Chitosan-thiamine pyrophosphate as a novel carrier for siRNA delivery.
OBJECTIVE
A novel siRNA carrier was formulated between chitosan (CS) and thiamine pyrophosphate (TPP). Their ability to deliver siRNA were evaluated in stable and constitutive EGFP-expressing HepG2 cells.


METHODS
CS-TPP was prepared by dissolving CS in TPP solution at a CS:TPP molar ratio of 1.5:1. Complexes of CS-TPP/siRNA were formed at varying weight ratios and characterized using gel electrophoresis. Their morphologies and particle sizes were evaluated, and the transfection efficiency and cytotoxicity of CS-TPP/siRNA complexes were examined in stable and constitutive EGFP-expressing HepG2 cells.


RESULTS
Gel electrophoresis results indicated that binding of CS-TPP and siRNA depended on the molecular weight (MW) and weight ratio of CS, and the particle sizes of CS-TPP/siRNA complexes were in nano-size. The CS-TPP-mediated siRNA silencing of the endogenous EGFP gene occurred maximally with 70-73% efficiency. The CS-TPP/siRNA complex with the lowest MW of CS (20 kDa) at a weight ratio of 80 showed the strongest inhibition of gene expression, which was higher than Lipofectamine 2000. Over 90% the average cell viabilities of the complexes were observed by MTT assay.


CONCLUSIONS
This study suggests that CS-TPP is straightforward to prepare, safe and exhibits significantly improved siRNA delivery potential in vitro.
Rojanarata
Theerasak
T
Faculty of Pharmacy, Silpakorn University, Nakhonpathom, Thailand.
Opanasopit
Praneet
P
Techaarpornkul
Sunee
S
Ngawhirunpat
Tanasait
T
Ruktanonchai
Uracha
U
D002470:Cell Survival; D048271:Chitosan / Q000008:administration & dosage*; D004337:Drug Carriers; D006801:Humans; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics; D013835:Thiamine Pyrophosphate / Q000008:administration & dosage*; D014162:Transfection
D004337:Drug Carriers; D034741:RNA, Small Interfering; D048271:Chitosan; D013835:Thiamine Pyrophosphate