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A micromachined interface for airborne sample-to-liquid transfer and its application in a biosensor system
KTH, School of Electrical Engineering (EES), Microsystem Technology (Changed name 20121201).
Biosensor Applications Sweden AB.
KTH, School of Electrical Engineering (EES), Microsystem Technology (Changed name 20121201).ORCID iD: 0000-0001-8248-6670
KTH, School of Electrical Engineering (EES), Microsystem Technology (Changed name 20121201).ORCID iD: 0000-0001-9552-4234
2006 (English)In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 6, no 12, 1504-1509 p.Article in journal (Refereed) Published
Abstract [en]

A novel micromachined interface for airborne sample-to-liquid adsorption and droplet-to-liquid transfer was designed and fabricated. It enables a robust sheet liquid flow serving as an adsorption site. The interface was characterised for flow and pressure properties and tested successfully for the transfer/adsorption of different samples. A qualitative theoretical model of the device characteristics is presented. We also used the interface to introduce a novel method and system for fast detection of dust- and vapour-based narcotics and explosives traces. The microfluidic vapour-to-liquid adsorption interface was coupled to a set of downstream QCM sensors. The system was tested successfully, with 50 ng cocaine samples rendering 15 Hz frequency shifts and with 100 ng heroine samples rendering 50 Hz frequency shifts. Gravitation invariance of the open liquid interface was demonstrated successfully, with the interface mounted upside down as well as vertically. The detection time was reduced to half of the time needed in previous systems. Machine size, weight and cost were reduced.

Place, publisher, year, edition, pages
RSC Publishing, 2006. Vol. 6, no 12, 1504-1509 p.
National Category
Control Engineering
URN: urn:nbn:se:kth:diva-14188DOI: 10.1039/b612526nISI: 000243212600011ScopusID: 2-s2.0-33846206078OAI: diva2:331616

QC 20100723

Available from: 2010-07-23 Created: 2010-07-23 Last updated: 2015-06-18Bibliographically approved
In thesis
1. MEMS Interfaces for Bioanalysis Systems
Open this publication in new window or tab >>MEMS Interfaces for Bioanalysis Systems
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

This thesis deals with various aspects of using open microfluidic interfaces. Three specific areas of application are studied.

The first is air-to-liquid interfacing in biosensors with possibilities for component inte­gration. A micromachined interface for airborne sample-to-liquid and droplet-to-liquid adsorption is discussed. It enables a robust sheet liquid flow serving as adsorption site. The inter­face properties are presented. Along with the interface, a novel method and system for rapid detection of dust and vapour-based narcotics and explosives traces is introduced. The QCM sensor detection principle with antibody immunoassay is described. Having shown the working principles of molecular adsorption to liquid surface and molecular detection with QCM technology, an integrated device is introduced. Diffusion as an effective transport mechanism in this microfluidic device is discussed. By holding the two components (inter­face and QCM) together with a double-sided adhesive, anisotropically vertically conductive tape, we achieve three functions, namely fixation, electrical connection and liquid sealing. Finally, enhanced electrostatic trapping of small particles to the liquid interface is demon­strated.

The second area concerns open microfluidics for the integration of capillary electropho­resis and mass spectroscopy. A technique for hyphenation between CE and MALDI-MS is presented. Two closed fused-silica capillaries were connected via a silicon chip comprising an open microcanal. The influence of the capillary-to-microcanal connection is discussed, as well as a simple technique to control evaporation from the open microcanal.

The third area concerns microfluidics enabling studies of single cells in asymmetric en­vironments. Using extracellular matrix or synthetic gel-embedding cells in an assay chamber, cells thrive and proliferate. This makes it possible to carry out medium to long term cultiva­tion of cells in a more physiological, controlled 3D environment than in traditional 2D cul­tures. The gels are discussed in terms of handling as well as their properties. A gel and micro­fluidic device for three dimensional cell culture with microgradient environments is pre­sented. Finally, a method for studying cilia-forming cells in asymmetric microfluidic environments is presented. Bending the primary cilium with a fluid flow will give rise to a response, but sensitivity to flow direction has only been sparsely studied. Design considerations are presented and discussed.

Abstract [sv]

Den här avhandlingen diskuterar olika aspekter av den öppna gränsytan hos styckevis öppna mikrofluidiksystem. Tre specifika användningsområden har studerats.

Det första är gränsytan mellan luft och vätska i en biosensor och de användningsområ­den som finns här. Ett mikrofabricerat interface för adsorption av luftburna substanser samt dropp-absorption diskuteras. Här används en rörlig vätskeyta som adsorbtionsyta och dess egenskaper presenteras. En ny metod för sprängämnes- och narkotikadetektering med interfa­cet introduceras. QCM-tekniken i kombination med antikroppskemi beskrivs. En integrerad lösning med dessa tekniker introduceras där diffusion utgör en effektiv transportmekanism. Med en dubbelsidig ledande tejp hålls komponenterna ihop, tätas och förses med ström. Slut­ligen presenteras elektrostatisk infångning av partiklar där den ena elektroden utgörs av väts­keytan.

Det andra området berör ett öppet mikrofluidiksystem för integrering av kapillärelek­trofores och masspektrometri. Teknik för att koppla ihop CE och MALDI-MS presente­ras. Två glaskapillärer har kopplats ihop med ett kiselchip med en öppen mikrokanal. Kopp­lingen mellan kapillären och chippet diskuteras liksom en enkel teknik för att kontrol­lera avdunstningen från den öppna mikrokanalen.

Det tredje området diskuterar hur mikrofluidik möjliggör studier av cellulära reaktioner i asymmetriska miljöer. Med inbäddning av celler i extracellulär matris eller syntetisk gel fås fysiologiskt relevant lokal miljö för celltillväxt och celldelning. Detta möjliggör studier av cellutveckling och cellreaktioner under lång tid i faktisk 3D-miljö till skillnad från den nuva­rande etablerade 2D-miljön. Gelerna diskuteras ur en hanteringssynpunkt liksom utifrån sina egenskaper. Ett system för cellodling i 3D med gradi­entmiljö presenteras och diskuteras. Slutligen presenteras ett system för studier av ciliefor­mande cellers respons där asymmetriska flöden ger upphov till böjning av cilier. Olika de­signaspekter diskuteras.

Place, publisher, year, edition, pages
Stockholm: KTH, 2008. xii, 56 p.
Trita-EE, ISSN 1653-5146 ; 2008:002
microfluidic interfacing, microfluidics, µTAS, sample transfer, biosensor, electronic nose, surface tension, quartz crystal microbalance, QCM, narcotics detection
National Category
Control Engineering
urn:nbn:se:kth:diva-4609 (URN)978-91-7178-846-7 (ISBN)
Public defence
2008-02-08, Sal M3, KTH, Brinellvägen 64, Stockholm, 10:00
QC 20100927Available from: 2008-01-18 Created: 2008-01-18 Last updated: 2010-09-27Bibliographically approved

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