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Updated: Feb 11, 2026
17:14
Compact Quantum Dots for Single-molecule Imaging
Published on: October 9, 2012
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Quantum-dot antibody conjugation visualized at the single-molecule scale with high-speed atomic force microscopy
Takayuki Umakoshi1, Hikari Udaka2, Takayuki Uchihashi3
1Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita Osaka 565-0871, Japan.
Colloids and Surfaces. B, Biointerfaces
|April 21, 2018
Summary
High-speed atomic force microscopy visualizes quantum dot-antibody conjugates at the single-molecule level. This technique reveals dynamic antibody behavior during conjugation and offers insights into conjugate formation and stability.
Area of Science:
- Biophysics
- Nanotechnology
- Immunology
Background:
- Semiconductor quantum dots (QDs) conjugated with antibodies are valuable bioprobes, combining QD fluorescence with antibody specificity.
- Understanding the molecular conformation of QD-antibody conjugates at the single-molecule scale is crucial for advancing bioprobe development.
Purpose of the Study:
- To directly image quantum dot-antibody conjugates at the single-molecule scale using high-speed atomic force microscopy (HS-AFM).
- To investigate the dynamic molecular behavior and conformational changes during the conjugation process.
Main Methods:
- Utilized high-speed atomic force microscopy (HS-AFM) for high spatiotemporal resolution imaging.
- Observed QD-antibody conjugates at the single-molecule level to capture dynamic events.
Main Results:
- Observed dynamic splitting of individual antibodies during conjugation.
- Visualized QD-antibody conjugates with single-molecule scale details.
- Identified an intermediate conjugation state with repeated antibody attachment and detachment.
- Revealed significant fluctuation in antibody recognition areas due to Brownian motion.
Conclusions:
- HS-AFM provides unprecedented single-molecule visualization of QD-antibody conjugates.
- Dynamic observations reveal complex conjugation processes and antibody behavior.
- HS-AFM is a powerful tool for quantitative analysis of bioconjugates.
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