A method for producing a support for determining analytes. The method comprises the steps of (a) providing a support comprising at least one channel, comprising a conduit having an intake and an outlet for passing fluid from the intake to the outlet, in the support body, (b) passing liquid with building blocks for synthesizing polymeric receptors through the channel or channels of the support body, (c) site- and/or time-specifically immobilizing the receptor building blocks in each case on predetermined positions in the channel or channels by illumination and (d) repeating steps (b) and (c) until the required receptors have been synthesized in each case on the predetermined positions.