pH responsive micelles based on copolymers mPEG-PCL-PDEA: The relationship between composition and properties

Polymeric micelles with pH response are considered as promising drug carriers for cancer therapy. In this study, copolymers methoxy-poly (ethylene glycol)-b-poly (ε-caprolactone)-b-poly (diethylaminoethyl methacrylate) (mPEG-PCL-PDEA) were designed and synthesized to investigate the relationship between number of pH responsive units and micelle properties. The structures of these copolymers were characterized by nuclear magnetic resonance, Fourier transform infrared, gel permeation chromatograph, differential scanning calorimetry and water contact angle. The micelles of the copolymers were obtained, the micelle properties were studied by critical micellization concentration, micelle size, morphology, pH response, cytotoxicity and drug loading/release. Moreover, dissipative particle dynamics (DPD) was used to investigate the structure of the micelles under different pH. The results showed that the micelle properties including pH sensitivity, cytotoxicity and drug loading/releasing performance, were related to PDEA units in copolymers. So, mPEG-PCL-PDEA micelles with suitable composition are promising as drug carriers due to their high pH sensitivity, low cytotoxicity and good drug loading/releasing performance.