Droplet manipulation

An emulsion is a biphasic solution including dispersed small oil droplets in an aqueous phase. Because of the small channel size and high fluid velocity in micromixers, high shear force is applied to fluids, resulting in the generation of an emulsion in addition to enhancement of the mixing performance. The emulsion produced using micromixers has the characteristics of stability without surfadant. 

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Controlling Surface Wetting by Electrochemical Reactions of Monolayers and Applications for Droplet Manipulation... 

Some keywords for further reading on measurements of electrical properties using the SFM are pulsed-force mode [33, 404, 405], special SFM tips [406-409], lithography assisted by electric potentials [244, 254, 410-426], measurements of polarisation and water droplet manipulation [427-429] or reading and writing of ferroelectric domains and piezoactivity [393, 430-438]. 

D.-H. Lee, H. Hwang and J.-K. Park, Droplet manipulation using optically-induced dielectrophoresis in a chaimel-integrated optoelectronic tweezers, The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, November 1-5, 2009, Jeju Island, Korea. 

Automated droplet-based manipulation methods described in this article include electrowetting, dielectrophoretic, thermocapillary, surface acoustic wave (SAW), and pressure-driven channel-based droplet systems. Fabrication of arrays of elements to control these droplet manipulation methods typically involves the use of photolithography. The methods of addressing of the elements have become increasingly sophisticated with several efforts to utilize passive- and active-matrix control strategies. Trends and issues associated with each method are described. 

Perhaps the most well-developed droplet manipulation method is that of electrowetting. Electrowetting involves an electrostatic reduction of the contact angle of a sessile droplet or a droplet sandwiched between plates. If electrowetting is applied to one side of the droplet, translational motion can be induced. As shown in Fig. 1, the droplet will move to the activated electrode. Additionally, for droplets... 

Clearly, there has been substantial research into droplet formation and control methods. Although these droplet manipulation methods are critical to the development of Lab-on-a-Qiip systems, integration issues associated with the readout method for particular analytical techniques also represent significant challenges. Thus, in the following section, we describe the research findings associated with droplet Lab-on-a-Chip systems that implement real analytical methods. 

One unique advantage of the current droplet manipulation method is that the actuation can be continued even after a solidification reaction occurred inside a droplet. As shown in Fig. 6, not only a liquid droplet but also droplets containing solid precipitates or hydrogel and even a solid sphere can be actuated on the BCD system. The biochemical solidification reaction inside a droplet is demonstrated as the formation of a calcium carbonate crystal which is related to an in vitro study of biomineralization of marine organisms. When the Na2C03 and CaCla droplets are coalesced, by the BCD actuation of the coalesced droplet, the mixing and solidification reaction is accelerated and completed in... 

Gu SQ et al (2011) Multifunctional picoliter droplet manipulation platform and its application in single cell analysis. Anal Chem 83(19) 7570-7576... 

Acoustic droplet ejection Acoustic levitation of droplets Acoustic particle concentration Drop on demand Droplet manipulation Droplet transport by surface acoustic waves Radiation pressure Surface acoustic waves... 

Clearly, there has been substantial research into droplet formation and control methods. Although these droplet manipulation methods are critical to the development of Lab-on-Chip systems, integration issues associated with... 

Despites its simplicity in implementation, thermocapillary pumping was not fully exploited in tnicrofluidics research community. Thermocapillary may have a big impact in droplet-based digital microfluidics. Besides droplet transport, thermocapUlary force can be used for other droplet manipulation functions such as splitting, merging and dis-... 

Z. Wang, J. Zhe, Recent advances in particle and droplet manipulation for lab-on-a-chip devices based on surface acoustic waves. Lab on a Chip 11 (2011) 1280-1285. 

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