| abstract |
The invention relates to a method for demonstrating the presence of molecules, particularly biomolecules, present in a fluid phase, allowing rapid, specific marker-free demonstration of both low-molecular molecules and biomolecules. TO this end, an optical grating comprising a first fluid phase and disposed on a substrate in the form of periodic structures having periodicity of 190 nm to 10 µm, is brought into contact with a second fluid phase. Prior to, during, or after said contact, the molecules to be demonstrated, having the ability to modify the optical properties of the optical grating, are added to the first or the second fluid phase. The demonstration of modified properties of the optical grating is ultimately performed, as soon as the first fluid phase is brought into contact with both the second fluid phase and the molecules to be demonstrated, by means of a measurement of the modified reflection or transmission of light at the optical grating, or the changing spatial progression of the diffraction pattern. |