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Active liquid degassing in microfluidic systems
KTH, School of Electrical Engineering (EES), Micro and Nanosystems. (Microsystem Technology Lab)
Universiteit Antwerpen. (Laboratory of Medical Microbiology)
Mobidiag Ltd.
KTH, School of Electrical Engineering (EES), Micro and Nanosystems.ORCID iD: 0000-0002-0441-6893
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2013 (English)In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 13, no 22, 4366-4373 p.Article in journal, Editorial material (Refereed) Published
Abstract [en]

We present a method for efficient air bubble removal in microfluidic applications. Air bubbles are extracted from a liquid chamber into a vacuum chamber through a semipermeable membrane, consisting of PDMS coated with amorphous Teflon (R) AF 1600. Whereas air is efficiently extracted through the membrane, water loss is greatly reduced by the Teflon even at elevated temperatures. We present the water loss and permeability change with the amount of added Teflon AF to the membrane. Also, we demonstrate bubble-free, multiplex DNA amplification using PCR in a PDMS microfluidic device.

Place, publisher, year, edition, pages
RSC Publishing, 2013. Vol. 13, no 22, 4366-4373 p.
Keyword [en]
Air Bubble Formation, Pcr, Devices, Chip, Channels, Removal, Valves, Trap, Flow
National Category
Biological Sciences
URN: urn:nbn:se:kth:diva-125061DOI: 10.1039/c3lc50778eISI: 000325946800014ScopusID: 2-s2.0-84886056493OAI: diva2:639319
EU, FP7, Seventh Framework Programme

QC 20131114

Available from: 2013-08-06 Created: 2013-08-06 Last updated: 2015-06-18Bibliographically approved
In thesis
1. Polymer microfluidic systems for samplepreparation for bacterial detection
Open this publication in new window or tab >>Polymer microfluidic systems for samplepreparation for bacterial detection
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sepsis, caused by blood stream infection, is a very serious health condition thatrequires immediate treatment using antibiotics to increase the chances for patientsurvival. A high prevalence of antibiotic resistance among infected patients requiresstrong and toxic antibiotics to ensure effective treatment. A rapid diagnostic devicefor detection of antibiotic resistance genes in pathogens in patient blood would enablean early change to accurate and less toxic antibiotics. Although there is a pressingneed for such devices, rapid diagnostic tests for sepsis do not yet exist.In this thesis, novel advances in microfabrication and lab-on-a-chip devices arepresented. The overall goal is to develop microfluidics and lab-on-a-chip systems forrapid sepsis diagnostics. To approach this goal, novel manufacturing techniques formicrofluidics systems and novel lab-on-a-chip devices for sample preparation havebeen developed.Two key problems for analysis of blood stream infection samples are that lowconcentrations of bacteria are typically present in the blood, and that separation ofbacteria from blood cells is difficult. To ensure that a sufficient amount of bacteria isextracted, large sample volumes need to be processed, and bacteria need to be isolatedwith high efficiency. In this thesis, a particle filter based on inertial microfluidicsenabling high processing flow rates and integration with up- and downstream processesis presented.Another important function for diagnostic lab-on-a-chip devices is DNA amplificationusing polymerase chain reaction (PCR). A common source of failure for PCRon-chip is the formation of bubbles during the analysis. In this thesis, a PCR-on-chipsystem with active degassing enabling fast bubble removal through a semipermeablemembrane is presented.Several novel microfabrication methods were developed. Novel fabrication techniquesusing the polymer PDMS that enable manufacturing of complex lab-on-a-chipdevices containing 3D fluidic networks and fragile structures are presented. Also,a mechanism leading to increased accuracy in photopatterning in thiol-enes, whichenables rapid prototyping of microfluidic devices, is described. Finally, a novel flexibleand gas-tight polymer formulation for microfabrication is presented: rubbery OSTE+.Together, the described achievements lead to improved manufacturing methodsand performances of lab-on-a-chip devices, and may facilitate future development ofdiagnostic devices.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. xiv, 65 p.
TRITA-EE, ISSN 1653-5146 ; 2014:038
National Category
Engineering and Technology
urn:nbn:se:kth:diva-151244 (URN)978-91-7595-244-4 (ISBN)
Public defence
2014-10-03, FR4 (Oskar Klein-auditoriet), Roslagstullsbacken 21, Stockholm, 10:00 (English)

QC 20140916

Available from: 2014-09-17 Created: 2014-09-15 Last updated: 2014-09-19Bibliographically approved

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