Abstract: A method for detecting and influencing an uptake of bioactive substances in a hydrogel material and/or release of bioactive substances from the hydrogel material, wherein the hydrogel material is a polymer network formed from charged and uncharged building blocks, the affinity of which network for bioactive substances is configurable by parameters defining the charged building blocks, and whose electrical charge storage capacity depend on interaction with the hydrogel binding of bioactive substances to the hydrogel material. When the hydrogel material is contacted with a biofluid, a change in electrical resistance and/or a change in charge storage capacity of the hydrogel material is detected. Uptake or a release of bioactive substances from the hydrogel material into the biofluid is determined by change in electrical resistance. The invention further relates to a suitable electrically conductive hydrogel material.

Abstract: The invention relates to a method for manufacturing an elastic and flexible fiber with a pre-de-termined non-circular cross-sectional geometry, the method comprising extrusion of an elasto-mer from a nozzle onto a substrate, wherein the pre-determined non-circular cross-sectional geometry of the fiber is determined by the height and velocity of the nozzle relative to the sub-strate. The invention relates to an elastic and flexible fiber produced using the method, wherein the fiber comprises an elongated indentation along a length of the fiber (groove). The invention relates to methods for producing preferably biocompatible microfluidic, electrically conducting or light-guiding fibers using the methods of the invention. The invention further re-lates to elastic and flexible fibers produced by the method.