TY - JOUR
T1 - The impact of long term freezing on the mechanical properties of porcine aortic tissue
AU - O'Leary, Siobhan A.
AU - Doyle, Barry J.
AU - McGloughlin, Tim M.
N1 - Copyright © 2014 Elsevier Ltd. All rights reserved.
PY - 2014/9
Y1 - 2014/9
N2 - Background: Preservation of the native artery[U+05F3]s functionality can be important in both clinical and experimental applications. Although, simple cryopreservation techniques offer an attractive solution to this problem, the extent to which freezing affects the tissue[U+05F3]s properties is widely debated. Earlier assessments of the mechanical properties post-freezing have been limited by one or more of the following: small sample numbers, uncontrolled inter-specimen/animal variability, failure to account for the impact of potential errors in thickness measurements, short storage times and uniaxial test methods. Material and methods: Biaxial mechanical tests were performed on porcine aortic samples (n=89) extracted from superior, middle and inferior regions of five aortas, stored in isotonic saline at -20°C for 1 day, 1 week, 1, 6 and 12 months, thawed and retested. The sample[U+05F3]s weight and thickness were also measured pre and post-freezing. A total of 178 tests were performed and elastic modulus was assessed by calculating the slope of the Cauchy stress-stretch curve at the low and high stretch regions in both the circumferential (θ) and longitudinal (L) directions. Results: The weight of the samples increased post-freezing. However, in general, no significant difference was found between the elastic modulus of porcine aortic tissue before and after freezing at -20°C and was unaffected by storage time. Although more accurate measuring instruments are warranted to confirm this finding, minor changes to the elastic modulus as a result of freezing were negatively correlated with regional variances i.e. changes in the elastic modulus decreased from the superior to the inferior region. Conclusions: These results indicate that for applications which require preservation of the gross mechanical properties, storing the tissue at -20. °C in isotonic saline, for an extended period of time, is acceptable.
AB - Background: Preservation of the native artery[U+05F3]s functionality can be important in both clinical and experimental applications. Although, simple cryopreservation techniques offer an attractive solution to this problem, the extent to which freezing affects the tissue[U+05F3]s properties is widely debated. Earlier assessments of the mechanical properties post-freezing have been limited by one or more of the following: small sample numbers, uncontrolled inter-specimen/animal variability, failure to account for the impact of potential errors in thickness measurements, short storage times and uniaxial test methods. Material and methods: Biaxial mechanical tests were performed on porcine aortic samples (n=89) extracted from superior, middle and inferior regions of five aortas, stored in isotonic saline at -20°C for 1 day, 1 week, 1, 6 and 12 months, thawed and retested. The sample[U+05F3]s weight and thickness were also measured pre and post-freezing. A total of 178 tests were performed and elastic modulus was assessed by calculating the slope of the Cauchy stress-stretch curve at the low and high stretch regions in both the circumferential (θ) and longitudinal (L) directions. Results: The weight of the samples increased post-freezing. However, in general, no significant difference was found between the elastic modulus of porcine aortic tissue before and after freezing at -20°C and was unaffected by storage time. Although more accurate measuring instruments are warranted to confirm this finding, minor changes to the elastic modulus as a result of freezing were negatively correlated with regional variances i.e. changes in the elastic modulus decreased from the superior to the inferior region. Conclusions: These results indicate that for applications which require preservation of the gross mechanical properties, storing the tissue at -20. °C in isotonic saline, for an extended period of time, is acceptable.
KW - Aortic tissue
KW - Biaxial testing
KW - Cryopreservation
KW - Freezing
KW - Long term storage
KW - Mechanical properties
KW - Preservation
KW - Vascular
UR - http://www.scopus.com/inward/record.url?scp=84902202650&partnerID=8YFLogxK
U2 - 10.1016/j.jmbbm.2014.04.015
DO - 10.1016/j.jmbbm.2014.04.015
M3 - Article
C2 - 24922621
AN - SCOPUS:84902202650
SN - 1751-6161
VL - 37
SP - 165
EP - 173
JO - Journal of the Mechanical Behavior of Biomedical Materials
JF - Journal of the Mechanical Behavior of Biomedical Materials
ER -