Degradation of methoxy-poly (ethylene glycol)-block-poly(α-carboxyl-ε-caprolactone)/magnetite nanocomposites in vitro polymer degradation and stability

Abstract Methoxy-poly (ethylene glycol)-block-poly (α-carboxyl-e-caprolactone)/Fe3O4 nanocomposites (mPEG-b-PCCL@Fe3O4) with spherical shape, more negative and smoother surface and core-sell structure were prepared by simply changing the solvent. Their degradation behavior was systematically investigated at 37 °C in distilled water and buffers with different pH values. The mPEG-b-PCCL micelles were used as the contrast. Although the acid inhibition and basic promoting degradation were observed for both mPEG-b-PCCL@Fe3O4 and micelles, the existence of magnetite nanoparticles (MNPs) and more surface –COOH slowed down the degradation of nanocomposites due to the dissociation hindrance of –COOH, the hydrophobicity and the cross-linking effects of MNPs. The degradation of mPEG-b-PCCL@Fe3O4 underwent the surface degradation at initial time and bulk degradation after complete swelling of the hydrophobic core. These investigations suggested that the degradation of mPEG-b-PCCL@Fe3O4 was more designable and controllable than that of micelles.