Monitoring the quality of frozen-thawed venous segments using bioimpedance spectroscopy

Abstract

Objective: Storage at temperatures as low as −80 °C and below (cryopreservation) is considered a method for long-term preservation of cells and tissues, and especially blood vessel segments, which are to be used for clinical operations such as transplantation. However, the freezing and thawing processes themselves can induce injuries to the cells and tissue by damaging the structure and consequently functionality of the cryopreserved tissue. In addition, the level of damage is dependent on the rate of cooling and warming used during the freezing-thawing process. Current methods for monitoring the viability and integrity of cells and tissues after going through the freezing-thawing cycle are usually invasive and destructive to the cells and tissues. Therefore, employing monitoring methods which are not destructive to the cryopreserved tissues, such as bioimpedance measurement techniques, is necessary. In this study we aimed to design a bioimpedance measurement setup to detect changes in venous segments after freezing-thawing cycles in a noninvasive manner. Approach: A bioimpedance spectroscopy measurement technique with a two-electrode setup was employed to monitor ovine jugular vein segments after each cycle during a process of seven freezing-thawing cycles. Main results: The results demonstrated changes in the impedance spectra of the measured venous segments after each freezing-thawing cycle. Significance: This indicates that bioimpedance spectroscopy has the potential to be developed into a novel method for non-invasive and non-destructive monitoring of the viability of complex tissue after cryopreservation.

Decellularization of Porcine Carotid Arteries: From the Vessel to the High-Quality Scaffold in Five Hours

“…According to that study, saline (which we used as our storage solution in this study) did not produce such strong damage related to mitochondria, cytoplasm, and nuclear structure in endothelial cells of rat aortas ( Neil et al, 2002 ). Still, in our case, this mild damage could have an effect on easier accessibility of detergents into cells than that of the cells of vessels that were cryopreserved immediately after explantation and fast-thawed to avoid cell damage by ice crystal formation ( Amini et al, 2020 ). Moreover, we observed high variability in the content of elastic fibers between individual animals, which can also contribute to the different levels of decellularization, disregarding the storage conditions.…”

“…The FN samples were kept at 4°C for storage/transport and used within 3 h from the explant. The CN specimens were thawed in a water bath at 37°C for 10 min to reduce the damage due to potential recrystallization inside the cells ( Amini et al, 2020 ). The arteries were allowed to assimilate to room temperature for 20 min before starting the mechanical measurement.…”