All-in-One Zinc-Doped Prussian Blue Nanozyme for Efficient Capture, Separation, and Detection of Copper Ion (Cu2+ ) in Complicated Matrixes

Copper is a vital micronutrient for lives and an important ingredient for bactericides and fungicides. Given its indispensable biological and agricultural roles, there is an urgent need to develop simple, affordable, and reliable methods for detecting copper in complicated matrixes, particularly in underdeveloped regions where costly standardized instruments and sample dilution procedures hinder progress. The findings that zinc-doped Prussian blue nanoparticle (ZnPB NP) exhibits exceptional efficiency in capturing and isolating copper ions, and accelerates the generation of dissolved oxygen in a solution of H2 O2 with remarkable sensitivity and selectivity, the signal of which displays a positive correlation with the copper level due to the copper-enhanced catalase-like activity of ZnPB NP, are presented. Consequently, the ZnPB NP serves as an all-in-one sensor for copper ion. The credibility of the method for copper assays in human urine and farmland soil is shown by comparing it to the standard instrumentation, yielding a coefficient of correlation (R2 = 0.9890), but the cost is dramatically reduced. This ZnPB nanozyme represents a first-generation probe for copper ion in complicated matrixes, laying the groundwork for the future development of a practical copper sensor that can be applied in resource-constrained environments.

Fully integrated wearable microneedle biosensing platform for wide-range and real-time continuous glucose monitoring

Wearable microneedle sensors for continuous glucose monitoring (CGM) have great potential for clinical impact by allowing access to large data sets to provide individualized treatment plans. To date, their development has been challenged by the accurate wide linear range tracking of interstitial fluid (ISF) glucose (Glu) levels. Here, we present a CGM platform consisting of a three-electrode microneedle electrochemical biosensor and a fully integrated radio-chemical analysis system. The long-term performance of the robust CGM on diabetic rats was achieved by electrodepositing Prussian blue (PB), and crosslinking glucose oxidase (GOx) and chitosan to form a 3D network using glutaraldehyde (GA). After redox by GOx, PB rapidly decomposes hydrogen peroxide and mediates charge transfer, while the 3D network and graphite powder provide enrichment and release sites for Glu and catalytic products, enabling a sensing range of 0.25-35 mM. Microneedle CGM has high sensitivity, good stability, and anti-interference ability. In diabetic rats, CGM can accurately monitor Glu levels in the ISF in real-time, which are highly consistent with levels measured by commercial Glu meters. These results indicate the feasibility and application prospects of the PB-based CGM for the clinical management of diabetes. STATEMENT OF SIGNIFICANCE: This study addresses the challenge of continuous glucose monitoring system design where the narrow linear range of sensing due to the miniaturization of sensors fails to meet the monitoring needs of clinical diabetic patients. This was achieved by utilizing a three-dimensional network of glutaraldehyde cross-linked glucose oxidase and chitosan. The unique topology of the 3D network provides a large number of sites for glucose enrichment and anchors the enzyme to the sensing medium and the conductive substrate through covalent bonding, successfully blocking the escape of the enzyme and the sensing medium and shortening the electron transfer and transmission path.

Physicochemical and pharmacotechnical characterization of Prussian blue for future Prussian blue oral dosage forms formulation

Ferric hexacyanoferrate, Fe4 [Fe(CN)6]3 · xH2O, known as Prussian blue (PB), has proven its effectiveness as an antidote in cases of accidental poisoning or poisoning caused by radioactive materials such as cesium (Cs) and thallium (Tl); which due to their solubility in water, when absorbed by the human body, cause serious damage to vital organs. The local development of a drug with PB as an active ingredient arises as a response to the civil and military needs established within the Ministry's pharmacy request for national defense. This fact contemplates the circumstances related to public health protection in the nuclear, radiological, biological and chemical (NRBQ) of the emergency institutions in health and national security. In this paper and by using various analytical techniques, the characterization of the locally synthesized PB with pharmaceutical quality has been described, as a first step to predict its behavior in the preparation of a drug that contains it as an active ingredient. The research findings demonstrate that locally synthesized PB is suitable for use in oral dosage forms, enabling the local development of drug formulations incorporating PB, thus being able to potentially become a main resource in the treatment of Cs and Tl poisoning in any accidental or intended of the population. This development opens up the possibility of creating drug formulations that incorporate PB at a local level, making it a potentially significant resource in the treatment of Cs and Tl poisoning. The ability to locally produce and utilize PB in oral dosage forms could be crucial in addressing cases of accidental or intentional exposure within the population. This advancement not only contributes to the scientific understanding of PB but also holds promising implications for practical applications in public health and emergency situations.

Elaborating the Crystal Water of Prussian Blue for Outstanding Performance of Sodium Ion Batteries

Prussian blue (PB) is one of the main cathode materials with industrial prospects for the sodium ion battery. The structural stability of PB materials is directly associated with the presence of crystal water within the open 3D framework. However, there remains a lack of consensus regarding whether all forms of crystal water have detrimental effects on the structural stability of the PB materials. Currently, it is widely accepted that interstitial water is the stability troublemaker, whereas the role of coordination water remains elusive. In this work, the dynamic evolution of PB structures is investigated during the crystal water (in all forms) removal process through a variety of online monitoring techniques. It can be inferred that the PB-130 °C retains trace coordination water (1.3%) and original structural integrity, whereas PB-180 °C eliminates almost all of crystal water (∼12.1%, including both interstitial and coordinated water), but inevitably suffers from structural collapse. This is mainly because the coordinated water within the PB material plays a crucial role in maintaining structural stability via forming the -N≡C-FeLS-C≡N- conjugate bridge. Consequently, PB-130 °C with trace coordination water delivers superior reversible capacity (113.6 mAh g-1), high rate capability (charge to >80% capacity in 3 min), and long cycling stability (only 0.012% fading per cycle), demonstrating its promising prospect in practical applications.

Flexible Composite Electrochromic Device with Long-Term Bistability Based on a Viologen Derivative and Prussian Blue

Viologen and Prussian blue (PB) exhibit good electrochromic properties, but certain limitations still exist. To improve the electrochromic properties of viologen, a viologen derivative 1,1'-bis(4-(bromomethyl)benzyl)-[4,4'-bipyridine]-1,1'-diium hexafluorophosphate (BBDV) was synthesized, and its electrochromic properties were investigated. Additionally, a flexible composite electrochromic device (FC-ECD) was prepared by using BBDV and PB as active materials. The structure of the FC-ECD was PET-ITO/gel electrolyte-BBDV/PB/PET-ITO. The applied voltage required for the FC-ECD was found to be lower than that of the ECD based on BBDV(FBBDV-ECD). Compared to FBBDV-ECD, FC-ECD exhibited a higher optical contrast (71.42%) and cyclic stability (89.51%). The FC-ECD exhibited multicolor changes under different applied voltages (ranging from -2.0 to +1.6 V). Especially, the color of the FC-ECD remained stable for 14 h after the removal of the applied voltage.

Highly-Efficient Gallium-Interference Tumor Therapy Mediated by Gallium-Enriched Prussian Blue Nanomedicine

Prussian blue (PB)-based nanomedicines constructed from metal ion coordination remain restricted due to their limited therapeutic properties, and their manifold evaluation complexity still needs to be unraveled. Owing to the high similarities of its ionic form to iron (Fe) and the resulting cellular homeostasis disruption performance, physiologically unstable and low-toxicity gallium (Ga) has garnered considerable attention clinically as an anti-carcinogen. Herein, Ga-based nanoparticles (NPs) with diverse Ga contents are fabricated in one step using PB with abundant Fe sites as a substrate for Ga substitution, which aims to overcome the deficiencies of both and develop an effective nanomedicine. A systematic comparison of their physicochemical properties effectively reveals the saturated Ga introduction state during the synthesis process, further identifying the most Ga-enriched PB NPs with a substitution content of >50% as a nanomedicine for subsequent exploration. It is verified that the Ga interference mechanisms mediated by the most Ga-enriched PB NPs are implicated in metabolic disorders, ionic homeostasis disruption, cellular structure dysfunction, apoptosis, autophagy, and target activation of the mammalian target of the rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) pathways. This study provides significant guidance on exploiting clinically approved agents for Ga interference and lays the foundation for the next generation of PB-based theranostic agents.

Degradation of norfloxacin by red mud-based prussian blue activating H2O2: A strategy for treating waste with waste

The massive accumulation of red mud (RM) and the abuse of antibiotics pose a threat to environment safety and human health. In this study, we synthesized RM-based Prussian blue (RM-PB) by acid solution-coprecipitation method to activate H2O2 to degrade norfloxacin, which reached about 90% degradation efficiency at pH 5 within 60 min and maintained excellent catalytic performance over a wide pH range (3-11). Due to better dispersion and unique pore properties, RM-PB exposed more active sites, thus the RM-PB/H2O2 system produced more reactive oxygen species. As a result, the removal rate of norfloxacin by RM-PB/H2O2 system was 8.58 times and 2.62 times of that by RM/H2O2 system and PB/H2O2 system, respectively. The reactive oxygen species (ROS) produced in the degradation process included ·OH, ·O2- and 1O2, with 1O2 playing a dominant role. The formation and transformation of these ROS was accompanied by the Fe(III)/Fe(II) cycle, which was conducive for the sustained production of ROS. The RM-PB/H2O2 system maintained a higher degradation efficiency after five cycles, and the material exhibited strong stability, with a low iron leaching concentration. Further research showed the degradation process was less affected by Cl-, SO42-, NO3-, and humic acids, but was inhibited by HCO3- and HPO42-. In addition, we also proposed the possible degradation pathway of norfloxacin. This work is expected to improve the resource utilization rate of RM and achieve treating waste with waste.

Synthesis of Prussian blue-embedded magnetic micro hydrogel for scavenging of cesium from aqueous solutions; Batch and dynamic investigations

A magnetic micro porous structure composite based on alginate and Prussian blue (M-SA-PB) was simply prepared for cesium removal from the aqueous solutions. The gelation and formation of PB proceeded through the same step, which made the PB homogenously distributed and firmly attached to the alginate matrix. The homogenizer was applied to break down the bulky gel structure into micro-ones, and the lyophilizer will provide the porous structure. Batch cesium sorption experiments showed that the adsorption kinetics and isotherms were attributed to the pseudo-second-order model and Langmuir isotherm. Moreover, the Cs-ion is favorably adsorbed on the M-SA-PB composite surface as a monolayer towards Cs, with a maximum adsorption capacity reach of 191.0 mg/g. Furthermore, the M-SA-PB adsorbent showed excellent adsorption selectivity of Cs from multiple-ion solutions. Our work was extended to use the M-SA-PB composite in dynamic cesium sorption. The column studies showed that the removal efficiency of Cs+ increased with increasing bed depth as well as the initial cesium concentration. Finally, as previously mentioned, the M-SA-PB could be considered an excellent Cs+ scavenger employing both batch and dynamic approaches, which makes it a promising adsorbent for practical investigations.

Enhanced Photothermal Activity of Nanoconjugated System via Covalent Organic Frameworks as the Springboard

The development of nanomaterials with high photothermal conversion efficiency has been a hot issue. In this work, a novel photothermal nanomaterial is synthesized using Prussian blue nanocubes (PBNCs) as the photothermal active substance and covalent organic framework (COF) as the substrate. The as-prepared COF@PBNCs show a high photothermal conversion efficiency of 59.1%, significantly higher than that of pure PBNCs (32.5%). A new circuit path is generated with the combination of COF, which prevents the direct combination of thermal electrons and holes, as well as enhances the nonradiation transition of PBNCs. Besides, the imine groups on COF as the coordination and reduction agent allow the in situ growth of PBNCs, and the dense micropores of COF as the ideal heat conduction channels can also be the potential factors for the enhanced photothermal property. The photothermal property of COF@PBNCs is further used in the construction of immunosensor for the detection of furosemide (FUR). With the help of handheld thermal imager, the concentration of FUR can be easily read, thus shedding a new light in the construction of visual sensor for simple and low-cost point-of-care testing.

Prussian blue (PB) modified gold nanoparticles as a SERS-based sensing platform for capturing and detection of pyrazinoic acid (POA)

Pyrazinoic acid (POA) is a metabolite of the anti-tuberculosis drug pyrazinamide (PZA), and its detection can be used to assess the resistance of Mycobacterium tuberculosis in cultures, as only sensitive strains of the bacteria can metabolize PZA into POA. Prussian blue is a well-known metal-organic framework compound widely used in various sensing platforms such as electrochemical, photochemical, and magnetic sensors. In this study, we present a novel sensing platform based on Prussian blue-modified gold nanoparticles (AuNPs) designed to enhance the affinity of POA towards the sensing surface and to capture POA molecules from aqueous solutions. This SERS-based method allows for the selective enrichment of POA, which can be detected in both pure aqueous solution and in the presence of its pro-drug PZA. The limit of detection (LOD) for POA was estimated to be 1.08 μM in pure aqueous solution and 0.18 mM in the presence of PZA. Furthermore, the precision of the SERS method was verified by the relative standard deviation (RSD) of 3.34-12.02% for three parallel samples using different matrices, i.e. aqueous solution, spiked river water and spiked simulated saliva. The recoveries of the samples ranged from 92.65 to 118.51%. These all demonstrate the potential application of the proposed detection scheme in medical research.

Bufotalin-loaded biomimetic Prussian blue nanoparticles for colorectal cancer chemo-photothermal ferroptosis therapy

Purpose: We constructed biomimetic nanoparticles with biocompatible, tumor-targeting, laser-responsive properties for ferroptosis-induced colorectal cancer chemo-photothermal therapy, with the aim to realize double-hit ferroptosis treatment for colorectal cancer. Methods: The nanoparticles were prepared by first loading the chemotherapy drug bufotalin (CS-5) with Prussian blue (PB), then combining a hybridized erythrocyte-tumor membrane (M) with PB@CS-5 to produce PB@CS-5@M. The chemo-photothermal therapy efficiency of PB@CS-5@M was tested by in vitro and in vivo experiments. Results and conclusion: The combined PB and CS-5 act as promising ferroptosis inducers to enhance ferroptosis efficacy. The hyperthermia induced by laser stimulation can trigger PB to release CS-5 and iron and ferrous ions, which further promotes ferroptosis.

Electrochemical surface reconstruction of Prussian blue-modified nickel sulfide to form iron-nickel bilayer hydroxyl oxides for efficient and stable oxygen evolution reaction processes

The oxygen evolution reaction (OER) is an important semi-reaction in the electrocatalytic water splitting for hydrogen energy production, and the development of efficient and low-cost electrocatalysts to solve the problem of slow 4-electron transport kinetics in the OER process is key. In this work, a pre-electrocatalyst with the heterogeneous interfacial structure, Prussian blue-modified nickel sulfide with sulfur vacancies (PB/NS-Sv), was designed and then converted to iron-nickel bilayer hydroxyl oxides in oxygen-rich vacancies (FeOOH/NiOOH-Ov@NS) through electrochemical oxidative reconstruction to obtain a truly stable and efficient active material. The study utilized in situ Raman to observe the transition from PB/NS-Sv to FeOOH/NiOOH-Ov@NS during the reaction. The electronic density of states in FeOOH/NiOOH-Ov@NS is regulated by the bilayer hydroxyl metal oxide synergistic effect and the abundant oxygen defect of Mental-OOH-Ov, which significantly improves OER catalytic performance. FeOOH/NiOOH-Ov@NS requires a low overpotential of only 257 mV in 1 mol/L KOH at 100 mA cm-2 current density, has a small Tafel slope of 35.2 mV dec-1 and has excellent stability for 150 h at 100 mA cm-2 current density, making it a promising candidate for industrial applications.

Boosting the Self-Recharging of Polypyrrole/Prussian Blue Electrochromic Device by Potential Difference-Driven Alternative Redox

Energy-storage electrochromic (EC) devices are a kind of recently developed device integrating energy-saving and energy-storage functions. To minimize energy consumption, a self-rechargeable energy-storage EC device with fast recovery speed is highly desired. Herein, a polypyrrole (PPy)/Prussian blue (PB) double-layer film with a potential difference is initially constructed and fabricated into a fast-recovery self-rechargeable EC device. Due to the existence of potential difference, the reduced PPy can be oxidized by PB, and subsequently Prussian white (the reduced state of PB) can be oxidized by O2 dissolved in electrolyte. Thus, the self-coloration/self-recharging process can be boosted by an alternative redox occurring in the solid/solid/liquid interfaces of PPy/PB/dissolved O2 instead of common solid/liquid interfaces or solutions. After self-recharging for 1 h, 65.0% of the open-circuit voltage and 45.2% of the total capacity can be recovered. Simultaneously, the synergy effect in this PPy and PB system enables a large optical modulation of 63.3% at 800 nm, a high open-circuit voltage of 1.20 V, and a large initial specific capacity of 87.8 mA·h·g-1 at 1.0 A·g-1. The design of double-layer film with a potential difference for boosting the self-coloration/self-recharging process of EC devices provides a new strategy for next-generation self-powered energy-storage EC devices.

Efficient removal of cesium ions using Prussian blue loaded on magnetic porous biochar synthesized by one-step calcination

Prussian blue (PB) is widely used for the selective removal of radioactive cesium ions (Cs+) from aqueous solutions. Due to its small size and easy dispersion in water, PB requires a carrier that is both inexpensive and easily separable. Magnetic porous biochar (MPBC) was formed by activating starch with FeCl3 through a one-step calcination method. MPBC can be used as a carrier for Prussian blue, which is easily separated from the solution. This composite material (PB/MPBC) has a rich pore structure and maintains effective surface area, which can facilitate the penetration of Cs+ into the adsorbent. Besides, PB/MPBC exhibits high selectivity and good adsorption capacity achieving a large removal capacity of 101.43 mg/g. Thus, this study provides a novel approach for preparing composites with efficient removal of Cs+.

Highly Sensitive Immunochromatographic Detection of Porcine Myoglobin as Biomarker for Meat Authentication Using Prussian Blue Nanozyme

This study was aimed at the sensitive immunodetection of porcine myoglobin (MG) as a species-specific biomarker in meat products. The enhanced lateral flow immunoassay (LFIA) was created in the sandwich format using monoclonal antibodies (Mab) with specificity to porcine MG and labeled by Prussian blue nanoparticles (PBNPs) as peroxidase-mimicking nanozymes. Signal amplification was provided by the colored product of oxidation catalyzed by the PBNPs. Several Mab-PBNP conjugates with different antibody loads were synthesized; the one that provided the best analytical characteristics of the LFIA was selected. Advanced optimization of the test system was carried out. As a result, the visual limit of detection (LOD) of MG was 1.5 ng/mL. Involvement of the catalytic nanozyme properties allowed the LOD to be decreased by ~9 times in comparison to the LFIA based on gold nanomarkers, and by ~27 times compared to the LFIA based on PBNP coloration. The assay time was 30 min, including catalytic enhancement. A simple technique of meat sample pre-treatment aimed at effective MG extraction and matrix disposal was proposed. The specificity of the LFIA towards the pork meat was demonstrated. The applicability of the created test system was shown by testing extracts obtained from finished meat products.

Spectrophotometric Determination of Cysteine Hydrochloride Content by Ferric Chloride-Potassium Ferricyanide

In the acidic medium, hydrosulfuryl(-SH) in cysteine hydrochloride can reduce Fe3+ to Fe2+, then Fe2+ react with potassium ferricyanide to form KFe[Fe(CN)6](soluble Prussian blue). Prussian blue has a maximum absorption at 727 nm, Bill's law is observed between mass concentration of cysteine hydrochloride and absorbance of Prussian blue, the content of cysteine hydrochloride is indirectly determinated by measuring the absorbance of Prussian blue. An accurate, simple, fast spectrophotometric method for the determination of cysteine hydrochloride content by ferric chloride-potassium ferricyanide has been established. The optimal determination conditions of cysteine hydrochloride content are explored. The cysteine hydrochloride content is determinate by this method.

Resolving Deactivation of Low-Spin Fe Sites by Redistributing Electron Density toward High-Energy Sodium Storage

Prussian blue (PB) has been an emerging class of cathode material for sodium-ion batteries due to its low cost and high theoretical capacity. However, their working voltage and capacity are substantially restricted due to the deactivation of low-spin Fe sites. Herein, we demonstrate a universal strategy to activate the low-spin Fe sites of PB by hybridizing them with the π-π conjugated electronic conductors. The redistribution of electron density between π-π conjugated conductors and PB effectively promotes the participation of low-spin Fe sites in sodium storage. Consequently, the low-spin Fe-induced plateau is greatly aroused, resulting in a high specific capacity of 148.4 mAh g-1 and remarkable energy density of 444.2 Wh kg-1. In addition, the excellent structural stability enables superior cycling stability over 2500 cycles and outstanding rate performance. The work will provide fundamental insight into activating the low-spin Fe sites of PB for advanced battery technologies.

Nanoarchitectonics of Bimetallic MOF@Lab-Grade Flexible Filter Papers: An Approach Towards Real-Time Water Decontamination and Circular Economy

This study presents a novel approach to decontaminate ferrocyanide-contaminated wastewater. The work effectively demonstrates the use of bimetallic Mo/Zr-UiO-66 as a super-adsorbent for rapid sequestration of Prussian blue, a frequently found iron complex in cyanide-contaminated soils/groundwater. The exceptional performance of Mo/Zr-UiO-66 is attributed to the insertion of secondary metallic sites, which deliver synergistic effects, benefiting the inherent qualities of the framework. Moreover, to extend the industrial applications of metal-organic frameworks (MOFs) in real-world scenarios, an approach is delivered to structure the nanocrystalline powders into MOF-based macrostructures. The work demonstrates an interfacial process to develop continuous MOF nanostructures on ordinary laboratory-grade filter papers. The novelty of the work lies in the development of robust free-standing filtration materials to purify PB dye-contaminated water. Additionally, the work embraces a circular economy concept to address problems related to resource scarcity, excessive waste production, and maintenance of economic benefits. Consequently, the PB dye-loaded adsorbent waste is re-employed for the adsorption of heavy metals (Pb2+ and Cd2+ ). Simultaneously, the study aims to address the problems related to the real-time handling of powdered adsorbents, and the generation of ecologically harmful secondary waste, thereby, progressing toward a more sustainable system.

The Development of Reagentless Amperometric Glucose Biosensor Based on Gold Nanostructures, Prussian Blue and Glucose Oxidase

Precise blood glucose detection plays a crucial role in diagnosing and medicating diabetes, in addition to aiding diabetic patients in effectively managing their condition. In this research, a first-generation reagentless amperometric glucose biosensor was developed by combining the graphite rod (GR) electrode modification by gold nanostructures (AuNS) and Prussian blue (PB) with glucose oxidase (GOx)-an enzyme that can oxidize glucose and produce H2O2. Firstly, AuNS was electrochemically deposited on the GR electrode (AuNS/GR), and then PB was electrochemically synthesized on the AuNS/GR electrode (PB/AuNS/GR). Finally, GOx was immobilized over the PB/AuNS nanocomposite with the assistance of Nafion (Nf) (Nf-GOx/PB/AuNS/GR). An application of PB in the design of a glucose biosensor enables an easy electrochemical reduction and, thus, the determination of the H2O2 produced during the GOx-catalyzed oxidation of glucose in the sample at a low operation potential of -0.05 V vs. Ag/AgCl/KCl3 mol L-1. In addition, AuNS increased the electrochemically active surface area, improved the GOx immobilization and ensured a higher analytical signal. The developed glucose biosensor based on the Nf-GOx/PB/AuNS/GR electrode exhibited a wide linear range, from 0.025 to 1 mmol L-1 of glucose, with a 0.0088 mmol L-1 limit of detection, good repeatability and high selectivity over electroactive interfering substances. The developed biosensor is convenient for the determination of glucose in the physiological environment.

3D Honeycomb Fe/MXene Derived from Prussian Blue Microcubes with a Tunable Structure for Efficient Low-Frequency and Flexible Electromagnetic Absorbers

The unique layered structure and high conductivity of MXene materials make them highly promising for microwave absorption. However, the finite loss mechanism and severe agglomeration present challenging obstacles for ideal microwave absorbers, which could be effectively improved by constructing a three-dimensional (3D) porous structure. This study reports a 3D honeycomb MXene using a straightforward template method. The 3D MXene framework offers ample cavities to anchor the Prussian blue microcubes and their derivatives including Fe microboxes and Fe clusters by a simple annealing process. Based on the superiority of the 3D honeycomb architecture and magnetic-dielectric synergistic effects, the Fe/MXene absorbers demonstrate outstanding microwave absorption capabilities with the optimum reflection loss value of -40.3 dB at 2.00 mm in the low-frequency range from 4.2 to 5.6 GHz. The absorber also manifests superior radar wave attenuation by finite element analysis and exhibits great potential to be a flexible and thermal insulation material in a wide range of temperatures. This work proposes a useful reference for the design of 3D MXene-based porous architectures, and the synergistic magnetic-dielectric strategy further expands the potential of MXene-based absorbers, enabling them to be used as flexible and highly efficient microwave absorbers.

Challenges in development and management of orphan drugs-a case study of Prussian blue insoluble

Prussian blue insoluble (PB) is an antidote for decorporation of radioactive and non-radioactive isotopes of thallium and cesium. Its dosage in the form of capsules, Radiogardase-Cs, is a United States Food and Drug Administration approved formulation since 2003. In India and many other countries, this drug is not available and in case of requirement it is imported from US or Europe. The author has worked extensively to make PB capsules available in India. The drug was recently approved by the Indian drug regulatory agency, Central Drugs Standard Control Organisation and is now available commercially in India. However this drug needs special attention as it is an orphan drug with limited requirement. The post-approval phase of this drug poses a different set of challenges and the author has highlighted some key issues with probable approaches for post-approval product management.

GSH-Triggered/Photothermal-Enhanced H2S Signaling Molecule Release for Gas Therapy

Traditional treatment methods for tumors are inefficient and have severe side effects. At present, new therapeutic methods such as phototherapy, chemodynamic therapy, and gasodynamic therapy have been innovatively developed. High concentrations of hydrogen sulfide (H2S) gas exhibit cancer-suppressive effects. Herein, a Prussian blue-loaded tetra-sulfide modified dendritic mesoporous organosilica (PB@DMOS) was rationally constructed with glutathione (GSH)-triggered/photothermal-enhanced H2S signaling molecule release properties for gas therapy. The as-synthesized nanoplatform confined PB nanoparticles in the mesoporous structure of organosilica silica due to electrostatic adsorption. In the case of a GSH overexpressed tumor microenvironment, H2S gas was controllably released. And the temperature increases due to the photothermal effects of PB nanoparticles, further enhancing H2S release. At the same time, PB nanoparticles with excellent hydrogen peroxide catalytic performance also amplified the efficiency of tumor therapy. Thus, a collective nanoplatform with gas therapy/photothermal therapy/catalytic therapy functionalities shows potential promise in terms of efficient tumor therapy.

Redox Targeting-based Neutral Aqueous Flow Battery with High Energy Density and Low Cost

Neutral aqueous flow batteries with common traits of the redox flow batteries, such as the independence of energy and power, scalability and operational flexibility, and additional merits of outstanding safety and low corrosivity show great promise for storing massive electrical energy from solar and wind energy. Particularly, the ferricyanide/ferrocyanide ([Fe(CN)6 ]3-/4- ) couple has been intensively employed as redox mediator to store energy in the catholyte ascribed to its abundance, low corrosivity, remarkable redox reversibility and stability. However, the low energy density arising from poor solubility of [Fe(CN)6 ]3-/4- restricts their commercial applications for energy storage systems. In this study, the practical energy density of a [Fe(CN)6 ]3-/4- -based catholyte is significantly boosted from 10.5 to 92.8 Wh L-1 by combining the counter-ion effect and the single-molecule redox-targeting (SMRT) reactions between [Fe(CN)6 ]3-/4- and Prussian blue (Fe4 [Fe(CN)6 ]3 , PB)/Prussian white (PW). Paired with concentrated K2 S anolyte, we demonstrate a neutral aqueous SMRT-based PB-Fe/S flow battery with ultra-long lifespan over 7000 cycles (4500 h) and ultra-low chemical cost of electrolytes in the cell as 19.26 $ kWh-1 . Remarkably, under the influences of SMRT reactions in the presence of PB granules in the catholyte, the capacity after 7000 cycles of the PB-Fe/S flow battery is 181.8 % of the initial capacity without PB.

In vitro and in vivo removal efficacy of insoluble Prussian blue in combination with calcium polystyrene sulfonate for thallium

The similarities between thallium and potassium have suggested the use of calcium polystyrene sulfonate (CPS), an oral ion exchange resin, as a potential agent against thallium intoxication. Therefore, the study was an attempt to evaluate the efficacy of CPS and Prussian blue when given alone or in combination against thallium toxicity. The effect on binding capacity was investigated in terms of contact time, amount of CPS, influence of pH, simulated physiological solutions and interference of potassium ions. Also, rats were given single dose of thallium chloride (20 mg kg-1) and the treatment with PB and CPS was given for 28 days as CPS 30 g kg-1, orally, twice a day, PB 3 g kg-1, orally, twice a day and their combination. The effect of antidotal treatment was evaluated by calculating the thallium levels in various organs, blood, urine and feces. The results of the in vitro study indicated exceedingly quick binding in the combination of CPS and PB as compared to PB alone. Also, it was found that the binding capacity at pH 2.0 was considerably increased for PB with CPS (184.656 mg g-1) as compared to PB (37.771 mg g-1). Furthermore, statistically significant results were obtained in the in vivo study as after 7th day, thallium levels in blood of rats treated with combination were reduced by 64% as compared to control group and 52% as compared to alone PB treated group. Also, Tl retention in liver, kidney, stomach, colon and small intestine of combination treated rats was significantly reduced to 46%, 28%, 41%, 32% and 33% respectively, as compared to alone PB treated group. These findings demonstrate this as a good antidotal option against thallium intoxication.

Peptide-Functionalized Prussian Blue Nanomaterial for Antioxidant Stress and NIR Photothermal Therapy against Alzheimer's Disease

Excessive accumulations of reactive oxygen species (ROS) and amyloid-β (Aβ) protein are closely associated with the complex pathogenesis of Alzheimer's disease (AD). Therefore, approaches that synergistically exert elimination of ROS and dissociation of Aβ fibrils are effective therapeutic strategies for correcting the AD microenvironment. Herein, a novel near infrared (NIR) responsive Prussian blue-based nanomaterial (PBK NPs) is established with excellent antioxidant activity and photothermal effect. PBK NPs possess similar activities to multiple antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase, which can eliminate massive ROS and relieve oxidative stress. Under the NIR irradiation, PBK NPs can generate local heat to disaggregate Aβ fibrils efficiently. By modifying CKLVFFAED peptide, PBK NPs display obvious targeting ability for blood-brain barrier penetration and Aβ binding. Furthermore, in vivo studies demonstrate that PBK NPs have outstanding ability to decompose Aβ plaques and alleviate neuroinflammation in AD mouse model. Overall, PBK NPs provide evident neuroprotection by reducing ROS levels and regulating Aβ deposition, and may accelerate the development of multifunctional nanomaterials for delaying the progression of AD.