bioprosthetic materials , either natural or synthetic , are treated with trivalent aluminum cations to prevent in vivo calcification . such bioprosthetic materials include porcine aortic valve leaflets , bovine pericardium , aortic homografts , biocompatible elastomers , and the like which are intended for invasive , or in - dwelling use in a human or animal body . simple incubation of the natural bioprosthetic materials in an aluminum ion - containing solution , such as aqueous alcl 3 , prior to implantation has been found to inhibit calcification of the biomaterial over a prolonged period and to do so without adverse side effects . incorporation of an aluminum - containing compound into the formulation for polymers , such as polyurethane , has also been found to inhibit calcification with no adverse side effects .