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Parametric analysis of a novel semi-circular microfluidic CD-ELISA valve.

Lin SI - J Biol Eng (2011)

Bottom Line: Together with supporting experiments, simulation based on two-phase flow theory is used in this study, and the feasibility of this novel valve design is confirmed.From both the experimental results and the simulated results, it is evident that the narrowest channel width and the contact angle are the primary factors influencing valve burst frequency.These can be used as the main controlling factors during the design.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Power Mechanical Engineering, National Formosa University, Taiwan. samlin7@ms41.hinet.net.

ABSTRACT
CD-ELISA uses the microfluidic ranking method and centrifugal force to control the testing solution as it flows into the reaction region. The most challenging part of CD-ELISA is controlling the flow process for different biological testing solutions, i.e. the controlling sequence for the microfluidic channel valves. The microfluidic channel valve is therefore the most important fluid channel structure for CD-ELISA. In this study, we propose a valve design suitable for a wide range rotational speeds which can be applied for mass production (molding). Together with supporting experiments, simulation based on two-phase flow theory is used in this study, and the feasibility of this novel valve design is confirmed. Influencing design factors for the microfluidic channel valves in CD-ELISA are investigated, including various shapes of the arc, distance d, radius r, the location of the center of the circle, and the contact angle. From both the experimental results and the simulated results, it is evident that the narrowest channel width and the contact angle are the primary factors influencing valve burst frequency. These can be used as the main controlling factors during the design.

No MeSH data available.


Various structures. (a) Two possible structures when the narrowest width for the microfluidic channel is 0.04 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). (b) Two possible structures when the narrowest width for the microfluidic channel is 0.240 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). The marked units are in mm.
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Figure 7: Various structures. (a) Two possible structures when the narrowest width for the microfluidic channel is 0.04 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). (b) Two possible structures when the narrowest width for the microfluidic channel is 0.240 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). The marked units are in mm.

Mentions: After fixing two parameters (d at 0.05 mm and s at 0.15 mm), we investigate the effects of changes in radius r on the burst frequency. Simulated results are shown in Figure 6. It is observed that larger values for radius r (or smaller values for s-r) cause larger values in burst frequency (rpm). When the radius r is between 0.11 and 0.13 mm (or when the s-r value is between 0.02 and 0.04 mm), the changes are most noticeable, and the average rotational speed increases from 1220 to 1520 rpm. The burst frequency when the narrowest width of the microfluidic channel is 40 um (or s-r is 0.02 mm) can differ from the burst frequency when the narrowest width for the microfluidic channel is 240 um (or s-r is 0.12 mm) by as much as 500 rpm. This is very useful in practical application. Figure 7 illustrates the reasons for having different burst frequencies when the width of the microfluidic channel is the same. Figure 7(a) shows the two possible structures when the narrowest width for the microfluidic channel is 40 um. One structure has a fixed radius r and variable s (dotted line), and the other structure has a fixed radius s, and variable r (solid line). These two structures cover different contacting surface areas of the microfluidic channel under the same radius region (in this sample structure, the ratio for these two areas is approximately 0.83). The angle between the structure and the direction of flow are different for these two structures, and therefore the resistance encountered by the fluid is different. For the first (dotted line) structure, the resistance is greater. Additionally, the contacting surface area is greater than the second (solid line) structure. The burst frequency would be higher than the second structure (about 200 rpm, as shown in Figure 6). Figure 7(b) shows the two possible structures when the narrowest width for the microfluidic channel is 240 um. In this case, since the microfluidic channel is much wider, the regions covered by both structures, the dotted line or solid line, are similar to each other (in this sample structure, the ratio for these two areas is approximately 0.92). The effect of fluid resistance decreases since the microfluidic channel is wider. The resultant burst frequencies by both structures show little difference (about 50 rpm, as shown in Figure 6).


Parametric analysis of a novel semi-circular microfluidic CD-ELISA valve.

Lin SI - J Biol Eng (2011)

Various structures. (a) Two possible structures when the narrowest width for the microfluidic channel is 0.04 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). (b) Two possible structures when the narrowest width for the microfluidic channel is 0.240 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). The marked units are in mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3306004&req=5

Figure 7: Various structures. (a) Two possible structures when the narrowest width for the microfluidic channel is 0.04 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). (b) Two possible structures when the narrowest width for the microfluidic channel is 0.240 mm. One structure has a fixed radius r and varying s (dotted line). The other structure has a fixed radius s, and varying r (solid line). The marked units are in mm.
Mentions: After fixing two parameters (d at 0.05 mm and s at 0.15 mm), we investigate the effects of changes in radius r on the burst frequency. Simulated results are shown in Figure 6. It is observed that larger values for radius r (or smaller values for s-r) cause larger values in burst frequency (rpm). When the radius r is between 0.11 and 0.13 mm (or when the s-r value is between 0.02 and 0.04 mm), the changes are most noticeable, and the average rotational speed increases from 1220 to 1520 rpm. The burst frequency when the narrowest width of the microfluidic channel is 40 um (or s-r is 0.02 mm) can differ from the burst frequency when the narrowest width for the microfluidic channel is 240 um (or s-r is 0.12 mm) by as much as 500 rpm. This is very useful in practical application. Figure 7 illustrates the reasons for having different burst frequencies when the width of the microfluidic channel is the same. Figure 7(a) shows the two possible structures when the narrowest width for the microfluidic channel is 40 um. One structure has a fixed radius r and variable s (dotted line), and the other structure has a fixed radius s, and variable r (solid line). These two structures cover different contacting surface areas of the microfluidic channel under the same radius region (in this sample structure, the ratio for these two areas is approximately 0.83). The angle between the structure and the direction of flow are different for these two structures, and therefore the resistance encountered by the fluid is different. For the first (dotted line) structure, the resistance is greater. Additionally, the contacting surface area is greater than the second (solid line) structure. The burst frequency would be higher than the second structure (about 200 rpm, as shown in Figure 6). Figure 7(b) shows the two possible structures when the narrowest width for the microfluidic channel is 240 um. In this case, since the microfluidic channel is much wider, the regions covered by both structures, the dotted line or solid line, are similar to each other (in this sample structure, the ratio for these two areas is approximately 0.92). The effect of fluid resistance decreases since the microfluidic channel is wider. The resultant burst frequencies by both structures show little difference (about 50 rpm, as shown in Figure 6).

Bottom Line: Together with supporting experiments, simulation based on two-phase flow theory is used in this study, and the feasibility of this novel valve design is confirmed.From both the experimental results and the simulated results, it is evident that the narrowest channel width and the contact angle are the primary factors influencing valve burst frequency.These can be used as the main controlling factors during the design.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Power Mechanical Engineering, National Formosa University, Taiwan. samlin7@ms41.hinet.net.

ABSTRACT
CD-ELISA uses the microfluidic ranking method and centrifugal force to control the testing solution as it flows into the reaction region. The most challenging part of CD-ELISA is controlling the flow process for different biological testing solutions, i.e. the controlling sequence for the microfluidic channel valves. The microfluidic channel valve is therefore the most important fluid channel structure for CD-ELISA. In this study, we propose a valve design suitable for a wide range rotational speeds which can be applied for mass production (molding). Together with supporting experiments, simulation based on two-phase flow theory is used in this study, and the feasibility of this novel valve design is confirmed. Influencing design factors for the microfluidic channel valves in CD-ELISA are investigated, including various shapes of the arc, distance d, radius r, the location of the center of the circle, and the contact angle. From both the experimental results and the simulated results, it is evident that the narrowest channel width and the contact angle are the primary factors influencing valve burst frequency. These can be used as the main controlling factors during the design.

No MeSH data available.