title: Recent advances of siRNA delivery by nanoparticles.
abstract: BACKGROUND
  The field of RNA interference technology has been researched extensively in recent years. However, the development of clinically suitable, safe and effective drug delivery vehicles is still required.
  
  
  METHODS
  This paper reviews the recent advances of non-viral delivery of small interfering RNA (siRNA) by nanoparticles, including biodegradable nanoparticles, liposomes, polyplex, lipoplex and dendrimers. The characteristics, composition, preparation, applications and advantages of different nanoparticle delivery strategies are also discussed in detail, along with the recent progress of non-viral nanoparticle carrier systems for siRNA delivery in preclinical and clinical studies.
  
  
  CONCLUSIONS
  Non-viral carrier systems, especially nanoparticles, have been investigated extensively for siRNA delivery, and may be utilized in clinical applications in the future. So far, a few preliminary clinical trials of nanoparticles have produced promising results. However, further research is still required to pave the way to successful clinical applications. The most important issues that need to be focused on include encapsulation efficiency, formulation stability of siRNA, degradation in circulation, endosomal escape and delivery efficiency, targeting, toxicity and off-target effects. Pharmacology and pharmacokinetic studies also present another great challenge for nanoparticle delivery systems, owing to the unique nature of siRNA oligonucleotides compared with small molecules.
authors.affiliation: Division of Pharmaceutical Sciences, Arnold & Marie Schwartz College of Pharmacy, Long Island University, 75 DeKalb Avenue, Brooklyn, NY 11201-5497, USA. xudong.yuan@liu.edu
authors.forename: Xudong
authors.initials: X
authors.lastname: Yuan
authors.forename: Sandy
authors.initials: S
authors.lastname: Naguib
authors.forename: Zhiqian
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000818:Animals; D002986:Clinical Trials as Topic; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D004337:Drug Carriers; D034741:RNA, Small Interfering