Exploring single-molecule interactions: heparin and FGF-1 proteins through solid-state nanopores.

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Protein-protein interactions are vital for cellular functions like growth and repair.
• Heparin-fibroblast growth factor 1 (FGF-1) complex abnormalities are linked to diseases such as cancer and neurological disorders.
• Single-molecule analysis offers precise insights into these interactions.

Purpose of the Study:

• To investigate heparin-FGF-1 interactions at the single-molecule level using solid-state nanopore technology.
• To characterize the formation and properties of heparin-FGF-1 complexes without protein modification.
• To demonstrate the utility of nanopore sensing for studying protein complex dynamics.

Main Methods:

• Fabrication of 17 ± 1 nm solid-state nanopores using a controlled dielectric breakdown approach.
• Single-molecule translocation of individual heparin and FGF-1 proteins through nanopores.
• Analysis of current blockade signals to differentiate protein translocations and identify complex formation.

Main Results:

• Distinct current blockade signatures were observed for individual heparin and FGF-1 proteins.
• FGF-1's positively charged domains interacted with pore walls, causing higher current blockade.
• Binding of heparin stabilized FGF-1, forming complexes with larger excluded volumes, evidenced by increased current blockades.

Conclusions:

• Solid-state nanopore sensing is a sensitive method for characterizing individual proteins and their interactions.
• The study confirms heparin-FGF-1 binding and complex formation at the single-molecule level.
• This technique holds potential for developing novel medical therapies and advancing diagnostics.