Detection of bacterial and fungal contamination is of extreme importance in the fields of medical products or food packaging. Here a diagnostic tool based on pectinase and cellulase triggered release of a dye from a crosslinked polysaccharide matrix was developed. The hydrogel-based bioresponsive matrix consisted of carboxymethylcellulose (CMC) as a substrate for cellulases and polygalacturonate (PGA) as substrate for pectinases. To improve the stability of the hydrogels, methacrylic groups were inserted as crosslinking molecules. For polymerisation, two different methods were used, namely UV and thermal crosslinking. Controlled release triggered by extracellular enzymes of potentially pathogenic/contaminating microorganisms was investigated by the incorporation of Alizarin into the hydrogels. UV polymerised hydrogels turned out to be more suitable than thermal crosslinked polymers. Integration of such polymer based bioresponsive systems in medical surfaces or package systems could therefore act as an in situ monitoring system for detecting the presence of bacteria or fungi like e.g. Aspergillus species. (C) 2011 Elsevier Ltd. All rights reserved.