Patient held device for cortisol monitoring in depressed patients

Cortisol, which is related to stress levels, has been shown to be linked with brain changes in depression. A method of regular monitoring of cortisol levels by patients at home may enable the early identification of a depressive relapse. Currently, available methods of monitoring cortisol require complex processing in the laboratory, and are not suitable for regular monitoring on a daily basis. This work proposes the development of a new patient held device, capable of measuring cortisol levels in samples of saliva or blood spots. The device will incorporate optical and electrical impedance spectroscopy techniques to provide analysis of the samples, and to provide a rapid quantification of cortisol. Both methods have previously been used to measure different analytes in blood and saliva. It is believed that by combining them together, a more sensitive, accurate and rapid measurement of cortisol will be feasible. In this work, optical and electrical impedance spectroscopic fingerprinting of cortisol (hydrocortisone) in solutions of water, saliva and blood plasma will be achieved in-vitro. The two technologies will be combined into an integrated system suitable for home-use by patients. Finally, the device will be tested in-vivo on donated saliva and blood spot samples from healthy volunteers and the results will be correlated with conventional assay measurements (ELISA). This work will provide a useful tool for patients with depression to identify possible relapses and act to prevent further episodes. In the long term, this work could ultimately lead to non-invasive transcutaneous technology for continuous measurement of stress levels in depressed patients.