Highly sensitive immunoassay for the diagnosis of acute myocardial infarction using silica spheres encapsulating a quantum dot layer

Hyojeong Han, Jae Chul Pyun, Hyein Yoo, Hong Seog Seo, Byung Hwa Jung, Young Sook Yoo, Kyoungja Woo, Min Jung Kang

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13 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)10157-10163
Number of pages7
JournalAnalytical Chemistry
Issue number20
Publication statusPublished - 2014 Oct 21


ASJC Scopus subject areas

  • Analytical Chemistry

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