Development and Stability of a New Brain Phantom for Leachables Screening from Deep Brain Stimulations Probes

Abstract Implantable medical devices must meet biocompatibility requirements before clinical use, making the profiling of extractables and leachables crucial for assessing risks. Although guidelines outline methods for identifying extractables, they lack guidance on the monitoring of leachables. This study evaluates the stability of a brain phantom stored at 37 °C for 180 days for leachables monitoring. White matter (WM) and gray matter (GM) components, creating an emulsion‐gel with cholesterol, agar, and carboxymethylcellulose, are separated. Homogeneity is assessed using polydispersity index (PDI), and stability is investigated using Young's modulus (YM), rheological behavior, and apparent diffusion coefficient of water (ADCs) immediately after preparation and after 180 days of storage. PDI values are 0.258 ± 0.009 for WM and 0.362 ± 0.008 for GM. YM values are 2.32 ± 0.14 kPa for WM and 1.11 ± 0.11 kPa for GM. Dynamic viscosities are 16.62 ± 6.36 kPa s for WM and 5.99 ± 2.79 kPa s for GM at 0.1 rad s⁻¹. ADCs are 1130 ± 64 µm² s⁻¹ for WM and 1449 ± 34 µm² s⁻¹ for GM. All parameters remain within physiological range during 180 days at 37 °C. Comparison with clinical data is necessary to validate this medium for leachable studies.