Electrohydrodynamic Generation and Delivery of Monodisperse Picoliter Droplets Using a Poly(dimethylsiloxane) Microchip

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• 作者：Sung Jae Kim ; Yong-Ak Song ; Paul L. Skipper ; Jongyoon Han
• 刊名：Analytical Chemistry
• 出版年：2006
• 出版时间：December 1, 2006
• 年：2006
• 卷：78
• 期：23
• 页码：8011 - 8019
• 全文大小：842K
• 年卷期：v.78,no.23(December 1, 2006)
• ISSN：1520-6882

文摘

We developed a drop-on-demand microdroplet generatorfor the discrete dispensing of biosamples into a bioanalytical unit. This disposable PDMS microfluidic devicecan generate monodisperse droplets of picoliter volumedirectly out of a plane sidewall of the microfluidic chip byan electrohydrodynamic mechanism. The droplet generation was accomplished without using either an insertedcapillary or a monolithically built-in tip. The minimumdroplet volume was ~4 pL, and the droplet generation wasrepeatable and stable for at least 30 min, with a typicalvariation of less than 2.0% of drop size. The Taylor cone,which is usually observed in electrospray, was suppressedby controlling the surface wetting property of the PDMSdevice as well as the surface tension of the sample liquids.A modification of the channel geometry right before theopening of the microchannel also enhanced the continuous droplet generation without applying any externalpumping. A simple numerical simulation of the dropletgeneration verified the importance of controlling thesurface wetting conditions for the droplet formation. Ourmicrodroplet generator can be effectively applied to adirect interface of a microfluidic chip to a biosensing unit,such as AMS, MALDI-MS or protein microarray-typebiochips.