A Washing-Free and Easy-to-Operate Fluorescent Biosensor for Highly Efficient Detection of Breast Cancer-Derived Exosomes

Abstract

Traditional detection methods for protein tumor markers in the early screening of breast cancer are restricted by complicated operation procedures and unstable reproducibility. As one of alternative emerging tumor markers, exosomes play an important role in diagnosing and treating cancers at the early stage due to traceability of their origins and great involvement in occurrence and development of cancers. Herein, a washing-free and efficient fluorescent biosensor has been proposed to realize simple and straightforward analysis of breast cancer cell-derived exosomes based on high affinity aptamers and G quadruplex-hemin (G4-hemin). The whole reaction process can be completed by several simple steps, which realizes washing-free and labor-saving. With simplified operation procedures and high repeatability, the linear detection range for this developed fluorescent biosensing strategy to breast cancer cell-derived exosomes is from 2.5 × 105 to 1.00 × 107 particles/ml, and the limit of detection is down to 0.54 × 105 particles/ml.

Advancements and Clinical Significance of Breast Cancer Exosome Detection

“…Fluorescence-based assay techniques combine the high specificity of aptamers with the excellent fluorescence catalytic performance of G4-hemin to detect HER2 protein, enabling quantitative detection of exosomes through fluorescent signal output. The linear detection range for breast cancer cell-derived exosomes is 2.5 × 10 5 to 1.00 × 10 7 particles/mL, with a detection limit of 0.54 × 10 5 particles/mL [43]. Additionally, a fluorescence aptamer sensor based on aggregation-induced emission luminogens (AIEgens) and graphene oxide (GO) has been used to analyze three tumorassociated proteins (EpCAM, EGFR, and HER2) on exosomes from breast tumor plasma samples.…”

Recent developments in isolating methods for exosomes

“…For example, Zhang et al (2022b) performed label-free detection of PD-L1 in exosomes based on the surface plasmon resonance biochip (SPR-ExoPD-L1) to provide effective information for the diagnosis and treatment of cancer. Either a fluorescent biosensor (Chen et al, 2022) or a ROX-labeled aptamer (ROX-Apt) assembled on the surface of MoS2-AuNSs specifically bound to CD63 can be used to detect exosomes (Pan et al, 2022).…”

Paper-based biosensors as point-of-care diagnostic devices for the detection of cancers: a review of innovative techniques and clinical applications

“…Addition of tyramine causes the formed G4-hemine complex to generate a fluorescent signal using H2O2. The fluorescence intensity allows quantitative detection of exosomes (90,91). An et al investigated the short-term changes in exosomal protein levels before treatment, after chemotherapy (gemcitabine-based chemotherapy), and in the middle of chemoradiotherapy in locally advanced pancreatic cancer to find potential biomarkers of response to treatment.…”