Vacuum/compression valving (VCV) using parrafin-wax on a centrifugal microfluidic CD platform

Wisam Al-Faqheri; Fatimah Ibrahim; Tzer Hwai Gilbert Thio; Jacob Moebius; Karunan Joseph; Hamzah Arof; Marc Madou

doi:10.1371/journal.pone.0058523

Vacuum/compression valving (VCV) using parrafin-wax on a centrifugal microfluidic CD platform

PLoS One. 2013;8(3):e58523. doi: 10.1371/journal.pone.0058523. Epub 2013 Mar 11.

Authors

Wisam Al-Faqheri¹, Fatimah Ibrahim, Tzer Hwai Gilbert Thio, Jacob Moebius, Karunan Joseph, Hamzah Arof, Marc Madou

Affiliation

¹ Medical Informatics and Biological Micro-electro-mechanical Systems Specialized Laboratory, Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia.

Abstract

This paper introduces novel vacuum/compression valves (VCVs) utilizing paraffin wax. A VCV is implemented by sealing the venting channel/hole with wax plugs (for normally-closed valve), or to be sealed by wax (for normally-open valve), and is activated by localized heating on the CD surface. We demonstrate that the VCV provides the advantages of avoiding unnecessary heating of the sample/reagents in the diagnostic process, allowing for vacuum sealing of the CD, and clear separation of the paraffin wax from the sample/reagents in the microfluidic process. As a proof of concept, the microfluidic processes of liquid flow switching and liquid metering is demonstrated with the VCV. Results show that the VCV lowers the required spinning frequency to perform the microfluidic processes with high accuracy and ease of control.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Centrifugation*
Equipment Design
Microfluidics / instrumentation*
Microfluidics / methods*
Paraffin
Pressure*
Temperature
Waxes*

Substances

Waxes
Paraffin

Grants and funding

This research was financially supported by University of Malaya, Ministry of Higher Education High Impact Research (UM/HIR/MOHE/ENG/05), and University of Malaya Research Grant (UMRG: RG023/09AET). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors would like to acknowledge Prof. Dr. Noorsaadah Abd Rahman from Department of Chemistry, Faculty of Science, University of Malaya and her grant “Hitsto-Lead: Designing Dengue Virus Inhibitors, National Biotechnology Directorate (NBD) Initiative-Malaysian Institute of Pharmaceuticals and Nutraceuticals (IPharm),Ministry of Science, Technology and Innovation (MOSTI IPHARM 53-02-03-1049)” for partially sponsoring the initial set-up of the CD Spin Test System. MM also acknowledges support of WCU (World Class University) program (R32-2008-000-20054-0) through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology.