Design Analyses of Capillary Burst Valves in Centrifugal Microfluidics

Abstract

(a) P m (b) Fig. 1 This paper presents current research in analysis of passive microfluidic capillary burst valves. A capillary burst valve stops the liquid flow using a capillary pressure barrier that develops when the channel cross section expands abruptly. Valves of this type provide the capability of precise control on sample location in microfluidic device. Detailed numerical analyses of the valve behaviour is presented and compared with experimental measurements. A model for the valve is then extracted that characterizes the valve performance for various common cross sections.

Theoretical development and critical analysis of burst frequency equations for passive valves on centrifugal microfluidic platforms

“…5, the burst “rpm” decreases non-linearly when the hydraulic diameter of the channel, D h increases. This result is in agreement with the results from the literature by Zeng et al [30], Glière et al [11], and Chew et al [6]. …”

“…For comparison purposes, some results from the literature are summarized as follows: Zeng et al [30] showed that for a rectangular channel, the burst pressure increases when the hydraulic diameter is reduced from 250 to 36 μm. This translates to a decrease in burst “rpm” with an increase in hydraulic diameter.…”

“…While the 1D model describes capillary pressure in both, hydrophobic and hydrophilic valves, more complex 2D and 3D models address hydrophilic valves only [4, 16, 24]. Numerous variations of these 1D, 2D, and 3D models include modified 1D equations that consider the capillary pressure difference at the inlet and outlet of a channel [30, 32], modified 1D equations that take into account the heterogeneity of the channel surfaces [3, 8, 20, 22], and models that include the channel opening wedge angle β in the 1D equation [7, 11]. …”

Microfluidic Device for Rapid (<15 min) Automated Microarray Hybridization

“…Capillary valves contain the reagents in their specific reservoirs. The physical principle involved in capillary valves is based on the surface tension, which develops when the cross section of a hydrophilic capillary expands abruptly (26,27 ). The flow sequence is achieved by shifting the balance between the capillary forces and centrifugal pressure (28 ).…”

Vertical liquid transportation through capillary bundle structure using centrifugal force

“…2. The capillary bundle structure will form hydrophobic barriers which can apply to burst valves (Cho et al 2007;Chen et al 2008;Zeng et al 2000). Thus the filter sustains the liquids loaded from the first upper unit reservoir by the aide of surface tension.…”