EPR-Effect and Nano-medicine Backdoor or Bottleneck?

Cancers are a leading cause of death today as they will be in the future. Chemotherapy is one of the major weapons we have in the ill equipped battle against this important human threat. Despite several drawbacks, nanoparticle based drug delivery systems (DDS) hold promise to ameliorate anticancer chemotherapy. From the beginning of “Nano medicine” by the discovery of liposomes by Bangham et al. in 1965 [1] till the recent boost of papers about various new materials and combined strategies in the last decade, a vast number of chemotherapeutic agents has been loaded or encapsulated into different kinds of nanoparticles. Many approaches have been successfully tested, at least in preclinical studies [2]. Unfortunately, only very few “Nano medicines” are in clinical practice today, despite the fact that they accumulate in human tumors by the same mechanism as DDS do in animal models.