title: Erythrocytes-based synthetic delivery systems: transition from conventional to novel engineering strategies.
abstract: BACKGROUND
  Erythrocytes (red blood cells [RBCs]) and artificial or synthetic delivery systems such as liposomes, nanoparticles (NPs) are the most investigated carrier systems. Herein, progress made from conventional approach of using RBC as delivery systems to novel approach of using synthetic delivery systems based on RBC properties will be reviewed.
  
  
  METHODS
  We aim to highlight both conventional and novel approaches of using RBCs as potential carrier system. Conventional approaches which include two main strategies are: i) directly loading therapeutic moieties in RBCs; and ii) coupling them with RBCs whereas novel approaches exploit structural, mechanical and biological properties of RBCs to design synthetic delivery systems through various engineering strategies. Initial attempts included coupling of antibodies to liposomes to specifically target RBCs. Knowledge obtained from several studies led to the development of RBC membrane derived liposomes (nanoerythrosomes), inspiring future application of RBC or its structural features in other attractive delivery systems (hydrogels, filomicelles, microcapsules, micro- and NPs) for even greater potential.
  
  
  CONCLUSIONS
  In conclusion, this review dwells upon comparative analysis of various conventional and novel engineering strategies in developing RBC based drug delivery systems, diversifying their applications in arena of drug delivery. Regardless of the challenges in front of us, RBC based delivery systems offer an exciting approach of exploiting biological entities in a multitude of medical applications.
authors.affiliation: CSIR-Central Drug Research Institute, Pharmacokinetics & Metabolism Division , B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031 , India +91 522 2771940 Ext-4853 ; +91 522 2771941 ; rabi_bhatta@cdri.res.in , rabi.cdri@gmail.com.
authors.forename: Manisha
authors.initials: M
authors.lastname: Bhateria
authors.forename: Ramakrishna
authors.initials: R
authors.lastname: Rachumallu
authors.forename: Rajbir
authors.initials: R
authors.lastname: Singh
authors.forename: Rabi Sankar
authors.initials: RS
authors.lastname: Bhatta
mesh_terms: D060846:Cell Engineering; D016503:Drug Delivery Systems; D004912:Erythrocytes / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D008081:Liposomes; D053758:Nanoparticles; D013194:Staining and Labeling / Q000379:methods
chemical_list: D008081:Liposomes
keywords: liposomes; nanoerythrosomes; nanoparticles; polymeric multilayered microcapsules; red blood cells