title: Nanocarriers: a tool to overcome biological barriers in siRNA delivery.
abstract: BACKGROUND
  siRNA has poor in vivo stability and has a plasma half life of only a few minutes after intravenous administration. These problems can be overcome by conjugating/encapsulating siRNA with various nanosystems. Surface modifications of such nanosystems can further improve the cellular uptake of siRNA-nanosystems. In this review, the authors have highlighted the problems encountered in siRNA delivery, conjugation strategies and nanosystems for siRNA delivery and for improving their in vivo delivery performance.
  
  
  METHODS
  The authors briefly cover various problems encountered in siRNA delivery and discuss nanocarriers for overcoming these biological barriers.
  
  
  CONCLUSIONS
  siRNA binding and unpacking are important factors for optimizing the interactions between siRNA and nanosystems. Several crucial conjugation parameters, such as the conjugation site of siRNA, and the nature of molecules to be conjugated (charge, molecular weight and hydrophobicity), should be carefully considered for maximising delivery efficiency of siRNA conjugated nanosystems.
authors.affiliation: Council of Scientific and Industrial Research (CSIR), Institute of Himalayan Bioresource Technology, Biotechnology Division, Nanobiology Lab, Palampur-176061 (HP), India.
authors.forename: Avnesh
authors.initials: A
authors.lastname: Kumari
authors.forename: Vineet
authors.initials: V
authors.lastname: Kumar
authors.forename: Sudesh Kumar
authors.initials: SK
authors.lastname: Yadav
mesh_terms: D000818:Animals; D004337:Drug Carriers / Q000008:administration & dosage / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods / Q000639:trends; D018014:Gene Transfer Techniques / Q000639:trends*; D006801:Humans; D053758:Nanoparticles / Q000008:administration & dosage*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism
chemical_list: D004337:Drug Carriers; D034741:RNA, Small Interfering