Near‐Infrared‐Responsive Digital PCR‐Assisted Renal Cancer Exosomal miRNAs Insights and Regulation of Macrophage Polarization

Abstract Exosomes derived from tumors are critical agents in intercellular communication and the tumor microenvironment, offering a rich source of signatures for renal cell carcinoma (RCC) diagnosis. Conventional diagnostic techniques often suffer from limited sensitivity and can be invasive. This study presents an innovative approach using near‐infrared (NIR) digital PCR (dPCR) with black phosphorus‐embedded gelatin microcarriers for profiling exosomal miRNAs and modulating STAT3 signaling and macrophage polarization. Microcarriers produced via microfluidics, characterized by their phase‐change and photothermal properties, are subjected to thermal cycling using a custom NIR source. The study identified a 4.2‐fold increase in miR‐210 levels in RCC cells (ACHN and A498) compared to normal cells (HK‐2), with miR‐126 and miR‐30c levels decreasing by 7–9 times. Additionally, the method achieved a 20‐fold enrichment of miRNA‐34 in exosomes, leading to reduced STAT3 expression and decreased M2 macrophage polarization after co‐incubation. This pioneering dPCR method provides a robust tool for early RCC detection through exosomal miRNA profiling and opens new avenues for therapeutic exosome engineering. The study underscores the potential of dPCR‐based exosome genotyping in identifying cancer biomarkers and developing novel treatment strategies.