title: Highly sensitive immunoassay for the diagnosis of acute myocardial infarction using silica spheres encapsulating a quantum dot layer.
abstract: Commercial ELISA kits for substance P (SubP), which are helpful for the clinical diagnosis of acute myocardial infarction, are limited in efficacy because of low sensitivity. A highly sensitive immunoassay was developed using silica spheres encapsulating a quantum dot-layer (SQS) and labeling antibodies, on a Parylene A-modified plate. The high sensitivity was possible by taking advantage of the enhanced photoluminescence of the SQS and dense immobilization of SubP on a Parylene A-modified plate. Glutaraldehyde was used for cross-linking of SQS to the anti-SubP antibody and SubP to the Parylene A coating. The SQS-linked immunosorbent assay (SQSLISA) was optimized and validated. The dynamic range for the assay was 1-10000 pg/mL with a linear correlation factor of 0.9992 when the competitive SQSLISA was employed. The intra- and interday accuracies were 93-100% and 87-122%, respectively. The reproducibility was lower than 11%. The developed method was applied to clinical samples collected from healthy controls (n = 30) and acute myocardial infarction (n = 16) and it displayed a high correlation with the commercial ELISA kit, with a limit of detection that was 30-fold lower. Clinical sample analysis confirmed that SubP is a promising diagnostic marker for acute myocardial infarction. The SQSLISA is expected to be a practical and useful assay tool.
authors.affiliation: Molecular Recognition Research Center, Korea Institute of Science and Technology (KIST) , Seoul 136-791, Republic of Korea.
authors.forename: Hyojeong
authors.initials: H
authors.lastname: Han
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Pyun
authors.forename: Hyein
authors.initials: H
authors.lastname: Yoo
authors.forename: Hong Seog
authors.initials: HS
authors.lastname: Seo
authors.forename: Byung Hwa
authors.initials: BH
authors.lastname: Jung
authors.forename: Young Sook
authors.initials: YS
authors.lastname: Yoo
authors.forename: Kyoungja
authors.initials: K
authors.lastname: Woo
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Kang
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D009203:Myocardial Infarction / Q000175:diagnosis*; D045663:Quantum Dots; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D012822:Silicon Dioxide