Label-Free Electrochemical Biosensor Based on Electrospun rGO/Ag/PANI Nanofibers for Sensitive Detection of HER2-Positive Breast Cancer Cells

Abstract

In this work, we present the development of a novel label-free electrochemical biosensor based on electrospun nanofibers composed of reduced graphene oxide (rGO), silver nanoparticles (AgNPs), and polyaniline (PANI) for the sensitive detection of HER2-overexpressing breast cancer cells. The rGO/Ag/PANI nanofibers were deposited onto a glassy carbon electrode (GCE), providing a highly conductive and biocompatible interface with a large surface area for antibody immobilization and efficient electron transfer. The sensor demonstrated a wide linear detection range from 10 to 10⁶ cells/mL and achieved an impressively low detection limit of 2 cells/mL for SK-BR3 cells (a HER2-positive breast cancer cell line), without the need for chemical labeling or signal amplification. The platform also showed high selectivity toward HER2-positive cells compared to HER2-negative controls. Recovery experiments in artificially spiked blood samples indicated >90% recovery, highlighting the sensor's robustness in complex biological environments under controlled in vitro conditions. Overall, the rGO/Ag/PANI-based nanofiber biosensor offers an effective strategy for rapid, label-free detection of target cancer cells in laboratory settings, and holds potential for further adaptation toward non-invasive diagnostic platforms following future clinical validation.