Screening Prostate Cancer Cell‐Derived Exosomal MicroRNA Expression with Photothermal‐Driven Digital PCR

Abstract Exosomes are cell‐derived extracellular vesicles which enclose genetic substances from their origin cells, offering a good source of biomarkers. Many efforts have been made to develop non‐invasive exosome‐based clinical diagnosis, which are urgently needed for prostate cancer, as traditional methods are criticized due to the inaccuracy and discomfort. In this study, a simple, universal process for genotyping of exosome‐derived microRNAs using nanoparticles to capture exosomes and the novel photothermal droplet digital polymerase chain reaction (ddPCR) assay to detect target molecules is presented. To detect the target sensitively and simply, the smart ddPCR thermocycling of the agarose microcarriers can be controllably realized via embedding photothermal MXene and magnetic nanoparticles composite, and then irradiating with a homemade automated near‐infrared control module. Duplex photothermal‐driven ddPCR cooperating with dual TaqMan probes enabled simultaneously and quantitatively detecting copy numbers of prostate oncogenes microRNA‐21‐5p, microRNA‐375‐3p, and metastasis microRNA‐574‐3p along with the control microRNA‐30a‐5p within the extracted exosomes. The results show that the expression levels of these biomarkers in prostate cancer cell lines PC‐3 and DU145 are 7–210 folds higher than those in healthy control cells HaCaT and HUVEC. Thus, it is believed that these versatile exosomal microRNA genotyping approaches are potentially valuable for diverse clinical applications.