Probing Amyloid β and the Antibody Interaction Using Atomic Force Microscopy.

Area of Science:

• Biochemistry
• Neuroscience
• Biophysics

Background:

• Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) plaque accumulation.
• Aβ peptide's role in neurotoxicity and AD pathogenesis is critical.
• Understanding Aβ-antibody interactions is key for diagnostic and therapeutic development.

Purpose of the Study:

• To investigate the molecular interactions between amyloid-beta (Aβ) and specific antibodies.
• To compare the binding characteristics of two distinct antibodies targeting Aβ.
• To evaluate the potential of these antibodies for developing Aβ sensors.

Main Methods:

• Utilized atomic force microscopy (AFM) to probe Aβ-antibody interactions at the single-molecule level.
• Employed single molecular force spectroscopy (SMFS) for quantitative binding analysis.
• Modified AFM probes and glass substrates with specific antibodies and Aβ peptides, respectively.

Main Results:

• Quantified the dissociation constants for single Aβ-antibody42 and Aβ-antibody16 interactions.
• Determined a dissociation constant of 5.2 × 10⁻³ s⁻¹ for Aβ-antibody42.
• Found that Aβ-antibody42 exhibited a 5.3 times longer bond lifetime compared to Aβ-antibody16.

Conclusions:

• Antibody42 demonstrates superior binding kinetics and stability with Aβ compared to antibody16.
• The findings suggest antibody42 is a more suitable candidate for the development of sensitive Aβ sensors.
• This research provides valuable insights into Aβ-antibody interactions for Alzheimer's disease research.