Permeation of dimethyl sulfoxide into articular cartilage at subzero temperatures

Abstract

Abstract:Osteochondral allografting has been proved to be a useful method to treat diseased or damaged areas of joint surfaces. Operational long-term stocks of grafts which supply a buffer between procurement and utilization would contribute to the commercialization or industrialization of this technology. Vitrification has been thought to be a promising method for successful preservation of articular cartilage (AC), but high concentration cryoprotectants (CPAs) are used which may cause high cellular toxicity. An effective way to reduce CPA toxicity is to increase CPA concentration gradually while the temperature is lowered. Understanding the mechanism of CPA permeation at subzero temperatures is important for designing the cryopreservation protocol. In this research, the permeation of dimethyl sulfoxide (Me 2 SO) in ovine AC at subzero temperatures was studied experimentally. Pretreated AC discs were exposed in Me 2 SO solutions for different time (0, 5, 15, 30, 50, 80, and 120 min) at three temperature levels (−10, −20, and −30 °C). The Me 2 SO concentration within the tissue was determined by ultraviolet (UV) spectrophotometry. The diffusion coefficients were estimated to be 0.85×10 −6 , 0.48×10 −6 , and 0.27×10 −6 cm 2 /s at −10, −20, and −30 °C, respectively, and the corresponding activation energy was 29.23 kJ/mol. Numerical simulation was performed to compare two Me 2 SO addition protocols, and the results demonstrated that the total loading duration could be effectively reduced with the knowledge of permeation kinetics.

Numerical Study of Heat and Mass Transfer during Cryopreservation Process with Application of Directed Interval Arithmetic

“…It is also important to know the interval extracellular and intracellular concentrations, which are described by the following interval equations [ 13 , 14 , 15 , 18 , 22 , 27 , 40 , 41 ]: where is the interval diffusion coefficient, is the cell volume (the superscript 0 represents the initial moment of simulation), is the osmotically inactive volume of cells (for chondrocytes it is equal to 0.41 ), where is the isotonic volume of cells. The interval normalized cell volume is defined: …”

“…Cryopreservation by slow freezing [ 9 ] and by vitrification [ 10 , 11 , 12 ] can both be analyzed. These models are considered not only for articular cartilage [ 12 , 13 , 14 , 15 , 16 ] but also for other biological tissues or cells, such as stem cells [ 9 , 17 , 18 ].…”

“…The microscale mass transfer model should be supplemented by the following analyses: mass transport in the extracellular matrix and thermal processing in the tissue. The model of mass transport at the macroscale is based on Fick’s second law, which provides for a concentration at a given time associated with diffusion [ 10 , 12 , 13 , 14 , 15 , 16 , 33 ]. The temperature distribution is determined from the Fourier equation [ 9 , 10 , 11 , 13 , 14 ].…”

Numerical Modeling of Heat and Mass Transfer during Cryopreservation Using Interval Analysis

“…Models representing cryopreservation by slow freezing [23] and vitrification [12,24,25] have been created. Different biological tissues and cells such as stem cells [23,26,27] and articular cartilage [25,[28][29][30][31] have been analyzed.…”

“…The mass transport modeling during cryopreservation is divided into: (1) macroscale flow and (2) cell-level transfer. To model the mass transfer phenomenon on a macroscale, Fick's second law is used, which determines the local concentration over time caused by diffusion [12,25,[28][29][30][31]45]. Sometimes, Fick's second law is complemented by a velocity vector, which is defined by, e.g., the Navier-Stokes equation [11,17,34,46].…”