Electrochemical detection
Signal detection occurs directly in the channel, by virtue of integrated micro-electrodes. The outcome of enzymatic substrate transformation is an electro- active product, which is measured by redox-cycling on the electrodes. The system makes use of conventional enzymes, such as horse radish peroxidase (HRP) or alkaline phosphatase (ALP).
Electrochemical detection offers several advantages over absorbance measurements:
The detected current is proportionate to the analyte concentration (as opposed to depending on a total number of molecules, as is the case with luminescence measurement). Therefore, the response obtained in a miniaturized system is identical to that obtained in large volumes, and detection limits are readily brought to the pico-molar level in the micro-devices.
Moreover, electrochemical detection is not influenced by matrix opacity, which is particularly advantageous for direct measurements in serum, urine, CSF, and other matrixes.
Benefits
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Reduced time-to-result: A full assay can be performed in 10 minutes due to the small reaction volume, compared to conventionally several hours
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Convenience: Pocket-sized cartridges, handled with a minimum of care, are repeatedly regenerated over days. No need for instrument servicing, since fluidics are solely driven by gravity and capillary force
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Cost-efficiency: Minimal reaction chamber volume implies >10-fold reduction in ELISA kit reagent consumption which, with chip regeneration convenience, results in most competitive data- point pricing.
GRAVI™- Chip: Biosensor for ultra-fast ELISA
GRAVI™- Chip is the core element of diagnoSwiss technology. This consumable chip, which emanated from the combination of microfluidics and electrochemistry technologies, is a revolutionary device which is easily amenable to a wide range of analytical applications.
GRAVI™- Chip is factually a polymer cartridge with an array of micro-channels, designed for running magnetic bead-based ELISA protocols with standard immunology reagents.
The micro-channels, with incorporated electrodes for electrochemical readout of enzymatic reactions, are suited for regeneration upon signal detection. With incubation times adapted to assay kinetics, beads and reagents are greatly pre-concentrated in 100 nl to yield results in the pg/ml range.
