7. Biochip pitfalls and solutions

The principle of detection on DNA microarrays is based on fluorescence emission from the labeled target, which hybridizes or interacts with the probe attached to the support. However, much of the fluorescent light is trapped by the support. As a result, very small quantities of targets (e.g. very weakly expressed genes) can remain invisible. To overcome this drawback, CEA researchers, in partnership with Thalès Angénieux and Apibio, have developed Ibis, a glass slide specially designed to reflect more light back to the detector. Other companies, such as ArrayIt, are marketing mirror blades that can boost the signal-to-noise ratio (SNR) by 2 to 10 times.

However, fluorescence absorption is not the only problem when reading biochips. And with good reason: reading takes place after washing and drying, once all possible pairings or interactions have taken place. But...