3D SERS-based biosensor for the selective detection of circulating cancer-derived exosomes

Circulating cancer cells or exosomes derived from these cells constitute a solid predictive marker of the disease activity. However, the low frequency of the cells and exosomes provides a technical challenge for diagnostic devices. In this review, we present the current state of the art for utilizing exosomes derived from cancerous cells as a predictive marker. The review focuses on deploying 3D surface-enhanced Raman spectroscopy (SERS) as a technique to address the detectability of low-frequency biomarkers. We also provide a review on the material techniques employed to enhance the detection signal, by utilizing porosity that enhances the surface area, thus facilitating the detection at low biomarker frequency.