Exploring the Confinement Effect of Carbon Nanotubes on the Electrochemical Properties of Prussian Blue Nanoparticles

Single-walled carbon nanotubes as a reducing agent for the synthesis of a Prussian blue-based composite: a quartz crystal microbalance study

We investigated the synthesis mechanism of Prussian blue (PB) crystals supported on single-walled carbon nanotubes (SWCNTs), by performing in situ quartz crystal microbalance (QCM) measurements to probe the change in the electrode mass during the reaction, and using photoirradiation at designated stages of the process. We found that in contrast to existing hypotheses, light irradiation played no role in the synthesis process of Prussian blue on SWCNTs. On the other hand, the number of electrons transferred per one mole of the obtained product, and the number of electrons transferrable from SWCNTs, calculated from the density of states (DOS) of the SWCNTs in the sample, both favor the hypothesis of the reaction being triggered by direct electron transfer from SWCNTs to Fe³⁺, which occurs because of the energy difference between the Fermi level of SWCNTs and redox potential of Fe³⁺ ions.

A novel uric acid biosensor based on regular Prussian blue nanocrystal/ upright graphene oxide array nanocomposites

Objective:

Regular Prussian blue nanocrystals (RPB) were grown upright on graphene oxide flakes (GO), which were on the surface of a custom screen-printed carbon electrode (SPCE), using a spray method assisted by a constant magnetic field (CMF).

Method:

After immobilizing uricase, the uric acid biosensor Uricase/RPB/CMF-GO/SPCE was obtained. The detection range of the sensor response to UA was 0.005~2.525 mM, and the detection limit was as low as 3.6 μM. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that compared to amorphous electrodeposited Prussian blue (EDPB), RPB more favorably accelerated electron transport.

Result:

This novel uric acid biosensor exhibits high sensitivity over, a wide concentration range, strong anti- interference ability, and good stability and reproducibility.

Conclusion:

Thus, it has good application prospects for determining uric acid in physiological samples

Gold Microstructures/Polyaniline/Reduced Graphene Oxide/Prussian Blue Composite as Stable Redox Matrix for Label-free Electrochemical Immunoassay of α-Fetoprotein

Sensitivity amplification strategies in label-free electrochemical immunosensors are mainly limited by redox molecules leaking and degradation of electrical conductivity caused by layers of decoration. Herein, a relatively stable and sensitive label-free electrochemical immunosensor based on a hierarchically flower-like gold microstructures/polyaniline/reduced graphene oxide/prussian blue (HFG/PANI/rGO/PB) composite modified electrode was stepwise fabricated for determination of α-fetoprotein (AFP). In this process, the effect of PANI and rGO on the proposed immunosensor was studied. In detail, PANI/rGO due to the unique electrochemical properties can effectively prevent PB leakage and form a stable sensing platform, which causes sensitive responsiveness and thus a more satisfied detection limit. Meanwhile, the HFG with good biological compatibility can effectively immobilize plenty of antibodies. Under optimal conditions, the HFG/PANI/rGO/PB modified immunosensor exhibited an excellent linearity (0.01 - 30 ng/mL) and a low detection limit (0.003 ng/mL) (S/N = 3), suitable specificity as well as stability and reproducibility towards AFP. The present work offered a promising platform for clinical hepatocellular carcinoma diagnostics.