The invention relates to a bioactive hydrogel as a hybrid material of heparin and star-branched polyethylene glycol with functionalized end groups, wherein the heparin is bound directly by reaction of the carboxyl groups activated with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimides/N-hydroxysulfosuccinimide (EDC/s-NHS) with the terminal amino groups of the polyethylene glycol covalently by amide bonds.