Electric Field-Induced Exosome Lysis and Quantification of TSG101-Derived Protein via Electrochemical Sensing

Exosomes that contain TSG101 biomarkers are synthesized by both healthy and malignant cells and have the potential to accurately diagnose a wide range of diseases, including cancer. For exosomal protein quantification, exosomes must be isolated from serum and then used for protein extraction. Ultracentrifugation is the most common way to isolate. Although detergents are commonly employed to extract the encapsulated exosomal proteins, they may compromise their protein integrity. The present work involves two detailed studies: the lysing of exosomes immobilized on the Au screen printed electrode (SPE) and the development of a nonfaradaic electrochemical sensor by utilizing SPE to quantity TSG101 protein. To lyse exosomes attached to the SPE surface, we applied different amplitudes of square signals to the SPE to disrupt the exosomes and facilitate the release of their contents. The lysate solution was utilized for electrochemical impedance spectroscopy (EIS) by faradic and nonfaradic techniques. Results of both types of EIS were similar, showing that nonfaradaic sensing could be an effective alternative. Hence, we employed nonfaradaic EIS to quantify the TSG101 protein released by electric lysis and validated the result with ELISA. We achieved a linear response, specifically at concentrations ranging from 0.125 to 8 ng/mL, with a detection limit of 0.10 ng/mL for human serum. Cross-reactivity analysis demonstrated selectivity to TSG101 with minimal interaction with nonspecific biomolecules.

I. Introduction

TSG101 is a multidomain protein enriched in exosomes that plays a significant role in cancer biology by contributing to exosome biogenesis, cargo sorting, intercellular communication, and physiological activities, including regulation of cell proliferation, invasion, mortality, and potentially serving as a biomarker for cancer detection and prognosis [1], [2], [3]. Its overexpression in breast, ovarian, colorectal, lung, prostate, and cervical cancer suggests a crucial role in carcinogenesis [4], [5]. To facilitate TSG101 quantification, exosomes must be isolated and lysed.