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%.

Cell-free DNA analysis is becoming adopted for first line aneuploidy screening, however for most healthcare programs, cost and workflow complexity is limiting adoption of the test. We report a novel cost effective method, the Vanadis NIPT assay, designed for high precision digitally-enabled measurement of chromosomal aneuploidies in maternal plasma. Reducing NIPT assay complexity is achieved by using novel molecular probe technology that specifically label target chromosomes combined with a new readout format using a nanofilter to enrich single molecules for imaging and counting without DNA amplification, microarrays or sequencing. The primary objective of this study was to assess the Vanadis NIPT assay with respect to analytical precision and clinical feasibility. Analysis of reference DNA samples indicate that samples which are challenging to analyze with low fetal-fraction can be readily detected with a limit of detection determined at <2% fetal-fraction. In total of 286 clinical samples were analysed and 30 out of 30 pregnancies affected by trisomy 21 were classified correctly. This method has the potential to make cost effective NIPT more widely available with more women benefiting from superior detection and false positive rates.

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A flow injection thermal microbiosensor was designed for the simultaneous determination of multiple analytes. The biosensor consisted of five thin-film thermistors which were located along a single microchannel. The device was fabricated on a quartz chip by micromachining. The feasibility of employing this system for the detection of two independent enzyme reactions was demonstrated using two different pairs of enzymes, urease-penicillinase and urease-glucose oxidase. The enzymes were immobilized on agarose beads, which were then sequentially packed into distinct regions of the microchannel. Using this method, samples containing urea mixed with penicillin V or with glucose were simultaneously analysed. Linear ranges of up to 20 mmol l-1 urea, 40 mmol l-1 penicillin V and 8 mmol l-1 glucose (saturated with 02) were obtained using a flow rate of 30 p1 min-1 and a sample volume of 20 pl. The relative standard deviations for urea and penicillin V assays were 1.13 and 2.42% for the first 100 samples and 1.17 and 2.78% for 200 samples, respectively. The sensor is capable of analysing 25 samples per hour.

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