A novel cortisol biosensor for point-of-care testing in patients CSC

A salivary cortisol biosensor would be a useful tool at the point of care in the eye clinic when assessing patients with central serous chorioretinopathy (CSC), as it would assist in excluding systemic causes of CSC such as Cushing’s syndrome.
This project proposes the development of a novel electrochemical cortisol biosensor employing antibody-functionalised gold nanoparticles. Propargyl-PEG₄-thiol will be used to functionalise the gold nanoparticle surface, while azido-PEG₁₂-NHS ester will modify the anti-cortisol antibody. The azide-antibody conjugate will then react with the propargyl-modified nanoparticles to form a stable triazole linkage. Conjugation will be verified using ultraviolet-visible spectrophotometry, and commercially available hydrocortisone will serve as a positive control. The functionalised nanoparticle will be incorporated into a novel electrochemical transducer platform designed for use with human saliva samples.
This biosensor is intended for integration into wearable and point-of-care systems (such as in the eye clinic), offering a sensitive, specific, and non-invasive method for real-time cortisol monitoring. This sensor could be used in the ophthalmology clinic to detect an elevated cortisol in patients with central serous chorioretinopathy and other pachychoroidopathies. This would be a useful tool to screen for secondary causes of central serous chorioretinopathy. Such technology could enable ophthalmologists who review patients with CSC on a regular basis to establish a cortisol day curve profile thereby improving the diagnosis and management of the patient’s associated endocrine and stress-related disorders.