Supercritical carbon dioxide-based sterilization of decellularized heart valves.
OBJECTIVE
The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization.


BACKGROUND
Aortic tissue grafts have been utilized to repair damaged or diseased valves. Although, the tissues for grafting are collected aseptically, it does not eradicate the risk of contamination nor disease transfer. Thus, sterilization of grafts is mandatory. Several techniques have been applied to sterilize grafts; however, each technique shows drawbacks. In this study, we compared several sterilization techniques: supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide for impact on the sterility and mechanical integrity of porcine decellularized aortic valves.


METHODS
Valve sterility was characterized by histology, microbe culture, and electron microscopy. Uniaxial tensile testing was conducted on the valve cusps along their circumferential orientation to study these sterilization techniques on their integrity.


RESULTS
Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile. The tensile strength of supercritical carbon dioxide treated valves (4.28 ± 0.22 MPa) was higher to those valves treated with electrolyzed water, gamma radiation, ethanol-peracetic acid and hydrogen peroxide (1.02 ± 0.15, 1.25 ± 0.25, 3.53 ± 0.41 and 0.37 ± 0.04 MPa, respectively).


CONCLUSIONS
Superior sterility and integrity were found in the decellularized porcine aortic valves with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues.


CONCLUSIONS
Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile using histology, microbe culture and electron microscopy assays. The cusp tensile properties of supercritical carbon dioxide treated valves were higher compared to valves treated with other techniques. Superior sterility and integrity was found in the decellularized valves treated with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues.
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Ryan S
RS
Hennessy
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Soumen
S
Jana
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Brandon J
BJ
Tefft
Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN.
Meghana R
MR
Helder
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Melissa D
MD
Young
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Rebecca R
RR
Hennessy
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Nicholas J
NJ
Stoyles
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Amir
A
Lerman
Decontamination; decellularized; heart valve; tensile properties; tissue engineering