Lecture of Juan Santiago

Guest lecture at BIOS,

the Lab-on-a-Chip group

December 14^th: 15.30 PM

Room: B1224

Building: Hogekamp

Electrokinetic Microfluidics at

Extreme Scales

Juan G. Santiago

Department of Mechanical Engineering
Stanford University
Stanford, CA 94305-3030, USA
juan.santiago@stanford.edu

http://microfluidics.stanford.edu

Abstract—Microfabrication technology enables the application of electrokinetics as a method of performing chemical analyses and achieving liquid pumping in electronically-controlled microchip systems with no moving parts. We are exploring electrokinetic assays with extreme scales of length and charge density with a goal of achieving chips with new and optimized functionality. This talk reviews studies of isotachophoretic sample preconcentration and nanochannel electrophoresis at Stanford. We have optimized isotachophoresis and use leading-to-sample ion concentration ratios of order 10¹⁵ and local electric fields of 4 kV/cm to effect order one micron concentration shock waves and millionfold sample stacking in 120 s. We can detect as low as 100 attomolar sample concentrations, and can separate and detect unlabeled analytes. We are also studying and leveraging the unique separation modalities offered by nanoscale electrokinetic channels. We use 40 and 100 nm deep fused silica channels to independently measure mobility and valence of small ions. We also use these devices to separate 10 to 100 base pair DNA in the absence of a gel separation matrix.

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Home News & Highlights People Vacancies Research Education & Assignments Publications Intranet Internal Links External links Movies Sitemap Search	weblink \| News archive \| Archive Highlights \| Promotie film Ana Valero Lecture of Juan Santiago Guest lecture at BIOS, the Lab-on-a-Chip group December 14^th: 15.30 PM Room: B1224 Building: Hogekamp Electrokinetic Microfluidics at Extreme Scales Juan G. Santiago Department of Mechanical Engineering Stanford University Stanford, CA 94305-3030, USA juan.santiago@stanford.edu http://microfluidics.stanford.edu Abstract—Microfabrication technology enables the application of electrokinetics as a method of performing chemical analyses and achieving liquid pumping in electronically-controlled microchip systems with no moving parts. We are exploring electrokinetic assays with extreme scales of length and charge density with a goal of achieving chips with new and optimized functionality. This talk reviews studies of isotachophoretic sample preconcentration and nanochannel electrophoresis at Stanford. We have optimized isotachophoresis and use leading-to-sample ion concentration ratios of order 10¹⁵ and local electric fields of 4 kV/cm to effect order one micron concentration shock waves and millionfold sample stacking in 120 s. We can detect as low as 100 attomolar sample concentrations, and can separate and detect unlabeled analytes. We are also studying and leveraging the unique separation modalities offered by nanoscale electrokinetic channels. We use 40 and 100 nm deep fused silica channels to independently measure mobility and valence of small ions. We also use these devices to separate 10 to 100 base pair DNA in the absence of a gel separation matrix.