Silane-dextran chemistry on lateral flow polymer chips for immunoassays.
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%.
Jönsson
Christina
C
Amic AB, Uppsala, Sweden.
Aronsson
Magnus
M
Rundström
Gerd
G
Pettersson
Christer
C
Mendel-Hartvig
Ib
I
Bakker
Jimmy
J
Martinsson
Erik
E
Liedberg
Bo
B
MacCraith
Brian
B
Ohman
Ove
O
Melin
Jonas
J
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
D015415:Biomarkers; D003516:Cycloparaffins; D003911:Dextrans; D012545:Schiff Bases; D012821:Silanes; D002097:C-Reactive Protein