Samples down to 100 nanoliters

A new miniaturized bioassay promises to provide a way to measure the pharmacological activity and other properties of biological substances that is faster, cheaper and more efficient than standard laboratory methods. The technology was developed by Singapore’s Institute of Bioengineering and Nanotechnology (IBN) and is being marketed by spin-off company Curiox Biosystems. The new assay, named DropArray, slashes the time needed to run certain lab tests by over 60 per cent and reduces consumable costs by nearly 90 per cent, while maintaining the same level of flexibility and convenience as conventional platforms, the company claims. DropArray’s unique integration of surface chemistry and microfluidics reduces the amount of material and reagent required by up to 1,000 times, while simultaneously cutting the reaction time by up to ten-fold. Each DropArray chip comprises a small (25 x 75 mm) flat rectangular patterned glass slide, with hundreds or thousands of hydrophilic glass “wells” surrounded by a hydrophobic coating. The chips can be used for common laboratory processes such as heterogeneous bioassays, after which a bench-top station completes the rinsing process and reads the results. IBN’s DropArray is able to miniaturize bioassays from 50–100 µl down to 100 nl, making it easier to conduct tests that are challenging with conventional technology. These include cancer stem cell immunoassays, and protein-based assays such as ELISA using reagents such as human leptin and endostatins that are in short supply.