Peroxy Research Articles

Synthesis and Structure of Urea-Formaldehyde Oligomers with Peroxide Groups

The possibility of synthesis in the presence of tert-butyl peroxymethanol (TBPM) or tert-butyl hydroperoxide (TBHP) of urea-formaldehyde oligomers with peroxide groups (UFOP) has been considered. Zinc oxide was used as the reaction catalyst. The effect of the initial components ratio, the reaction temperature and the process time on the characteristics and yield of the obtained oligomers was studied. Methods for obtaining UFOP using a mixture of TBPM and TBHP as a component are proposed. The structure of the synthesized UFOP was confirmed by IR- and NMR-spectroscopic studies.

Mechanistic Study of the Aqueous Reaction of Organic Peroxides with HSO3− on the Surface of a Water Droplet

AbstractAqueous reactions between organic peroxides and SO2 are of intense interest in atmospheric science because of their ubiquitous implications for sulfate formation in secondary aerosols. However, the relative yields of the reaction products (inorganic vs. organic sulfates) remain controversial (i.e., 90 % vs. 40–70 % for inorganic sulfate) due in part to the lack of understanding of the underlying reaction mechanisms. Here, our computational results suggest that the reactions of HSO3− (dissolved SO2) with organic peroxides are initiated on the surface of water nanodroplets and then proceed under two reaction pathways, in which the S atom of HSO3− attacks either the O1 or O2 atom of the peroxide group ‐O(O2)O(O1)H, leading to the formation of inorganic and organic sulfates, respectively. Notably, we find that thse reaction initiated by O1 atom exhibits a relatively low energy barrier and high reaction rate, which favours the formation of inorganic sulfate.

Mechanistic Study of the Aqueous Reaction of Organic Peroxides with HSO3 - on the Surface of a Water Droplet.

Aqueous reactions between organic peroxides and SO2 are of intense interest in atmospheric science because of their ubiquitous implications for sulfate formation in secondary aerosols. However, the relative yields of the reaction products (inorganic vs. organic sulfates) remain controversial (i.e., 90 % vs. 40-70 % for inorganic sulfate) due in part to the lack of understanding of the underlying reaction mechanisms. Here, our computational results suggest that the reactions of HSO3 - (dissolved SO2 ) with organic peroxides are initiated on the surface of water nanodroplets and then proceed under two reaction pathways, in which the S atom of HSO3 - attacks either the O1 or O2 atom of the peroxide group -O(O2)O(O1)H, leading to the formation of inorganic and organic sulfates, respectively. Notably, we find that thse reaction initiated by O1 atom exhibits a relatively low energy barrier and high reaction rate, which favours the formation of inorganic sulfate.

Hydrogen Peroxide: Its Use in an Extensive Acute Wound to Promote Wound Granulation and Infection Control - Is it Better Than Normal Saline?

Background: Hydrogen peroxide (H2O2) is used as a topical antiseptic in contaminated wounds caused by road traffic accidents. It kills bacteria by producing oxidation through local, nascent, free oxygen radicals. It also removes dirt from the wound due to its frothing action. H2O2 is synthesized by various cells as an active biochemical agent that affects cell biological behavior through complex chemical reactions. H2O2 has also been used as a wound cleaning agent, removing debris, preventing infection, and causing hemostasis due to its exothermic reaction with blood. Despite its widespread use, there is scanty literature on its use to promote granulation tissue formation. Objective: In the orthopaedics literature, studies on H2O2 use are very limited and its potential is underestimated. In the present study, we would like to report our protocol of use of H2O2 for its tremendous potential for stimulating granulation and early wound healing. Material and Methods: A total of 53 patients with large acute extensive lower limb contaminated wounds reported to the emergency department have been included with and without lower limb fracture. In group A (43 patients) wound management was done using 7% H2O2 and group B (10 patients) was treated by only saline dressing as a control group. Results: In the present study, daily dressing by 7% H2O2 solution and provide solution gives excellent results compared to the Saline group. Granulation tissue appeared much earlier with a mean SD 6.3 ± 6.8 days in the hydrogen peroxide group as compared to the Saline group where granulation tissue appeared in 9.3 ± 8.4 days. Conclusion: Spontaneous wound healing is a controlled balance between destructive and healing processes. It is mandatory to remove damaged tissue to promote healing by secondary intention and minimize infection. The dynamic effect of H2O2 promotes faster healing, stimulates granulation, and minimizes infection by oxidative stress.

Does application of hydrogen peroxide to the dermis reduce incidence of Cutibacterium acnes during shoulder arthroplasty: a randomized controlled trial.

Prosthetic joint infections (PJIs) following shoulder arthroplasty are a major source of morbidity and are most commonly caused by Cutibacterium acnes, a bacteria found concentrated in the dermis. Skin preparation using hydrogen peroxide has been shown to reduce positive cultures; however, direct application to the dermis has not been investigated. The purpose of this study is to determine whether the application of hydrogen peroxide to the dermis affects the incidence of positive C acnes cultures. A prospective, randomized controlled trial of patients undergoing primary shoulder arthroplasty by a single fellowship-trained surgeon was performed between February and November 2020. Enrolled patients were randomized to either receive standard skin preparation and antibiotic prophylaxis with or without an additional application of hydrogen peroxide to the dermis following incision. Culture samples were taken from the skin, dermis, glenohumeral joint, and air. Laboratory personnel and patients were blinded to randomization, and all cultures were held for 14 days. Culture positivity rate along with culture site, day of culture positivity, and bacterial abundance of positive cultures were analyzed. Stratified analysis by gender and age of ≤69 years was also performed. Sixty patients undergoing primary arthroplasty were randomized. The group receiving hydrogen peroxide (n =30) and the control group (n = 30) were similar in age (71.1 ± 7.1 vs. 73.4 ± 9.8; P = .30), body mass index (29.4 ± 5.7 vs. 28.5 ± 6.0; P = .57), gender (P = .64), hand dominance (P = .65), and surgery type (P = .90). The overall rate of at least 1 positive culture was 18%. All positive cultures were C acnes. The positive culture rate in the hydrogen peroxide (20%) and control group were similar (16%; P > .99). There were no positive glenohumeral joint cultures and no wound complications. There was no significance difference in the culture site, day of culture positivity, and bacterial abundance. Stratification analysis by gender and age also demonstrated similar rates of C acnes between study groups. Standard skin preparation and antibiotic prophylaxis results in an overall low rate of skin and dermis culture positivity. The use of hydrogen peroxide after initial incision did not significantly alter the rate of positive C acnes cultures during shoulder arthroplasty and did not increase wound complications.

Mechanism of Post-Radiation-Chemical Graft Polymerization of Styrene in Polyethylene.

Structural and morphological features of graft polystyrene (PS) and polyethylene (PE) copolymers produced by post-radiation chemical polymerization have been investigated by methods of X-ray microanalysis, electron microscopy, DSC and wetting angles measurement. The studied samples differed in the degree of graft, iron(II) sulphate content, sizes of PE films and distribution of graft polymer over the polyolefin cross section. It is shown that in all cases sample surfaces are enriched with PS. As the content of graft PS increases, its concentration increases both in the volume and on the surface of the samples. The distinctive feature of the post-radiation graft polymerization is the stepped curves of graft polymer distribution along the matrix cross section. A probable reason for such evolution of the distribution profiles is related to both the distribution of peroxide groups throughout the sample thickness and to the change in the monomer and iron(II) salt diffusion coefficients in the graft polyolefin layer. According to the results of electron microscope investigations and copolymer wettability during graft polymerization, a heterogeneous system is formed both in the sample volume and in the surface layer. It is shown that the melting point, glass transition temperature and degree of crystallinity of the copolymer decreases with the increasing proportion of graft PS. It is suggested that during graft polymerization a process of PE crystallite decomposition (melting) and enrichment of the amorphous phase of graft polymer by fragments of PE macromolecules occurs spontaneously. The driving force of this process is the osmotic pressure exerted by the phase network of crystallites on the growing phase of the graft PS.

Effect of vitamin C treatment on some central nervous system functions in young rats whose mothers treated with hydrogen peroxide during the lactation period

This study was designed to evaluate the effect of vitamin on young rats whose mothers exposed to 1% hydrogen peroxide in drinking water during the lactation period on the function of the nervous system. The study consisted of three groups, Control group, hydrogen peroxide group, vitamin C with hydrogen peroxide group, showed that treatment with hydrogen peroxide for mothers led to significant decrease in the weights of young-rats-age21 days and significant increase in the righting reflex test, cliff avoidance and the olfactory discrimination test in young rats at age of week and also in the onset movement test and at the time of negative geotaxis test in-young-rats age21days. Treatment of mothers with hydrogen peroxide caused significant decrease in open-field activity and number of times standing on backlists during 3minutes and in the approach response, touch and sound of young rats at age 21 days. While, hydrogen peroxide treated group resulted in significant increase in time of negative geotaxis test and hydrogen peroxide had no effect on response of tail pinch as compared to other groups. When treating mothers with vitamin C significant increase in weights of youngsters age21days, as well as in onset of movement test and in number of squares cutoff within 3minutes in open-field activity and number of times standing on backlists during 3minutes in young-rats age 21 days. Also there was significant decrease in righting reflex test, olfactory distinction and negative geotaxis test compared to hydrogen peroxide treated group. It was concluded from the study that vitamin C plays an important role as an antioxidant by improving the nervous system function in young rats their mothers exposed to with hydrogen peroxide in drinking water.

Molecular Engineering of Hydrogels for Rapid Water Disinfection and Sustainable Solar Vapor Generation.

Consumption of unsafe water is a major cause of morbidity and mortality in developing regions. Pasteurizing or boiling water to remove pathogens is energy-intensive and often impractical to off-grid communities. Therefore, low capital cost, rapid and energy-efficient water disinfection methods are urgently required to address global challenges of safe water access. Here, anti-bacterial hydrogels (ABHs) with catechol-enabled molecular-level hydrogen peroxide generators and quinone-anchored activated carbon particles are designed for effective water treatment. The bactericidal effect is attributed to the synergy of hydrogen peroxide and quinone groups to attack essential cell components and disturb bacterial metabolism. ABHs can be directly used as tablets to achieve >99.999% water disinfection efficiency within 60min without energy input. No harmful byproducts are formed during the treatment process, after which the ABH tablets can be easily removed without residues. Taking advantage of their excellent photothermal and biofouling-resistant properties, ABHs can also be applied as solar evaporators to achieve stable water purification under sunlight (≤1kW m-2 ) after months of storage and operation in bacteria-containing river water. The ABH platform offers reduced energy and chemical demands for point-of-use water treatment technologies in remote areas and emergency rescue applications.

ДОСЛІДЖЕННЯ ВЛАСТИВОСТЕЙ, ОСОБЛИВОСТЕЙ СТРУКТУРИ І ТЕХНОЛОГІЧНИХ МОЖЛИВОСТЕЙ НОВИХ ПОЛІМЕРНИХ МАТЕРІАЛІВ ДЛЯ НАПОВНЮВАННЯ-ДОДУБЛЮВАННЯ ШКІРИ

The paper presents the results of research of two new industrial polymer materials in the form of the Syntan RS3L product and the Syntan F187 product. It has been experimentally established that these materials differ in appearance, structure, and physicochemical properties. So, the first product is a solution of polyacrylates and is well compatible with water, while the second product is a synthetic composition of melamine-formaldehyde resins and inorganic compounds based on aluminium, iron, potassium, sulfur, silicon in the form of a powder, which is partially soluble in water. Using the method of infrared spectroscopy, the features of the structure of polymeric materials are determined – the presence of various groups and bonds, which indicates the polyfunctional nature of both reagents. It was found that after treatment of a chrome tanned collagen preparation with Syntan LF187, the optical density in the IR spectrum of collagen changes to the greatest extent at a frequency of 876-873 cm-1, which corresponds to stretching vibrations of O-O groups of peroxides in the protein structure. When exposed to the Syntan RS3 product, significant changes are observed in the frequency range 1240-1235 cm-1, which corresponds to the stretching and deformation vibrations of the nitrogen-containing Amide II groups, amines and OH groups of alcohols. When studying the technological capabilities of polymeric materials as reagents for filling and retanning chrome tanned leather for shoe uppers from cattle raw materials, it was found that, according to the organoleptic assessment and the indicator of the generalized objective function, the best were leather samples processed with 2.0 % of the Syntan RS3 product. The results obtained can be explained by the peculiarities of the distribution and interaction of materials in the structure of the dermis, the essence of which is the formation of strong and at the same time flexible bonds, which has a positive effect on the formation of the structure and quality indicators of leather. To confirm the obtained data, it is planned to conduct semi-production tests. It is expected that the quality of the finished product will improve, and the existing vegetable and synthetic tanning agents will be replaced with a modern, more efficient and environmentally friendly polymer material.

Study of the effect of Ultraviolet UV-induced oxidative stress in male white rats (Rattus rattus)

The present study was designed to investigate some of the physiological effects in the blood of white male rats exposed to oxidative stress induced by hydrogen peroxide in drinking water at a concentration of 0.5% for a period of 50 days and to compare it with the group exposed to ultraviolet rays at a rate of 6 watts per candle for a period of 50 days First:- The results showed a significant increase (P≤0.05)in the group of rats exposed to radiation in the group of ultraviolet rays (18 watts) UV3 and hydrogen peroxide both when compared with the control group. In radical Peroxy nitrite level and in total white blood cell count and for both Ly % and GR%. The results also showed a significant increase (P≤0.05) in the level of glucose. Second:- There was a significant decrease at a significant level (P≤0.05)in the level of glutathione in the group of rats exposed to UV3 radiation and the hydrogen peroxide group alike when compared with the control group, with a significant decrease at a significant level of (P≤0.05)in the activity of the enzyme glutathione. Glutathione peroxidase and a significant decrease (P≤0.05)in the volume of packed blood cells, the hemoglobin value, the red blood cell count, and the platelet value, with a significant decrease of MO..% Third:- The occurrence of signs of blurred vision in the eyes of the ultraviolet rays group with a strength (3 candles) in addition to the darkening of the tail in a clear and striking way and the lack of movement and activity compared to the hydrogen peroxide group and the rays group, the strength of one candle.

Long-term surface modification of PEEK polymer using plasma and PEG silane treatment

Despite the several advantages of the Polyetheretherketone (PEEK) polymer, its wide application is limited due to its hydrophobic nature and poor surface adhesion performance. The plasma treatment can effectively transform the hydrophobic surface to hydrophilic. However, their effects are for a short duration, and the modified surfaces gradually lose their wetting and surface adhesion properties. In this work, we have reported a combined effect of plasma and PEG Silane treatment for permanent hydrophilic modification and improved adhesion strength of PEEK surfaces. The time-dependent changes in the contact angles, XPS, and ATR-FTIR spectra results were carefully recorded to investigate the surface properties of the modified surfaces. It was observed that the functional groups and polar component of surface energy played a pivotal role in long-term modification of PEEK surfaces. The Plasma and PEG Silane treated PEEK surface retained a very low contact angle and high content of hydroxide, carboxylic acid, and peroxide groups as compared to the plasma-treated PEEK surfaces. The lap shear test confirms the long-term effects of Plasma and PEG Silane treatment on adhesion properties with high bonding strength after 48 days of sample storage, which was dropped for Plasma treated surface just after 7 days of storage.

Novel metal-free N-doped bio-graphenes and their MoO3 bifunctional catalysts for ultra-deep oxidative desulfurization of heavy fuel

• Synthesis of N-doped graphene from Arabic gum and Gelatin as metal-free catalysts. • Different N-dopant shows different type of nitrogen, surface area, and nitrogen content N-doped graphene produced by hexamethylenetetramine shows the highest catalytic activity. • MoO 3 in N-doped graphene enhance the catalytic activity. We developed here a green procedure for the synthesis of novel N–doped bio-graphenes from Arabic gum as a natural source by using different N-dopants (urea, hexamethyleneteramine, and ethylenediamine) and Gelatin as a carbon source containing N species. The effect of these dopants on the type of nitrogen species, nitrogen contents, and surface structure of graphene catalysts was investigated on their catalytic properties for oxidative removal of sulfur compounds in fuel oil. All of doped graphenes show the pyridinic and pyrrolic nitrogen species, while the graphene doped with hexamethylenetetramine shows the highest amount of nitrogen with some content of amine group as well as pyridinc-N and pyrrolic-N. This N-doped graphene indicates the highest catalytic activity due to the type of nitrogen species, higher nitrogen content, and higher surface area. The resulting immobilized catalysts with MoO 3 also show the similar trend in catalytic activities. Nitrogen doping increase the electron density of peroxo groups by donating electrons to Mo-centers which enhance the catalytic activity by decreasing the oxidation barrier.

Reconstructing the Environmental Degradation of Polystyrene by Accelerated Weathering.

The fragmentation of macro- into microplastics (MP) is the main source of MP in the environment. Nevertheless, knowledge about degradation mechanisms, changes in chemical composition, morphology, and residence times is still limited. Here, we present a long-term accelerated weathering study on polystyrene (PS) tensile bars and MP particles using simulated solar radiation and mechanical stress. The degradation process was monitored by gel permeation chromatography (GPC), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), 13C magic-angle spinning (MAS) NMR spectroscopy, tensile testing, and Monte Carlo simulations. We verified that degradation proceeds in two main stages. Stage I is dominated by photooxidation in a near-surface layer. During stage II, microcrack formation and particle rupturing accelerate the degradation. Depending on the ratio and intensity of the applied stress factors, MP degradation kinetics and lifetimes vary dramatically and an increasing amount of small MP fragments with high proportions of carboxyl, peroxide, and keto groups is continuously released into the environment. The enhanced surface area for adsorbing pollutants and forming biofilms modifies the uptake behavior and interaction with organisms together with potential ecological risks. We expect the proposed two-stage model to be valid for predicting the abiotic degradation of other commodity plastics with a carbon-carbon backbone.

Heterogeneous interactions between SO<sub>2</sub> and organic peroxides in submicron aerosol

Abstract. Atmospheric models often underestimate particulate sulfate, a major component in ambient aerosol, suggesting missing sulfate formation mechanisms in the models. Heterogeneous reactions between SO2 and aerosol play an important role in particulate sulfate formation and its physicochemical evolution. Here we study the reactive uptake kinetics of SO2 onto aerosol containing organic peroxides. We present chamber studies of SO2 reactive uptake performed under different relative humidity (RH), particulate peroxide contents, peroxide types, and aerosol acidities. Using different model organic peroxides mixed with ammonium sulfate particles, the SO2 uptake coefficient (γSO2) was found to be exponentially dependent on RH. γSO2 increases from 10−3 at RH 25 % to 10−2 at RH 71 % as measured for an organic peroxide with multiple O–O groups. Under similar conditions, the kinetics in this study were found to be structurally dependent: organic peroxides with multiple peroxide groups have a higher γSO2 than those with only one peroxide group, consistent with the reactivity trend previously observed in the aqueous phase. In addition, γSO2 is linearly related to particle-phase peroxide content, which in turn depends on gas–particle partitioning of organic peroxides. Aerosol acidity plays a complex role in determining SO2 uptake rate, influenced by the effective Henry's Law constant of SO2 and the condensed-phase kinetics of the peroxide–SO2 reaction in the highly concentrated aerosol phase. These uptake coefficients are consistently higher than those calculated from the reaction kinetics in the bulk aqueous phase, and we show experimental evidence suggesting that other factors, such as particle-phase ionic strength, can play an essential role in determining the uptake kinetics. γSO2 values for different types of secondary organic aerosol (SOA) were measured to be on the order of 10−4. Overall, this study provides quantitative evidence of the multiphase reactions between SO2 and organic peroxides, highlighting the important factors that govern the uptake kinetics.

Marriage of Peroxides and Nitrogen Heterocycles: Selective Three-Component Assembly, Peroxide-Preserving Rearrangement, and Stereoelectronic Source of Unusual Stability of Bridged Azaozonides.

Stable bridged azaozonides can be selectively assembled via a catalyst-free three-component condensation of 1,5-diketones, hydrogen peroxide, and an NH-group source such as aqueous ammonia or ammonium salts. This procedure is scalable and can produce gram quantities of bicyclic stereochemically rich heterocycles. The new azaozonides are thermally stable and can be stored at room temperature for several months without decomposition and for at least 1 year at -10 °C. The chemical stability of azaozonides was explored for their subsequent selective transformations including the first example of an aminoperoxide rearrangement that preserves the peroxide group. The amino group in aminoperoxides has remarkably low nucleophilicity and does not participate in the usual amine alkylation and acylation reactions. These observations and the 15 pKa units decrease in basicity in comparison with a typical dialkyl amine are attributed to the strong hyperconjugative nN→σ*C-O interaction with the two antiperiplanar C-O bonds. Due to the weakness of the complementary nO→σ*C-N donation from the peroxide oxygens (a consequence of "inverse α-effect"), this interaction depletes electron density from the NH moiety, protects it from oxidation, and makes it similar in properties to an amide.

Prediction of Solution Behavior via Calorimetric Measurements Allows for Detailed Elucidation of Polyoxometalate Transformation.

The solution behavior of a polyoxometalate cluster, LiNa-U24Pp12 (Li24Na24[(UO2O2)24(P2O7)12]) that consists of 24 uranyl ions, peroxide groups, and 12 pyrophosphate linkers, was successfully predicted based on new thermodynamic results using a calorimetric method recently described for uranyl peroxide nanoclusters (UPCs), molybdenum blues, and molybdenum browns. The breakdown of LiNa-U24Pp12 and formation of U24 (Li24[UO2O2OH]24) was monitored in situ via Raman spectroscopy using a custom heating apparatus. A combination of analytical techniques confirmed the simultaneous existence of U24Pp12 and U24 midway through the conversion process and U24 as the single end product. The application of a molecular weight filter resulted in a complete and successful separation of UPCs from solution and, in conjunction with DOSY results, confirmed the presence of large intermediate cluster building blocks.

Boosting the Stability of Boron Peroxides through Subphthalocyanine Coordination

The great potential of subphthalocyanines (SubPcs) to stabilize boron peroxides has been demonstrated. In particular, a subphthalocyanato boron (III) peroxide has been prepared in good yield via boron triflate. This derivative is remarkably stable under ambient conditions and can be fully characterized. The impact of the peroxide group on the structural and optoelectronic properties of SubPc was examined by NMR and UV/Vis spectroscopies, as well as single-crystal X-ray diffraction analysis. Moreover, density functional theory calculations were performed to explain the experimental results. The reactivity of this peculiar boron peroxide as an oxidant and a Lewis base was also studied.

A comparative analysis of in-office vital 6% hydrogen peroxide activated charcoal tooth whitening treatment enhanced with an 810nm diode laser, compared to 35% hydrogen peroxide bleaching

Laser dental bleaching is considered to be a contemporary approach to enhancing the in-office power bleaching procedure.
 Objective
 Investigate if laser enhanced 6% Hydrogen Peroxide (HP) solution is equivalent to 35% HP solution over a two-visit power bleaching treatment protocol. In a randomised double-blinded clinical trial, 43 patients were assigned to a group that received either the laser-enhanced 6% Hydrogen Peroxide (n=21) treatment, or the standard 35% Hydrogen Peroxide (n=22) treatment, over two visits, with a one-week interval. Activated charcoal HP paste was prepared for both groups. The laser enhanced 6% HP group received a dosage of 90 J/cm² per bleaching cycle using 810nm diode laser. Tooth colour was measured at the beginning and end of each session registering parameters L*, a* and b*, and tooth sensitivity. The calculated difference between these Parameters, ∆E, was the primary data focus. The mean ∆E over the treatment duration was used to answer the research question by a t-test to evaluate group differences at 5% significance level. The analysis revealed that the null hypothesis could not be rejected and the results were inconclusive. The observations expound the idea of an absorption enhancement mechanism, rather than a free radical activation, as the technique for improving bleaching outcomes.

A simple desulfurization process to achieve high efficiency, sustainability and cost-effectivity via peroxotungstate catalyst

• Peroxotungstate presented higher desulfurization efficiency than peroxomolybdate. • The [BMIM]PF 6 was used as extraction solvent and as catalyst entrapment. • Peroxotungstate promoted high desulfurization efficiency using low amounts of oxidant, catalyst and solvent. • Complete desulfurization was achieved after 40 min using H 2 O 2 /S = 4. • Catalyst and [BMIM]PF 6 solvent were reused for consecutive cycles with high efficiency. The creation of more sustainable and high efficient desulfurization system, capable to operate under cost-effective conditions, led to the application of peroxopolyoxometalates as active oxidative catalysts. These compounds present active peroxo groups in their structure that promote easily the oxidation of sulfur compounds in the presence of low amounts of oxidant (H 2 O 2 /S = 4). The sustainability of the desulfurization of a multicomponent model diesel (2000 ppm S) was increased by the optimization of various parameters, such as nature and volume of extraction solvent, oxidant and catalyst. The Venturello peroxotungstate ((Bu 4 N) 3 PW 4 ) showed to be a catalyst able to complete desulfurize a model diesel (after only 40 min), under lower amounts of solvent, oxidant and catalyst, than the analogues peroxomolybdate ((Bu 4 N) 3 PMo 4 ) compound. Furthermore, the (Bu 4 N) 3 PW 4 /[BMIM]PF 6 system was able to be reused for six consecutive desulfurization cycles maintaining its efficiency. The oxidized sulfur compounds were removed from [BMIM]PF 6 phase in the end of each catalytic cycle. This simple procedure guarantees the cost-efficiency of the process, promoting the reuse of the catalyst and the solvent for various consecutive cycles, without the need of heterogenization techniques.

Doxorubicin-loaded hydrogen peroxide self-providing copper nanodots for combination of chemotherapy and acid-induced chemodynamic therapy against breast cancer

In recent years, chemodynamic therapy (CDT) has gained increasing interest in cancer treatment. In contrast to photodynamic therapy and sonodynamic therapy, extrinsic excitations such as laser or ultrasound are not required in CDT. As a result, the CDT performance is not limited by the penetration depth of the external irritation. However, CDT relies heavily on hydrogen peroxide (H2O2) in the tumour microenvironment (TME). Insufficient H2O2 in the TME limits the CDT performance, and the most reported methods to produce H2O2 in the TME are dependent on oxygen supply, which is restricted by the hypoxic TME. In this study, H2O2 self-providing copper nanodots were proposed, and the drug doxorubicin (DOX) was successfully loaded to construct DOX-nanodots. Our results showed that the nanodots produced H2O2 in the weakly acidic TME due to the peroxo group and further generated the most active hydroxyl radical (OH) through the Fenton-like reaction. This process was pH-dependent and did not occur in a neutral environment. In addition to OH, the nanodots also produced singlet oxygen (1O2) and superoxide anions (O2–) in the cancer cells. The copper nanodots performed promising CDT against breast cancer in vitro and in vivo, with enhanced cell apoptosis and decreased cell proliferation. The combination of chemotherapy and CDT using DOX-nanodots further improved the therapeutic effects. The treatments showed good biocompatibility with no obvious toxicity in major tissues, possibly due to the specific OH generation in the weakly acidic TME. In summary, the H2O2 self-providing copper nanodots in combination with DOX showed promising cancer-curing effects due to the oxygen-independent and tumour-specific production of reactive oxygen species and the cooperation of chemotherapy.