Gradient generation by an osmotic pump and the behavior of human mesenchymal stem cells under the fetal bovine serum concentration gradient

Abstract

This paper describes a method to generate a concentration gradient using an osmosis-driven pump, without the need for bulky peripheral devices, such as an electric syringe pump or a pneumatic pump. By the osmosis, the flow in the microfluidic channel can be controlled even to a very slow speed (nanolitre scale), which enables its application to generate the stable and wide (width = 4 mm) concentration gradient profile, even within a short flow path. A computational simulation was also performed to predict the local distribution of the solute concentration and velocity-pressure profile in the microfluidic chip. The performance of the osmosis-driven pump was evaluated by culturing human mesenchymal stem cells within the concentration gradient of fetal bovine serum. The effects of the gradient on attachment, viability and morphology of the cells were analyzed and quantified. The cell density in a higher serum concentration region was twice greater than that in the pure culture media. The compact, cost-effective, self-powered and osmosis-based gradient generation system can be useful for biomedical and chemical applications.

Responses of endothelial cells to extremely slow flows

“…1͒. Flow was generated by osmotic pumps and the flow rate was controlled by altering concentrations of polyethylene glycol ͑PEG͒ ͑Sigma-Aldrich, St. Louis, MO͒ in aqueous solution: [14][15][16] briefly, PDMS cubic chambers ͑inner space of 5 ϫ 5 ϫ 5 mm͒ with a window of cellulose membrane ͑5 ϫ 5 mm, used as the osmotic membrane͒ were connected to tubing and filled with de-ionized ͑DI͒ water. An osmotic pressure was generated as a result of the solute differential between the inner chamber filled with water and the outer chamber filled with PEG solution, resulting in flow.…”

“…Here, we utilize a previously reported osmotic pump [14][15][16] to generate the required extremely slow flows over ECs attached to the surface of a microfluidic channel rather than embedded in hydrogels and analyze their responses; modeling the internal lumen of developing blood vessel. Slow flows with extremely low shear stresses ͑10 −2 −10 −4 dyn/ cm 2 ͒, which cover a diffusiondominant flow regime which is useful for evaluating the role of the indirect mechanism, were achieved and applied to the single layered endothelial cells.…”

Development and Applications of Microfluidic Devices for Cell Culture in Cell Biology

“…Chemical concentration gradients are regulated to control many basic cell functions and biological processes such as gene regulation (MAPK-mediated bimodal gene expression and adaptive gradient sensing in yeast), cancer metastasis [44,45] cellular chemotaxis [37,46] and migration [47,48], differentiation, development [49,50], immune response [51,52], wound healing [53,54] and embryogenesis [55].…”

Microfluidic Bioreactors for Cell Culturing: A Review

“…Murine embryonic stem cells [240] Control of soluble factors hMSCs [241] Culturing of stem cells in polyester conical microwells Murine embryonic stem cells, human hepatoblastoma [242] Comparison of Human mesenchymal stem cells (hMSCs) differentiation rate under different conditions hMSCs [243] Optimisation of embryoid bodies (EBs) formation in embryonic stem cells…”