High-throughput Methods For GMO Detection Based On MACOR System And Microfluidic Technique

The detection of genetically modified organisms (GMOs) is a primarystep of GMO regulation. The wide application of gene technology led to thedramatically increasing of the number of different genetically modifiedorganisms (GMOs) commercialized and the diversity of genetic modificationsin these GMOs. The analytical approaches being faster, cheaper and allowingfor high throughput will be the future trend. Herein, we developed aMultiplex Amplification on a Chip with Readout on an Oligo microarray(MACRO) system specifically for convenient GMO detection，and initiatedadditional study on the2ndmethod which is based on microfluidic technology.The MACRO system is composed of a microchip for the PCRamplification of multiplex GMO targets, an oligo microarray for the detectionof the amplified products, and a GDP program to read out the detection results.The PCR amplification of the targets in the microchip restricts each target in adifferent microspore, thus it is different from that in conventional multiplePCR, in which all the targets are amplified in the same reaction mixture, thusavoided limitations of conventional multiple PCR. The developed microchipcontained a total of91targets (18universal elements,20exogenous genes,45events, and8endogenous reference genes) that covers97.1%of all GMevents that have been commercialized till2012. We demonstrate that thespecificity of MACRO is almost100%, and its limit of detection (LOD) issuitable for practical applications. Moreover, the results obtained fromsimulated complex samples and blind samples with MACRO were completelyconsistent with expectations and the results of independently performedreal-time PCRs, respectively. Demonstrating the high potential of MACRO tobe preferred applied to simultaneously detect the most commercialized GM crops effectively.Meanwhile we tested the possibility to develop novel high-throughputdetection methods based on microfluidic technology, which is associated withmicro total analysis systems (μTAS), and has already been used in manyfields. Among all the subcategories of microfluidics, droplet-basedmicrofluidics can create discrete droplets using immiscible phases. In thisstudy, we set up two microfluidic platforms for multiplex targetsamplification in millions of droplets, driven by mechanical force andpneumatic force, respectively. Our preliminary results showed that themechanical force driven microfluidic platform was not suitable for a mass oftargets amplification requirements for GMO detection because of its inherentshortages such as hysteresis quality, pulse effect and bad repeatability, and thepoor quality of the microfluidic chip developed by native companies. Sincethe pneumatic driven platform is a highly integrated microfluidic system,which has been widely applied into several areas, we are currently test theposibility to apply the MFCS (Microfluidic Controlled System) to GMOdetection.