An Appraisal of Aptasensors for Dopamine Measurement in Biofluids: A Review

Dopamine (DA) mediates various physiological functions across the body within the digestive and renal systems and in the blood circulation. It also plays a key role in motivated behaviors as a brain neurotransmitter (NT) in animals and humans and in the etiology of several neurodegenerative disorders such as Parkinson’s disease. Nevertheless, selective tracking of DA in biofluids in the presence of competitive chemicals and NTs remains a challenge. The aptamer (Apt)-based sensors (aptasensors) could offer a valid strategy for DA measurement in bodily fluids due to their high specificity. This study provides a comprehensive and comparative review of the state of the art of all the electrochemical and optical aptasensors for DA detection. The function of the aptasensors has been discussed in DA assay by considering various aspects such as the utilized Apt sequences, their immobilization protocol on the platform, engineered sensing interface, and diverse probes and modifiers in the electrochemical and optical approaches. Notably, a few of the published aptasensing techniques in both electrochemical or optical domains have already achieved very high sensitivity for DA tracking below picomolar and femtomolar range with temporal resolutions down to seconds. Resolution of some of remaining challenges, such as biocompatibility of substrates used and improving the temporal resolution, can enhance the prospects of using aptasensors in live tissue for chronic DA screening.