In the study, trastuzumab-modified curcumin nanoparticles (Anti-Cur NPs) functionalized screen printed electrode (SPE) was constructed for targeted BT-474 cells diagnosis as the cytosensing interface of a novel impedance cytosensor. Cur NPs with multifunctional properties were fabricated by the wet milling-solvent evaporation method to produce biologically compatible NPs without any further operation. Then, trastuzumab, which was selected for increasing nanocurcumin adherence affinity notably for cancer cells, was attached to the surface of Cur NPs. Based on the characterization studies, Anti-Cur NPs functionalized cytosensor displayed suitable surfaces due to hydrophilic, biocompatible, and targeted features where cancer cells could attach efficiently. The offered impedimetric diagnosis depended on the peculiar interaction between trastuzumab functional groups and HER-2 receptors which were highly overexpressed on breast cancer cells (BT-474). The findings revealed that the developed Anti-Cur NPs based platform enhanced the impedimetric signal and improved detection sensitivity for the BT-474 cells was attained in a vast linear range (1.0 × 102 – 8.0 × 104 cells mL−1) with a low detection limit (65 cells mL−1). Thus, the constructed cytosensor enabled impedance based monitoring of the cell behavior regarding the processes of cell attachment in a quantitative aspect with highly reproducible responses. Anti-Cur NP/SPE based cytosensor platform provided sensitive and fast measurement of the low amount of BT-474 cells in early diagnosis with an outstanding performance which was assigned to the well-defined and targeted nanocurcumin on the substrate.