"It works much like a known litmus paper that shows the pH of the solution, such as pool water. Similarly, special nanophotonic chip particles are introduced, most commonly silver or gold, and which have the ability to attract a particular DNA. When these DNA molecules are captured on the nanoparticles, it changes the color of the light that falls on it. The disadvantage of these biosensors is that it is still necessary to have a special surface of nanopho- notic chip for every kind of DNA, "said Petr Dvorak, who works at the Faculty of Mechanical Engineering and the research center of CEITEC BUT.