Macrocyclic Peptide-Conjugated Tip for Fast and Selective Molecular Recognition Imaging by High-Speed Atomic Force...

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Label-free molecular recognition at the nanoscale is a significant challenge.
• Existing methods often require molecular labeling, limiting real-time analysis.
• Developing techniques for selective, high-resolution detection of unlabeled molecules is crucial for biological research.

Purpose of the Study:

• To demonstrate high-speed atomic force microscopy (HS-AFM) for real-time, label-free recognition of membrane receptors.
• To validate the use of synthetic macrocyclic peptides conjugated to AFM tips for selective molecular binding.
• To optimize the interaction between functionalized AFM tips and target receptors for enhanced detection.

Main Methods:

• Utilized high-speed atomic force microscopy (HS-AFM) for imaging and molecular recognition.
• Conjugated synthetic macrocyclic peptides (aMD4) to AFM tips for selective binding.
• Tested interactions on human hepatocyte growth factor receptor (hMET) on mica surfaces and lipid bilayers.
• Optimized linker length and rigidity for peptide-receptor interaction.
• Employed phase contrast imaging for discrimination between target and non-target molecules.

Main Results:

• Achieved selective, real-time recognition of unlabeled human hepatocyte growth factor receptor (hMET) using HS-AFM with aMD4-functionalized tips.
• Demonstrated successful discrimination between hMET and its murine homologue, which does not bind to aMD4.
• Maintained high spatial resolution in simultaneous topographic imaging due to small ligand and linker size.
• Optimized linker properties to maximize the interaction between the functionalized tip and hMET.

Conclusions:

• HS-AFM with macrocyclic peptide-functionalized tips offers a powerful platform for label-free molecular recognition.
• The method provides high selectivity and minimal disruption to spatial resolution.
• This approach has broad potential for detecting various membrane receptors in diverse biological applications.