Porphyrin-nanosensor conjugates. New tools for the measurement of intracellular response to reactive oxygen species.

Reactive oxygen species (ROS) have for some time been implicated in the onset and progression of medical conditions including cancer, ageing, heart disease and Alzheimer's disease. Recently, it has been postulated that ROS play a much more subtle role in intracellular signalling mechanisms as second messengers. Given the importance of these species in influencing cellular processes, it is surprising that tools for studying intracellular levels of ROS are extremely limited and devices for studying the cells' response to internally generated ROS are virtually non-existent. In order to study the response of cells to intracellular ROS we have designed a nano-scale device that can both generate ROS and simultaneously monitor the cells' reaction as a function of changes in the important signalling ion, calcium. Here we report the synthesis, characterisation, and calibration of a new ROS nano-probe and demonstrate its ability to detect cellular response to elevated levels of intracellular ROS.