Counterfeiting of products such as paper money, documents, watches, mechanical spare parts etc. causes huge damages – not only financial penalties for many companies but also a loss of safety arrangements in many fields. Thus, protection against counterfeiting becomes more and more important. One possibility to ensure protection against forgery is to label the original products with special markers. In our study, we investigate and develop new, effective procedures to generate and use diatom shells as such security particles. The following characteristics offer considerable advantages: • Diatoms have very characteristic 3D-shell structures • The silica shells are very stable against high temperatures and acids • They show an enormous richness in species diversity • Significant modifications of the shell structure can be carried out • They can be combined with other security particles The aim of our study is 1) to select, sample and cultivate appropriate species, 2) to modify their shells in an efficient, highly specific way, 3) to gain new insights in morphogenesis and its regulation and 4) to develop ideal solutions to apply and verify specific diatoms on selected products.