Electrochemical biosensors in exosome analysis; a short journey to the present and future trends in early-stage evaluation of cancers

The tumor microenvironment consists of a multiplicity of cells such as cancer cells, fibroblasts, endothelial cells, and immune cells within the specific parenchyma. It has been indicated that cancer cells can educate other cells within the tumor niche in a paracrine manner by the release of nano-sized extracellular vesicles namely exo-somes (Exo), resulting in accelerated tumor mass growth. It is suggested that exosomal cargo with remarkable information can reflect any changes in metabolic and proteomic profiles in parent tumor cells. Therefore, exo-somes can be touted as prognostic, diagnostic, and therapeutic elements with specific biomarkers in patients with different tumor types. Despite the advantages, conventional exosome separation and purification protocols are time-consuming and laborious with low abnormal morphology and purity rate. During the last decades, biosensor-based modalities, as emerging instruments, have been used to detect and analyze Exo in biofluids. Due to suitable specificity, sensitivity, and real-time readout, biosensors became promising approaches for the analysis of Exo in in vitro and in vivo settings. The inherent advantages and superiority of electrochemical bio-sensors in the determination of tumor grade based on exosomal cargo and profile were also debated. Present and future challenges were also discussed related to the application of electrochemical biosensors in the clinical setting. In this review, the early detection of several cancer types associated with ovaries, breast, brain, colon, lungs, T and B lymphocytes, liver and rare types of cancers were debated in association with released exosomes.

Automated summary

The tumor microenvironment is made up of multiple cell types, including cancer cells, fibroblasts, endothelial cells, and immune cells. Studies have shown that cancer cells can influence other cells within the tumor region by releasing nano-sized extracellular vesicles known as exosomes in a paracrine manner, leading to accelerated tumor growth. Exosomes carry valuable information and can reflect changes in metabolic and proteomic profiles in parent tumor cells, making them potential prognostic, diagnostic, and therapeutic tools with specific biomarkers for different types of tumors. However, traditional exosome separation and purification methods are time-consuming and laborious with low abnormal morphology and purity rate. In recent years, biosensor-based techniques have emerged as promising approaches for the detection and analysis of exosomes in biofluids due to their suitable specificity, sensitivity, and real-time readout. This review also discusses the potential advantages of electrochemical biosensors in determining tumor grade based on exosomal cargo and profile, as well as the present and future challenges in applying electrochemical biosensors in a clinical setting.