NVIGOREA AB commercialises the world's first nanocellulose-based filter paper that is capable of sifting away all types of viruses from protein solutions, cell culture media, or water in principle as easily as brewing coffee. We can tailor the pore size distribution of the filter paper on nanoscale with high precision, so that e.g. 12-nm antibodies can be separated from 20-nm viruses without loss of a valuable protein and with high virus clearance efficiency. While separating particles based on size differences may sound simple, achieving it on nanoscale requires years of research and special competences.