title: A micromachined interface for airborne sample-to-liquid transfer and its application in a biosensor system.
abstract: 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.
authors.affiliation: Microsystem Technology Laboratory, School of Electrical Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden. Thomas.Frisk@ee.kth.se
authors.forename: Thomas
authors.initials: T
authors.lastname: Frisk
authors.forename: David
authors.initials: D
authors.lastname: Rönnholm
authors.forename: Wouter
authors.initials: W
authors.lastname: van der Wijngaart
authors.forename: Göran
authors.initials: G
authors.lastname: Stemme
mesh_terms: D000327:Adsorption; D000336:Aerosols / Q000737:chemistry; D000906:Antibodies / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003042:Cocaine / Q000737:chemistry*; D004867:Equipment Design; D005740:Gases; D003932:Heroin / Q000737:chemistry*; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods*; D010316:Particle Size; D044367:Phase Transition; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000336:Aerosols; D000906:Antibodies; D005740:Gases; D003932:Heroin; D003042:Cocaine; D012825:Silicon