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Nano-visualization of oriented-immobilized IgGs on immunosensors by high-speed atomic force microscopy
Masumi Iijima1, Masaharu Somiya, Nobuo Yoshimoto
1Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
Insights
Bio-nanocapsules (BNCs) enable oriented immobilization of immunoglobulin G (IgG) for enhanced biosensing. High-speed atomic force microscopy (HS-AFM) visualized IgG movement, revealing rotational Brownian motion at the single-molecule level.
Area of Science:
- Biosensing
- Biophysics
- Nanotechnology
Background:
- Oriented immobilization of sensing molecules is crucial for biosensor development.
- Conventional techniques struggle to observe real-time movement of immunoglobulin G (IgG) at the single-molecule level.
- Bio-nanocapsules (BNCs) displaying Staphylococcus aureus protein A's Z domain (ZZ-BNC) were developed for enhanced IgG immobilization.
Purpose of the Study:
- To investigate the surface structure of ZZ-BNC using high-speed atomic force microscopy (HS-AFM).
- To observe the real-time movement of mouse IgG3 molecules immobilized on ZZ-BNC in solution.
- To demonstrate the utility of ZZ-BNC and HS-AFM for studying single-molecule dynamics in biosensing.
Main Methods:
- High-speed atomic force microscopy (HS-AFM) for high-resolution surface imaging.
- Development of bio-nanocapsules (BNCs) displaying ZZ domains for oriented IgG immobilization.
- In-solution observation of single mouse IgG3 molecules tethered to ZZ-BNC.
Main Results:
- HS-AFM revealed the fine surface structure of ZZ-BNC.
- ZZ-BNC facilitated the oriented immobilization of IgG molecules.
- The Fv regions of immobilized IgG molecules exhibited rotational Brownian motion.
- Real-time single-molecule movement of IgG on ZZ-BNC was successfully observed.
Conclusions:
- ZZ-BNC serves as an effective scaffold for oriented IgG immobilization in biosensing applications.
- HS-AFM enables visualization and analysis of single-molecule dynamics, including rotational Brownian motion.
- This approach enhances understanding of sensing molecule behavior on biosensor surfaces.
Abstract:
Oriented immobilization of sensing molecules on solid phases is an important issue in biosensing. In case of immunosensors, it is essential to scrutinize not only the direction and shape of immunoglobulin G (IgG) in solution but also the real-time movement of IgGs, which cannot be achieved by conventional techniques. Recently, we developed bio-nanocapsules (BNCs) displaying a tandem form of the IgG Fc-binding Z domain derived from Staphylococcus aureus protein A (ZZ-BNC) to enhance the sensitivity and antigen-binding capacity of IgG via oriented-immobilization. Here, we used high-speed atomic force microscopy (HS-AFM) to reveal the fine surface structure of ZZ-BNC and observe the movement of mouse IgG3 molecules tethered onto ZZ-BNC in solution. ZZ-BNC was shown to act as a scaffold for oriented immobilization of IgG, enabling its Fv regions to undergo rotational Brownian motion. Thus, HS-AFM could decipher real-time movement of sensing molecules on biosensors at the single molecule level.
