Abstract
Titanium nitride (TiN) is widely utilized in microelectrode array fabrication for electrophysiological recordings due to its relatively low noise levels, long term stability, and exceptional biocompatibility. Atomic layer deposition (ALD) is a well-established approach for the fabrication of TiN thin films, offering great control over the thickness and properties of the films. Although, advanced procedures have been reported to develop micro and nanostructured electrodes, TiN thin film has yet not been widely applied as electrode material for electrochemical sensing, and characterization of these ALD fabricated TiN films is lacking. Here, we study the use of TiN thin films as electrochemical signal transducer for neurotransmitter dopamine (DA) detection with emphasis on investigation the effect of oxygen functionalities on the electrochemical performance of the films. We find that in order to have high enough sensitivity and selectivity the electrode material used to realize the measurements must be modified. In this work, we described TiN thin film surface modification through hybridization of microfabrication and nanocomposite approaches. Because of its good adhesion, TiN is considered as a high interesting support for Pt catalyst. Therefore, ALD was used to deposit TiN thin films and to design Pt nanoparticles (Pt NPs) on highly conductive boron-doped silicon. Further modification was done through multiwalled carbon nanotubes (MWCNTs), which were immobilized on Pt NPs/ TiN hybrid electrode by Nafion film. Synergistic effect of Pt NPs, MWCNTs, and Nafion film caused significant increase in the electrocatalytic activity towards DA electrooxidation. The proposed sensor material was characterized by focused ion beam milling combined with scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), spectroscopic ellipsometry, contact angle measurement and its electrochemical behavior was studied by cyclic voltammetry (CV). CV technique was applied for sensing DA in the range of 0.05–35 µM (R2 = 0.990) with a good sensitivity (16.31 μA/μM) and a low detection limit of 40 nM (for S/N = 3). The developed sensor exhibited reasonable response time and good stability.
Highlights
Parkinson’s disease (PD) is the second most common chronic pro gressive neurodegenerative disorder, with distinct motor and non-motor symptoms stemming from pathology in both the central and peripheral nervous systems [1]
We have demonstrated Atomic layer depo sition (ALD) Titanium nitride (TiN)-based sensors for dopamine electrochemical detection and covered their characterization, modification, and electrochemical applications
TiN/Air sample was selected for further development through the use of both multiwalled carbon nanotubes (MWCNTs)/ Pt nano particles (Pt NPs) nanocomposite-modified sensor
Summary
Parkinson’s disease (PD) is the second most common chronic pro gressive neurodegenerative disorder, with distinct motor and non-motor symptoms stemming from pathology in both the central and peripheral nervous systems [1]. The early diagnosis of PD remains limited since the understanding of the mechanism of the loss of dopaminergic (DA) neurons is incomplete. The main clinical symptoms of PD occur when approximately 70% of DA neurons in the region of substantia nigra (SN) have been lost [2]. Available PD diagnostics are based on clinical symptoms that can find other types of neurodegenerative disorders [3]. To tackle these challenges, identification of biomarkers associated with PD to improve early diagnosis, to monitor disease pro gression and to discriminate PD from the other diseases with extrapy ramidal symptoms, are needed [4,5,6]. Its metabolites have been considered as a potential biomarker for the early diagnosis of PD [13,14]
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