Precise and simultaneous SERS detection of sertraline and serotonin on large-scale sub-20 nm plasmonic gold nanocone arrays

A highly sensitive and reproducible SERS platform for sertraline and serotonin detection is presented using large-scale, cost-effective, and facile fabrication of sub-20 nm nanogaps in plasmonic gold nanocone (AuNC) arrays. They , ensure a high density of uniform electromagnetic enhancement sites, giving the platform "hot-spot" consistency. The sertraline limit of detection (LOD) of 88 ng/mL is two orders of magnitude lower than clinical values, representing the lowest SERS-based LOD for sertraline reported to date. The LOD for serotonin, 27 ng/mL, is lower than its blood levels, even in depression. Moreover, simultaneous, parallel detection of both analytes within artificial cerebrospinal fluid (aCSF) mimicking physiological composition was achieved with no sample pretreatment, highlighting the platform's high selectivity. Our method shows great potential for complex antidepressant therapeutic monitoring in clinical conditions.