Currently, cardiovascular diseases (CVDs) are the leading cause of death globally. According to the WHO, the number of CVDs-related deaths increases by 20% annually. C-reactive protein (CRP), a biomarker for CVDs that sharply rises during cardiac events, was used to monitor these critical conditions at an early stage. To address the need for highly sensitive, selective, and portable CRP detection, a nickel-doped copper ferrite nanoparticle-based electrochemical biosensor was developed. In this work, optimized nickel-doped copper ferrite (Ni