Imide-linked phthalocyanine-based covalent organic framework for electrochemical sensing of human epidermal growth factor receptor 2

In this work, we present the design of a novel aptasensor based on an imide-linked, phthalocyanine-derived covalent organic framework (Im-COF) for the electrochemical detection of human epidermal growth factor receptor 2 (HER2). The electrocatalyst (cobalt phthalocyanine-based Im-COF) employed is a two-dimensional (2D) layered material with strong π-π interactions and push-pull electronic effects that enhance signal generation. To the best of our knowledge, Im-COF is applied for the first time in HER2 electrochemical detection. HER2 detection was performed using differential pulse voltammetry (DPV) over the concentration of 2.0-40 pg mL^-1, enabling assessment of detection limits, selectivity, stability, repeatability and real-sample performance. Among the fabricated sensors, the GCE/Im-COF/Apt (Apt = aptamer) platform exhibited the lowest limit of detection (0.093 pg mL^-1) and the highest analytical sensitivity. Furthermore, the fabricated biosensor (GCE/Im-COF/Apt) further showed good stability, repeatability, selectivity and favourable applicability for real-sample analysis.