Homogeneous electrogenerated chemiluminescence immunoassay for the determination of digoxin employing Ru(bpy)(2)(dcbpy)NHS and carrier protein.
A highly sensitive homogeneous electrogenerated chemiluminescence (ECL) immunoassay for the determination of anti-digoxin antibody and digoxin hapten was developed employing Ru(bpy)(2)(dcbpy)NHS (bpy = 2,2'-bipyridyl; dcbpy = 2,2'-bipyridine-4,4'-dicarboxylic acid; NHS = N-hydroxysuccinimide ester) as an electrochemiluminescent label and bovine serum albumin (BSA) as a carrier protein. A digoxin hapten was indirectly heavily labelled with Ru(bpy)(2)(dcbpy)NHS through BSA to form Ru(bpy)(2)(dcbpy)NHS-BSA-digoxin conjugate. The ECL intensity of the immunocomplex of the conjugate with anti-digoxin antibody markedly decreased when the immunoreaction between Ru(bpy)(2)(dcbpy)NHS-BSA-digoxin conjugate and anti-digoxin antibody took place. Two formats, direct homogeneous immunoassay for anti-digoxin antibody and competitive immunoassay for digoxin, were developed to determine anti-digoxin antibody and digoxin, respectively. The anti-digoxin antibody concentration in the range 7.6 x 10(-8)-7.6 x 10(-6) g/mL was determined by direct homogeneous format. Digoxin hapten was determined throughout the range 4.0 x 10(-10)-1.0 x 10(-7) g/mL with a detection limit of 1.0 x 10(-10) g/mL by competitive format. The relative standard derivation for 6.0 x 10(-9) g/mL was 4.3%. The method has been applied to assaying digoxin in control human serum.
Zhang
Chengxiao
C
Department of Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, People's Republic of China. cxzhang@snnu.edu.cn
Qi
Honglan
H
Zhang
Meining
M
D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry; D000906:Antibodies / Q000032:analysis; D002352:Carrier Proteins / Q000737:chemistry; D004077:Digoxin / Q000032:analysis* / Q000276:immunology; D006241:Haptens / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods*; D009942:Organometallic Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013388:Succinimides / Q000737:chemistry
D000906:Antibodies; D002352:Carrier Proteins; D006241:Haptens; D009942:Organometallic Compounds; D013388:Succinimides; D012710:Serum Albumin, Bovine; D015082:2,2'-Dipyridyl; C058014:ruthenium bis(bipyridine)dicarboxybipyridine; D004077:Digoxin; C001426:N-hydroxysuccinimide