Non-survival rat endovascular testbed for early-stage evaluation of untethered magnetic microrobots

Early-stage in vivo evaluation of microrobot navigation controllability and acute device-tissue interaction remains methodologically underdeveloped. In vitro and ex vivo approaches often fail to balance technological readiness, physiologic relevance, and reproducibility. To address this gap, here we present a non-survival, acute in vivo endovascular testbed in the rat inferior vena cava (IVC). Rat IVC supports studying microrobots with characteristic sizes of 0.1-4 mm and integrates key methodological components, including vascular access, continuous blood flow, anticoagulation strategies, fluoroscopic imaging guidance, and acute in vivo performance benchmarking. The testbed enables systematic assessment of minimum viable in vivo performance metrics for early-stage endovascular microrobots, including image-guided navigation success rate, traversal time, path deviation, acute vessel interaction, deployment/retrieval and device integrity. Common failure modes and practical troubleshooting strategies are provided to support reproducibility across laboratories. The non-survival design is a deliberate methodological choice that isolates acute, engineering-relevant performance while avoiding confounding long-term biological responses. Accordingly, the protocol addresses questions of early design feasibility and control performance but does not evaluate chronic biocompatibility or therapeutic efficacy. By establishing a reproducible intermediate validation stage, this testbed de-risks subsequent survival and large-animal studies in translational microrobot development.