A new technique for the production of nanoscale polymer networks on surfaces is presented. Bifunctional oligomeric building blocks react with trifunctional linkers and couple to activated polymer surfaces. PEG diamines were used as branch molecules in the network which were linked by either a trifunctional epoxide or a trifunctional acid chloride. The network with mesh size of 22 nm and more contains amino and hydroxy or carboxylic-acid groups. The concentration can be varied by the preparation conditions and by adding other substances like amino acids or amine-functionalized biotin to the reaction system. As an example, FITC-tagged streptavidin was coupled to biotin in the network with a concentration of up to 37 pmol.cm(-2).