Emergence of graphene-based biosensors for improved treatment response prediction in major depressive disorder: a perspective

Abstract Major depressive disorder (MDD), a leading cause of disability worldwide, is primarily characterized by symptoms such as loss of interest and depressed mood. Although effective treatment strategies are generally available for MDD, there is a large variability in treatment response between individual patients. Therefore, there is an urgent need to identify reliable and easily accessible predictors to guide treatment decisions. To date, there are no tests that can predict the individual treatment response based on biofluids such as blood, serum, plasma, and saliva. Due to the increasing number of patients suffering from MDD, there is an urgent need for modern techniques such as biosensors to predict the treatment outcome and to potentially identify responsive subgroups for individual treatments. Recent research on various biomarkers for MDD provides an opportunity to develop biosensors to overcome the challenges faced by the conventional diagnostic tools. Over the past decade, considerable efforts have been made to achieve this goal. In this process, graphene and its derivatives have worked as an excellent transducer materials for the design of sensitive electrochemical and electrical biosensing platforms. Therefore, the integration of graphene with the potential MDD biomarkers offers a promising approach towards the realization of reliable and cost-effective biosensors. This perspective provides an insight into the recent developments in the electrochemical and electrical biosensors for MDD biomarker quantification designed using graphene and its derivatives. We also discuss the major challenges and next steps required for the development and further optimization of biosensors for monitoring the response to different treatment options in MDD.