Dual-modal MRI phantom with tunable iron deposition via coaxial electrospinning for neuroimaging validation

Reliable phantoms for validating diffusion tensor imaging (DTI) and T2/T2* mapping are crucial for standardizing neuroimaging, especially in the context of iron-related neurodegeneration. Here, a novel dual-functional MRI phantom is developed using coaxial electrospinning to embed Fe3O4 nanoparticles within polycaprolactone (PCL) microfibres. The resulting hollow, axon-mimicking fibres exhibit tunable magnetic and mechanical properties that simulate iron deposition in neural tissue. The phantom's architecture and Fe3O4 concentration modulate fractional anisotropy, mean diffusivity, and relaxation times, effectively recapitulating MRI signatures observed in diseases like Alzheimer’s and Parkinson’s. Comprehensive physicochemical characterization confirms structural fidelity, thermal behaviour, and anisotropic mechanical response. Crucially, the phantom enables simultaneous DTI and T2/T2* imaging under clinical MRI protocols, offering a standardized, reproducible platform for imaging validation and harmonization. This multifunctional approach bridges a critical gap in quantitative neuroimaging and presents a new class of intelligent biomaterials for MRI system calibration and pathology modelling.