Microfluidic Line-Free Mass Sensor Based on an Antibody-Modified Mechanical Resonator

Area of Science:

• Biosensing
• Microfluidics
• Mechanical Resonators

Background:

• Traditional mass sensors often require power supply lines, limiting their application.
• Label-free techniques enhance sensitivity but can be complex.
• Microfluidic systems offer precise sample handling and reusability.

Purpose of the Study:

• To develop a line-free mass sensor integrating microfluidics and label-free detection.
• To improve sensor sensitivity, reusability, and enable high-throughput analysis.
• To demonstrate the sensor's capability for analyzing human salivary cortisol.

Main Methods:

• Fabrication of a disk-shaped mechanical resonator (4 mm diameter, 0.5 mm thickness) using photolithography.
• Integration of a piezoelectric element for vibration excitation, creating a line-free design.
• Incorporation of a microfluidic mechanism for rapid sample washing and reusability.

Main Results:

• Achieved a high Q-factor of 7748 and resonance frequency of 1.402 MHz, even in liquid environments.
• Demonstrated successful analysis of human salivary cortisol concentration.
• Validated sensor reusability through effective microfluidic washing protocols.

Conclusions:

• The microfluidic line-free mass sensor is suitable for accurate salivary hormone analysis.
• The sensor's high-throughput capability makes it ideal for point-of-care testing.
• The developed sensor offers a sensitive, reusable, and power-independent solution for biosensing.