DC-biased AC-electroosmotic and AC-electrothermal flow mixing in microchannels. Lab Chip 9:802-809

Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 3 Research Link, Singapore 117602.
Lab on a Chip (Impact Factor: 6.12). 04/2009; 9(6):802-9. DOI: 10.1039/b813639d
Source: PubMed


This paper presents a novel approach of mixing two laminar flowing streams in microchannels. The mixer consists of a pair of electrodes disposed along a fluidic channel. By energizing the electrodes with a DC-biased (2.5 V) AC voltage (20 Vpp), an electrokinetic flow is induced with a flow profile perpendicular to that of the incoming laminar streams of liquids to be mixed. As a result, the flow lines of the incoming streams and the induced flow are forced to crossover and very efficient stirring and mixing at short mixing length can be achieved. The mixer can be operated from the AC-electroosmotic (ACEO) (sigma=1 mS/m, f=100 kHz) to the AC-electrothermal (ACET) (sigma=500 mS/m, f=500 kHz) flow regimes. The mixing efficiency in the ACEO regime was 92%, with a mixing length of 600 microm (Q=2 microL/min), an estimated mixing time of 69 ms and an induced ACEO flow velocity of approximately 725 microm/s. The mixing efficiency in the ACET regime was 65% for a mixing length of approximately 1200 microm. The mixer is efficient and suitable for mixing reagents in a fluid media from low to high conductivity as required in diverse microfluidic applications.

1 Follower
29 Reads
  • Source
    • "One of the well-known passive micromixers is the staggered herringbone mixer (SHM), which was proposed by Stroock et al. (2002). In the past, the SHM was investigated in Williams et al. (2008), Du et al. (2010), Choudhary et al. (2011), Kang et al. (2008), Kee and Gavriilidis (2008), Xu et al. (2011), Liu et al. (2004) and optimized in Mott et al. (2006), Cortes-Quiroza et al. (2009, 2010), Ansari and Kim (2007, 2008), Lynn and Dandy (2007), Song et al. (2008), Lee and Voldman (2007), Hossain et al. (2010). Cortes-Quiroza et al. conducted one of the latest shape optimization works for the SHM (Cortes- Quiroza et al. 2009, 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper discusses a flexible layout design method of passive micromixers based on the topology optimization of fluidic flows. Being different from the trial and error method, this method obtains the detailed layout of a passive micromixer according to the desired mixing performance by solving a topology optimization problem. Therefore, the dependence on the experience of the designer is weaken, when this method is used to design a passive micromixer with acceptable mixing performance. Several design disciplines for the passive micromixers are considered to demonstrate the flexibility of the layout design method for passive micromixers. These design disciplines include the approximation of the real 3D micromixer, the manufacturing feasibility, the spacial periodic design, and effects of the Péclet number and Reynolds number on the designs obtained by this layout design method. The capability of this design method is validated by several comparisons performed between the obtained layouts and the optimized designs in the recently published literatures, where the values of the mixing measurement is improved up to 40.4% for one cycle of the micromixer.
    Biomedical Microdevices 06/2012; 14(5):929-45. DOI:10.1007/s10544-012-9672-5 · 2.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nanotubes and nanowires have sparked considerable interest in biosensing applications due to their exceptional charge transport properties and size compatibility with biomolecules. Among the various biosensing methodologies incorporating these nanostructured materials in their sensing platforms, liquid-gated field-effect transistors (LGFETs)-based device configurations outperform the conventional electrochemical measurements by their ability in providing label free, direct electronic read-out, and real-time detection. Together with integration of a microfluidic channel into the device architecture, nanotube- or nanowires-based LGFET biosensor have demonstrated promising potential toward the realization of truly field-deployable self-contained lab-on-chip devices, which aim to complement the existing lab-based methodologies. This review addresses the recent advances in microfluidic-integrated carbon nanotubes and inorganic nanowires-based LGFET biosensors inclusive of nanomaterials growth, device fabrication, sensing mechanisms, and interaction of biomolecules with nanotubes and nanowires. Design considerations, factors affecting sensing performance and sensitivity, amplification and multiplexing strategies are also detailed to provide a comprehensive understanding of present biosensors and future sensor systems development. KeywordsBiosensor-Carbon nanotubes-Nanowires-Label-free detection-Field-effect transistor
    Microfluidics and Nanofluidics 12/2010; 9(6):1185-1214. DOI:10.1007/s10404-010-0640-1 · 2.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Electrokinetic phenomena originally developed in colloid chemistry have drawn great attention in micro- and nano-fluidic lab-on-a-chip systems for manipulation of both liquids and particles. Here we present an overview of advances in electrokinetic phenomena during recent decades and their various applications in micro- and nano-fluidics. The advances in electrokinetics are generally classified into two categories, namely electrokinetics over insulating surfaces and electrokinetics over conducting surfaces. In each category, the phenomena are further grouped according to different physical mechanisms. For each category of electrokinetics, the review begins with basic theories, and followed by their applications in micro- and/or nano-fluidics with highlighted disadvantages and advantages. Finally, the review is ended with suggested directions for the future research.
    Microfluidics and Nanofluidics 09/2012; 13(2). DOI:10.1007/s10404-012-0971-1 · 2.53 Impact Factor
Show more


29 Reads
Available from