Electrodes Based on a Titanium Dioxide Nanotube–Spherical Silver Nanoparticle Composite for Sensing of Proteins

Abstract

The aim of the research was to provide electrochemical, chemical, phase, and microscopic characteristics of electrodes based on titanium dioxide nanotubes (TNTs) containing uniformly deposited, nonagglomerated spherical silver nanoparticles (AgNPs). The nanoparticles were produced with the use of electrodeposition and sputter deposition methods. This paper presents the results of research of these platforms with the use of the following techniques: electrochemical impedance spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy. Evaluation of the adsorption of proteinsbovine serum albumin (BSA)was carried out to establish the possibility of the use of the electrodes in a low-cost, simple detection system without surface functionalization. The research proved that the AgNP deposition facilitated the electron transfer increasing their conductivity properties as well as promoting the protein adsorption. The AgNPs/TNT electrodes showed a high selectivity to the BSA–anti-BSA complex. Half an hour of immobilization was enough to completely saturate the TNT electrodes, whereas for AgNPs/TNTs, 1 h of immobilization seemed to be not enough. The impedance parameter changes for electrodes with the AgNPs reached even about 300%. The biggest changes were noted for the platform obtained using cyclic voltammetry, so it is the best detection platform for biosensing.

Electrochemical and Mechanical Properties of Hexagonal Titanium Dioxide Nanotubes Formed by Sonoelectrochemical Anodization

“…The porosity of the analyzed hexagonal structures increased with the increasing diagonality of the hTNTs; that is, for the hTNTs samples with a similar height of 3500-4000 nm, a diagonal increase caused a decrease in porosity (Table 3). The equivalent circuit [49][50][51][52] shown in Figure 3g was fitted to the EIS results for compact and hexagonal TiO2 (Figure 3), and the fit parameters are listed in Table 4. The components of this equivalent circuit are the electrolyte resistance (Rs), resistance (R1), and admittance (constant phase element, CPE1) of the outer tube layer (R1) and the resistance (R2) and admittance (CPE2) of the barrier layer [49].…”

“…The values of Rs and R1 correlate with the diagonality of hTNTs in 3.5% NaCl and Ringer's solutions, and their values are similar to those of the compact TiO2 layer. The increased diagonal of the hTNTs increases the electric resistance due to the solution bulk between the electrodes (Rs) and a better corrosion re- The equivalent circuit [49][50][51][52] shown in Figure 3g was fitted to the EIS results for compact and hexagonal TiO 2 (Figure 3), and the fit parameters are listed in Table 4. The components of this equivalent circuit are the electrolyte resistance (Rs), resistance (R1), and admittance (constant phase element, CPE1) of the outer tube layer (R1) and the resistance (R2) and admittance (CPE2) of the barrier layer [49].…”

Copper–Ruthenium Composite as Perspective Material for Bioelectrodes: Laser-Assisted Synthesis, Biocompatibility Study, and an Impedance-Based Cellular Biosensor as Proof of Concept

“…[ 2 ] p. 70 and refs. [ 45 , 46 , 47 ]). Despite the remarkable electrochemical properties and biocompatibility of the noble metals, there are also disadvantages such as their expensiveness and difficulties in processing [ 40 ].…”