Identification for a large-volume food-borne bacteria on a fully integrated portable centrifugal disc

Herein, we present a fully integrated portable centrifugal microsystem for multiplex detection of food poisoning bacteria with a large volume of sample up to 1 mL. The microsystem consists of a portable rotary genetic analyzer and a fully integrated lab-on-a-disc device. The portable rotary genetic analyzer is equipped with a couple of heating blocks, a motor and a UV-Vis optical detector. The device was designed with two units: a 3D printed solution-loading cartridge and a centrifugal microfluidic disc. All the essential solutions for the LAMP reaction (a sample, a washing, an elution and a LAMP cocktail solution) are stored inside the cartridge, and orderly released into centrifugal microdevice by a rotation program. Each unit of the device was designed with 20 reaction chambers for simultaneously detecting 19 kinds of food poisoning bacteria in one test. To increase the amount of a sample to 1 mL, we incorporated the super absorbent polymer (SAP) in the waste chamber to absorb the sample and washing solution during the device operation. The whole process was automatically conducted from bead-based DNA extraction to isothermal DNA amplification by EBT-mediated LAMP reaction to colorimetric and UV-vis detection of amplicons in 60 min to identify three kinds of bacteria (Escherichia coli O157:H7, Salmonella Typhimurium, and Vibrio parahaemolyticus).