RPA has enabled researchers in Germany to develop an automated DNA amplification and chemiluminescence microarray platform that can simultaneously identify and quantify multiple viral and bacterial contaminants in water.
The multiplex technology is an adaptation of a flow-through device called the MCR 3 (microarray chip reader, third generation), which has been developed by Dr. Michael Seidel at the Technical University of Munich’s (TUM) Institute for Hydrochemistry (Head Prof. Dr. Niessner). The researchers’ team originally designed the flow-based MCR 3 system to process automated immunoassays for food and water safety testing. The potential to combine RPA for isothermal DNA amplification with streptavidin-HRP labelling for chemiluminescence detection on the same chip opened up opportunities for developing a portable, field-based system for water testing.
The team reconstructed the device’s chip loading unit to incorporate a controllable thermoelectric heating module, and to integrate a hybridization chamber. “The 37-40°C temperature at which RPA operates is ideal for flow-through microarrays,” Dr Seidel points out. “This is a key feature of RPA that allows us to carry out on-chip amplification. The higher temperatures required by other isothermal amplification techniques can cause water in the chip to evaporate, which will ruin the experiment or destroy the microarray. RPA is the most promising method that we know for working directly on DNA microarrays.”