A DNA nanostructured biosensor for electrochemical analysis of HER2 using bioconjugate of GNR@Pd SSs—Apt—HRP

•Three-dimensional DNA tetrahedron was utilized for the highly enhanced capture of breast cancer biomarker HER2.•The bioconjugate of GNR@Pd SSs—Apt—HRP together amplified the electrochemical signals significantly.•This biosensor exhibited a high detection specificity and sensitivity with a lower detection limit (0.15 ng mL-1) for HER2. Sensitive and accurate detection of human epidermal growth factor receptor 2 (HER2) can contribute to the clinical diagnosis and individual treatment of breast cancer. In this work, a DNA nanostructured biosensor was developed for electrochemical analysis of HER2 sensitively using the bioconjugate of gold nanorod@Pd superstructures—aptamer—horseradish peroxidase (GNR@Pd SSs—Apt—HRP) as the signal probe to realize signal amplification. We constructed a biosensing interface by immobilizing DNA tetrahedron with expanded aptamer, on the gold electrode to detect HER2 more efficiently and specifically. Besides, signal nanoprobe consisted of GNR@Pd SSs, aptamer and natural HRP was designed. The bioconjugate of GNR@Pd SSs—Apt—HRP was equipped with the functions of recognition with specificity and signal amplification based on enzymatic catalysis simultaneously. In virtue of aptamer, HER2 was discerned and caught to establish a DNA tetrahedron-HER2-nanoprobes sandwich-type structure on gold electrode surface. The developed biosensor exhibited limit of detection as low as 0.15 ng mL−1 toward HER2. Meanwhile, it delivered a wide range of linearity from 10 to 200 ng mL−1. The results prove that this proposed biosensor have the applicability and potential to develop powerful diagnostic tools for breast cancer in the future.