Ultrasensitive Detection Of Serotonin Enabled By Biosensors For Early Diagnosis Of Neurological Diseases

Abstract

Several neurological brain illnesses like anxiety, stress, depression and mood disorders are mainly associated with the dysregulation of the neurotransmitter levels in the physiological fluid, viz. blood, urine etc. Among all the neurotransmitters, serotonin (5-Hydroxytryptamine or 5-HT), a biologicalamine is responsible for emotion and mood, and also helps in regulating body temperatures, painperception, and sleep cycle.Nowadays, different studiesacrosstimelinehave also reportedtheinvolvement of serotonergic pathways in the occurrence of various neurological disorders. Due to theabove crisis trace level neurotransmitter detection becomes necessaryfor diagnosis of neurologicaldiseases. In this context of trace level detection, biosensors tried to develop immense interest dueto their advantages over the traditional laboratory-based sophisticated instrumentation, tedioussample-pretreatment, time-consuming and trained manpower. In order to carry out biosensorfabrication,nanomaterialincorporationcoupledwithrecognitionelementshowcasesapivotalrolein achieving higher sensitivity. Therefore, several strategies adapted towards surface engineeringgenerally facilitates stable immobilization of therecognition elements, whereas nanomaterialincorporation enhances the electronic properties and larger area, which will ultimately lead to thesensitive determinationofthetargetanalyte. newlinePresently, this thesis mainly deals with the detection of 5-HT coupled with different recognitionelements on 3D nanomaterial substrate with a view to increase the commercial viability of thefabricated biosensors. Moreover, the authors have tried to assess 5-HT at a lower regime with aview to establish it as a potential biomarker. The thesis presents the design and development of azincoxide(ZnO)nanorod field-effecttransistor(FET)withintroduction of embeddedgateelectrode alongwithoptimizedparameters ofZnOnanostructures. newline newlineBesides antibody, the usage of another biorecognition element molecularly imprinted polymer(MIP)interfacedon3DZnOnanorodFETdeviceforu