Degradation of Hyper-Branched Poly(ethylenimine)-graft-poly(caprolactone)-block-monomethoxyl-poly(ethylene glycol) as a Potential Gene Delivery Vector
✍ Scribed by Yu Liu; Terry Steele; Thomas Kissel
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 426 KB
- Volume
- 31
- Category
- Article
- ISSN
- 1022-1336
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✦ Synopsis
Abstract
Water‐soluble hyper‐branched poly(ethylenimine)‐graft‐poly(caprolactone)‐block‐monomethoxyl‐poly(ethylene glycol) cationic copolymers (hy‐PEI‐PCL‐mPEG) have shown potential for gene delivery. The degradation behavior of this type of copolymer is studied. Effects of the molecular weight of the hyper‐branched PEI (hy‐PEI), and the length of the mPEG and PCL blocks are investigated. The degradation is mainly monitored by the changes of molecular weight by GPC‐MALLS. The molecular weight changes of the copolymers in different aqueous solutions have been characterized as a function of incubation time at 37°C from 0 to 45 d. The micelle size and pH value have also been recorded accordingly to monitor the degradation in water. The investigation reveals that copolymers containing hy‐PEI2k degrade faster than others containing hy‐PEI10k and hy‐PEI25k based on the same mPEG‐PCL block, while copolymers those contain mPEG5k degrade faster than those containing mPEG2k and mPEG0.55k based on the same PCL segments and hy‐PEI. An inhibitory effect of acidic conditions and acceleration in basic media have been found for degradation in different buffers. A higher ionic strength of the buffer accelerated the degradation. The molecular weight of copolymer is reduced to 95% within one day with 10 mg·mL^−1^ of lipase while 70% remains with 5 mg·mL^−1^ of lipase. These investigations suggest that the degradation of hy‐PEI‐PCL‐mPEG can be designed and the degradation period is reasonable for gene‐transfer in vivo.
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