Abstract
This paper describes a single-molecule sandwich immunoassay method that utilizes total internal reflection fluorescence microscopy (TIRFM) at the single-molecule level for nanoarray protein chip applications. Nanoarray patterning of a biotin-probe with a spot diameter of 179 ± 1 nm was performed successfully on a (3-mercaptopropyl)trimethoxysilane (MPTMS)-coated glass substrate by atomic force microscopy (AFM). The formation of biotin patterns was confirmed directly by observing the heights of bound streptavidin and biotin-antibody on glass substrates using an AFM in contact mode. Target protein molecules (or antigen) at the zepto-molar (zM) concentration level (× 10-21 M) were detected on MPTMS-coated glass nanoarray protein chips by TIRFM. Finally, cytokine clinical samples (i.e. TNF-α and IL-1α) as cancer marker protein molecules were applied to nanoarray protein chips, and detection limits were at 600 zM.
Original language | English |
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Pages (from-to) | 933-938 |
Number of pages | 6 |
Journal | Analyst |
Volume | 134 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2009 |
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Biochemistry
- Environmental Chemistry
- Spectroscopy
- Electrochemistry