title: Gateways for the intracellular access of nanocarriers: a review of receptor-mediated endocytosis mechanisms and of strategies in receptor targeting.
abstract: BACKGROUND
  The last 10 years have seen a dramatic growth in understanding and controlling how complex, drug-loaded (nano)structures, as well as pathogens, or biopharmaceuticals can gather access to the cytoplasm, which is a key step to increasing the effectiveness of their action.
  
  
  METHODS
  The review offers an updated overview of the current knowledge of endocytic processes; furthermore, the cell surface receptors most commonly used in drug delivery are here discussed on the basis of their reported internalization mechanisms, with examples of their use as nanocarrier targets taken from the most recent scientific literature.
  
  
  RESULTS
  Knowledge of molecular biology details is increasingly necessary for a rational design of drug delivery systems. Here, the aim is to provide the reader with an attempt to link a mechanistic knowledge of endocytic mechanisms with the identification of appropriate targets (internalization receptors) for nanocarriers.
  
  
  CONCLUSIONS
  Much advance is still needed to create a complete and coherent biological picture of endocytosis, but current knowledge already allows individuation of a good number of targetable groups for a predetermined intracellular fate of nanocarriers.
authors.affiliation: Ain Shams University, Department of Pharmaceutics, Faculty of Pharmacy, Monazamet El Wehda El Afrikia St, El Abbassia, Cairo, Egypt.
authors.forename: Noha M
authors.initials: NM
authors.lastname: Zaki
authors.forename: Nicola
authors.initials: N
authors.lastname: Tirelli
mesh_terms: D000818:Animals; D001692:Biological Transport; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004705:Endocytosis; D006801:Humans; D051379:Mice; D053758:Nanoparticles; D036103:Nanotechnology; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D004337:Drug Carriers; D011956:Receptors, Cell Surface