Flexible Paper-Based Immunosensor for the Detection of Specific Cancer-Derived Exosomes

Abstract

This study aims at an electrochemical paper-based device for the selective and sensitive detection of exosomes as an economical and flexible platform. Using a laser cutter, a three-electrode platform was patterned on a hydrophobic paper and then synthetic carbon and silver ink were screen-printed onto the paper. Anti-human CD9 antibody was covalently attached to the surface of a carbon ink electrode enriched with graphene oxide aerogel/CoFe2O4@chitosan nanocomposite. The immobilization, incubation, and binding time of the capture antibody were investigated as effective parameters. Under optimum conditions, the differential pulse voltammetry data were used to establish a calibration plot that covered 500 to 5×106 exosoms/µL with a detection limit of 100 exosome/µL. This method was implemented successfully for the detection of exosomes in a serum sample. As the results show, the fabricated biosensor is capable of detecting exosomes for the early diagnosis of cancers.

Flexible electrochemical paper-based device for detection of breast cancer-derived exosome using nickel nanofoam 3D nanocomposite

“…Exosomes were puri ed from serum-free culture media of MCF-7 cell as described in the previous work [31]. Brie y, MCF-7 cells were grown in the culture medium of DMEM with penicillin/streptomycin (1%) without bovine serum for 72 h at 37°C and wet atmosphere (CO 2 5%).…”

“…Finally, to purify and separate PAA, it was washed with water and then centrifuged at 9000 rpm [34]. The details of the synthesis of carbon and silver inks and the preparation of the Ag/AgCl reference electrode have been described in detail in our previous work [31]. Then, 4 µL of AuNPs@rGO/Ninanofoam porous nanocomposite (5 mg/mL) was casted on the surface of the carbon working electrode.…”