Laser-induced forward transfer of biomolecules

Microarrays of biomolecules are interesting in the development of biosensors and play an important role as efficient tools for gene and protein identification. In this work we present a study to prove that the laser-induced forward transfer (LIFT) technique is a good tool for the deposition of DNA microarrays. In the laser-induced forward transfer technique a pulsed laser is used to project a tiny amount of a liquid solution containing the biomolecules onto a solid substrate. We focused a Nd:YAG laser beam (355 nm wavelength) through a transparent glass plate on a titanium film that coated its rear side and acted as radiation absorber. The titanium film was, in turn, coated by a liquid solution of salmon sperm DNA. A poly-L-lysine coated substrate was placed parallel to this solution-metal-glass system (ribbon), at 100 mum, and facing the liquid film. In this way we deposited microarrays of micrometric droplets of this solution by firing the laser while displacing the ribbon and the substrate respect to the laser beam. The adhesion of the DNA to the substrate was demonstrated by labeling the DNA microarrays with ethidium bromide and detecting them by fluorescence microscopy. (C) 2003 Elsevier B.V. All rights reserved.