An integrative microfluidic device for isolation and ultrasensitive detection of lung cancer-specific exosomes from patient urine.

Exosomes, derived from various biofluids, may serve as potential biomarkers for cancer early detection. Nevertheless, exosome clinical translation remains challenging due to the lack of reliable isolation and detection methods. Herein, we present a novel integrated microfluidic device specifically designed for isolation and in-situ detection of lung cancer-specific exosomes collected from patient's urine. The new device has been fabricated using polymethyl methacrylate (PMMA) and a nanoporous gold (Au) nanocluster membrane modified with the capture antibody. The second antibody-conjugated Au nanorod probe was then loaded to identify and quantify lung cancer-specific exosomes using a dark field microscope. AuNC-Exosome-AuR complex produces a significant scattering wavelength shift and an improved scattering intensity due to resonance Rayleigh scattering, which enables the ultrasensitive detection of exosomes with a LOD below 1000 particles/mL. The proteomic analysis revealed that the high-purity exosomes has been isolated by the device. We then validated this method with 500 μL urine samples from lung cancer patients and controls, which showed great promise for differentiating early-stage lung cancer patients from healthy individuals. Taken together, the presented method is fast and ultrasensitive and can be easily adapted for the isolation and detection of cancer specific exosomes from other malignant tumors.