title: Silane-dextran chemistry on lateral flow polymer chips for immunoassays.
abstract: The prognosis for patients suffering from cardiovascular and many other diseases can be substantially improved if diagnosed at an early stage. High performance diagnostic testing using disposable microfluidic chips can provide a platform for realizing this vision. Amic AB (Uppsala, Sweden) has developed a new microfluidic test chip for sandwich immunoassays fabricated by injection molding of the cycloolefin-copolymer Zeonor. A highly ordered array of micropillars within the fluidic chip distributes the sample solution by capillary action. Since wetting of the pillar array surface is the only driving force for liquid distribution precise control of the surface chemistry is crucial. In this work we demonstrate a novel protocol for surface hydrophilization and antibody immobilization on cycloolefin-copolymer test chips, based on direct silanisation of the thermoplastic substrate. Dextran is subsequently covalently coupled to amino groups, thus providing a coating with a low contact angle suitable for antibody immobilization. The contact angle of dextran coated chips is stable for at least two months, which enables production of large batches that can be stored for extended periods of time. We demonstrate the utility of the presented platform and surface chemistry in a C-reactive protein assay with a detection limit of 2.6 ng ml(-1), a dynamic range of 10(2) and a coefficient of variance of 15%.
authors.affiliation: Amic AB, Uppsala, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Jönsson
authors.forename: Magnus
authors.initials: M
authors.lastname: Aronsson
authors.forename: Gerd
authors.initials: G
authors.lastname: Rundström
authors.forename: Christer
authors.initials: C
authors.lastname: Pettersson
authors.forename: Ib
authors.initials: I
authors.lastname: Mendel-Hartvig
authors.forename: Jimmy
authors.initials: J
authors.lastname: Bakker
authors.forename: Erik
authors.initials: E
authors.lastname: Martinsson
authors.forename: Bo
authors.initials: B
authors.lastname: Liedberg
authors.forename: Brian
authors.initials: B
authors.lastname: MacCraith
authors.forename: Ove
authors.initials: O
authors.lastname: Ohman
authors.forename: Jonas
authors.initials: J
authors.lastname: Melin
mesh_terms: D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002318:Cardiovascular Diseases / Q000097:blood; D003516:Cycloparaffins / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D012545:Schiff Bases / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D015415:Biomarkers; D003516:Cycloparaffins; D003911:Dextrans; D012545:Schiff Bases; D012821:Silanes; D002097:C-Reactive Protein