Four-Channel Ultrasonic Sensor for Bulk Liquid and Biochemical Surface Interrogation

Area of Science:

• * Acoustic physics
• * Biosensing technology
• * Custom electronics design

Background:

• * Bulk acoustic wave (BAW) and surface acoustic wave (SAW) biosensors require precise electronic instrumentation.
• * Characterizing liquid properties and biological interactions in real-time demands sensitive detection methods.

Purpose of the Study:

• * To develop custom electronics for ultrasonic biosensors.
• * To measure time-of-flight (TOF) and acoustic properties in real-time.
• * To demonstrate the system's capability for detecting changes in liquid salinity and DNA interactions.

Main Methods:

• * Designed and implemented a four-channel ultrasonic system with a 25 MHz frequency.
• * Integrated a microcontroller with Python and SciPy for data analysis.
• * Utilized piezoelectric and capacitive micromachined ultrasound transducers.
• * Measured TOF changes in response to varying water salinity and DNA oligonucleotide binding with gold nanoparticles (Au NPs).

Main Results:

• * Demonstrated a linear response to water salinity changes, attributed to density-dependent TOF variations.
• * Successfully detected real-time DNA oligonucleotide interactions via Au NP binding.
• * Observed an exponential decrease in the TOF signal due to increased local density from Au NP binding.
• * Achieved significantly stronger sensor signals compared to previous prototypes.

Conclusions:

• * The developed ultrasonic system effectively characterizes acoustic properties of liquids and real-time biological interactions.
• * The system shows high sensitivity to changes in solution density and specific molecular binding events.
• * The use of Au NPs enhances biosensor signal strength for oligonucleotide detection.