The present invention concerns a method for functionalization, via topographical modification, of the surfaces of nanofibrillated (NFC) cellulose films into non-porous, water-resistant platforms, usable in diagnostic applications. The method includes a carboxylation of the NFC-film via TEMPO-mediated oxidation, and optionally an activation via EDS/NHS chemistry and, finally, the reactivity of the film can be tested using anti-human IgG. The invention also concerns the thus prepared functionalized NFC films, as well as the use thereof as platforms for diagnostical assays.
