low-cost-3d-printed-microfluidic-devices-for-rapid-prototyping

Low-Cost 3D-Printed Microfluidic Devices for Rapid Prototyping and Biological Applications

Microfluidic devices offer precise control over solution mixing and gradient generation, essential for cell-based assays in cryobiology and biomedical ...

University of Saskatchewan

Maintenance of cells within a volume range compatible with their functional integrity is a critical determinant of cell survival after cryopreservation, and quantifying this osmotically induced damage is a part of the rational design of improved cryopreservation protocols. The degree that cells tolerate osmotic stress significantly impacts applicable cryoprotocols, but there has been little research on the time dependence of this osmotic stress. Additionally, the flavonoid silymarin has been shown to be hepatoprotective. Therefore, here we test the hypotheses that osmotic damage is time-dependent and that flavonoid inclusion reduces osmotic damage. In our first experiment, cells were exposed to a series of anisosmotic solutions of graded hypo- and hypertonicity for 10-40 min, resulting in a conclusion that osmotically induced damage is time dependent. In the next experiment, adherent cells preincubated with silymarin at the concentration of 10 mol/L and 10 mol/L showed a significant increase in cell proliferation and metabolic activity after osmotic stress compared to untreated matched controls. For instance, when adherent cells preincubated with 10 mol/L silymarin were tested, resistance to osmotic damage and a significant increase (15%) in membrane integrity was observed in hypo-osmotic media and a 22% increase in hyperosmotic conditions. Similarly, significant protection from osmotic damage was observed in suspended HepG2 cells in the presence of silymarin. Our study concludes that osmotic damage is time dependent, and the addition of silymarin leads to elevated resistance to osmotic stress and a potential increase in the cryosurvival of HepG2 cells.

Silymarin mediated osmotic responses and damage in HepG2 cell suspensions and monolayers.

Monitoring cellular processes across different levels of complexity, from the cellular to the tissue scale, is important for understanding tissue structure and function. However, it is challenging to monitor and estimate these structural and dynamic interactions within three-dimensional (3D) tissue models.

Multiscale transport and 4D time-lapse imaging in precision-cut liver slices (PCLS).

This study challenges the conventional belief that animal cell membranes lack a significant hydrostatic gradient, particularly under anisotonic conditions, as demonstrated in the human hepatoma cell line HepG2. The Boyle van't Hoff (BvH) relation describes volumetric equilibration to anisotonic conditions for many cells. However, the BvH relation is simple and does not include many cellular components such as the cytoskeleton and actin cortex, mechanosensitive channels, and ion pumps. Here we present alternative models that account for mechanical resistance to volumetric expansion, solute leakage, and active ion pumping. We found the BvH relation works well to describe hypertonic volume equilibration but not hypotonic volume equilibration. After anisotonic exposure and return isotonic conditions cell volumes were smaller than their initial isotonic volume, indicating solutes had leaked out of the cell during swelling. Finally, we observed HepG2 cells undergo regulatory volume decrease at both 20 °C and 4 °C, indicating regulatory volume decrease to be a relatively passive phenomenon and not driven by ion pumps. We determined the turgor-leak model, which accounts for mechanical resistance and solute leakage, best fits the observations found in the suite of experiments performed, while other models were rejected.

Article	Year
Silymarin mediated osmotic responses and damage in HepG2 cell suspensions and monolayers. Cryobiology\| PubMed ID: 37301358	2023
Multiscale transport and 4D time-lapse imaging in precision-cut liver slices (PCLS). PeerJ\| PubMed ID: 38426134	2024
HepG2 cells undergo regulatory volume decrease by mechanically induced efflux of water and solutes. Biomechanics and modeling in mechanobiology\| PubMed ID: 39012455	2024

Iqra Azam

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