Magnetic nanoparticles (MNPs) are gaining importance in the biomedical field because of their versatility for various applications, ranging from diagnostic contrast imaging to tumor ablation through hyperthermia [1]. Their nanoscale dimensions enable superparamagnetic effects, which are crucial for efficient manipulation under external magnetic fields. However, achieving functional and sensitive measurements of MNPs properties remains challenging. This study addresses this gap by employing a gradiometer approach employing MNPs suitable for biofunctionalization application and considering a no-shielded setup for in-vivo application.