title: Poly(α-glutamic acid) combined with polycation as serum-resistant carriers for gene delivery.
abstract: The transfection efficiency of cationic polymers decreases dramatically in the presence of serum, which hampers the in vivo application of these polymers for gene delivery. Due to its shielding effect of poly(alpha-glutamic acid) (PGA) from negatively charged serum proteins, it was introduced into DNA polyplexes to overcome the serum inhibitory effect. In the present studies, the transfection efficiency of DNA/PEI/PGA terplex system was compared to PEI 25 kDa and Lipofectamine 2000 in the presence of serum. The successful formation of DNA/PEI/PGA terplexes was confirmed by their near-neutral surface charge. Interaction between components in the terplex system demonstrated that PGA was competing with DNA to combine with PEI. PEI/PGA combined carriers were not cytotoxic at a C/N ratio higher than 0.3. The in vitro transfection efficiency of DNA/PEI/PGA terplexes was not significantly different from those of DNA/PEI25kDa in serum-free medium. Importantly, in serum-containing medium, the DNA terplexes at their optimal C/N ratios maintained the same level of transfection efficiency as that of serum-free medium, even though the transfection efficiency of PEI 25 kDa and Lipofectamine 2000 was significantly decreased under serum-containing conditions. CLSM results confirmed that the cellular import of pDNA delivered by PEI/PGA combined carriers was more efficient than PEI 25 kDa alone under serum-containing conditions. Therefore, PGA could be used as a versatile serum-resistant reagent to overcome the serum inhibitory effect of polycations for gene delivery.
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-sen University, University Town, Guangzhou 510006, PR China.
authors.forename: Cuifeng
authors.initials: C
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Feng
authors.forename: Jingjing
authors.initials: J
authors.lastname: Deng
authors.forename: Yuefang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xin
authors.initials: X
authors.lastname: Zeng
authors.forename: Lina
authors.initials: L
authors.lastname: Han
authors.forename: Shirong
authors.initials: S
authors.lastname: Pan
authors.forename: Chuanbin
authors.initials: C
authors.lastname: Wu
mesh_terms: D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry*; D018014:Gene Transfer Techniques; D006367:HeLa Cells; D006801:Humans; D011073:Polyamines / Q000008:administration & dosage / Q000737:chemistry*; D000071228:Polyelectrolytes; D011099:Polyglutamic Acid / Q000008:administration & dosage / Q000737:chemistry* / Q000235:genetics; D044967:Serum / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D011073:Polyamines; D000071228:Polyelectrolytes; D011099:Polyglutamic Acid