Sensing 5-HT by specific aptamer modified nanostructures in chronic restraint stress-induced depression mice

Depression is a severe psychiatric syndrome, characterized by its high prevalence and substantial socioeconomic impact. 5-Hydroxytryptamine (5-HT) has been correlated with both the pathogenesis and treatment of major depression. There is a lack of sensitive methods for detecting 5-HT levels in the brain to characterize depression onset and severity. Tetrahedral DNA nanostructures (TDNs) show promises as 5-HT sensors due to their ability to confer diverse target specificity and permeate the blood-brain barrier. In this study, we constructed a nanoscale complex, 5-HT-TDNs, by combining TDNs with a specific 5-HT aptamer and 6-Carboxyfluorescein. The 5-HT-TDNs targeted decreased 5-HT in the brains of mice subjected to chronic restraint stress-induced depression. Following fluoxetine administration to these mice, we observed a significant increase of 5-HT in brain tissue using 5-HT-TDNs. This work illustrates the potential for sensitively and stably indicating neurotransmitters such as 5-HT in individuals with depression.