This paper reports an efficient method to measure fluid viscosity in microchannels using hydrodynamic diverging chamber and digital counting. A proposed microfluidic viscometer is designed to have two inlets for sampl...
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ISBN:
(纸本)9781424457618;9781424457649
This paper reports an efficient method to measure fluid viscosity in microchannels using hydrodynamic diverging chamber and digital counting. A proposed microfluidic viscometer is designed to have two inlets for sample as well as reference fluids, and a divergencing channel with 89 channels for digital counting. DI water and SDS solutions are used as a reference fluid and a sample fluid, respectively. The viscosities measured by the proposed microfluidic viscometer are compared with the ones measured by a commercially available viscometer (HAAKE MARS). The averaged deviation for four different viscosities measured by both viscometers is only about 2.5 %. Additionally, the microfluidic viscometer gives more consistent value, especially in low shear rate regime.
This paper presents a mechanical cell lysis microfluidic chip with an ultra-sharp nano-blade array fabricated by simple and cost effective crystalline wet etching of (110) silicon. The ultra-sharp nano-blade array is ...
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ISBN:
(纸本)9781424457618;9781424457649
This paper presents a mechanical cell lysis microfluidic chip with an ultra-sharp nano-blade array fabricated by simple and cost effective crystalline wet etching of (110) silicon. The ultra-sharp nano-blade array is simply formed by the undercutting during the crystalline wet etching process. The sharpness of the silicon nano-blade is less than 10 nm after the undercutting. EL4 mouse T-lymphoma cells are used for the demonstration of the mechanical lysis chip, and the cells are easily disrupted by the silicon nano-blade array without helping of additional reagents or electrical sources. The time-resolved observation of the mechanical cell lysis shows that the developed silicon nano-blade array is enough to easily disrupt the cell membrane even at very low flow rate of 0.7 ¿¿/hr.
In this paper, a novel microelectrical impedance spectroscopy (μEIS) with three-dimensional interdigitated electrodes (3D-IDE) is developed to differentiate normal and cancerous cells. The device utilizes a microflui...
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In this paper, a novel microelectrical impedance spectroscopy (μEIS) with three-dimensional interdigitated electrodes (3D-IDE) is developed to differentiate normal and cancerous cells. The device utilizes a microfluidic tunnel structure, which forces cells to be squeezed. Thus, the enlarged contact area between cells and electrodes allows the device to measure the intrinsic electrical signal of the cells with a higher sensitivity than a noncontact case. The cell squeezing is realized by fabricating smaller microfluidic channel than cell size. The electrical impedances are measured through 3D-IDE. The device well distinguishes normal human breast cell (MCF-10A) and early-stage human breast cancer cell (MCF-7) with a phase difference of 1.42° at 500 kHz. The proposed device also features a high repeatability because the phase change is as small as 0.27° (which is sufficiently smaller than the phase difference between normal and cancer cell) before and after the each cell assay.
Complicated and time-consuming cell purification processes prevent a micro cell lysis device from integrating with LOC (Lab-on-a-chip) or μ-TAS (μ-Total Analysis system) devices for cell analysis. In this paper, we ...
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We proposed a new method to measure the frequency-dependent attenuation of bio cells using piezoelectric ultrasonic transducer. The polyvinylidene fluoride (PVDF) polymer was employed as piezoelectric material to take...
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We proposed a new method to measure the frequency-dependent attenuation of bio cells using piezoelectric ultrasonic transducer. The polyvinylidene fluoride (PVDF) polymer was employed as piezoelectric material to take an advantage of its low acoustic impedance (2.7 Mrayl) so that the transmission of acoustic power will be improved by impedance matching with that of liquid medium. The thickness of PVDF film is 110 ¿m and the resonance frequency of the 1 st thickness mode is 8.7 MHz. In order to characterize the fabricated ultrasonic transducer, a transducer and an acoustic wave reflector were positioned face to face. The output voltage for reflected transmitted ultrasonic wave was measured with impulse method and was transformed into the Round Trip Insertion Loss (RTIL) where the dominant frequency ranges from 5 MHz to 9 MHz.
Contents and implementation of a computer laboratory for undergraduate electromagnetics are described. The laboratory consists of four 3-hour sessions covering vector calculus, Maxwell's equations (integral and di...
Contents and implementation of a computer laboratory for undergraduate electromagnetics are described. The laboratory consists of four 3-hour sessions covering vector calculus, Maxwell's equations (integral and differential forms), wave propagation in materials, and wave behavior at planar interfaces. Each session contains theory (in the Help file), animations (where relevant) and a quiz. The program runs on IBM compatible 486-based PCs in a Windows environment and uses the Borland C ++ 4.0 compiler.
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