DualChip GMO - a new tool to facilitate the screening for GMO in the food and feed chain


Since most laboratories test their food and feed products by methods that do not allow a broad sample screening for GM crops, a major problem of the current GMO detection system has become increasingly visible. The number of GM crops worldwide constantly is rising and a corresponding increase of approved and unapproved GMOs in the food and feed chain must be expected. Consequently, there is an obvious need for screening tools that allow the simultaneous detection of different GMOs in a sample in one step. Considerable time and expense may be saved by GMO detection laboratories if they have an indication of which GMO is likely to be present in a sample.


In the course of the Co-Extra project, a new method of multiplex screening - the DualChip GMO - has been developed and will be commercialized by Eppendorf Array Technologies (Belgium). 

A broad range of specific DNA molecules, corresponding to specific DNA elements of GMOs, are immobilized separately on glass slides. The current version of the DualChip contains 117 such spots, each with a specific DNA element in each case (14 genes + 20 controls in triplicate). The immobilised DNA on the glass slide "captures" specific DNA elements of GMOs - if present in the sample - and the bound DNA sequences of GMOs are made visible by a subsequent colorimetric reaction. The result is an indicative pattern of visual spots on the glass slide (see pictures below).


Example of the detection of GMO elements with the DualChip GMO. A characteristic pattern of visual/silver-stained spots on the chip identifies a specific GMO. (Source: Eppendorf)
Example of the detection of GMO elements with the DualChip GMO. A characteristic pattern of visual/silver-stained spots on the chip identifies a specific GMO. (Source: Eppendorf)
The current version of the DualChip GMO detects six different DNA elements that are typical for a broad range of GM crops. For the analysis of the result, a software tool provided with the kit identifies the GMOs contained in a given sample. 

The DualChip GMO: A glass slide, which contains specific spots with different GM elements (Source: Eppendorf)
The DualChip GMO: A glass slide, which contains specific spots with different GM elements (Source: Eppendorf)
The current DualChip GMO microarray can be used to detect most EU-approved GM crops and the significant expansion of its spectrum of detectable GM crops already has begun. 

The suitability of the method recently was validated by a collaborative ring trial organised by the Joint Research Centre of the EC that involved several participants of the Co-Extra consortium. The trial showed that target DNA can be detected to a level of 0.1%.