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Major depressive disorder (MDD) is a mood disorder that includes symptoms like persistent sadness, lack of motivation and constant tiredness. Currently, diagnosis for MDD includes the DSM-5 Diagnostic Criteria, however, there is a need for a risk assessment tool to complement this.
The term “gut-brain axis” refers to the bidirectional communication between the bacteria in the gastrointestinal tract and the brain. Cross-sectional studies show significant differences in the gut microbiota composition between healthy individuals and MDD patients. Of particular interest are the dysregulated bacterial metabolites butyrate, GABA, and indole, which have profound effects and influence on the development and progression of MDD. In particular, individuals with higher concentrations of indole and lower concentrations of GABA and butyrate can be profiled as patients with a greater risk for MDD.
As such, our team designed a two-cell consortium tri-input biosensor that can independently assess the levels of butyrate, GABA, and indole in addition to assessing the combined effect and overall risk for MDD, seen as high indole, low GABA, and low butyrate. The Dry Lab subteam further modeled the system for further validation, and to identify the system’s sensitivity to the metabolites. The Human Practices Sub team then assessed our sensor's potential for implementation and also researched the impact of mental illness in our own communities.