Atomic force microscopy investigation of viruses

Area of Science:

• Virology
• Nanotechnology
• Microscopy

Background:

• Atomic force microscopy (AFM) is a powerful tool for visualizing nanoscale biological structures.
• Viruses exhibit a wide range of sizes and morphologies, presenting challenges for detailed structural analysis.

Purpose of the Study:

• To highlight the utility of AFM in characterizing viral architectures and internal features.
• To compare AFM's capabilities with traditional electron microscopy techniques.

Main Methods:

• AFM imaging of various viruses, including small satellite viruses, mimivirus, HIV, icosahedral particles, vaccinia, and bacteriophages.
• Enzymatic and chemical dissection of virions to reveal internal structures and nucleic acids.
• Application of AFM to both fixed and unfixed samples in diverse environments (air, fluids).

Main Results:

• AFM successfully delineated the detailed architectures of viruses ranging from 17 nm to 750 nm.
• Surface imaging provided distinct information compared to electron microscopy, sometimes at higher resolution.
• Internal structures and nucleic acids (DNA/RNA) were visualized after sample dissection.
• AFM demonstrated non-destructive imaging capabilities on individual viruses and infected cells.

Conclusions:

• AFM is a versatile and valuable technique for high-resolution imaging of viral structures.
• It offers complementary and sometimes superior information to electron microscopy.
• AFM's non-perturbative nature and adaptability make it promising for future virological research.