Photo-Electrochemical Sensing of Dopamine by a Novel Porous TiO2 Array-Modified Screen-Printed Ti Electrode

Abstract

In this paper, the development of a nanoporous TiO2 array-modified Ti electrode for photo-electrochemical (PEC) sensing of dopamine (DA) is reported. A porous TiO2 array-modified electrode was fabricated from the controlled anodic oxidation of a Ti working electrode of commercial screen-printed electrodes (SPE). The anodization process and the related morphological and microstructural transformation of the bare Ti electrode into a TiO2/Ti electrode was followed by scanning electron microscopy (SEM) and UV-visible reflectance spectroscopy (DR-UV-Vis). The modified electrode was irradiated with a low-power (120 mW) UV-Vis LED lamp (λ = 400 nm) and showed good performance for the detection of DA with a large linear response range, a sensitivity of 462 nA mM−1 cm−2, and a limit of detection of 20 µM. Moreover, it showed higher photocurrents in the presence of DA in comparison to some foreign species such as ascorbic acid, uric acid, glucose, K+, Na+, and Cl−. Thus, this proposed low-cost photo-electrochemical sensor, with the advantage of very simple fabrication, demonstrates potential applications for the determination of dopamine in real samples.

Biomaterials constructed for MSC-derived extracellular vesicle loading and delivery—a promising method for tissue regeneration

“…Due to their structural plasticity and machinability, biomaterials are more likely to act as scaffolds in tissue engineering. Intrinsic cells are recruited to the area’s biomaterials implanted for local regeneration, which is achieved by binding or loading growth factors on the scaffold, or the scaffold itself is suitable for cell cultivation and adhesion no matter in vitro or in vivo ; both of the methods provide conditions and environments suitable for tissue regeneration, such as adequate blood supply, an anti-inflammation immune microenvironment, and a favorable habitat for stem cell expansion ( Tavella et al, 2018 ; Li et al, 2021b ).…”

Emerging materials for the electrochemical detection of COVID-19

“…Gold (Au) is a safe choice, as among the electrochemical biosensors it is the most investigated material, being explored in combination with various substrate platforms (screen printed electrodes, polymer base platforms, etc). However, the properties of substrate material affect the efficiency of sensors, while many concerns have been expressed about the reproducibility of the deposition of the sensing layer onto the substrate surface [76] .

Figure 5 (Ai) A schematic illustration of a label-free platform, able to immobilize COVID-19 antibodies on the Au electrodes, coated with RBD SARS-CoV-2 spike-protein; (Aii) Change of the electrical double layer resistance between the Au surface and the RBD bound on it, when antibodies are detected (samples A,B are infected with the virus, while sample C is not) [70] ; (Bi) Au-based SARS-CoV-2 sensor in one chip with three operating modes; (Bii) Comparison of electroanalytical signals between SARS-CoV-2 (2003) cDNA and SARS-CoV2-cDNA [71] ; (C) Electrodeposited Au nanoparticles, where thiol is immobilized/self-assembled and operated as probe for bound the RNA/c-RNA of SARS-CoV-2 [72] ; (Di, Dii) Change in electric properties of a cell-membrane, when the S1 protein (antigen) of SARS-CoV-2 is bound with the immobilized antibody on the Au electrode surface (screen-printed electrode) [73] .

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Disposable Capacitive Biosensor for Dopamine Sensing

“…The prepared Tyr biosensor showed good detection performance towards dopamine compared to previously reported sensors and biosensors (Table 1). [13–32] …”

“…A detailed discussion of Tyr catalyzed dopamine oxidation reaction has been provided in later sections. Several kinds of functionalized electrochemical sensors [24–30] and biosensors [31,32] were also reported for dopamine screening, however, the detection limits of fabricated electrodes were found to be high (Table 1). [13–32] …”