Shear force near-field optical microscope based on Q-controlled bimorph sensor for biological imaging in liquid

Area of Science:

• Biophysics
• Microscopy
• Materials Science

Background:

• Liquid viscous damping significantly reduces sensitivity and resolution in shear force microscopy of biological samples.
• Existing methods struggle to maintain performance in physiological liquid environments.

Purpose of the Study:

• To develop and validate an alternative force detection scheme for biological imaging in liquid.
• To enhance the sensitivity and resolution of shear force near-field microscopy in aqueous environments.

Main Methods:

• Utilized a bimorph-based cantilever sensor with integrated force feedback.
• Theoretically and experimentally analyzed the sensor's dynamics and sensitivity.
• Operated the cantilever near its resonance frequency with force feedback in water.

Main Results:

• Achieved a quality factor (Q-factor) up to 10^3 in water without altering intrinsic resonance frequency or spring constant.
• Demonstrated high sensitivity and stability in shear force imaging of mouse brain sections and human skin tissues.
• Obtained a resolution of approximately 50 nm in liquid imaging.

Conclusions:

• The developed force feedback sensor significantly improves shear force microscopy performance in liquid.
• The system offers enhanced sensitivity, stability, and resolution suitable for biological cell imaging.
• This approach provides a reliable method for imaging delicate biological samples in their native liquid environment.