Flow characteristics of polar liquids in microfluidic immunosensors

Autor: Siddhartha Panda, Ramchander Chepyala
Rok vydání: 2013
Předmět:
Zdroj: Microfluidics and Nanofluidics. 16:729-741
ISSN: 1613-4990
1613-4982
DOI: 10.1007/s10404-013-1257-y
Popis: There is an interest in microfluidic devices for disease detection. In microfluidic immunosensors, the microchannel surfaces are functionalized with a stack of intermediate linker molecules to the specific antibodies. The efficiency of these immunosensors depends on the effective capture of antigens flowing in the carrier fluid by the surface-immobilized antibodies. The diffusion of these antigens to these antibody-immobilized surfaces is governed by the velocity profile, which in turn is governed by the interaction of the carrier fluid molecules with the surface antibodies. We report a systematic study to characterize fluid flow of different polar liquids (water, methanol and isopropyl alcohol) in trapezoidal Si microchannels, of about 100 μm hydraulic diameter, functionalized with intermediate molecular layers along with three different antibodies immobilized via these molecular layers. The friction constants were calculated from the pressure drop measurements. We attempted to understand the solid–liquid interactions in terms of the friction constants as a function of the solid surface free energies of the terminal antibody layers (which are affected by the energetics of the underlying layers) immobilized on to the microchannels, and the polarities of the liquids flowing through these microchannels. Correlations of liquid polarities with the friction constants were seen for almost all the functionalized surfaces. A reasonable correlation of the surface energies with the friction constants was seen for most of the surfaces studied. Possible reasons for the behaviors are discussed. The measured friction constants and the knowledge of the solid–liquid interactions could facilitate improved designs of microfluidic immunosensors.
Databáze: OpenAIRE
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