科研之友
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摘要
To improve transfection efficiency and reduce the cytotoxicity of polymeric gene vectors, reducible polycations (RPC) were synthesized from low molecular weight (MW) branched polyethyleneimine (bPEI) via thiolation and oxidation. RPC (RPC-bPEI(0.8) (kDa)) possessed MW of 5 kDa-80 kDa, and 50%-70% of the original proton buffering capacity of RPC-bPEI(0.8) (kDa) was preserved in the final product. The cytotoxicity of RPC-bPEI0.8 (kDa) was 8-19 times less than that of the gold standard of polymeric transfection reagents, bPEI(25) (kDa). Although bPEI(0.8) (kDa) exhibited poor gene condensing capacities (similar to 2 mu m at a weight ratio (WR) of 40), RPC-bPEI(0.8) (kDa) effectively condensed plasmid DNA (pDNA) at a WR of 2. Moreover, RPC-bPEI(0.8) (kDa)/pDNA (WR >= 2) formed 100-200 nm-sized particles with positively charged surfaces (20-35 mV). In addition, the results of the present study indicated that thiol/polyanions triggered the release of pDNA from RPC-bPEI(0.8) (kDa)/pDNA via the fragmentation of RPC-bPEI(0.8) (kDa) and ion-exchange. With negligible polyplex-mediated cytotoxicity, the transfection efficiencies of RPC-bPEI(0.8) (kDa)/pDNA were approximately 1200-1500-fold greater than that of bPEI(0.8) (kDa)/pDNA and were equivalent or superior (similar to 7-fold) to that of bPEI(25) (kDa)/pDNA. Interestingly, the distribution of high MW RPC-bPEI0.8 (kDa)/pDNA in the nucleus of the cell was higher than that of low MW RPC-bPEI(0.8) (kDa)/pDNA. Thus, the results of the present study suggest that RPC-bPEI(0.8) (kDa) has the potential to effectively deliver genetic materials with lower levels of toxicity.
- 出版日期2011-2
