Chitosan-Thiamine Pyrophosphate as a Novel Carrier for siRNA Delivery
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- Rojanarata, T., Opanasopit, P., Techaarpornkul, S. et al. Pharm Res (2008) 25: 2807. doi:10.1007/s11095-008-9648-6
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.
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.
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.
This study suggests that CS-TPP is straightforward to prepare, safe and exhibits significantly improved siRNA delivery potential in vitro.