Quantitative detection of neurotransmitter using aptamer: From diagnosis to therapeutics.

Neurotransmitters, the small molecule chemical messenger responsible for nervous system regulation and can control joy, fear, depression, insomnia, craving for carbohydrates, drugs, and alcohols. Variation in neurotransmitter levels is a characteristic manifestation of several neurological diseases. Accurate diagnosis of these diseases caused due to an imbalance in neurotransmitter level followed by impaired transmission of signals between neurons and other body parts remains a great challenge for the clinicians. Recent evidences reveal, artificial single-stranded nucleotides called 'aptamer' are widely used as biosensors, antibody substitutes, diagnostic agents, and for targeted therapy. These aptamers are superior candidate both for early detection and diagnosis of many neurological disorders caused due to suboptimal level of neurotransmitters. Presently, noninvasive neurotransmitter detection by aptamer has been found to be an easy, fast, and cost-effective choice. In addition, increased specificity, stability, affinity, and reproducibility of aptamers, high throughput screening of aptamer-based sensing platforms have been observed. Moreover, clinical applicability of aptamer has also proved to be efficacious, though still at a preliminary stage. Herein, we review salient features of aptamerbased sensing technology used for neurotransmitter detection particularly their chemical modifications, selection, assay development, immobilization, therapeutic efficiency, and stability for early diagnosis of diseases caused due to neurotransmitter imbalance.