Acoustofluidic Device to Transform Point-Of-Care sEV-Based Diagnostics

Rapid and sensitive detection of small extracellular vesicles (sEVs)—key biomarkers in cancer and organ health monitoring—remains challenging due to the need for multiple preprocessing steps and bulky laboratory instruments. Conventional assays such as Western blotting are time-consuming and require large sample volumes, limiting clinical usability. Now, a new acoustofluidic system offers a fast, low-cost solution capable of processing small sample volumes while providing high sensitivity and biomarker specificity within minutes.

Developed by researchers at Duke University (Durham, NC, USA), the acoustofluidic device integrates sharp-edge microstructures with acoustically induced vortices to concentrate biomarker-bound microbeads for rapid fluorescence readout. The microchip, made of a PDMS microchannel with embedded sharp edges, uses a piezoelectric buzzer to generate localized sound waves that manipulate particle movement. By combining antibody-functionalized microbeads for sEV capture and on-chip optical quantification, the platform enables size-selective separation and concentration of target complexes.

Image: The acoustofluidic device is designed for sample preparation and detection of small extracellular vesicles (Photo courtesy of Tony Jun Huang/Duke University)

The study, published in Cyborg and Bionic Systems, detailed how the device exploits the interaction of sound waves and microstructures to generate vortices that trap microbead–sEV aggregates while smaller nanoparticles flow freely. When activated (90 Vpp, 4 kHz), 5-µm beads rapidly concentrate at microstructure tips within 120s, while 400-nm nanoparticles remain dispersed when validated via real-time fluorescence imaging. In clinical validation, EGFR-positive sEVs from HeLa cells produced a fluorescence intensity ratio six times higher than negative controls, with detection completed in just 20 minutes.

The modular design allows researchers to switch biomarkers by changing bead surface antibodies, enabling adaptable detection of diverse sEV populations. Compared to Western blotting (five or more hours), the device reduces analysis time to under 30 minutes while maintaining high specificity. Future work aims to improve signal uniformity across microstructures and develop parallel channels for multi-marker detection, broadening its use in point-of-care diagnostics and liquid biopsy applications.

"The acoustofluidic chip leverages localized acoustic streaming to spatially separate microbead-sEV conjugates from unbound nanoparticles, achieving 6-fold signal enhancement for EGFR-positive sEVs in just 20 minutes," said study author Tony Jun Huang.

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