Principle of Operation
The Optimiser workflow (Figure 2) mirrors standard ELISA assay steps, however, the volumes used are significantly smaller, and washing steps are reduced.
Sample/reagent volumes as small as 5–10 μL are added to each well and drawn through the microchannel via capillary forces. Each microchannel, where binding occurs, holds 4.5 μL of liquid, and excess liquid is channeled to an absorbent pad under the microplate.
The sequence of reagent/sample additions is demonstrated in Figure 2. For each successive addition, the capillary barrier is broken at the microchannel inlet, and all previous reagents are flushed into the absorbent pad. Flushing excess liquid effectively removes unbound materials and also prevents cross-contamination of reagents within the microchannel. By making multiple additions of sample containing analyte, sensitivity can be tuned up to 100-fold higher than single additions of analyte.
Automating the process further enhances ELISA assay efficiency and increases throughput. An automated pipetting station, such as BioTek’s Precision™ Microplate Pipetting System, automatically loads analytes and reagents into the microfluidics microplate, and the multistation platform allows operation of multiple Optimiser microplates. Automation increases pipetting precision compared to manual methods, especially at the low volumes used in the Optimiser workflow, and also allows the user to attend to other tasks while the instrument is in operation.
As the Optimiser plate conforms to SBS recommended microplate specifications, it can be read in any standard fluorescence microplate reader.