Dual-Modal Aptasensor for Sensitive Detection of Non-Small Cell Lung Cancer Exosomes Utilizing Two-Dimensional Nanopaper Co@g-CN@PB.

Nonsmall cell lung cancer (NSCLC), due to its lack of early symptoms, has become one of the leading causes of cancer-related deaths globally. Exosomes, small membrane vesicles secreted by cells, are widely present in human bodily fluids. In the bodily fluids of NSCLC patients, the quantity of extracellular vesicles is double that of healthy individuals, suggesting their potential as biomarkers for screening NSCLC. This study designed a dual-modal aptasensor that integrated excellent sensitivity in electrochemical detection and portability in fluorescence detection into one device. AuNPs were functionalized with exosome-capturing probes containing thiol-modified CD63 aptamers, which were immobilized on screen-printed gold electrodes. On the other hand, the carboxylated CD63 aptamer was immobilized on the surface of PB-modified g-CN loaded with Co-SANs particles (Co@g-CN@PB). By combining these components, a sandwich structure (AuNPs/Apt1/Exo/Apt2- Co@g-CN@PB) was constructed, forming a probe for specific exosome recognition. First, the samples were preliminarily assessed for their positive or negative status under a fluorescence inverted microscope. Subsequently, a more in-depth quantitative analysis was conducted on suspected positive samples using electrochemical or fluorescence analysis methods. The detection limits for electrochemical analysis and fluorescence analysis were 66.68 and 33.5particles/mL, respectively. In the analysis of clinical serum exosome samples, the developed dual-modal aptasensor effectively distinguished serum specimens from those of NSCLC patients and healthy volunteers. This highlighted the inspection capability of the dual-modal adapter sensor, especially in point-of-care testing, making it a highly suitable tool for clinical applications.