CONTEXT

With the development in the comprehension of complex metabolic processes, the need for mechanistic and functional studies using 'omic' technologies has raised. The first DNA array experiment was published in 1982 and the technology has never stopped to improve since that date. The two major objectives of this evolution are the miniaturization and densification of the spots on the micro-array.

Previous methods to produce protein chips relied on expressing and purifying proteins to be printed on the array. But advanced methods were more recently developed such as NAPPA (Nucleic Acid Programmable Protein Array), PISA (Protein In situ Array) and DAPA (DNA Array to Protein Array), that allows the synthesis of fresh protein in situ on the array. The newly synthesized proteins are made from surface-spotted DNA and carry a tag that allows its binding to a second surface that corresponds to the protein chips. The drawback of these methods is that the expression of thousands of proteins is made in a single large compartment with a risk of diffusion and cross-contamination between protein spots. To avoid these problems these techniques use heavy or expensive solutions such as capture of the C-Ter tagged synthesized proteins by antibodies or DNA spots with large spacing.