Single-fluorophore imaging with an unmodified epifluorescence microscope and conventional video camera

Area of Science:

• Biophysics
• Molecular Biology
• Microscopy

Background:

• Studying molecular machines requires high-resolution imaging techniques.
• Current methods for single-molecule imaging are often complex and require specialized equipment.
• There is a need for accessible methods to study molecular mechanisms in real-time.

Purpose of the Study:

• To demonstrate real-time imaging of single fluorophores using conventional microscopy.
• To enable the study of molecular machines at the single-molecule level in an active biological environment.
• To encourage the adoption of 'single-molecule physiology'.

Main Methods:

• Utilized a conventional Olympus IX70 microscope with epifluorescence excitation.
• Employed a standard silicon-intensified target (SIT) video camera.
• Imaged individual Cy3 fluorophores attached to biomolecules (gelsolin, actin, heavy meromyosin) in aqueous solution.

Main Results:

• Successfully imaged individual, moving or stationary Cy3 fluorophores in real time.
• Demonstrated the capability with three distinct experimental systems involving actin and myosin.
• Showed that neither a powerful laser nor an extremely sensitive camera was necessary.

Conclusions:

• Conventional microscopy is sufficient for single-molecule imaging of fluorophores.
• This accessible technique facilitates 'single-molecule physiology'.
• Opens avenues for studying molecular machine function and mechanisms in their native, active state.