antagonists; D009294:Narcotics; D008694:Methamphetamine; D010622:Phencyclidine