Low Concentrations Of H2O2 Research Articles

Degradation of ciprofloxacin by hydrogen peroxide activated with pyrite under simulated sunlight

Ciprofloxacin (CIP) residues in the environment pose risks to both human health and ecosystems. In this study, we explored the effect of hydrogen peroxide (H2O2) on CIP degradation, activated by pyrite (FeS2) under simulated sunlight. XRD, XRF, EDS, XSP, DRS, and PL tests confirmed the high purity of FeS2 and its photocatalytic properties. With [CIP] = 30 μM, [FeS2] = 0.2 g/L, [H2O2] = 0.2 mM, CIP removal reached 87.6 %. The removal rate of TOC reached 55.3 % after 60 min of light exposure, and hydroxyl radicals (OH) contributed 72.7 % to the process. H2O2 utilization was 67.5 %, and the system operated effectively across a pH range of 2.00 to 8.00. CIP removal in river water reached 87.9 % after 3 h of light exposure, though the degradation was slower than in ultrapure water. Cl−, SO42−, and NO3− had little effect on degradation, whereas H2PO4−, CO32−, and HCO3− significantly inhibited the process as their concentrations increased. In livestock wastewater, the simulated sunlight-FeS2/H2O2 system was less effective, but after diluting the wastewater 100 times, CIP removal reached 87.6 % after 60 min. The degraded solutions showed no significant toxicity. These findings suggest that FeS2, combined with simulated sunlight, can effectively catalyze low concentrations of H2O2 to produce OH radicals, removing antibiotics from livestock wastewater.

Nanozymes as Antibacterial Agents: New Concerns in Design and Enhancement Strategies.

Nanozymes exhibiting natural enzyme-mimicking catalytic activities as antibacterial agents present several advantages, including high stability, low cost, broad-spectrum antibacterial activity, ease of preparation and storage, and minimal bacterial resistance. Consequently, they have attracted significant attention in recent years. However, the rapid expansion of antimicrobial nanozyme research has resulted in pioneering reviews that do not comprehensively address emerging concerns and enhancement strategies within this field. This paper first summarizes the factors influencing the intrinsic activity of nanozymes; subsequently, we outline new research considerations for designing antibacterial nanozymes with enhanced functionality and biosafety features such as degradable, imageable, targeted, and bacterial-binding nanozymes as well as those capable of selectively targeting pathogenic bacteria while sparing normal cells and probiotics. Furthermore, we review novel enhancement strategies involving external physical stimuli (light or ultrasound), the introduction of extrinsic small molecules, and self-supplying H2O2 to enhance the activity of antibacterial nanozymes under physiological conditions characterized by low concentrations of H2O2 and O2. Additionally, we present non-redox nanozymes that operate independently of highly toxic reactive oxygen species (ROS) alongside those designed to combat less common pathogenic bacteria. Finally, we discuss current issues, challenges faced in the field, and future prospects for antibacterial nanozymes.

StEPF2 and StEPFL9 Play Opposing Roles in Regulating Stomatal Development and Drought Tolerance in Potato (Solanum tuberosum L.)

Stomata are essential for photosynthesis and water-use efficiency in plants. When expressed in transgenic Arabidopsis thaliana plants, the potato (Solanum tuberosum) proteins EPIDERMAL PATTERNING FACTOR 2 (StEPF2) and StEPF-LIKE9 (StEPFL9) play antagonistic roles in regulating stomatal density. Little is known, however, about how these proteins regulate stomatal development, growth, and response to water deficit in potato. Transgenic potato plants overexpressing StEPF2 (E2 plants) or StEPFL9 (ST plants) were generated, and RT-PCR and Western blot analyses were used to select two lines overexpressing each gene. E2 plants showed reduced stomatal density, whereas ST plants produced excessive stomata. Under well-watered conditions, ST plants displayed vigorous growth with improved leaf gas exchange and also showed increased biomass/yields compared with non-transgenic and E2 plants. E2 plants maintained lower H2O2 content and higher levels of stomatal conductance and photosynthetic capacity than non-transgenic and ST plants, which resulted in higher water-use efficiency and biomass/yields during water restriction. These results suggest that StEPF2 and StEPFL9 functioned in pathways regulating stomatal development. These genes are thus promising candidates for use in future breeding programs aimed at increasing potato water-use efficiency and yield under climate change scenarios.

Sono-Catalytic Tooth Whitening and Oral Health Enhancement with Oxygen Vacancies-Enriched Mesoporous TiO2 Nanospheres: A Nondestructive Approach for Daily Tooth Care.

Tooth discoloration and the breeding of oral microorganisms pose threats to both one's aesthetic appearance and oral health. Clinical whitening agents based on H2O2 with high concentrations are effective in tooth whitening and bacterial elimination but may also cause enamel demineralization, gingival irritation, or cytotoxicity, necessitating professional supervision. Herein, leveraging sono-catalysis effects, a nondestructive and convenient tooth whitening strategy was developed, utilizing oxygen vacancies (OVs)-enriched mesoporous TiO2 nanospheres. The introduction of OVs leads to TiO2 bandgap narrowing, boosting the generation of reactive oxygen species (ROS) by TiO2 under ultrasound treatment. Additionally, through the chemocatalysis effect, the ROS yield can be further augmented by employing OVs-enriched TiO2 in conjunction with an extremely low concentration of H2O2 (1%) during ultrasound treatment. Hence, under ultrasound treatment simulating daily tooth brushing using an electronic toothbrush, the combination of OVs-enriched TiO2 and 1% H2O2 proves to be effective in whitening teeth stained by tea, coffee, and mix juice. Furthermore, the combination of OVs-enriched TiO2 and 1% H2O2 demonstrates potent bacterial-killing and biofilm-eradicating effects under ultrasound treatment within an extremely short duration (5 min). Additionally, given the mesoporous structure, curcumin, serving as an anti-inflammatory agent, can be efficiently loaded into OVs-enriched TiO2 and then controllably released through ultrasound treatment. The curcumin-loaded TiO2 facilitates the transition of macrophages to the anti-inflammatory M2 phenotype, potentially alleviating oral inflammation induced by bacterial infection without showing any biotoxicity. The OVs-enriched TiO2 based sono-catalysis tooth whitening procedure provides the convenience of whitening teeth during daily brushing without requiring professional supervision.

Stress-Induced Production of Bioactive Oxylipins in Marine Microalgae.

Microalgae, stemming from a complex evolutionary lineage, possess a metabolic composition influenced by their evolutionary journey. They have the capacity to generate diverse polyunsaturated fatty acids (PUFAs), akin to those found in terrestrial plants and oily fish. Also, because of their numerous double bonds, these metabolic compounds are prone to oxidation processes, leading to the creation of valuable bioactive molecules called oxylipins. Moreover, owing to their adaptability across various environments, microalgae offer an intriguing avenue for biosynthesizing these compounds. Thus, modifying the culture conditions could potentially impact the profiles of oxylipins. Indeed, the accumulation of oxylipins in microalgae is subject to the influence of growth conditions, nutrient availability, and stressors, and adjusting these factors can enhance their production in microalgae culture. Consequently, the present study scrutinized the LC-MS/MS profiles of oxylipins from three marine microalgae species (two Haptagophytes and one Chlorophyte) cultivated in 1 L of photobioreactors under varying stress-inducing conditions, such as the introduction of H2O2, EtOAc, and NaCl, during their exponential growth phase. Approximately 50 oxylipins were identified, exhibiting different concentrations depending on the species and growth circumstances. This research suggests that microalgae metabolisms can be steered toward the production of bioactive oxylipins through modifications in the culture conditions. In this instance, the application of a low dose of hydrogen peroxide to Mi 124 appears to stimulate the production of nonenzymatic oxylipins. For Mi136, it is the application of salt stress that seems to increase the overall production of oxylipins. In the case of Mi 168, either a low concentration of H2O2 or a high concentration of AcOEt appears to have this effect.

Using flow-through reactor to enhance ferric ions electrochemical regeneration in electro-fenton for wastewater treatment

Electrochemical regeneration of ferric ions catches more and more attention since it could decrease iron sludge to avoid the sludge problem while it could simultaneously obtain similar robust removal efficiency to refractory organic contaminants in wastewater treatment as the normal Fenton agent method. However, the electrochemical regeneration of ferric ions in aqueous solution was very slow. In this paper, the mass transfer limit of ferric ions in electro-Fenton reaction was evaluated. Koutecky-Levich equation reveals an extremely low diffusion coefficient (D0) value of ferric ions since its complex coordination of [Fe(HO)x(H2O)6-x]3-x. The D0 value was only 2.70 × 10−6 cm2·s−1. Flow-through reactor was therefore introduced in which the ferric ions was designed to penetrate through the 73.1 μm porous holes in the graphite fiber electrode. The μm-scaled confinement of ferric ions diffusion inside the holes was proved to successfully enhance the reduction current of ferric ions by more than 200 % since the diffusion distance of the ferric ions was significantly decreased in the flow-through reactor. However, besides the benefit of the flow-through reactor, the ferric ions reduction electro-Fenton (FeRR electro-Fenton) in flow-through still faces both the pH limit and H2O2 decomposition problems. Hydrogen evolution reaction (HER) could also cause the decrease of pH which exceeded the optimal pH window for Fenton and therefore destroyed the electro-Fenton reaction consequently although the electrochemical reaction of FeRR was 770 mV prior to HER reaction. The regeneration of Fe (II) process simultaneous destruction of H2O2 since H2O2 e-reduction was 120 mV prior to FeRR reaction, which resulted in only very low H2O2 concentration suitable for FeRR electro-Fenton. Even using stepwise addition of H2O2 in electro-Fenton, the decomposition of H2O2 still could not be avoided. Although the decomposition of H2O2 quite limited the application of FeRR electro-Fenton in real application, FeRR electro-Fenton still supports the enhancement removal efficiency of the refractory organic contaminants under low organic contaminants application.

Efficient hydrogen peroxide synthesis with Pluggable Capsule cathode for Electro-Fenton treating actual landfill leachate

Membrane concentrate of landfill leachate is the typical refractory wastewater with high contaminants concentration, high complexity, and high toxicity, posing a huge potential threat to the surface and subsurface water. Electro-Fenton (EF) based on in-situ synthesis of H2O2 is an effective method for the treatment of refractory organic pollutants. However, the low accumulative concentration of H2O2 and the poor scalability of the system remain major bottlenecks, limiting the practical application of EF. This study presented a modular air-breathing cathode, Pluggable Capsule Cathode (PCC), for efficient in-situ H2O2 synthesis through 2-electron oxygen reduction reaction (ORR). Based on PCC, corridor reactors (CR) were fabricated for in-situ H2O2 synthesis and actual landfill leachate treatment. Operated under the optimal conditions (dual-chamber, A/V=240 cm2 L−1, 2 M NaOH electrolytes and J=20 mA cm−2), the H2O2 concentration reached 28.1 g/L. In the EF system based on single-chamber CR equipped with PCCs, 81 % of COD and 89 % of NH3-N in landfill leachate were removed within 3 h. The total cost of landfill leachate treatment by the EF system based on CR-PCC was calculated as $ 5.06 m−3. The PCC based EF system was a promising process for the treatment of actual refractory wastewater, which provides a new insight for the structure design of cathode and reactor in the future.

Controllable synthesis of amidoximated self-propelled tubular micromotors for enhanced uranium recovery: non-invasive mixing and on-the-move capturing

Micro-/nanomotors that combine attributes of autonomous movement and adsorption performance are attractive for efficient pollutant treatment. However, micro/nanomotors design still suffers from challenges including complex manufacturing processes, specific instrument demands and low yields. Herein, we proposed amidoxime-functionalized polydopamine tubular micromotors (DNBMs-AO) and demonstrated their application for rapid selective adsorption of uranium from contaminated seawater. The whole fabrication procedure is simplified and straightforward by curcumin templating and in-situ reduction/graft method. The manganese dioxide (MnO2) catalyst and amidoxime groups are subsequently anchored on the outer and inner side of nanotube surface. Besides, the distribution and amount of modified MnO2 and amidoxime groups can be manipulated via directly changing the reduction time. DNBMs-AO are driven and propelled by microbubbles produced by MnO2-triggered catalytic decomposition of hydrogen peroxide, which can reach high velocity at 302.6 μm s−1. The static adsorption results indicate that the adsorption of U(VI) onto DNBMs-AO can be better described by Langmuir model with the maximum adsorption capacity of 313.9 mg/g. Moreover, the motion of DNBMs-AO can efficiently improve the U(VI) diffusion under low H2O2 concentration, and enhance the adsorption kinetics to approximately 2.5 times. DNBMs-AO also exhibits high selectivity towards U(VI) and excellent performance stability, endowing its potential application in environmental engineering field.

AI‐Assisted Plasmonic Enhanced Colorimetric Fluidic Device for Hydrogen Peroxide Detection from Cancer Cells

AbstractHydrogen peroxide (H2O2) is an essential molecule to various physiological processes and is commonly used for the detection and monitoring of glucose and cell viability. Furthermore, it is identified as a signal of oncogenic growth due to its widespread presence within the cancer cell environment. However, the low concentrations of H2O2 released by cancer cells' metabolism challenge current detection methods' capabilities and their practicality for translation to clinical applications. Colorimetric assays with simple readouts are a promising solution, provided that their sensitivity and rapidity in detecting H2O2 improve. Here, a plasmonic enhanced nanopatterned platform is proposed coupled with an Amplex Red assay to monitor the color change of H2O2 released from cancer cells. The nanopatterned platform embedded into a multiplexed microfluidic device enhances the kinetics of the reaction ≈7 times. This approach has reached a limit of detection of 1 pm when tested in breast (MCF‐7) and prostate (PC‐3) cancer media. The collected color images are processed and analyzed by a machine learning algorithm that categorizes them into “high” or “low‐to‐no” concentrations of H2O2 with 91% accuracy. This study is a step toward developing a device for highly sensitive H2O2 detection that is easily adaptable, user‐friendly, portable, and automated.

Fe-doped herbal medicine-based carbon dots nanozyme as safe and effective antimicrobial and wound healing agent

Bacterial infections pose a serious worldwide public health concern and play an important role in slowing or dramatically delaying wound healing. However, traditional antibiotics are faced with obstacles such as bacterial resistance and unsatisfactory biocompatibility, which has impeded further clinical translation. In recent years, antimicrobial nanomaterials have emerged as viable alternatives for combating bacterial infections, and carbon dots (CDs) have received particularly widespread attention due to their superior characteristics. In this work, a simple and eco-friendly one-step hydrothermal method was employed using the natural herbal medicine Eucommia ulmoides as a biomass carbon source to synthesize an Fe-doped CDs nanozyme (Fe-CDs) with good peroxidase-like (POD-like) activity, high biocompatibility, and strong antimicrobial activity for safe and effective antimicrobial therapy and the promotion of wound healing. L929 cells co-cultured with Fe-CDs did not show significant cytotoxicity and favored cell proliferation at appropriate concentrations. In addition, Fe-CDs catalyzed the decomposition of low-concentration H2O2 to ·OH, leading to enhanced antimicrobial activity. Both in vitro and in vivo experiments demonstrated that Fe-CDs exhibit potent antibacterial properties, the ability to promote cell migration and angiogenesis, and significant potential for promoting the healing of infected wounds. In summary, a green and safe antimicrobial nanozyme based on a biomass herbal medicine was developed in this work, offering promising insight into the development of novel antimicrobial materials and tissue regeneration engineering.

Production of nutritionally active compounds from Spirulina platensis under various stress conditions

The free-floating, filamentous cyanobacteria Spirulina platensis is highly valued and in great demand worldwide for its high-value colors and phytonutrients. These compounds find use in health foods, feed, medicines, and diagnostics. The primary objective of this work was to enhance the growth of Spirulina under both oxidative and physiological stress conditions in order to maximize the synthesis of phycocyanin and carotenoid pigments. Cultures were subjected to different concentrations of hydrogen peroxide (H2O2) and sodium chloride for varying temperatures and pH levels. Under lower concentrations of H2O2 (4mM), the maximum carotenoid content was increased, but the phycocyanin content was found to be stimulated at 10mM. Moreover, the synthesis of both pigments was shown to be highest under physiological stress circumstances (40mM and 60mM NaCl concentration) and at an optimal pH of 8-9, helped by a temperature range of 25-30℃. The experimental results demonstrate that both carotenoid and phycocyanin exhibit antioxidant properties even in the presence of oxidative stress. This suggests that the aforementioned circumstances can be applied in future investigations to extract different antioxidants from S. platensis.

Copper Single-Atom-Based Metal-Organic Framework for Ultrasound-Enhanced Nanocatalytic Therapy.

Chemodynamic therapy (CDT) is an emerging therapeutic modality triggered by endogenous substances in the tumor microenvironment (TME) to generate reactive oxygen species. However, the mild acid pH, low H2O2 concentration, and overexpressed glutathione can suppress the CDT efficiency. Herein, ultrasound (US)-triggered Cu2+-based single-atom nanoenzymes (FA-NH2-UiO-66-Cu, FNUC) are constructed with the performance of target and glutathione depletion. In the TME, the single-atom Cu sites of FNUC consume glutathione and the FNUC:Cu+ generates •OH via peroxidase-like activity. The US-activated FNUC exhibits a fast •OH generation rate, a low Michaelis constant, and a large •OH concentration, indicating the cavitation effect of US promotes the •OH generation. Meanwhile, the tumor target of FNUC is confirmed by NIR-II fluorescence imaging, in which it is modified with IR-1061. Combined with the antitumor performance of FNUC in vitro and in vivo, the novel Cu-based SAzymes can achieve efficient and precise cancer treatment.

Defect and doping engineering mediated M-D-MIL(Fe)/Cu-C3N4 heterojunction with dual active centers for efficient tetracycline hydrochloride removal

It is essential to explore Fe-MOFs catalysts containing both multiple active sites and rapid charge separation for improving photo-Fenton performance. Herein, a defect and doping engineering mediated M-D-MIL(Fe)/Cu-C3N4 heterojunction with dual active centers was prepared and its removal performance was investigated against tetracycline hydrochloride. Characterization confirms that: (1) The ligand vacancies in M-D-MIL(Fe) can expose plenty of coordinatively unsaturated metal sites (Fe CUS), which enhance the Lewis acidity and optimize the adsorption of H2O2. Meanwhile, the built-in dual redox centers (Fe3+/Fe2+ and Cu+/Cu2+) can synergistically promote the activation of H2O2. (2) The ligand vacancies in M-D-MIL(Fe) and copper ion in C3N4 as electron trapping sites can optimize the carrier separation of single-component materials. Furthermore, the composites exhibit a suitable energy band structure, an oriented built-in electric field, and tight interfacial contacts, all of which collectively create an optimal pathway and driving force for the efficient transport of photoinduced charges. This, in turn, accelerates the Fe3+/Fe2+ redox cycle. Finally, M-D-MIL(Fe)/Cu-C3N4 demonstrates excellent photo-Fenton performance at low H2O2 concentrations (5 mM), with a kinetic rate (k) of 0.035 min⁻¹, which is 14.58, 18.42, 1.94, and 15.21 times higher than those of MIL-100(Fe), C3N4, M-D-MIL(Fe), and Cu-C3N4, respectively. The study presents an innovative idea with potential applications in environmental restoration.

Novel triphenylamine-pyrene-based AIEgens: Specific detection and imaging of H2O2 in aqueous solution and cells

H2O2 plays a key regulatory role as a bioendogenous reactive oxygen species in cells and organisms. However, excessive production or accumulation of H2O2 during mitochondrial oxidative stress may lead to oxidative damage of cellular proteins and trigger rheumatic diseases, cancers, and a variety of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. In addition, H2O2 is a very useful chemical widely employed in the textile and chemical industries, and its excessive emission not only pollutes the environment but also jeopardizes human health. Therefore, the sensitive and specific detection and removal of H2O2 is important for early diagnosis of diseases, treatment prognosis and environmental pollution monitoring. We have designed two novel triphenylamine-based AIEgens MOTPP and MOTPP-B, which each have a high solid-state fluorescence quantum yield and excellent aggregation-induced emission properties. MOTPP-B has high selectivity and anti-interference ability toward H2O2, a wide pH tolerance range, a sensing process that is complete in under 40 min, and a low detection limit of 120.77 nM. It has been successfully applied for the detection of low concentrations of H2O2 in the environment and to dual-channel imaging of low concentrations of exogenous H2O2 in living cells.

Controlled Delivery of H2O2: A Three-Enzyme Cascade Flow Reactor for Peroxidase-Catalyzed Reactions.

Peroxidases are promising catalysts for oxidation reactions, yet their practical utility has been hindered by the fact that they require hydrogen peroxide (H2O2), which at high concentrations can cause deactivation of enzymes. Practical processes involving the use of peroxidases require the frequent addition of low concentrations of H2O2. In situ generation of H2O2 can be achieved using oxidase-type enzymes. In this study, a three-enzyme cascade system comprised of a H2O2 generator (glucose oxidase (GOx)), H2O2-dependent enzymes (chloroperoxidase (CPO) or horseradish peroxidase (HRP)), and a H2O2 scavenger (catalase (CAT)) was deployed in a flow reactor. Immobilization of the enzymes on a graphite rod was achieved through electrochemically driven physical adsorption, followed by cross-linking with glutaraldehyde. Modeling studies indicated that the flow in the reactor was laminar (Reynolds number, R e < 2000) and was nearly fully developed at the midplane of the annular reactor. Immobilized CAT and GOx displayed good stability, retaining 79% and 84% of their initial activity, respectively, after three cycles of operation. Conversely, immobilized CPO exhibited a considerable reduction in activity after one use, retaining only 30% of its initial activity. The GOx-CAT-GRE system enabled controlled delivery of H2O2 in a more stable manner with a 4-fold enhancement in the oxidation of indole compared to the direct addition of H2O2. Using CPO in solution coupled with GOx-CAT-GRE yields of 90% for the oxidation of indole to 2-oxyindole and of 93% and 91% for the chlorination of thymol and carvacrol, respectively.

Production of Peroxymonocarbonate by Steady-State Micromolar H2O2 and Activated Macrophages in the Presence of CO2/HCO3- Evidenced by Boronate Probes.

Peroxymonocarbonate (HCO4-/HOOCO2-) is produced by the reversible reaction of CO2/HCO3- with H2O2 (K = 0.33 M-1, pH 7.0). Although produced in low yields at physiological pHs and H2O2 and CO2/HCO3- concentrations, HCO4- oxidizes most nucleophiles with rate constants 10 to 100 times higher than those of H2O2. Boronate probes are known examples because HCO4- reacts with coumarin-7-boronic acid pinacolate ester (CBE) with a rate constant that is approximately 100 times higher than that of H2O2 and the same holds for fluorescein-boronate (Fl-B) as reported here. Therefore, we tested whether boronate probes could provide evidence for HCO4- formation under biologically relevant conditions. Glucose/glucose oxidase/catalase were adjusted to produce low steady-state H2O2 concentrations (2-18 μM) in Pi buffer at pH 7.4 and 37 °C. Then, CBE (100 μM) was added and fluorescence increase was monitored with time. The results showed that each steady-state H2O2 concentration reacted more rapidly (∼30%) in the presence of CO2/HCO3- (25 mM) than in its absence, and the data permitted the calculation of consistent rate constants. Also, RAW 264.7 macrophages were activated with phorbol 12-myristate 13-acetate (PMA) (1 μg/mL) at pH 7.4 and 37 °C to produce a time-dependent H2O2 concentration (8.0 ± 2.5 μM after 60 min). The media contained 0, 21.6, or 42.2 mM HCO3- equilibrated with 0, 5, or 10% CO2, respectively. In the presence of CBE or Fl-B (30 μM), a time-dependent increase in the fluorescence of the bulk solution was observed, which was higher in the presence of CO2/HCO3- in a concentration-dependent manner. The Fl-B samples were also examined by fluorescence microscopy. Our results demonstrated that mammalian cells produce HCO4- and boronate probes can evidence and distinguish it from H2O2 under biologically relevant concentrations of H2O2 and CO2/HCO3-.

Bimetallic Photo-Activated and Steerable Janus Micromotors as Active Microcleaners for Wastewater.

Photoactive colloidal motors whose motion can be controlled and even programed via external magnetic fields have significant potential in practical applications extending from biomedical fields to environmental remediation. Herein, we report a "three in one" strategy in a Co/Zn-TPM (3-trimethoxysilyl propyl methacrylate) bimetallic Janus colloidal micromotor (BMT-micromotor) which can be controlled by an optical field, chemical fuel, and magnetic field. The speed of the micromotors can be tuned by light intensity and with the concentration of the chemical fuel of H2O2, while it could be steered and programed through magnetic field due to the presence of Co in the bimetallic part. Finally, the BMT-micromotors were employed to effectively remove rubidium metal ions and organic dyes (methylene blue and rhodamine b). Benefited of excellent mobility, multiple active sites, and hierarchical morphology, the micromotors exhibit excellent adsorption capacity of 103 mg·g-1 to Rb metal ions and high photodegradation efficiency toward organic dyes in the presence of a lower concentration of H2O2. The experimental characterizations and DFT calculations confirmed the strong interaction of Rb metal ions on the surface of BMT-micromotors and the excellent decomposition of H2O2 which enhanced the photodegradation process. We expect the combination of light and fuel sensitivity with magnetic controllability to unlock an excess of opportunities for the application of BMT-micromotors in water treatments.

A homologous membrane-camouflaged self-assembled nanodrug for synergistic antitumor therapy

Limited success has been achieved in ferroptosis-induced cancer treatment due to the challenges related to low production of toxic reactive oxygen species (ROS) and inherent ROS resistance in cancer cells. To address this issue, a self-assembled nanodrug have been investigated that enhances ferroptosis therapy by increasing ROS production and reducing ROS inhibition. The nanodrug is constructed by allowing doxorubicin (DOX) to interact with Fe2+ through coordination interactions, forming a stable DOX-Fe2+ chelate, and this chelate further interacts with sorafenib (SRF), resulting in a stable and uniform nanoparticle. In tumor cells, overexpressed glutathione (GSH) triggers the disassembly of nanodrug, thereby activating the drug release. Interestingly, the released DOX not only activates nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) to produce abundant H2O2 production for enhanced ROS production, but also acts as a chemotherapeutics agent, synergizing with ferroptosis. To enhance tumor selectivity and improve the blood clearance, the nanodrug is coated with a related cancer cell membrane, which enhances the selective inhibition of tumor growth and metastasis in a B16F10 mice model. Our findings provide valuable insights into the rational design of self-assembled nanodrug for enhanced ferroptosis therapy in cancer treatment. Statement of significanceFerroptosis is a non-apoptotic form of cell death induced by the iron-regulated lipid peroxides (LPOs), offering a promising potential for effective and safe anti-cancer treatment. However, two significant challenges hinder its clinical application: 1) The easily oxidized nature of Fe2+ and the low concentration of H2O2 leads to a low efficiency of intracellular Fenton reaction, resulting in poor therapeutic efficacy; 2) The instinctive ROS resistance of cancer cells induce drug resistance. Therefore, we developed a simple and high-efficiency nanodrug composed of self-assembling by Fe2+ sources, H2O2 inducer and ROS resistance inhibitors. This nanodrug can effectively deliver the Fe2+ sources into tumor tissue, enhance intracellular concentration of H2O2, and reduce ROS resistance, achieving a high-efficiency, precise and safe ferroptosis therapy.

Enhancing photocatalytic performance: Studying the synthesis and characterization of AgI-tuned TiO2/ZnO hybrid ternary nanocomposites

Eliminating phenol and other contaminants from wastewater is an essential step in addressing environmental issues. Using tailored photocatalysts is essential for the effective degradation of phenol via photocatalysis. The main objective of this study is to produce TiO2/ZnO/AgI nanocomposites employing the reflux approach in order to enhance the degradation of phenol in the presence of UV radiation. The nanocomposite incorporates TiO2 and ZnO, resulting in a narrowed band gap that enhances photocatalytic activity. The addition of AgI enhances electron transport capacities, resulting in an inclusive augmentation in performance. The physicochemical properties of the nanocomposite were extensively investigated applying an array of advanced techniques including as XRD, BET, FESEM, TEM, EDX and TGA spectroscopy practices. The combined effect of TiO2, ZnO, and AgI exhibits an approximately 100 % degradation of phenol, exceeding the individual performance of each component. The outcomes indicated that the operational parameters have a substantial impact on the photocatalytic activity, and the addition of H2O2 also improves degradation. The ideal conditions require a low concentration of H2O2 and a dose of 0.3 g/350 mL of nanocomposite. The reaction rate constant was reported as 6.96 × 10−3 min−1 under optimised conditions. The ternary nanocomposite exhibited recyclability for four successive cycles, eventually displaying ∼88 % degradation. The TiO2/ZnO/AgI nanocomposite system exhibits significant photocatalytic efficiency, which has important consequences for addressing environmental concerns caused by the persistent existence of various organic contaminants in water sources.

One-Pot Synthesis of Nanoflower-Like Zn2SnS4 as Nanozymes for Highly Sensitive Electrochemical Detection of H2O2 Released by Living Cells.

The sensitive and reliable nanozyme-based sensor enables the detection of low concentrations of H2O2 in biological microenvironments, it has potential applications as an in-situ monitoring platform for cellular H2O2 release. The uniformly dispersed bimetallic sulfide (Zn2SnS4) nanoflowers were synthesized via a one-pot hydrothermal method and the two kinds of metal ions can serve as morphology and structure directing agents for each other in the synthetic process. The nanoparticles were utilized as nanozyme materials to fabricate a novel electrochemical sensor, and it exhibits a distinct electrochemical response towards H2O2 with excellent stability and detection capability (with a minimum detection limit of 1.79 nM (S/N=3)), the excellent characteristics facilitate the precise detection of low concentrations of H2O2 in biological microenvironments. Use the macrophages differentiated from leukemia THP-1 cells as a representative sensing model, the sensor was successfully utilized for real-time monitoring of the release of H2O2 induced by living cells, which has significant potential applications in clinical diagnosis and cancer treatment.