Hydrogen sulfide-releasing micelles for promoting angiogenesis.

Hydrogen sulfide (HS), an important gaseous signalling molecule in the human body, has been shown to be involved in many physiological processes such as angiogenesis. Since the biological activities of HS are known to be significantly affected by the dose and exposure duration, the development of HS delivery systems that enable control of HS release is critical for exploring its therapeutic potential. Here, we prepared polymeric micelles with different HS release profiles, which were prepared from amphiphilic block copolymers consisting of a hydrophilic poly(-acryloyl morpholine) segment and a hydrophobic segment containing HS-releasing anethole dithiolethione (ADT) groups. The thermodynamic stability of the micelles was modulated by altering the ADT content of the polymers. The micelles with higher thermodynamic stability showed significantly slower HS release. Furthermore, the sustained HS release from the micelles enhanced migration and tube formation in human umbilical vein cells (HUVECs) and induced vascularlization in the chick chorioallantoic membrane (CAM) assay.