Spectroscopic techniques are always a challenge in photosynthetic research. Therefore more and more approaches aim in generally overcoming the need of probes and spectroscopy. One direction uses electrochemical biosensors to monitor the redoxchemistry of ROS as electric signals. Novel developments present electrochemical biosensors for real time monitoring of H2O2 generation at the level of sub-cellular organelles (Prasad et al., 2015). Electrochemical biosensors typically utilize enzymes to achieve ROS turnover, producing a current that can then be measured at the surface of an electrode (Pohanka and Skladai, 2008). For H2O2 sensing combined enzymes such as horseradish peroxidase (HRP) are used and novel materials like carbon nanotubes and polymeric matrices are used as electrodes to improve sensor sensitivity and specificity (Enomoto et al., 2013). A detailed review on typical electrochemical biosensor architectures is found e.g. in (Pohanka and Skladai, 2008). More recently novel types of electrochemical sensors have been developed and used for highly specific monitoring of ROS. For a review on electrochemical ROS sensors see also (Calas-Blanchard et al., 2014).
Electrochemical biosensors are produced with highly elaborated techniques like photolithography which is now used in the fabrication of lab- on-a-chip electrochemical biosensors (Enomoto et al., 2013).