Fully automated immunoassay for detection of prostate-specific antigen using nano-magnetic beads and micro-polystyrene bead composites, 'Beads on Beads'

Tadashi Matsunaga, Yoshiaki Maeda, Tomoko Yoshino, Haruko Takeyama, Masaaki Takahashi, Harumi Ginya, Junko Aasahina, Hideji Tajima

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Magnetic beads have served as a conventional bioassay platform in biotechnology. In this study, a fully automated immunoassay was performed using novel nano- and microbead-composites constructed by assembling nano-magnetic beads onto polystyrene microbeads, designated 'Beads on Beads'. Nano-sized bacterial magnetic particles (BacMPs) displaying the immunoglobulin G (IgG)-binding domain of protein A (ZZ domain) were used for the construction of 'Beads on Beads' via the interaction of biotin-streptavidin. The efficient assembly of 'Beads on Beads' was performed by gradual addition of biotin-labeled BacMPs onto streptavidin-coated polystyrene microbeads. Approximately 2000 BacMPs were uniformly assembled on a single microbead without aggregation. The constructed 'Beads on Beads' were magnetized and separated from the suspension by using an automated magnetic separation system with a higher efficiency than BacMPs alone. Furthermore, fully automated detection of prostate-specific antigens was performed with the detection limit of 1.48 ng mL-1. From this preliminary assay, it can be seen that 'Beads on Beads' could be a powerful tool in the development of high-throughput, fully automated multiplexed bioassays.

Original languageEnglish
Pages (from-to)331-339
Number of pages9
JournalAnalytica Chimica Acta
Volume597
Issue number2
DOIs
Publication statusPublished - 2007 Aug 10

Keywords

  • Bacterial magnetic particle
  • Fully automated immunoassay
  • Polystyrene microbeads
  • Prostate-specific antigen

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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