Low Concentrations Of Hydrogen Peroxide Research Articles

Upstream mobility and swarming of light activated micromotors.

Micromotors have been proposed for applications such as targeted drug delivery, thrombolysis, or sensing. However, single micrormotors are limited in the amount of payload they can deliver or force they can exert. Swarms of micromotors can overcome many of these challenges, however creating and controlling such swarms presents many challenges of its own. In particular, utilizing swarms in fluid flows is of significant importance for biomedical or lab-on-chip applications. Here, the upstream mobility and swarm formation of light driven micromotors in microchannel flows is demonstrated with maximum speeds around 0.1 mm s-1. Additionally, the light actuated microrobots operate in fairly low concentrations of hydrogen peroxide of approximately 1%. The micromotors form swarms at the boundary of the locally applied light pattern and the swarms can be moved by translating the light up or downstream.

An Autonomous Mobile Combination Disinfection System.

To address the common drawbacks of current disinfection robots, which include the potential for secondary environmental pollution, disinfection dead corners, and low efficiency, in this paper, an autonomous mobile combination disinfection system is proposed. The system utilizes ultraviolet (UV) radiation and a low-concentration hydrogen peroxide aerosol to kill pathogens. It comprises three parts: a human-computer interface, a mobile robot, and disinfection equipment. A disinfection process model with continuous and fixed-point modes was established, and the effective disinfection range, speed, and duration were quantitatively calculated. The developed prototype was tested on-site by a professional third-party testing agency. The experimental results demonstrated that the combination disinfection robot achieved a 92.95% disinfection rate of natural airborne bacteria in a room measuring 22 square meters with a height of 2.8 m in just 30 min. The disinfection efficiency is at least 25% higher compared to standalone UV lamp disinfection and also exhibits a noticeable improvement over standalone hydrogen peroxide aerosol disinfection. The system enables the environmentally friendly, rapid, efficient, and all-encompassing disinfection of natural airborne bacteria. Finally, various disinfection solutions and recommendations for different application scenarios and requirements are provided.

Magnetic-acoustic actuated spinous microrobot for enhanced degradation of organic pollutants

A growing interest in the development of efficient strategies for the removal of organic pollutants from polluted water is emerging. As such, artificial micro/nano machines performing excellent water purification tasks have recently attracted more research attention of scientists. Hereby a spinous Fe3O4@PPy microrobot is presented that towards an efficient organic pollutant removal by enhancing Fenton-like reaction. The microrobot is fabricated by wrapping polypyrrole (PPy) on a spiny magnetic template prepared from sunflowers pollen. Modulating the sound pressure and frequency of the ultrasonic field enables the Fe3O4@PPy microrobot to present multimode motion, such as violent eruption-like motion caused by local cavitation (ELM), march-like unific motion (MLM), and typhoon-like rotation toward the center gathered motion (TLM). This multimode motion achieves the sufficient locomotion of microrobots in three-dimensional space and effective contact with organic pollutants in polluted water. Furthermore, a 5.2-fold increase in the degradation rate of methylene blue has been realized using Fe3O4@PPy microrobots under low-concentration hydrogen peroxide conditions. Also, the magnetically controlled recovery of microrobots from water after the completion of the degradation task has been demonstrated. The magnetic-acoustic actuated spinous microrobot can be extrapolated to other catalytic microrobot, developing a new strategy for an easier implementation and recovery of microrobot in real applications of water purification.

A Combination of Blue Light at 460 nm and H2O2 for the Safe and Effective Eradication of Staphylococcus aureus in an Infected Mouse Skin Abrasion Model.

Antibiotic-free approaches are more important than ever to address the rapidly growing problem of the antibiotic resistance crisis. The photolysis of the bacterial virulence factor staphyloxanthin using blue light at 460 nm (BL460 nm) has been found to effectively attenuate Staphylococcus aureus to chemical and physical agents. However, phototherapy using BL640 nm still needs to be investigated in detail for its safety in eradicating Staphylococcus aureus in vitro and in vivo. In this study, we employed a 460 nm continuous-wavelength LED source and a low concentration of hydrogen peroxide to treat S. aureus under a culturing condition and a wound abrasion mouse model. The results demonstrated the safety of the combined therapy when it did not modify the bacterial virulence factors or the susceptibility to widely used antibiotics. In addition, the results of the mouse model also showed that the combined therapy was safe to apply to mouse skin since it did not cause adverse skin irritation. More importantly, the therapy can aid in healing S. aureus-infected wounds with an efficacy comparable to that of the topical antibiotic Fucidin. The aforementioned findings indicate that the concurrent application of BL460 nm and hydrogen peroxide can be used safely as an alternative or adjunct to antibiotics in treating S. aureus-infected wounds.

A novel cascade catalytic electrochemical biosensor based on bifunctional Mn3O4@AuNPs with self-supplied O2 property and glucose oxidase-like activity for ultrasensitive detection of microRNA

Herein, a bifunctional nanomaterial Mn3O4@AuNPs with self-supplied oxygen (O2) property and glucose oxidase-like activity was exploited to construct a novel cascade catalytic electrochemical biosensor for ultrasensitive detection of microRNA-499 (miRNA-499). Impressively, compared with the traditional AuNPs nanozyme with single glucose oxidase-like activity, the Mn3O4@AuNPs could not only act as a glucose oxidative mimetic enzyme to catalyze the oxidation of glucose to gluconic acid and the reduction of dissolved O2 to low concentration of hydrogen peroxide (H2O2) to obtain a electrochemical signal in the presence of hemin/G-quadruplex DNAzyme with peroxidase-like activity, but also electrocatalyze water splitting to obtain abundant dissolved O2 to further assist in the production of high concentration of H2O2 for a significantly improved electrochemical response. Meanwhile, with the aid of the target-induced dual Mg2+-assisted DNAzyme cleavage recycling amplification for the increasement of target miRNA-499 conversion efficiency, the proposed electrochemical biosensor achieved the ultrasensitive detection of miRNA-499 with a detection limit as low as 6.2 aM. As a result, this strategy might provide a potential method to upgrade the catalytic efficiency of mimic enzyme cascade reaction with eventual applications in bioanalysis and disease diagnosis.

Phenolic compounds interfere in the Ampliflu Red/peroxidase assay for hydrogen peroxide.

Methods employing horseradish peroxidase (HRP) are popular for quantification of hydrogen peroxide. This communication reports interference of the Ampliflu Red-HRP assay by phenolic compounds, abundant in food and beverages of plant origin. Concentrations of catechin, propyl gallate, quercetin and gallic acid lowering the yield of the product, resorufin, in this system by 50% were lower than 10μM. The extent of inhibition increased with decreasing hydrogen peroxide concentration. These results point to the necessity of a careful interpretation of results concerning the quantification of hydrogen peroxide in materials containing phenolic compounds with methods employing HRP, especially when low concentrations of hydrogen peroxide are concerned.

Hollow Cobalt Sulfide Nanospheres with Highly Enzyme-like Antibacterial Activities to Accelerate Infected Wound Healing.

The emergence of nanozymes presents a promising alternative to antibiotics for reactive oxygen species-mediated broad-spectrum antimicrobial purposes, but nanozymes still face challenges of low therapeutic efficiency and poor biocompatibility. Herein, we creatively prepared a novel kind of hollow cobalt sulfide (CoS) nanospheres with a unique mesoporous structure that is able to provide numerous active sites for enzyme-like reactions. The results revealed that 50 μg/mL of CoS nanospheres exhibited strong peroxidase- and oxidase-like activities under physiological conditions with the assistance of a low concentration of hydrogen peroxide (H2O2, 100 μM) while possessing highly efficient GSH-depletion ability, which endowed CoS nanospheres with triple enzyme-like properties to combat bacterial infections. The in vitro experiments demonstrated that the CoS nanozyme displayed significant antibacterial effects against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). The in vivo implantation showed that the synthesized CoS effectively eliminated bacteria and promoted the recovery of infected wounds in rats while exhibiting a low cytotoxicity. This study provides a promising treatment strategy to accelerate infected wound healing.

The harmful cyanobacterium Microcystis aeruginosa PCC7806 is more resistant to hydrogen peroxide at elevated CO2

Rising atmospheric CO2 can intensify harmful cyanobacterial blooms in eutrophic lakes. Worldwide, these blooms are an increasing environmental concern. Low concentrations of hydrogen peroxide (H2O2) have been proposed as a short-term but eco-friendly approach to selectively mitigate cyanobacterial blooms. However, sensitivity of cyanobacteria to H2O2 can vary depending on the available resources. To find out how cyanobacteria respond to H2O2 under elevated CO2, Microcystis aeruginosa PCC 7806 was cultured in chemostats with nutrient-replete medium under C-limiting and C-replete conditions (150 ppm and 1500 ppm CO2, respectively). Microcystis chemostats exposed to high CO2 showed higher cell densities, biovolumes, and microcystin contents, but a lower photosynthetic efficiency and pH compared to the cultures grown under low CO2. Subsamples of the chemostats were treated with different concentrations of H2O2 (0–10 mg·L−1 H2O2) in batch cultures under two different light intensities (15 and 100 μmol photons m−2·s−1) and the response in photosynthetic vitality was monitored during 24 h. Results showed that Microcystis was more resistant to H2O2 at elevated CO2 than under carbon-limited conditions. Both low and high CO2-adapted cells were more sensitive to H2O2 at high light than at low light. Microcystins (MCs) leaked out of the cells of cultures exposed to 2–10 mg·L−1 H2O2, while the sum of intra- and extracellular MCs decreased. Although both H2O2 and CO2 concentrations in lakes vary in response to many factors, these results imply that it may become more difficult to suppress cyanobacterial blooms in eutrophic lakes when atmospheric CO2 concentrations continue to rise.

Evaluation of disinfection methods for personal protective equipment (PPE) items for reuse during a pandemic.

The COVID-19 pandemic resulted in many supply chain issues, including crippling of essential personal protective equipment (PPE) needed for high-risk occupations such as those in healthcare. As a result of these supply chain issues, unprecedented crisis capacity strategies were implemented to divert PPE items such as filtering facepiece respirators (FFRs, namely N95s) to those who needed them most for protection. Large-scale methods for decontamination were used throughout the world to preserve these items and provided for their extended use. The general public also adopted the use of non-specialized protective equipment such as face coverings. So, the need for cleaning, decontamination, or disinfection of these items in addition to normal clothing items became a necessary reality. Some items could be laundered, but other items were not appropriate for washing/drying. To fill research gaps in small-scale, non-commercial cleaning and disinfection, this bench-scale research was conducted using small coupons (swatches) of multiple PPE/barrier protection materials inoculated with virus (non-pathogenic bacteriophages Phi6 and MS2) and tested against a range of decontamination methods including bleach-, alcohol- and quaternary ammonium compound (QAC)-based liquid sprays, as well as low concentration hydrogen peroxide vapor (LCHPV) and bench-scale laundering. In general, non-porous items were easier to disinfect than porous items, and the enveloped virus Phi6 was overall easier to inactivate than MS2. Multiple disinfection methods were shown to be effective in reducing viral loads from PPE coupons, though only laundering and LCHPV were effective for all materials tested that were inoculated with Phi6. Applications of this and follow-on full-scale research are to provide simple effective cleaning/disinfection methods for use during the current and future pandemics.

Wearable, Biodegradable, and Antibacterial Multifunctional Ti3C2Tx MXene/Cellulose Paper for Electromagnetic Interference Shielding and Passive and Active Dual-Thermal Management

An energy-saving scheme that can simultaneously realize electromagnetic interference (EMI) shielding, passive solar radiative heating, and active Joule heating in a single wearable device is still a huge challenge. Here, by combining the unique properties of Ti3C2Tx MXene and biocompatible cellulose nanofibers (CNFs), a flexible, degradable, and antibacterial multifunctional Ti3C2Tx/CNF paper (∼0.6 Ω/sq) is constructed through a facile vacuum filtration strategy. The resultant device not only exhibits an admirable EMI shielding effectiveness of ∼48.5 dB at the X-band and a superior heating property including dual-driven electrothermal and photothermal conversion without energy but also possesses wide temperature range regulation and long-time stability. More impressively, both high antibacterial efficiency (toward both gram-positive and gram-negative bacteria) and good degradability with low-concentration hydrogen peroxide solution can also be achieved in Ti3C2Tx/CNF papers. This study provides a promising platform for practical applications of multifunctional Ti3C2Tx/CNFs in EMI shielding, thermotherapy, heat preservation, and antibacterial protection in harsh environments, satisfying the demands for energy-saving, environmentally friendly, and sustainable development.

Determination of hydrogen peroxide by differential pulse polarography in advanced oxidation processes for water treatment

Knowing the concentration of hydrogen peroxide (H2O2) is crucial for the monitoring and optimizing the Fenton reaction in advanced oxidation processes. Several analytical methods exist to determine these concentrations, but their applications can be difficult because of low selectivity (interaction with other metals), the use of toxic compounds, or low concentrations (μmol LmmolL-1). To overcome these problems, we developed a differential pulse polarographic (DPP) method at the dropping mercury electrode (DME) with the following conditions: tg=1.0s, ΔE=−100mV and v=10mVs−1. Calibration curves had very high correlation coefficients (R2>0.999). The limits of detection and quantification were evaluated respectively at 13 and 21μmolL−1 with peak area measurements of hydrogen peroxide reduction (Ap). The DPP method was compared with other analytical methods (iodometric titration and spectrophotometry) for determining at low concentrations of H2O2 (in the order of mmolL−1 to μmol L−1) in Fenton and electro-Fenton processes. The method developed here allows measure low concentrations of hydrogen peroxide in Fenton and electro-Fenton processes in acidic solutions (∼3) and the presence of interfering species such as Fe3+ and dissolved oxygen.

Effectiveness, longevity, and color stability of in-office bleaching (6% H2O2 gel/Violet LED) and diastema closure with direct composite: 3-year follow-up

To reduce bleaching side effects, the use of low concentrations of Hydrogen Peroxide (HP) agents associated with hybrid light (violet LED/Diode Laser) has gained interest. Case report: The aim of this report is to describe a case of a 16-year-old patient that presented a complaint related to the color of his teeth and a maxillary midline diastema. In-office bleaching with 6% HP associated with hybrid light (violet LED/Diode Laser) was performed. The bleaching gel was applied once on the teeth and light-activated for 1 minute (15 times) followed by 1min intervals (15 times) with a total bleaching time of 30 minutes. After the bleaching procedure, the teeth were polished and the desensitizer was applied for 4 minutes. Two bleaching sessions were performed at a 1-week interval. The diastema was closed with direct resin composite restorations without any tooth preparation. The conventional 3-step bonding agent was used and A1 dentin shade and B1 enamel shade were used followed by polishing discs. At 3-year recall, discoloration and fractures were not found on the the teeth or restorations and patient was completely satisfied. Conclusion: the conservative and safe option of bleaching with a low-concentrated HP gel associated with violet LED light is an interesting option for young patients and presents longevity over time.

Passenger vehicle interior decontamination by low concentration hydrogen peroxide vapor following a wide area biological contamination incident.

To assess low concentration hydrogen peroxide (LCHP) (H2O2) vapor dispersed with a home humidifier for its ability to decontaminate vehicle interiors contaminated with Bacillus anthracis surrogate Bacillus atrophaeus spores. Efficacy of a vaporized 3% H2O2 solution was evaluated for liquid volumes, on/off vehicle heating, ventilation, and air conditioning (HVAC) system operations, and temperatures that ranged from 5 to 27°C. Survival of the spores was assessed by quantification of remaining viable spores with efficacy quantified in terms of mean log10 reduction. Decontamination efficacy after the 6-day dwell time increased when the 3% H2O2 liquid volume was doubled, increasing from 4-of-10 to 10-of-10 nondetects (zero colonies counted using standard dilution and filter plating) inside the vehicle cabin. Recirculating cabin air through the HVAC system during decontamination decreased efficacy to 6-of-10 non-detects. While no 6-log10 reduction in viable spores was observed on the cabin filter with the cabin filter kept in place, a 6-log10 reduction was achieved after its removal and placement in the cabin during treatment. Results from this study allow for informed decisions on the use of LCHP vapor as an effective decontamination approach for vehicle interiors.

In vitro and in vivo degradation correlations for polyurethane foams with tunable degradation rates.

Polyurethane foams present a tunable biomaterial platform with potential for use in a range of regenerative medicine applications. Achieving a balance between scaffold degradation rates and tissue ingrowth is vital for successful wound healing, and significant in vivo testing is required to understand these processes. Vigorous in vitro testing can minimize the number of animals that are required to gather reliable data; however, it is difficult to accurately select in vitro degradation conditions that can effectively mimic in vivo results. To that end, we performed a comprehensive in vitro assessment of the degradation of porous shape memory polyurethane foams with tunable degradation rates using varying concentrations of hydrogen peroxide to identify the medium that closely mimics measured in vivo degradation rates. Material degradation was studied over 12 weeks in vitro in 1%, 2%, or 3% hydrogen peroxide and in vivo in subcutaneous pockets in Sprague Dawley rats. We found that the in vitro degradation conditions that best predicted in vivo degradation rates varied based on the number of mechanisms by which the polymer degraded and the polymer hydrophilicity. Namely, more hydrophilic materials that degrade by both hydrolysis and oxidation require lower concentrations of hydrogen peroxide (1%) to mimic in vivo rates, while more hydrophobic scaffolds that degrade by oxidation alone require higher concentrations of hydrogen peroxide (3%) to model in vivo degradation. This information can be used to rationally select in vitro degradation conditions that accurately identify in vivo degradation rates prior to characterization in an animal model.

Current Status and Future Prospects In Managing Discoloured Teeth – A Review And Case Report

Tooth discoloration involves a wide range of treatment protocols for clinicians and patients in order to achieve an aesthetic result. Management of tooth discoloration may be interdisciplinary and involves both vital and nonvital teeth. Prosthodontic treatments are more invasive and involve loss of tooth structure as well as a life cycle of further treatment in the future.Vital teeth can be easily treated with low-concentration hydrogen peroxide products safely and effectively using an external approach and trays. For endodontically treated teeth, the walking bleach technique with hydrogen-releasing peroxide products is widespread. However, there is an association between external cervical root resorption with higher concentrations of hydrogen peroxide of 30%–35%. In this article, a brief reviewof managing tooth discoloration and a case report of nonvital bleaching will be discussed.

Bleaching effectiveness and cytotoxicity of new experimental formulation of niobium-based bleaching gel.

The development of new bleaching agents with minimum concentration of hydrogen peroxide (HP), without adverse effects, and with bleaching effectiveness, has great clinical relevance. The aim of this study was to evaluate the bleaching efficacy and cytotoxicity of a new niobium-based bleaching gel, compared to already available HP-based gels. For the bleaching efficacy analysis, 40 bovine incisors were randomly divided into 4 groups according to the established bleaching protocol: control, untreated; 35HP, 35% HP bleaching gel; 6HP, 6% HP bleaching gel; NbHP, niobium gel associated with 3% HP gel. The color variation was measured in a spectrophotometer and the values of ΔL, Δa, Δb, and ΔE obtained. For the cell viability assay by MTT, MC3T3 cells were exposed to bleaching gel extracts (1:500, 1:250, 1:125 dilutions; immediately and 24h). Statistical tests were performed (P < 0.05). The color alteration for all bleaching gels was significant compared to control (P < 0.05), but the NbHP gel showed a significant ΔE than other gels, with expressive color alteration at 14days (P < 0.05). The 35HP showed high cytotoxicity regarding control and the most groups in all periods and extracts analyzed (P < 0.05), while the NbHP showed greater cell viability than control in the immediate period, dilution of the 1:500 and superior to 6HP in the most extracts at 24h. The new experimental niobium-based gel has bleaching efficacy similar to that of gels with a high concentration of HP, and it has high cytocompatibility. The use of this new generation of niobium-based whitening gel associated with a low concentration of hydrogen peroxide represents the possibility of a tooth whitening with lower dentin sensitivity.

Efficacy and safety of low concentration hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma radiotherapy: a pilot cohort study.

Purpose: This study aimed to evaluate and analyze the efficacy and safety of low concentration (0.15%) hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma radiotherapy. Methods: Patients with nasopharyngeal carcinoma from Jiangxi cancer hospital were randomly divided into two cohorts. The training cohort (n= 50) received low concentration (0.15%) hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma radiotherapy, and the control cohort (n= 50) received 0.02% nitrofurazone lavage fluid. The primary endpoint of the study was result of short-term efficacy. Second endpoints were assessment of the linear visual analogue scale score and the incidences rate of nasopharyngeal radiation related toxicity. Results: All patients had completed the scheduled nasopharyngeal radiotherapy except two patients in control cohort. The complete response, partial response, stable disease and disease objective response of nasopharyngeal primary tumor observed in the training cohort included 18 cases, 23 cases, 9 cases and 41 cases respectively, while in the control cohort 20 cases, 25 cases, 5 cases and 45 cases were recorded, respectively. The study showed a significant discrepancy in the incidence rate of radiation-related mucosa damage between the two. Specifically, Grade 1 and 2 included 37 cases (74.0%) in the training cohort, while in the control cohort the cases were 20 (40.0%). Grade 3 and 4 damage however reported an incidence of 26.0% and 60%, respectively, which clearly constitutes a significant statistical difference (P = 0.002). The assessment of linear visual analogue scale showed that the patients self-conscious comfortable feeling in the training cohort were significantly higher than in the control cohort (P = 0.003). Conclusions: low concentration (0.15%) hydrogen peroxide as nasopharyngeal lavage fluid in the treatment for nasopharyngeal carcinoma patients is effective and safe, and can reduce nasopharyngeal local mucosa radiation related toxicity after radiotherapy.

Hydrogen peroxide detoxification through the peroxiredoxin/thioredoxin antioxidant system: A look at the pancreatic β-cell oxidant defense.

Reactive oxygen species (ROS), such as hydrogen peroxide, are formed when molecular oxygen obtains additional electrons, increasing its reactivity. While low concentrations of hydrogen peroxide are necessary for regulation of normal cellular signaling events, high concentrations can be toxic. To maintain this balance between beneficial and deleterious concentrations of hydrogen peroxide, cells utilize antioxidants. Our recent work supports a primary role for peroxiredoxin, thioredoxin, and thioredoxin reductase as the oxidant defense pathway used by insulin-producing pancreatic β-cells. These three players work in an antioxidant cycle based on disulfide exchange, with oxidized targets ultimately being reduced using electrons provided by NADPH. Peroxiredoxins also participate in hydrogen peroxide-based signaling through disulfide exchange with redox-regulated target proteins. This chapter will describe the catalytic mechanisms of thioredoxin, thioredoxin reductase, and peroxiredoxin and provide an in-depth look at the roles these enzymes play in antioxidant defense pathways of insulin-secreting β-cells. Finally, we will evaluate the physiological relevance of peroxiredoxin-mediated hydrogen peroxide signaling as a regulator of β-cell function.

Sensitivity of Janthinobacterium Lividum to Low Concentrations of Hydrogen Peroxide and the Effect of Mild Oxidative Stress on Pigment Yield

In the course of assessing the sensitivity of the Janthinobacterium lividum VKM B-3515 strain to low concentrations of hydrogen peroxide, it was found that at a content of 0.003% H2O2, the growth properties of the bacterium during submerged cultivation without pigmentation differed statistically insignificantly relative to the control variant at 16 hours of incubation and beyond. Whereas in the presence of peroxide at 12 hours the optical density was lower than in the control by 97%. When cultivating by the surface method, the respiration intensity did not significantly differ between the control and experimental variants. However, during the extraction of the pigment, it was found that in the presence of hydrogen peroxide, the optical density of the acetone extract significantly exceeds the control variant by 28%. It can be assumed that, at the same growth parameters of the culture, the biosynthesis of violacein is stimulated and the population can adapt to the peroxide content, and the peroxide concentration itself decreases due to the cost of catalytic reactions. Further studies of the sensitivity of J. lividum VKM B-3515 to various oxidizing agents will allow us to consider the effect of weak oxidative stress on the biosynthesis of violacein.

Removal of formaldehyde in water with low concentration of hydrogen peroxide catalyzed by lanthanum-silicon oxide composite

Removal of formaldehyde in water with low concentration of hydrogen peroxide catalyzed by lanthanum-silicon oxide composite