Surface Tension Triggered Wetting and Point of Care Sensor Design
| Autor: | Eric J. Falde, Mark W. Grinstaff, Stefan T. Yohe |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Glycerol
Maximum bubble pressure method Materials science Polymers Point-of-Care Systems Polyesters Biomedical Engineering Pharmaceutical Science Nanotechnology Surface finish Article Bile Acids and Salts Biomaterials Contact angle Surface tension Surface-Active Agents Pulmonary surfactant Animals Surface Tension Composite material chemistry.chemical_classification Polymer Surface energy Milk chemistry Wettability Wetting |
| Zdroj: | Advanced Healthcare Materials. 4:1654-1657 |
| ISSN: | 2192-2640 |
| Popis: | The wetting of a solid surface by a liquid is a common but intriguingly complex phenomenon.[1–3] The surface chemistry and topology as well as the pH, ionic strength, and additives in the liquid can affect the degree to which a surface is wetted - with minute changes often having significant effects. In fact, the wetting of materials with high surface roughness is especially sensitive to the surface tension of liquids with which they are in contact.[4,5] With the knowledge that changes in the surface tensions of biological fluids are indicators of medical conditions,[6–8] we hypothesize that a sensor could be designed that switches between wetted and non-wetted states with liquids of a specific surface tension. Specifically, we report a sensor based on a two-layer electrospun polymer mesh composed of a top responsive layer that responds to small changes in liquid surface tension to form a wetted or non-wetted material, and the bottom hydrophilic indicator layer that reveals a color change when wetted to aid visualization, as shown in Figure 1. Electrospun meshes of varying fiber diameters, pore sizes, and polymer compositions were fabricated to alter the surface free energy. If the solid-air and solid-liquid interfacial surface tensions are similar, a small change in liquid surface tension can cause a transition from a high apparent contact angle, heterogeneously wetted state (Cassie-Baxter state) to complete, homogenous wetting (Wenzel state),[4,5] which is the basis for the sensitivity of our system. Changes in both the liquid-air and liquid-solid interfacial tensions contribute to this effect, and both are lowered as surfactant levels increase. As prototypical examples, two sensors are prepared and evaluated to detect surface tension changes in human breast milk fat (45–48 mN/m) and urinary bile acid levels (50–54 mN/m), of interest for ensuring adequate nutrition to infants and for detecting chronic liver disease, respectively. |
| Databáze: | OpenAIRE |
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