A Disposable Dopamine Sensor Based on Oxidized Cellulose Nanofibril-Modified SPCE

Dopamine is a major catecholamine neurotransmitter that plays an essential role in the functioning of the human central nervous system. Imbalances in dopamine levels are associated with neurological disorders and depression. Thus, measuring the concentration of DA in human body fluids is significantly important. In this work, TEMPO-oxidized cellulose nanofibrils (TOCNFs) extracted from marram grass (Ammophilia arenaria), harvested in the central western part of Tunisia, were utilized to modify disposable screen-printed carbon electrodes (SPCEs) for the sensitive detection of dopamine in biological fluids. Differential pulse voltammetry (DPV) measurements displayed a sensitivity of 7.92 µA/µM and a detection limit of 10 nM. The disposable TOCNF-modified SPCE presents a charge transfer coefficient, α, comparable to that of a TOCNF/graphene/AgNP composite-modified GCE. Moreover, it exhibits good repeatability (RSD = 1.9%), good reproducibility (RSD = 2.3%), and appreciable storage stability (91% of its initial response after 3 weeks). The prepared disposable sensor showed satisfactory recovery of dopamine in human urine samples.