Fully automated immunoassay for detection of prostate-specific antigen using nano-magnetic beads and micro-polystyrene bead composites, 'Beads on Beads'.
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.
Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan. tmatsuna@cc.tuat.ac.jp
Tadashi
T
Matsunaga
Yoshiaki
Y
Maeda
Tomoko
T
Yoshino
Haruko
H
Takeyama
Masaaki
M
Takahashi
Harumi
H
Ginya
Junko
J
Aasahina
Hideji
H
Tajima
D000906:Antibodies / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000648:ultrastructure*; D011137:Polystyrenes; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000276:immunology*
D000906:Antibodies; D011137:Polystyrenes; D017430:Prostate-Specific Antigen