Nanophotonic Liquid Biopsy of Circulating Tumor Exosomes for Point-of-care Cancer Detection

Recently, we have developed PlAsmonic NanO-apeRture lAbel-free iMAging (PANORAMA) to detect individual nanoparticles as small as 25 nm using an array of gold nanodisks on invisible substrate (AGNIS). PANORAMA enables the counting, sizing, and localization of individual sEVs in both healthy individuals and cancer patients across various stages and types by utilizing AGNIS functionalized with antibodies against exosomal surface proteins CD9, CD63, and CD81. By quantifying a portion of exosomes from 20 µL blood plasma, PANORAMA can differentiate 205 cancer patients and 106 healthy individuals with a sensitivity of 99.5% and a specificity of 97.3%.[1] In this study, we report new results towards a hepatocellular carcinoma (HCC) test.
We have analyzed samples of three donor types: healthy plasma donors (HPD), non-cancer diseases patients (NCD) (including cirrhosis, fatty liver etc), and cancer patients (CP) (including liver cancer and cholangiocarcinoma). A test set of 76 samples were analyzed, comprising 13 HPD, 21 NCD, and 42 CP. Among them, the counts are 156±55 (HPD), 370±130 (NCD), and 458±100 (CP). To enhance specificity, we have next explored known molecular biomarkers such as cargo microRNAs (miRNAs): miR-126-3p, miR-222-3p, miR-31, miR-21, and miR-221. Using a standard molecular beacon probe design (3' BHQ2 quencher/5' Cy3), we have analyzed another sample set consisting of 80 samples (NCD and CP) in a blinded manner, yielding a sensitivity of 97%, a specificity of 95% (3 false positives and 1 false negative). ROC analysis for the blinded set yielded an AUC of 0.94.
Our study underscores the potential of PANORAMA in quantifying and profiling exosomes for HCC detection. The test runs on 20 µL of plasma without any additional sample preparation or isolation, and thus is highly suitable for routine test and point-of-care applications.

1. Plasmonic nano-aperture label-free imaging of single small extracellular vesicles for cancer detection. Commun Med 2024;4:100.