Fluorometric enzymatic autoindicating biosensor for H2O2 determination based on modified catalase

► An optical biosensor for H2O2 continuous monitoring has been developped. ► The sensor is based on catalase, which decomposes H2O2 giving O2. ► O2 is detected by an O2-sensitive fluorophore linked to catalase and entrapped into polyacrylamide (PAA). ► Alternatively, catalase entrapped into PAA can be coupled to a commercial O2 fluorescence sensor. ► This work opens the door to a new family of optical monitoring systems based on catalase.