Abstract

Exosomes as new biomarkers for cancer diagnosis have attracted attention because they are highly released by tumor cells in various biological fluids. In this study, an electrochemical paper-based immunosensor device (Exo-sensing paper) is introduced for the detection of exosome in the serum. The Exo-sensing paper is a three-electrode system that is prepared using pattern paper and carbon and silver inks. The sensor part of this immunosensor contains a three-dimensional porous nanocomposite of nickel nanofoam coupled with graphene oxide and gold nanoparticles. The high specific surface area of this nanocomposite increases the antibody loading on the sensor surface significantly and consequently leads to obtaining a wide linear range of 500–1 × 107 Exospore µL−1 with a detection limit of 110 Exosome µL−1. Due to some advantages of this constructed Exo-sensing paper such as easy storage, simple application, low cost and good selectivity in the real samples, this system has a good potential to be used as a point of care testing for in situ detection of the exosomes and is a promising strategy for minimally invasive liquid biopsy. Graphical abstract: (Figure presented.). © The Author(s), under exclusive licence to Springer Nature B.V. 2024.