{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,11]],"date-time":"2026-01-11T05:14:20Z","timestamp":1768108460615,"version":"3.49.0"},"reference-count":30,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2015,2,25]],"date-time":"2015-02-25T00:00:00Z","timestamp":1424822400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we propose an easy-to-implement passive liquid valve (PLV) for the microfluidic compact-disc (CD). This valve can be implemented by introducing venting chambers to control the air flow of the source and destination chambers. The PLV mechanism is based on equalizing the main forces acting on the microfluidic CD (i.e., the centrifugal and capillary forces) to control the burst frequency of the source chamber liquid. For a better understanding of the physics behind the proposed PLV, an analytical model is described. Moreover, three parameters that control the effectiveness of the proposed valve, i.e., the liquid height, liquid density, and venting chamber position with respect to the CD center, are tested experimentally. To demonstrate the ability of the proposed PLV valve, microfluidic liquid switching and liquid metering are performed. In addition, a Bradford assay is performed to measure the protein concentration and evaluated in comparison to the benchtop procedure. The result shows that the proposed valve can be implemented in any microfluidic process that requires simplicity and accuracy. Moreover, the developed valve increases the flexibility of the centrifugal CD platform for passive control of the liquid flow without the need for an external force or trigger.<\/jats:p>","DOI":"10.3390\/s150304658","type":"journal-article","created":{"date-parts":[[2015,2,26]],"date-time":"2015-02-26T10:07:43Z","timestamp":1424945263000},"page":"4658-4676","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Development of a Passive Liquid Valve (PLV) Utilizing a Pressure Equilibrium Phenomenon on the Centrifugal Microfluidic Platform"],"prefix":"10.3390","volume":"15","author":[{"given":"Wisam","family":"Al-Faqheri","sequence":"first","affiliation":[{"name":"Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"}]},{"given":"Fatimah","family":"Ibrahim","sequence":"additional","affiliation":[{"name":"Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"}]},{"given":"Tzer","family":"Thio","sequence":"additional","affiliation":[{"name":"Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"},{"name":"Faculty of Science, Technology, Engineering and Mathematics, INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800 Nilai, Negeri Sembilan, Malaysia"}]},{"given":"Norulain","family":"Bahari","sequence":"additional","affiliation":[{"name":"Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"}]},{"given":"Hamzah","family":"Arof","sequence":"additional","affiliation":[{"name":"Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"},{"name":"Department of Electrical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"}]},{"given":"Hussin","family":"Rothan","sequence":"additional","affiliation":[{"name":"Department of Molecular Medicine, Faculty of Medicine, University of Malaya,  50603 Kuala Lumpur, Malaysia"}]},{"given":"Rohana","family":"Yusof","sequence":"additional","affiliation":[{"name":"Department of Molecular Medicine, Faculty of Medicine, University of Malaya,  50603 Kuala Lumpur, Malaysia"}]},{"given":"Marc","family":"Madou","sequence":"additional","affiliation":[{"name":"Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, Faculty of Engineering, University of Malaya,  50603 Kuala Lumpur, Malaysia"},{"name":"Department of Biomedical Engineering, University of California, Irvine, 92697 CA,  USA"},{"name":"Department of Mechanical and Aerospace Engineering, University of California, Irvine,  92697 CA, USA"}]}],"member":"1968","published-online":{"date-parts":[[2015,2,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"601","DOI":"10.1146\/annurev.bioeng.8.061505.095758","article-title":"Lab on a CD","volume":"8","author":"Madou","year":"2006","journal-title":"Annu. 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