title: Chemical and structural modifications of RNAi therapeutics.
abstract: Small interfering RNA (siRNA), a 21-23nt double-stranded RNA responsible for post-transcriptional gene silencing, has attracted great interests as promising genomic drugs, due to its strong ability to silence target genes in a sequence-specific manner. Despite high silencing efficiency and on-target specificity, the clinical translation of siRNA has been hindered by its inherent features: poor intracellular delivery, limited blood stability, unpredictable immune responses and unwanted off-targeting effects. To overcome these hindrances, researchers have made various advances to modify siRNA itself and to improve its delivery. In this review paper, first we briefly discuss the innate properties and delivery barriers of siRNA. Then, we describe recent progress in (1) chemically and structurally modified siRNAs to solve their intrinsic problems and (2) siRNA delivery formulations including siRNA conjugates, polymerized siRNA, and nucleic acid-based nanoparticles to improve in vivo delivery.
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea.
authors.forename: Sook Hee
authors.initials: SH
authors.lastname: Ku
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea.
authors.forename: Sung Duk
authors.initials: SD
authors.lastname: Jo
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea.
authors.forename: Yeon Kyung
authors.initials: YK
authors.lastname: Lee
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea.
authors.forename: Kwangmeyung
authors.initials: K
authors.lastname: Kim
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea. Electronic address: sunkim@kist.re.kr.
authors.forename: Sun Hwa
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000818:Animals; D006801:Humans; D053758:Nanoparticles; D034622:RNA Interference; D034741:RNA, Small Interfering; D000067492:RNAi Therapeutics
chemical_list: D034741:RNA, Small Interfering
keywords: Chemical modification; RNA interference; Structural modification; siRNA; siRNA delivery