Carriers (lipid nanoparticles or AAV capsids) travel down a vessel toward
a target cell studded with surface receptors. Each carrier either gets
intercepted by patrolling immune cells, drifts past unbound, or binds a free
receptor and is endocytosed — releasing its CRISPR-Cas9 cargo, which is shown
editing the nuclear DNA with a bright flash.
P(bind) = receptor_density / (receptor_density + K_d)
P(clear) = immune_clearance_rate (checked before P(bind))
edit efficiency = cells_edited / particles_delivered
- Vehicle — LNPs bind more receptors per wave but are cleared faster; AAVs bind more selectively and evade clearance longer.
- Dose — number of carrier particles released per injection wave.
- Receptor density — how many binding sites the target cell displays; raises P(bind).
- Immune clearance — probability a carrier is intercepted by patrolling immune cells before it reaches the cell.
This mirrors the real trade-off in in vivo delivery: maximising binding
and minimising immune recognition are competing design goals for both LNP
and viral-vector platforms.