| Microfluidics community has tremendously grown over a decade and impacted several fields including biology, analytical chemistry, drug delivery, clinical diagnostics and many more. Using small sample volumes provides cost effectiveness and high throughput. There exists variety of lab-on-chip devices that perform discrete set of tasks such as dispensing, mixing, incubating, separation, etc. Integration of different components into a general purpose device presents substantial challenges in terms of materials and fabrication methods. Traditional 1:1 mixers cannot easily perform variable volume mixing due to built in architectures and rely on flow rate adjustments and channel geometries to achieve diverse mixing ratios. We have presented a general purpose monolithic PDMS device for variable volume mixing. Several bio-assays (glucose detection, PCR, etc) and analytical chemistry applications (enzyme kinetics, etc.) require mixing in various ratios. Also presence of air bubbles deteriorates mixing efficiency. An efficient degassing scheme and mixing protocol has been developed in the following work which allows homogeneous mixing of two or more fluids in different ratios. In the end, a cascaded mixing scheme for extreme ratios is demonstrated for serial dilution applications. |
