Opto-Acoustic Biosensing with Optomechanofluidic Resonators

TL;DR

This paper explores the use of opto-mechano-fluidic resonators (OMFRs) for acoustic biosensing, demonstrating their ability to measure fluid and bioanalyte properties through hybrid vibrational modes in a microfluidic system.

Contribution

The study introduces computational analysis of OMFR eigenfrequencies for acoustic sensing, highlighting new multi-parameter extraction methods from vibrational modes.

Findings

Eigenfrequency sensitivity to fluid and nanoparticle properties

Potential for multi-parameter acoustic measurements

Enhanced biosensing capabilities through optomechanical vibrations

Abstract

Opto-mechano-fluidic resonators (OMFRs) are a unique optofluidics platform that can measure the acoustic properties of fluids and bioanalytes in a fully-contained microfluidic system. By confining light in ultra-high-Q whispering gallery modes of OMFRs, optical forces such as radiation pressure and electrostriction can be used to actuate and sense structural mechanical vibrations spanning MHz to GHz frequencies. These vibrations are hybrid fluid-shell modes that entrain any bioanalyte present inside. As a result, bioanalytes can now reflect their acoustic properties on the optomechanical vibrational spectrum of the device, in addition to optical property measurements with existing optofluidics techniques. In this work, we investigate acoustic sensing capabilities of OMFRs using computational eigenfrequency analysis. We analyze the OMFR eigenfrequency sensitivity to bulk fluid-phase materials as well as nanoparticles, and propose methods to extract multiple acoustic parameters from multiple vibrational modes. The new informational degrees-of-freedom provided by such opto-acoustic measurements could lead to surprising new sensor applications in the near future.