Analyzing Single Giant Unilamellar Vesicles With a Slotline-Based RF Nanometer Sensor

Area of Science:

• Biophysics
• Electrical Engineering
• Materials Science

Background:

• Label-free detection of single cells is crucial for biological and medical advancements.
• Radio-frequency (RF) sensors offer a promising avenue for sensitive, reagent-free cellular analysis.
• Existing methods often require complex sample preparation or lack sensitivity for individual cell analysis.

Purpose of the Study:

• To develop and characterize a highly sensitive and tunable RF sensor for single-cell analysis.
• To demonstrate the sensor's capability for label-free detection and dielectric property extraction of giant unilamellar vesicles (GUVs).
• To establish a foundation for point-of-care health service technologies utilizing RF sensing.

Main Methods:

• Fabrication of a 100 nm slotline structure for a highly sensitive RF sensor.
• Utilizing high-concentration RF fields (~1.76×10^7 V/m) for enhanced interaction with GUVs.
• Employing two modeling approaches to extract dielectric properties from measured scattering parameters at ~2 GHz, ~2.5 GHz, and ~2.8 GHz.

Main Results:

• Achieved highly sensitive detection of GUVs with an initial |S| of ~-100 dB.
• Successfully synthesized and analyzed GUVs of varying molecular compositions.
• Obtained corresponding dielectric properties for analyzed GUVs.
• Demonstrated one-dimensional scanning of single GUVs.

Conclusions:

• The developed RF sensor provides a sensitive and tunable platform for label-free single-cell analysis.
• The method allows for the extraction of crucial dielectric properties of GUVs.
• This technology holds potential for advancing biological research and point-of-care diagnostics.