Ricerc@Sapienza

Aftermyocardial infarction, the heart’smechanical properties and its intrinsic capability to recover are
compromised.To improve this recovery, several groups have developed cardiac patches based on different
biomaterials strategies.Here, we developed polyvinylalcohol/dextran (PVA/Dex) elastic hydrogel patches,
obtained through the freeze thawing (FT) process, with the aimto deliver locally a potent natural
antioxidantmolecule, astaxanthin, and to assist the heart’s response against the generatedmyofibril stress.
Extensive rheological and dynamo-mechanical characterization of the effect of the PVAmolecularweight,
number of freeze-thawing cycles andDex addition on themechanical properties of the resulting hydrogels,
were carried out.Hydrogel systems based on PVA145 kDa andPVA47 kDablendedwithDex 40 kDa,
were chosen as themost promising candidates for this application. In order to improve astaxanthin
solubility, an inclusion system using hydroxypropyl-β-cyclodextrinwas prepared.This systemwas
posteriorly loadedwithin thePVA/Dex hydrogels. PVA145/Dex 1FT and PVA47/Dex 3FT showed the
best rheological and mechanical properties when compared to the other studied systems; environmental
scanning electronmicroscope and confocal imaging evidenced a porous structure of the hydrogels
allowing astaxanthin release. In vitro cellular behaviorwas analyzed after 24 h of contactwith astaxanthinloaded
hydrogels. In vivo subcutaneous biocompatibility was performed in rats using PVA145/Dex 1FT, as
the best compromise betweenmechanical support and astaxanthin delivery. Finally, ex vivo and in vivo
experiments showed goodmechanical and compatibility properties of this hydrogel.The obtained results
showed that the studiedmaterials have a potential to be used asmyocardial patches to assist infarcted heart
mechanical function and to reduce oxidative stress by the in situ release of astaxanthin.