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BioMed Research International
Volume 2013 (2013), Article ID 574136, 9 pages
Research Article

Chitosan Combined with Poly-L-arginine as Efficient, Safe, and Serum-Insensitive Vehicle with RNase Protection Ability for siRNA Delivery

Pharmaceutical Development of Green Innovations Group (PDGIG), Faculty of Pharmacy, Silpakorn University, Nakhon Pathom 73000, Thailand

Received 29 April 2013; Revised 5 June 2013; Accepted 5 June 2013

Academic Editor: Kamla Pathak

Copyright © 2013 Samarwadee Plianwong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Chitosan (CS) combined with poly-L-arginine (PLA) was formulated and evaluated for its performance to deliver siRNA to HeLa cells expressing enhanced green fluorescent protein (EGFP). Compared with the formulations using single polymer in which the polyplexes were completely formed at the weight ratio of >20 : 1 for CS/siRNA or 1 : 1 for PLA/siRNA, the combination of CS and PLA could reduce the amounts of the polymers required for the complete complexation with siRNA, thereby forming positively charged, nanosized polyplex at the weight ratio of CS/PLA/siRNA of 5 : 0.5: 1. In addition, while the transfection efficiency of CS/siRNA and PLA/siRNA was very low at physiological pH (7.4), CS/PLA/siRNA at the optimal weight ratio of 5 : 0.5 : 1 satisfactorily silenced the endogenous EGFP gene at pH 7.4 as well as at pH 6.4 without the deterrent effect from serum. The combined polymers could protect siRNA from RNase degradation over a period of at least 6 h. Furthermore, MTT assay results demonstrated that CS/PLA/siRNA complexes showed acceptably low cytotoxicity with 75% cell viability. Therefore, CS combined with PLA is easy to prepare, safe, and promising for use as an efficient siRNA delivery vehicle.