ELECTROCHEMICAL DETECTION OF DOPAMINE WITH p-DOPED SILICON NANOWIRES.

Abstract

Abstract Dopamine acts as a neurotransmitter in the human body that is accumulated in synaptic vesicles. The concentration of DA in the human blood and serum samples are found to be in the range of 1 µM – 1 nM. The abnormal level of DA in the human body can create a lot of physiological disorders such as Parkinson's disease, Alzheimer's disease, and a high-level of DA excretion in human urine is a biomarker for neuroblastoma, a type of cancer among children. Neuroblastoma is a disease that is very common among children. The p-doped SiNWs were used for the electrochemical detection of DA. In my research, p-doped SiNWs were deposited onto the surface of the glassy carbon electrode (GCE) followed by 2 wt% Nafion solution deposition. The Nafion/p-doped SiNWs/GCE composite was used as a working electrode. Cyclic voltammetry (CV) and chronoamperometry (CA) was performed to study the electrocatalytic activity of the composite under various pH conditions with CV and under pH 5.0 for CA analysis. A selectivity study was performed using a CA analysis at +0.4801 V potential. The optimum peak was observed at 20 µl deposition of p-doped SiNWs. The maximum current signal was achieved for the p-doped SiNWs using a 5 mM concentration of DA under pH 5.0 compared with n-doped and undoped SiNWs. The modified Nafion/p-doped SiNWs/GCE sensor shows the linear dynamic range of 10 µm – 10 mM in CV and 50 µm – 0.9 mM in CA analysis. The limit of detection of 26.4 ± 0.3 µM was achieved for dopamine. The Nafion/p-doped SiNWs/GCE sensor was found to be highly selective against uric acid (UA), acetaminophen (APAP), hydrogen peroxide (H2O2), folic acid (FA), and glucose (Glu).