Optimiser: The Next Generation of Microplates
The Optimiser™ integrates the Power of Microfluidics with traditional microplate architecture to offer tremendous performance gains. The Optimiser™ is SBS/ANSI compliant and can be used without any specialized liquid handling equipment and can be read by conventional microplate fluorescence readers. The high surface area to volume ratio and short diffusion distances of the microfluidic channels allows for rapid reactions (~ 5 min incubation/step for ~ 30 min sandwich immunoassays). The Optimiser™ can be used either in static mode (low sample volume) or flow-through mode (high sensitivity); with significant reagent savings in either case.
The Optimiser™ microplate combines microfluidics with the conventional 96-well architecture to deliver significant performance benefits for immunoassay applications; as illustrated for an IL-6 assay on the Optimiser™ using the static mode (for sample savings) and flow-through mode (for improved sensitivity).
The Optimiser™ incorporates microfluidic geometries to maximize the efficiency of assay reactions. Figure 1 shows a schematic of the Optimiser™ with view of one cell. For operation, reagents are sequentially added to the loading well, drawn into the channel by capillary forces and excess drawn out by absorbent pad. The microfluidic design ensures that the channel is not emptied by pad allowing for static incubation step. Subsequent liquid addition breaks capillary barrier at inlet and flow resumes.
IL-6 assay was tested on the Optimiser™ in a static incubation and flow-through mode and performance is compared to a standard 96-well plate. IL-6 antigen and antibody set was purchased from ebioscience, secondary antibody (HRP labeled) from KPL and Pierce QuantRed Substrate.
Assay protocol on conventional microplate: (suggested) 2 µg/mL capture Ab; wash; 300 µL of blocking buffer; wash; antigen in 8 concentrations from 10~800 pg/mL and 0 pg/ml; wash; 2 µg/mL detection Ab; wash; 5 µg/mL secondary Ab; wash; finally 50 µL of chemifluorescence working substrate. 100 µl each step unless specified; each incubation step = 1.5 hour at 37 C; each wash step 300 µl x 3 wash buffer.
Assay protocol on Optimiser™ (static mode): 2 µg/mL capture Ab; blocking buffer; 30 µL antigen in 8 concentration from 10~800 pg/mL and 0 pg/ml; 2 µg/mL detection Ab; 5 µg/mL HRP conjugated Streptavidin, 30 µL of washing buffer twice, finally chemifluorescence substrate. 7 µL each step unless specified; each incubation step = 5 min at room temp (~ 23 C); only 1 wash step.
Assay protocol on Optimiser™ (flow-through mode): Same protocol as static mode except 100 µl sample volume (33µl x 3) added and allowed to flow through, no incubation time between repeat loads or after final load of sample.
As shown in Figure 2, the Optimiser™ achieves similar sensitivity (MDL ~ 150 pg/ml) as a conventional microplate using less than a third of the sample volume in static incubation mode. In the flow-through mode, the pre-concentration effect of flowing antigen (sample) boosts the sensitivity by ~ 15x (MDL < 10 pg/ml).
The revolutionary Optimiser™ microplate design can allow users to optimize assays either with significant sample savings or with significant sensitivity gains. In either case, reagent consumption is reduced ~ 14x and total assay time is less than 30 minutes!
Source: Siloam Biosciences