There is an increasing demand for female fertility preservation. Cryopreservation of ovarian cortex tissue by means of vitrification can be done ad-hoc and for pre-pubertal individuals. Obtaining a homogeneous distribution of
protective agents in tissues is one of the major hurdles for successful preservation. Therefore, to rationally design vitrification strategies for tissues, it is needed to determine permeation kinetics of
cryoprotective agents; to ensure homogeneous distribution while minimizing exposure time and toxicity effects. In this study, Fourier transform infrared spectroscopy (FTIR) was used to monitor diffusion of different components into porcine ovarian cortex tissue. Water fluxes and permeation kinetics of
dimethyl sulfoxide (
DMSO),
glycerol (GLY),
ethylene glycol (EG), and
propylene glycol (PG) were investigated. Diffusion coefficients derived from FTIR data, were corroborated with differential scanning calorimetry and osmometer measurements. FTIR allowed real-time spectral fingerprinting of tissue during loading with mixtures of
protective agents, while discriminating between different components and water. Exposure to vitrification solutions was found to cause drastic initial
weight losses, which could be correlated with spectral features. Use of
heavy water allowed distinguishing water fluxes associated with
dehydration and permeation, both of which were found to precede permeation of
cryoprotective agents. Overall,
DMSO and EG were found to permeate faster than GLY and PG. In mixtures, however, solutes behave differently. The non-invasive spectroscopic method described here to study permeation of vitrification
solution components into ovarian tissue can be applied to many other types of engineered constructs, tissues, and possibly organs.