Facile Synthesis of Prussian Blue/Hollow Polypyrrole Nanocomposites for Enhanced Hydrogen Peroxide Sensing

Chemiluminescent/photothermal dual-mode lateral flow immunoassay based on CoFe PBAs/WS2 nanozyme for rapid and highly sensitive point-of-care testing of gentamicin

Serious adverse drug reactions of gentamicin (GM) significantly limit its clinical use, thus there is an urgent demand to develop reliable strategies to detect its concentration. In this study, we have developed a novel highly sensitive and portable lateral flow immunoassay (LFIA) based on CoFe PBAs/WS2 nanozyme mediated chemiluminescence (CL) and photothermal (PT) dual-mode POCT biosensor for the detection of GM, which successfully combines sensitive laboratory analyses with portable in situ analyses in the field. In this proof-of-principle work, the dynamic detection ranges of CL-LFIA and PT-LFIA mode were 1 pg mL-1 to 100 ng mL-1 and 50 pg mL-1 to 100 ng mL-1 with the limits of detection of 0.33 and 16.67 pg mL-1, respectively. The whole detection of CL-LFIA and PT-LFIA could be completed within 15 min and 30 min, respectively. The recoveries of GM spiked into complex matrices including milk, urine, and serum for CL-LFIA and PT-LFIA were 90.94%-109.74% and 94.49%-109.31%, respectively, indicating the reliability and applicability of the dual-mode LFIA in real samples. The dual-mode POCT biosensor could effectively overcome the false problems with improving accuracy and sensitivity, enabling user to precisely detect GM by laboratory analysis or on-site analysis depending on the source condition. Due to the complementary properties of CL-LFIA and PT-LFIA, the developed POCT biosensor can effectively ensure high-performance detection, showing the potential application of accurately detecting drug concentration in clinical practice.

Preparation of a nonenzymatic electrochemical sensor based on g-C3N4/MWO4 (M: Cu, Mn, ‎Co, Ni) composite for the determination of H2O2‎

‎ Hydrogen peroxide (H2O2) has a significant effect on physiological proceedings. In the ‎present research, a g-C3N4-based nanocomposite g-C3N4/MWO4(M: Cu, Mn, Co, Ni) was ‎prepared via the precipitation-calcination method. A...

Synthesis and Applications of Prussian Blue and Its Analogues as Electrochemical Sensors

Prussian blue (PB) and its analogue (PBA) are a kind of representative cyanide-based coordination polymer. They have received enormous research interest and have shown promising applications in the electrochemical sensing field due to their excellent electrochemical activity and unique structural characteristics including open framework structure, high specific surface area, and adjustable metal active sites. In this review, we summarize the latest research progress of PB/PBA as an electrochemical sensor in detail from three aspects: fabrication strategy, synthesis method and electrochemical sensor application. For the fabrication strategy, we discussed different fabrication methods containing the combination of PBA and carbon materials, metal nanoparticles, polymers, etc., respectively, as well as their corresponding sensing mechanism for improving performance. We also presented the synthesis methods of PB/PBA materials in detail, such as: coprecipitation, hydrothermal and electrodeposition. In addition, the effects of different methods on the morphology, particle size and productivity of PB/PBA materials are also concluded. For the application of electrochemical sensors, the latest progress of such materials as electrochemical sensors for glucose, H2O2, toxic compounds, and biomolecules have been summarized. Finally, we conclude remaining challenges of PB/PBA-based materials as electrochemical sensors, and provide personal perspectives for future research in this field.

Crumpled Graphene/Poly (azure I) Modified Electrode for Non-enzymatic Detection of Hydrogen Peroxide Secreted from Tumor Cells

Hydrogen peroxide (H₂O₂), an important representatives of reactive oxygen species, its aberrant expression is related to many diseases, including cancers. Therefore, it is very significant to design a reliable method for the real-time detection of endogenous H₂O₂. Herein, we describe preparing a poly (azure I)/crumpled graphene (cGN) modified electrode by an electro-polymerization method. The results showed that this electrode presented obvious electrocatalytic effect on the reduction of H₂O₂. Amperometric method was employed to monitor H₂O₂, and the amperometric response exhibited a good linear relationship with its concentration in the range of 8.0 × 10^-6 - 1.25 × 10^-3 mol/L; the detection limit reached to 6.7 × 10^-7 mol/L (S/N = 3). Furthermore, this modified also displayed good selectivity, long-term stability and a high anti-interference ability. Excitingly, the established method could be successfully used to detect H₂O₂ in human serum samples, and measured H₂O₂ secreted from living MCF-7 cells. It could have potential use in cancer diagnosis.

Prussian Blue: A Nanozyme with Versatile Catalytic Properties

Nanozymes, nanomaterials with enzyme-like activities, are becoming powerful competitors and potential substitutes for natural enzymes because of their excellent performance. Nanozymes offer better structural stability over their respective natural enzymes. In consequence, nanozymes exhibit promising applications in different fields such as the biomedical sector (in vivo diagnostics/and therapeutics) and the environmental sector (detection and remediation of inorganic and organic pollutants). Prussian blue nanoparticles and their analogues are metal–organic frameworks (MOF) composed of alternating ferric and ferrous irons coordinated with cyanides. Such nanoparticles benefit from excellent biocompatibility and biosafety. Besides other important properties, such as a highly porous structure, Prussian blue nanoparticles show catalytic activities due to the iron atom that acts as metal sites for the catalysis. The different states of oxidation are responsible for the multicatalytic activities of such nanoparticles, namely peroxidase-like, catalase-like, and superoxide dismutase-like activities. Depending on the catalytic performance, these nanoparticles can generate or scavenge reactive oxygen species (ROS).

Prussian blue nanoparticles: synthesis, surface modification, and biomedical applications

Prussian blue nanoparticles (PBNPs) are a nanomaterial that presents unique properties and an excellent biocompatibility. They can be synthesized in mild conditions and can be derivatized with polymers and/or biomolecules. PBNPs are used in biomedicine as therapy and diagnostic agents. In biomedical imaging, PBNPs constitute contrast agents in photoacoustic and magnetic resonance imaging (MRI). They are a good adsorbent to be used as antidotes for poisoning with cesium and/or thallium ions. Moreover, the ability to convert energy into heat makes them useful photothermal agents (PAs) in photothermal therapy (PTT) or as nonantibiotic substances with antibacterial properties. Finally, PBNPs can be both reduced to Prussian white and oxidized to Prussian green. A large window of redox potential exists between reduction and oxidation, which result in the enzyme-like characteristics of these NPs.

Facile Synthesis of Novel Prussian Blue-Lipid Nanocomplexes

Prussian blue (PB) is known for its multiple applications ranging from fine arts to therapeutics. More recently, PB nanoparticles have been pointed to as appealing photothermal agents (PA) when irradiated with wavelengths corresponding to the biological windows, namely regions located in the near infrared (NIR) zone. In addition, the combination of PB with other components such as phospholipids boosts their therapeutical potential by facilitating, for instance, the incorporation of drugs becoming suitable drug delivery systems. The novelty of the research relies on the synthesis procedure and characterization of hybrid lipid-PB nanoparticles with a high yield in a friendly environment suitable for photothermal therapy. This goal was achieved by first obtaining insoluble PB coated with oleylamine (OA) to facilitate its combination with lipids. The resulting lipid-PB complex showed a monomodal distribution of sizes with an overall size of around 100 nm and a polydispersity index of about 0.200. It highlights one critical step in the synthesis procedure that is the shaking time of the mixture of PB-OA nanoparticles with the lipid, which was found to be 48 h. This time assured homogeneous preparation without the need of further separation stages. Samples were stable for more than three months under several storage conditions.

Novel Enzyme-Free Multifunctional Bentonite/Polypyrrole/Silver Nanocomposite Sensor for Hydrogen Peroxide Detection over a Wide pH Range

Precise designs of low-cost and efficient catalysts for the detection of hydrogen peroxide (H₂O₂) over wide ranges of pH are important in various environmental applications. Herein, a versatile and ecofriendly approach is presented for the rational design of ternary bentonite-silylpropyl-polypyrrole/silver nanoarchitectures (denoted as BP-PS-PPy/Ag) via the in-situ photo polymerization of pyrrole with salinized bentonite (BP-PS) in the presence of silver nitrate. The Pyrrolyl-functionalized silane (PS) is used as a coupling agent for tailoring the formation of highly exfoliated BP-PS-PPy sheet-like nanostructures ornamented with monodispersed Ag nanoparticles (NPs). Taking advantage of the combination between the unique physicochemical properties of BP-PS-PPy and the outstanding catalytic merits of Ag nanoparticles (NPs), the as-synthesized BP-PS-PPy/Ag shows a superior electrocatalytic reduction and high-detection activity towards H₂O₂ under different pH conditions (from 3 to 10). Intriguingly, the UV-light irradiation significantly enhances the electroreduction activity of H₂O₂ substantially, compared with the dark conditions, due to the high photoelectric response properties of Ag NPs. Moreover, BP-PS-PPy/Ag achived a quick current response with a detection limit at 1 μM within only 1 s. Our present approach is green, facile, scalable and renewable.

Current Innovations of Metal Hexacyanoferrates-Based Nanocomposites toward Electrochemical Sensing: Materials Selection and Synthesis Methods

Mixed valence transition metal hexacyanoferrates (MeHCF)-Prussian blue and its analogs receive enormous research interest in the electrochemical sensing field. In recent years, conducting materials such as conducting polymer, carbon nanomaterial, and noble metals have been used to form nanocomposites with MeHCF. The scope of this review offers the reasons behind the preparation of various MeHCF based nanocomposite toward electrochemical detection. We primarily focus on the current progress of the development of MEHCF-based nanocomposites. The synthesis methods for these nanocomposites are also reviewed and discussed.

Microbial synthesis of hollow porous Prussian blue@yeast microspheres and their synergistic enhancement of organic pollutant removal performance

In this work, Prussian blue nanoparticles (PB NPs) were in situ grown on S. cerevisiae cells via one-step hydrothermal synthesis and the as-prepared Prussian blue@yeast (PB@yeast) hybrids exhibited synergistic adsorption and Fenton catalytic activities. FE-SEM, XRD and BET analysis of the prepared samples confirmed the successful formation of hollow porous structured PB@yeast microspheres, while FT-IR and XPS spectra indicated the fine structures were occupied by both functional adsorptive and catalytic sites. The experimental results of adsorption coupled Fenton reaction of PB@yeast hybrid microspheres revealed that the functional groups on the cell wall and the active iron sites in PB framework were fully utilized due to the triple synergistic effects of adsorption-Fenton catalysis-adsorption sites regeneration, thus endowing synergistically enhanced performance in removal of the selected cationic methylene blue (MB), anionic Methyl Orange (MO) and fluorescent brightener 71 (CXT) in aqueous solution. The high Fenton catalytic efficiency was related to the improvement of adsorption, in which the enrichment of contaminant molecules on the outer and inner surface of the hollow porous microspheres could lower mass transfer resistance and shorten charge transport pathways, thereby introducing more efficient Fenton catalytic activity than PB NPs.