Dip and Read Nanosensor for Calcium Ion Measurements in Sea Water

This topic requires the capability for enabling high sensitivity/high precision measurements of calcium concentrates in seawater. This proposal aims to demonstrate the feasibility of a novel high sensitive nanosensor that can be used to determine very low concentrations of calcium in seawater in the presence of a large background calcium concentration. The sensor approach uses the benefits of nanotechnology combined with molecular recognition to achieve high sensor sensitivity and high specificity so that the measurements are not affected by other ions like magnesium. Phase I results have indeed demonstrated a calcium detection sensitivity of a 5 μM in the presence of 100 mM concentrations of calcium in seawater. It is impervious to the presence of large concentrations of interfering magnesium ions and it can work well within the time scale of a Diel cycle. These results have been obtained using seawater at laboratory conditions. The goal of Phase II is to demonstrate that the sensor will function with the same features in conditions that are relevant to the needs of NOAA – the diver should be able to take the sensor to sea depths and temperatures needed to measure, in situ, the calcium concentration close to the coral itself.