Peptide-Guided Assembly of Silver Nanoparticles for the Diagnosis of HER2-Positive Breast Cancer

Peptide-engineered nanoparticles have great potential for biomedical research and application. In this work, we have designed and fabricated an electrochemical biosensor based on peptide-guided assembly of silver nanoparticles (AgNPs), in which a peptide is endowed with dual functions to recognize target and guide assembly of AgNPs. As a proof of concept, the performance of this biosensor is validated by quantifying human epidermal growth factor receptor 2 (HER2) protein. In detail, the end of the HER2-specific binding peptide is grafted with a positively charged peptide, which can guide the orderly assembly of AgNPs, while electrochemical signals can be obtained through phosphine-silver coordination. Using this electrochemical biosensor, HER2 protein can be quantified with high sensitivity and specificity, and the limit of detection can be as low as 0.05 pg/mL. Moreover, the antifouling electrode surface prepared by the modification of a layer of antifouling zwitterionic peptide allows this biosensor to be used for the detection of serum HER2 protein from breast cancer patients, which provides the clear evidence for the distinction of HER2+ breast cancer patients and HER2- breast cancer patients.