Integrated Acoustofluidic Manipulation and Oscillation-Stabilized Magnetic Relaxation Biosensing for Salmonella...

Area of Science:

• Biosensing
• Microfluidics
• Pathogen Detection

Background:

• Reliable pathogen detection in complex samples is challenging.
• Effective sample handling and stable signal generation are crucial for biosensing.

Purpose of the Study:

• To develop an acoustofluidic-magnetic relaxation biosensing (MRB) platform for Salmonella detection.
• To combine acoustofluidic particle manipulation with oscillation-stabilized magnetic readout.

Main Methods:

• Utilized a cylindrical-array region for enhanced Salmonella-immunomagnetic nanobead (IMNB) encounters via convective mixing.
• Employed a butterfly-shaped acoustic streaming vortex (BSAV) region for preferential retention of Salmonella-IMNB complexes and generation of a nanoscale-dominant outlet suspension.
• Applied an oscillation-assisted MRB system with axial micro-oscillation to suppress bead sedimentation/aggregation and stabilize the ΔT2 response.

Main Results:

• Achieved a linear response from 4.8 × 10^1 to 4.8 × 10^5 CFU/mL.
• Established a limit of detection of 29 CFU/mL with a total assay time of approximately 40 minutes.
• Demonstrated good specificity and satisfactory recoveries (92.68-103.95%) in spiked chicken samples.

Conclusions:

• The acoustofluidic restructuring of suspension composition enables stable and quantitative magnetic relaxation detection.
• The developed MRB platform shows promise for rapid and reliable Salmonella detection in complex food matrices.
• This approach offers a robust solution for pathogen detection challenges in real-world applications.