Publications by authors named "Jodie C Tokihiro"
Trigger valves are fundamental features in capillary-driven microfluidic systems that stop fluid at an abrupt geometric expansion and release fluid when there is flow in an orthogonal channel connected to the valve. The concept was originally demonstrated in closed-channel capillary circuits. We show here that trigger valves can be successfully implemented in open channels.
View Article and Find Full Text PDFCell-laden hydrogel constructs suspended between pillars are powerful tools for modeling tissue structure and physiology, though current fabrication techniques often limit them to uniform compositions. In contrast, tissues are complex in nature with spatial arrangements of cell types and extracellular matrices. Thus, we present Suspended Tissue Open Microfluidic Patterning (STOMP), which utilizes a removable, open microfluidic patterning channel to pattern multiple spatial regions across a single suspended tissue.
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- Trigger valves are essential components in microfluidic systems that control fluid flow by stopping it at expansions and allowing release through connected channels.
- This study successfully implements trigger valves in open channels and demonstrates how multiple valves can create layered capillary flow alongside main channels.
- A model for flow dynamics at these valves was developed and validated, with implications for applications in biosensing, sample preparation, hydrogel patterning, and organ-on-a-chip technologies.
Sperm cryopreservation is important for many individuals across the globe. Recent studies show that vitrification is a valuable approach for maintaining sperm quality after freeze-thawing processes and requires sub-microliter to microliter volumes. A major challenge for the adoption of vitrification in fertility laboratories is the ability to pipette small volumes of sample.
View Article and Find Full Text PDFThe true value of the contact angle between a liquid and a solid is a thorny problem in capillary microfluidics. The Lucas-Washburn-Rideal (LWR) law assumes a constant contact angle during fluid penetration. However, recent experimental studies have shown lower liquid velocities than those predicted by the LWR equation, which are attributed to a velocity-dependent dynamic contact angle that is larger than its static value.
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- The research focuses on improving capillary pumping by exploring two main methods: creating capillary channels with high pressures and utilizing absorbing materials like paper pads.
- The combination of capillary tree networks (which resemble tree branches) with paper pads enhances fluid movement by mimicking natural leaf structures.
- The study demonstrates that this system achieves impressive flow rates using different viscous liquids, surpassing traditional capillary trees, with sustained high velocities for extended periods.
The true value of the contact angle between a liquid and a solid is a thorny problem in capillary microfluidics. The Lucas-Washburn-Rideal (LWR) law assumes a constant contact angle during fluid penetration. However, recent experimental studies have shown lower liquid velocities than predicted by the LWR equation, which are attributed to a velocity-dependent dynamic contact angle that is larger than its static value.
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