Gold and Platinum Nanoparticle-Functionalized TiO₂ Nanotubes for Photoelectrochemical Glucose Sensing

Abstract

Developing stable photoelectrochemistry (PEC) glucose biosensors with high sensitivity and a low detection limit is highly desirable in the biosensor field. Herein, a highly sensitive and stable enzymatic glucose PEC biosensor is rationally designed and fabricated using a TiO2NTs/Au/Pt/GOx electrode. First, we prepared one-dimensional TiO2 nanotube arrays which could realize the orthogonalization of the light-incident direction and the carrier diffusion direction via anodization. Subsequently, we used the method of photoassisted deposition for anchoring Pt nanoparticles on TiO2NTs after electrodepositing Au nanoparticles. Among them, Au nanoparticles promote light absorption via the surface plasmon resonance effect and the separation of photogenerated carriers through forming a Schottky junction. Moreover, the Pt nanoparticles on the electrode surface can react with hydrogen peroxide (H2O2) generated from glucose (Glu) oxidation by glucose oxidase (GOx), accelerating the electron-transfer process during glucose oxidation and greatly improving the sensitivity of the glucose biosensor. As a result, TiO2NTs/Au/Pt/GOx exhibited excellent PEC performance, achieving a high sensitivity of 81.93 μA mM–1 cm–2 and a low detection limit (1.39 μM), far exceeding the performance of TiO2NTs/M/GOx (M = Au, Pt). Therefore, the introduction of Pt nanoparticles as active substances to promote enzymatic reactions is important for designing high-performance enzyme biosensors.

Functionalized Platinum Nanoparticles with Biomedical Applications

“…Tests were performed at higher concentrations; however, the stability and selectivity will be reduced at low concentrations (<0.8 mM). So, it can be said that gold and platinum nanoparticles have a synergistic effect on glucose-sensing due to their photocatalytic properties [ 66 ].…”

Gold Nanoparticles‐Titania Heterojunction: Photoelectrochemical Detection of Ciprofloxacin

“…Titanium dioxide was one of the first materials chosen for these analyses, considering its known photocatalytic properties [5–11] . However, this material has some disadvantages, due to the rapid recombination of the photogenerated charges and good activity only under intense UV light.…”

“…The photogenerated electrons can in fact remain in the nanoparticles, after the transfer through the interface, and the formation of a Schottky barrier turns out to be an efficient electron trap to prevent recombination. Furthermore, if metals with localized surface plasmon resonance (LSPR) properties are used, such as Au and Ag, the absorption in the visible region is also increased [9,16–20] …”

Surface Plasmon-Enhanced Photoelectrochemical Sensor Based on Au Modified TiO2 Nanotubes

“…In recent years, it has been found that noble metal nanoparticles with surface plasmon resonance (SPR) characteristics can improve the optical conversion efficiency of TiO 2 [36]. In particular, gold nanoparticles (AuNPs), because of their good stability, biocompatibility, synthetic controllability, and excellent catalytic performance [37], have become the research hotspot of SPR-enhanced optical activity [38,39].…”