Journal: Sensors (Basel, Switzerland)

Article Title: Designing a Microfluidic Device with Integrated Ratiometric Oxygen Sensors for the Long-Term Control and Monitoring of Chronic and Cyclic Hypoxia

doi: 10.3390/s150820030

Figure Lengend Snippet: Oxygen control microfluidic device layout, showing 3-D and cross-sectional views of the device as well as the position of the integrated optical oxygen sensors within the cell culture channel. The cell culture channel (C) is surrounded on three sides by gas control channels (L1GL, L1GR, and L3G), with hydration/bubble removal channels (L1H, L2H) between each of the gas channels and the centre channel. Inset shows trapping structures for 3-D cell cultures within the cell culture channel. Please note that the 3-D view is not to scale (microfluidic layers are spaced farther apart in the illustration than in the device to permit visualization of the three layers). Cross-sectional view is to scale.

Article Snippet: The oxygen control microfluidic device was simulated using COMSOL ® Multiphysics.

Techniques: Control, Cell Culture

Journal: Sensors (Basel, Switzerland)

Article Title: Designing a Microfluidic Device with Integrated Ratiometric Oxygen Sensors for the Long-Term Control and Monitoring of Chronic and Cyclic Hypoxia

doi: 10.3390/s150820030

Figure Lengend Snippet: Simulated and experimental oxygen levels within the microfluidic device, at various rates of fluid flow in the cell culture channel and bubble removal/hydration channels (the same rate supplied to all three channels). ( a ) Simulation geometry, showing the region analyzed (a 2-D slice near the channel bottom, through the region of the channel designed to contain cell cultures: the “cell-containing channel region”), as well as the input oxygen conditions; ( b ) Simulated oxygen levels within the channel at 0 µL/min fluid flow. Average oxygen level in this region was 0.03%, while the maximum was 0.06%; ( c ) Simulated oxygen levels within the channel at 0.5 µL/min fluid flow. Average oxygen level in this region was 0.03%, while the maximum was 0.05%; ( d ) Simulated oxygen levels within the channel at 1 µL/min fluid flow. Average oxygen level in this region was 0.03%, while the maximum was 0.05%; ( e ) Simulated oxygen levels within the channel at 10 µL/min fluid flow. Average oxygen level in this region was 2.01%, while the maximum was 7.33%; ( f ) Simulated oxygen levels within the channel at 15 µL/min fluid flow. Average oxygen level in this region was 3.86%, while the maximum was 11.2%; ( g ) False-colour images of measured oxygen profiles near the chip inlet, at 0.5, 1, 10, and 15 µL/min fluid flow, overlaid upon a brightfield microscope image of the channel. Average oxygen levels in the sensor patch regions were 0.01%, 0.009%, 6.5%, and 9.9% at 0.5, 1, 10, and 15 µL/min fluid flow, respectively.

Article Snippet: The oxygen control microfluidic device was simulated using COMSOL ® Multiphysics.

Techniques: Cell Culture, Microscopy

Journal: Sensors (Basel, Switzerland)

Article Title: Designing a Microfluidic Device with Integrated Ratiometric Oxygen Sensors for the Long-Term Control and Monitoring of Chronic and Cyclic Hypoxia

doi: 10.3390/s150820030

Figure Lengend Snippet: Oxygen gradient formation within the microfluidic oxygen control device. ( a ) Microfluidic channel setup for gradient measurement. L1GL was supplied with 10.34% oxygen, while L1GR and L3G were supplied with 0%; ( b ) Oxygen gradient measured inside the cell culture channel by the in situ sensors, after ~10 min equilibration. The plot shows the oxygen level vs. the position across the width of the cell culture channel ( i.e. , in the direction between L1GL and L1GR).

Article Snippet: The oxygen control microfluidic device was simulated using COMSOL ® Multiphysics.

Techniques: Control, Cell Culture, In Situ

Journal: Sensors (Basel, Switzerland)

Article Title: Designing a Microfluidic Device with Integrated Ratiometric Oxygen Sensors for the Long-Term Control and Monitoring of Chronic and Cyclic Hypoxia

doi: 10.3390/s150820030

Figure Lengend Snippet: Simulated and experimental oxygen equilibration times within the multilayer microfluidic device. ( a ) Time-dependent simulation results, showing the oxygen level at the centre of the cell culture channel after the oxygen level supplied to the gas control channels L1GL, L1GR, and L3G was switched from O 2 start to 0% at time 60 s, for values of O 2 start ranging from 7.33% to 21%, and flow rates Q ranging from 0 to 1 µL/min. Neither the O 2 start nor Q significantly affected the equilibration curves (e.g., the oxygen level at time 530 s only varied by 0.3% of O 2 start between all of the simulations, with the flow rate showing no effect on the curves, and the curves for O 2 start = 7.33% and 21% reaching 0.5% and 0.2% of O 2 start , respectively at t = 530 s); ( b ) Simulation and measurement of the oxygen levels within the oxygen control device, after the input gas level changed from 7.33% to 0% oxygen at time 1 min. System shows equilibration to less than 0.5% of the initial oxygen level within 530 s.

Article Snippet: The oxygen control microfluidic device was simulated using COMSOL ® Multiphysics.

Techniques: Cell Culture, Control