Ultrasensitive Dopamine Detection with Graphene Aptasensor Multitransistor Arrays

Abstract

Dopamine is a neurotransmitter with critical roles in the human brain and body, and abnormal dopamine levels underlie brain disorders such as Parkinsons Disease, Alzheimers Disease, and substance addiction. Herein, we present a novel high-throughput biosensor based on graphene multitransistor arrays (gMTAs) functionalized with a selective aptamer for robust ultrasensitive dopamine detection. The miniaturized biosensor integrates multiple electrolyte-gated graphene field-effect transistors (EG-gFETs) in an array configuration, fabricated by high-yield reproducible and scalable methodologies optimized at the wafer level. With these gMTA aptasensors, we reliably detected ultra-low dopamine concentrations in physiological buffers, including undiluted phosphate-buffered saline (PBS), artificial cerebral spinal fluid (aCSF), and high ionic strength complex biological samples. We report a record limit-of-detection (LOD) of 1 aM (10-18) for dopamine in both PBS, and dopamine-depleted brain homogenate samples spiked with dopamine. The gMTAs also display wide sensing ranges across all media, up to 100 M (10-8), with a 22 mV/decade peak sensitivity in aCSF. Furthermore, we show that the gMTAs can detect minimal changes in dopamine concentrations in small working volume biological CSF samples obtained from a mouse model of Parkinsons Disease.