Endocytosis,the mechanism by which live cells internalize exogenous substances,is thought to be a key step in drug or gene delivery.For eliciting better therapeutic effect,it is necessary to elucidate the pathways for the carrier overcoming the cell membrane barrier and figure out its specific intracellular target.Further,the understanding of in vivo biological behavior is another fundamental aspect.Rod-like viral nanoparticles such as tobacco mosaic virus and bacteriophages have recently attracted extensive research interest in biomedical applications,such as magnetic resonance imaging,gene delivery and tissue regeneration.