A new synthesis method and degradation of hyper-branched polyethylenimine grafted polycaprolactone block mono-methoxyl poly (ethylene glycol) copolymers (hy-PEI-g-PCL-b-mPEG) as potential DNA delivery vectors
✍ Scribed by Yu Liu; Juliane Nguyen; Terry Steele; Olivia Merkel; Thomas Kissel
- Book ID
- 104087926
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 714 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
Hyper-branched polyethylenimine grafted polycaprolactone block mono-methoxyl poly (ethylene glycol) copolymer (hy-PEI-g-PCL-b-mPEG) was obtained through the conjugation of mPEG-PCL with hyperbranched PEI (hy-PEI) based on the Michael addition. mPEG-PCL was synthesized by ring-opening polymerization of caprolactone using mPEG as the initiator. Compared earlier syntheses, this method offered a reduced number of reaction steps, milder reaction conditions, and a more efficient purification process. FTIR, 1 H NMR and 13 C NMR spectra proved the structure of the copolymers and controllability of this new synthesis method. Using 1 H NMR spectroscopy the degradation of these copolymers was evaluated. Cytotoxicity of copolymers and gene transfection efficiency of polyplexes displayed prominent composition dependence. Increasing the graft density of mPEG-PCL on hy-PEI and longer lengths of both PCL and mPEG within the copolymers investigated here reduced transfection and cytotoxicity on A549 cells. The hy-PEI-g-PCL-b-mPEG copolymers with very short PCL segments (342 Da and 570 Da) demonstrated 6-fold higher transfection efficiency than hy-PEI25k on A549 cells. The polyplexes of the most promising candidate, hy-PEI25k-g-(PCL570-b-mPEG2k) 1 , exhibited lower hemolysis compared to those of hy-PEI25k.