AAV Vector Biodistribution: Liver Sequestration vs Target Delivery

Adeno-associated virus (AAV) capsids are re-used as delivery shells in gene therapy, and where an injected dose actually ends up is decided by receptor-driven tissue tropism, not by where the clinician aims the needle. This simulator injects a pool of vector particles into a simplified circulatory network — liver, skeletal muscle, heart and CNS hanging off a shared circulation hub, the CNS wrapped in a translucent blood-brain-barrier shell — and lets each particle recirculate, pass by pass, until a serotype-specific receptor-binding probability captures it, the kidneys/immune system clear it, or it keeps circulating. Switching capsid serotype changes those per-organ binding odds; switching the injection route between systemic (IV) and local (direct) changes whether the liver gets first exposure at all, illustrating the central dose-limiting problem in real AAV gene therapy: hepatic sequestration of high-affinity serotypes.