A dual-aptamer biosensor based on NPG for one-step and rapid HER2 detection in breast cancer

The poor biological stability of antibodies and significant steric hindrance in HER2 immune biosensors limit their sensitivity and stability. To address this challenge, a dual-aptamer electrochemical biosensor was developed to enable one-step and highly sensitive detection of the breast cancer biomarker HER2. Two aptamers respectively recognize different epitopes of HER2, forming a sandwich structure. And by introducing the electrochemical reporter Mb onto the electrode surface, an electric current signal related to the concentration of HER2 is generated. To further enhance the current response and improve the sensitivity of HER2 detection, the nano-porous gold (NPG) was modified onto the electrode surface to increase the specific surface area and reduce the resistance. This dual-aptamer biosensor has a very wide linear range (1 pg/mL–100 μg/mL) in HER2 detection, with a limit of detection (LOD) as low as 0.212 pg/mL. The dual-aptamer biosensor shows a selectivity of over 10 3 times for interfering substances such as CEA, Ki-67, IgG, and nucleic acids; the signal remains stable at 92.7% after being stored at 4 °C for 15 days, with RSDs of less than 5% for high, medium, and low concentrations. Based on the above results, this dual-aptamer biosensor meets the clinical requirements of high sensitivity, specificity, long-term storage and repeated detection. Moreover, it is simple to operate, fast, and low in cost, providing a potential tool for early screening of breast cancer, monitoring of treatment efficacy, and prognosis assessment. • Eliminates antibodies, improving biological stability and reducing steric hindrance. • Dual aptamers sandwich strategy offers LOD of 0.212 pg/mL and a linear range of 9 orders of magnitude. • NPG modification boosts surface area and conductivity of screen-printed electrodes, enhancing detection sensitivity. • One-step detection with RSD < 5%, suitable for serum screening and point-of-care testing.