Ultrasensitive direct impedimetric immunosensor for detection of serum HER2

Assesment of human epidermal growth factor receptor 2 status is a key factor prompting definitive treatment decisions that help in reducing mortality rates associated with breast cancer. In this article, highly sensitive and low-cost impedimetric immunosensor using single-chain fragment variable antibody fragments was developed for quantitative detection of human epidermal growth factor receptor 2 from serum employing gold nanoparticle-modified disposable screen-printed carbon electrodes. The gold nanoparticles facilitate fast electron transfer and offer a biocompatible surface for immobilization of small antibody fragments in an oriented manner, resulting in improved antigen binding efficiency. The single-chain fragment variable antibody fragment-modified screen printed immunosensor exhibits wide dynamic range of 0.01-100 ng mL−1 and detection limit of 0.01 ng mL−1. The advantages offered by this platform in terms of high sensitivity, broad dynamic range and low-cost demonstrates great potential for improved monitoring of human epidermal growth factor receptor 2 levels for the management of breast and other cancers.