Novel laser printing technique for miniaturized biosensors preparation

A new laser backward transfer technique for printing transparent liquids which avoids the drawbacks associated with the preparation of the liquids in thin film form has been developed. The principle of operation consists in strongly focusing a short laser pulse underneath the free surface of the liquid. Subsurface absorption of the laser radiation results in the generation of a bubble and the propulsion of liquid away the surface, leading to material deposition on a substrate facing that surface. The substrate, being traversed by the laser beam, must be transparent to the laser radiation. It has been demonstrated that there exists a focusing depth range which allows the deposition of well-defined, uniform microdroplets on the substrate. In addition, it has been shown that very high degrees of reproducibility and resolution can be achieved. Finally, the preparation of microarrays of different biomolecules (proteins and DNA) has revealed that the technique is feasible for miniaturized biosensors production.