Abstract
A facile method is presented for achieving comprehensive two-dimensional droplet manipulations in closed microstructures consisting of microwell arrays and a straight microchannel. In this method, picoliter/nanoliter droplets with controllable sizes and numbers are sampled from nanoliter samples/reagents with almost 100% efficiency. Droplet motions are precisely controlled in the ±X-direction and ±Y-direction by managing hydrostatic pressure and magnetic repulsion, respectively. As a demonstration, a fluorescein-labeled droplet and a deionized droplet are successively generated and trapped in adjacent microwells. Then their positions are quickly exchanged without cross-contamination and fusion is implemented on-demand. After operations, hydrophobic ferrofluid can be completely replaced by mineral oil and droplets still remain in microwells safely. A typical fluorescence intensity-based assay is demonstrated: droplet arrays containing copper ion are diluted disproportionately first and then detected by addition of droplet arrays containing Calcein. With the ability of comprehensive two-dimensional droplet manipulations, this method could be used in various miniaturized biochemical analyses including requirements of multistep procedures and in situ monitoring.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 8029-34 |
| Number of pages | 6 |
| Journal | Analytical Chemistry |
| Volume | 83 |
| Issue number | 20 |
| DOIs | |
| State | Published - Oct 15 2011 |
Keywords
- Copper
- Dimethylpolysiloxanes
- Fluorescein
- Fluoresceins
- Ions
- Microarray Analysis
- Microfluidic Analytical Techniques
- Mineral Oil
- Nanotechnology