Photorelease of nitric oxide from Pluronic F127/chitosan hydrogels incorporating a water soluble ruthenium nitrosyl complex

In this paper, the NO donor trans-(Cl,Cl)-[Ru(FT)Cl2(NO)]Cl (Ru-NO) was incorporated in a Pluronic F127 (PL)-chitosan (CS) biocompatible hydrogel. Two concentrations were achieved (520 and 13 mu g g-1), resulting in hydrogels with sol-gel transition temperatures of around 36-38 degrees C, according to rheological studies. The presence of the Ru-NO complex did not significantly modify the thermal (DSC) and morphological (AFM) characteristics of the gels. For Ru-NO-embedded hydrogels, nitric oxide photorelease was evidenced at 400 nm. The quantum yield of photorelease was independent of the temperature at which the gel was maintained (25, 31, or 37 degrees C) and was found to be ca. 0.015. EPR as well as measurements using an electrochemical NO sensor also confirmed NO release upon light irradiation at 400 nm. In this paper, the NO donor trans-(Cl,Cl)-[Ru(FT)Cl2(NO)]Cl (Ru-NO) was incorporated in a Pluronic F127 (PL)-chitosan (CS) biocompatible hydrogel.