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A pH-sensitive multifunctional gene carrier assembled via layer-by-layer technique for efficient gene delivery

Authors Li, Liu D, Miao, Liu, Sun, Liu Y, Zhang N

Received 7 October 2011

Accepted for publication 24 November 2011

Published 21 February 2012 Volume 2012:7 Pages 925—939


Review by Single anonymous peer review

Peer reviewer comments 3

Peng Li, Donghua Liu, Lei Miao, Chunxi Liu, Xiaoli Sun, Yongjun Liu, Na Zhang

School of Pharmaceutical Science, Shandong University, Jinan, Shandong, People’s Republic of China

Background: The success of gene therapy asks for the development of multifunctional vectors that could overcome various gene delivery barriers, such as the cell membrane, endosomal membrane, and nuclear membrane. Layer-by-layer technique is an efficient method with easy operation which can be used for the assembly of multifunctional gene carriers. This work describes a pH-sensitive multifunctional gene vector that offered long circulation property but avoided the inhibition of tumor cellular uptake of gene carriers associated with the use of polyethylene glycol.
Methods: Deoxyribonucleic acid (DNA) was firstly condensed with protamine into a cationic core which was used as assembly template. Then, additional layers of anionic DNA, cationic liposomes, and o-carboxymethyl-chitosan (CMCS) were alternately adsorbed onto the template via layer-by-layer technique and finally the multifunctional vector called CMCS-cationic liposome-coated DNA/protamine/DNA complexes (CLDPD) was constructed. For in vitro test, the cytotoxicity and transfection investigation was carried out on HepG2 cell line. For in vivo evaluation, CMCS-CLDPD was intratumorally injected into tumor-bearing mice and the tumor cells were isolated for fluorescence determination of transfection efficiency.
Results: CMCS-CLDPD had ellipsoidal shapes and showed “core-shell” structure which showed stabilization property in serum and effective protection of DNA from nuclease degradation. In vitro and in vivo transfection results demonstrated that CMCS-CLDPD had pH-sensitivity and the outermost layer of CMCS fell off in the tumor tissue, which could not only protect CMCS-CLDPD from serum interaction but also enhance gene transfection efficiency.
Conclusion: These results demonstrated that multifunctional CMCS-CLDPD had pH-sensitivity, which may provide a new approach for the antitumor gene delivery.

Keywords: layer-by-layer, multifunctional nanovector, pH-sensitivity, gene delivery

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