Investigation of the abasic sites induced by hydrogen peroxide and methyl methanesulfonate in calf thymus DNA and BEAS-2B cells.

The primary goals of this study were to investigate the formation of abasic sites (AP sites) induced by methyl methanesulfonate (MMS) and hydrogen peroxide (H2O2), and to characterize specific types of these pro-mutagenic DNA lesions in calf thymus DNA (CT-DNA), and BEAS-2B human lung normal cell line. Furthermore, these profiles were compared with those observed in leukocytes derived from healthy controls (HC), breast cancer patients (BCP) before treatment, and 5-year survivors. Results indicated that both H2O2 and MMS induced the concentration- and time-dependent formation of AP sites in CT-DNA. To characterize the specific types of AP sites induced by H2O2 or MMS, we performed AP site cleavage assay using putrescine, T7 exonuclease (T7 Exo), and exonuclease III (Exo III). Results showed that the AP sites induced by H2O2 in CT-DNA were predominantly 5'-and 3'-nicked AP sites and no intact AP sites were detected. By contrast, the majority of AP sites generated by MMS in CT-DNA are not excisable and are classified as residual and intact AP sites. Similar approaches were performed in human BEAS-2B cells and comparable observations were confirmed in the cell-based model. Further investigation indicated that the profile of the AP sites observed in Taiwanese HC is identical to that of BEAS-2B cells treated with H2O2 whereas the pattern of AP sites detected in BCP is similar to that of CT-DNA exposed to H2O2, suggesting that these AP sites were produced primarily through reactive oxygen species (ROS) generation. More than 70 % of the AP sites in leukocytes derived from BCP were 5'-nicked and residual AP sites. Furthermore, the characteristics of the AP sites detected in 5-year survivors are comparable with the ones in HC by using putrescine cleavage assay. Overall, we speculate that deficiency in the DNA repair cascade may play a role in mediating the formation of specific types of AP sites detected in BCP.

A non-enzymatic hydrogen peroxide biosensor based on cerium metal-organic frameworks, hemin, and graphene oxide composite.

This study presents the development of a novel non-enzymatic electrochemical biosensor for the real-time detection of hydrogen peroxide (H2O2) based on a composite of cerium metal-organic frameworks (Ce-MOFs), hemin, and graphene oxide (GO). The Ce-MOFs served as an efficient matrix for hemin encapsulation, while GO enhanced the conductivity of the composite. Characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, and thermogravimetric analysis (TGA) confirmed the successful integration of hemin into the Ce-MOFs. The Ce-MOFs@hemin/GO-modified sensor demonstrated sensitive H2O2 detection due to the exceptional electrocatalytic activity of Ce-MOFs@hemin and the high conductivity of GO. This biosensor exhibited a linear response to H2O2 concentrations from 0.05 to 10 mM with a limit of detection (LOD) of 9.3 µM. The capability of the biosensor to detect H2O2 released from human prostate carcinoma cells was demonstrated, highlighting its potential for real-time monitoring of cellular oxidative stress in complex biological environments. To further assess its practical applicability, the sensor was tested in human serum samples, yielding promising results with recovery values ranging from 94.50 % to 103.29 %. In addition, the sensor showed excellent selectivity against common interfering compounds due to the outstanding peroxidase-like activity of the composite.

Systematic analysis and functional verification of citrus ascorbate peroxidases reveal that CsAPX01 and CsAPX02 negatively regulate citrus bacterial canker through the hydrogen peroxide regulation.

Ascorbate peroxidases (APXs) are antioxidant enzymes that play vital roles in redox homeostasis in plants. Citrus is susceptible to infection by Xanthomonas citri subsp. citri (Xcc), resulting in citrus bacterial canker (CBC). The present study used bioinformatic and expression analyses to investigate the APX family in Citrus sinensis. Bioinformatic research revealed the chromosomal locations, phylogeny, gene structure, promoter elements, functional domains, conserved motifs, and most likely physicochemical properties of the sequences. Six APXs clustered in three groups were identified, with each protein containing a single peroxidase domain. The promoter regions contained a variety of transcription factor-binding and hormone-response components. Xcc infection induced different CsAPX01 and CsAPX02 expressions in the CBC-susceptible Wanjincheng and CBC-resistant Kumquat varieties. Subcellular localization and transient expression showed that CsAPX01 and CsAPX02 were expressed in the cytoplasm and nucleus and had hydrogen peroxide (H2O2)-scavenging activity. Virus-induced gene silencing (VIGS) of CsAPX01 and CsAPX02 resulted in strong resistance to CBC and H2O2 bursts without effects on the plant phenotype. The current study focused on investigating and characterizing the citrus APX family. It was found that CsAPX01 and CsAPX02 exacerbated CBC by altering the balance of H2O2. These findings emphasize the importance of APXs in enhancing plant resistance to pathogens.

Neurotoxic mechanisms of dexamethasone in SH-SY5Y neuroblastoma cells: Insights into bioenergetics, oxidative stress, and apoptosis.

Despite the known therapeutic uses of dexamethasone (DEX), the specific mechanisms underlying its neurotoxic effects in neuronal cells, particularly in undifferentiated human neuroblastoma (SH-SY5Y) cells, remain inadequately understood. This study aims to elucidate these mechanisms, emphasizing bioenergetics, oxidative stress, and apoptosis, thereby providing novel insights into the cellular vulnerabilities induced by chronic DEX exposure. The findings revealed significant reductions in cell viability, altered membrane integrity with LDH leakage, decreased intracellular ATP production, and the electron transport chain complexes I and III activity inhibition. DEX significantly increased the release of the reactive species and peroxidation of lipids, as well as of Nrf2 expression. At the same time, it simultaneously led to a decline in the activities of the antioxidant catalase and superoxide dismutase enzymes, along with a depletion of glutathione reserves. The apoptosis process was exhibited by a significant elevation of caspases 3 and 8 activities with overexpression of mRNA BAX, inhibition of BCL-2, and a significant upregulation of the BAX/BCL-2 ratio. Assessment of neuronal development genes (GAP43, CAMK2A, CAMK2B, TUBB3, and Wnts) by quantitative PCR assay showed increased expression of CAMK2A, CAMK2B, and Wnt3a with a significant reduction in GAP43 mRNA levels. Collectively, this study proved that DEX was cytotoxic to SH-SY5Y via bioenergetic disruption, mitochondrial dysfunction, oxidative stress, and apoptosis.

Reactive oxygen species, electrode potential and pH affect CoCrMo alloy corrosion and semiconducting behavior in simulated inflammatory environments.

Crevice corrosion in modular taper junctions of hip or knee replacements using cobalt-chrome-molybdenum (CoCrMo) alloys remains a clinical concern. Non-mechanically-driven corrosion has been less explored compared to mechanically assisted crevice corrosion. This study hypothesized that solution chemistry within crevices, inflammation, and cathodic electrode potential shifts during fretting result in low pH and generate reactive oxygen species (ROS), affecting oxide film behavior. This study investigated how resistance and capacitance of the CoCrMo oxide film (i.e., corrosion resistance) are modified in simulated in vivo crevice environments of modular taper junctions. Six solutions were evaluated (two pH levels: 1 and 7.4 and four hydrogen peroxide (H2O2) concentrations: 0, 0.001, 0.01 and 0.1 M). Rp versus voltage and Mott-Schottky plots were created from symmetry-based electrochemical impedance spectroscopy (sbEIS). At pH 1, the semiconductor transition to p-type occurs at more anodic potentials and higher flat band potentials were found. H2O2 decreased the flat band potential and slope in the Mott-Schottky plot. Higher H2O2 in pH 7.4 solution significantly modified the oxide film, leading to increased donor density (p = 0.0004) and a 150-fold reduction in Rp in the cathodic potential range at -1 V (p = 0.0005). The most unfavorable condition (0.1 M H2O2 pH 1) resulted in a 250-fold lower resistance compared to phosphate buffered saline (PBS) pH 7.4 at -1 V (p = 0.0013). This study highlights the corrosion susceptibility of CoCrMo under adverse chemical and potential conditions, identifying increased defects in the oxide film due to ROS, hydrogen ions and electrode potential. STATEMENT OF SIGNIFICANCE: Corrosion of cobalt chrome molybdenum alloy caused by direct chemical attack in the crevice region of hip replacements, such as modular taper junctions, remains a clinical concern. The junction environment contains adverse chemical compositions, including high acidity and reactive oxygen species (ROS) due to inflammatory responses against the corrosion products. We simulate inflammatory environments with different pH levels and hydrogen peroxide, representative of ROS. We employ electrochemical impedance spectroscopy and apply stepwise voltage over the range induced by tribocorrosion processes. We relate the effect of adverse chemical components on corrosion and semiconducting behavior of the oxide film using Mott-Schottky analysis. This study shows how pH and ROS concentration compromises the oxide film potentially leading to non-mechanically induced corrosion.

Comparative Evaluation of Activated and Nonactivated Microbubbles on the Efficacy of Bleaching Agents.

INTRODUCTION: Intracoronal bleaching serves as a conservative option for nonvital teeth that exhibit discoloration. Hydrogen peroxide (H2O2) is frequently utilized in bleaching processes owing to its capability to produce free radicals. The main drawbacks of the currently available bleaching agents are the occurrence of cervical resorption and the multiple dental visits to achieve the desired result. Therefore, in our study, to address the limitations associated with cervical resorption and extended treatment duration for badly stained teeth, an attempt was made to incorporate a whitening agent (35% H2O2) with microbubbles. AIM:  This study aimed to compare and evaluate the effect of activated and nonactivated microbubbles on the efficacy of bleaching agents. METHODOLOGY:  Forty-five human central incisors were collected and divided into three groups: Group I (HP), H2O2 plain (n = 15) (Control); Group II (HPM), H2O2-infused microbubbles without ultrasonic activation (n = 15) (experimental group); and Group III (HPMU), H2O2-infused microbubbles with ultrasonic activation (n = 15) (experimental group). The crowns were artificially stained. Microbubbles containing 35% H2O2 were generated using the probe sonication method. The bleaching agent H2O2 plain (0.04 mL) was syringed into the pulp chamber in group I, while H2O2-infused microbubbles (0.04 mL) were syringed into group II and group III. Group III was further activated ultrasonically. The evaluation of color shade differences was conducted using the Vita Lumin shade guide at three time points: baseline, day 7, and day 14. RESULTS:  Data regarding color change using Vita shade were investigated for normality using the Kolmogorov Smirnov test and assessed a non-normal distribution. Intergroup comparisons at each particular time interval (baseline, day 7, and day 14) were analyzed using the Kruskal-Wallis H test followed by multiple pairwise comparisons using the Adjusted Bonferroni post hoc test. Intragroup comparisons between different time intervals were analyzed using related samples from Friedman's test followed by multiple pairwise comparisons using the post hoc Dunn test. The level of statistical significance was determined at P < 0.05. There was no statistical difference in the baseline values of all three groups. Group I (HP) exhibited an average increase of three Vita Lumin shade tabs on day 7 and day 14, respectively, whereas Group II (HPM) exhibited an average increase of six and four Vita Lumin shade tabs on day 7 and day 14, respectively, and Group III (HPMU) exhibited an average increase of 10 and 3 Vita Lumin shade tabs on day 7 and day 14, respectively. CONCLUSIONS:  Microbubbles containing H2O2 were more efficient and faster than plain H2O2 for bleaching, and the efficacy of bleaching was enhanced when activated using ultrasonic technology.

From Household Chemical to Medical Emergency: Stroke Induced by Hydrogen Peroxide Ingestion.

Hydrogen peroxide (H2O2) ingestion can lead to severe systemic complications, including neurological sequelae such as acute embolic stroke. We present a case of a 49-year-old male who accidentally ingested approximately 50-60 mL of 50% w/w hydrogen peroxide, resulting in encephalopathy, upper motor neuron quadriparesis, and pulmonary artery thrombosis. The patient's altered sensorium progressed to a stupor, accompanied by acute respiratory distress and abdominal gaseous distension. Imaging revealed multifocal hypodensities in the brain and saddle thrombus in the pulmonary arteries. Hyperbaric oxygen therapy initiated after diagnosis led to a significant improvement in motor power and resolution of abdominal distension during hospitalization. The pathophysiology involves gas embolization and oxidative stress-induced thrombosis. Management includes stabilizing the patient, dilution therapy, and supportive care, with hyperbaric oxygen therapy for severe cases. Prevention strategies focus on education and proper storage. Continuous monitoring and follow-up are essential for managing hydrogen peroxide poisoning. This case underscores the need for awareness and prompt intervention in hydrogen peroxide toxicity.

Navigating Treatment Dilemmas: Recalcitrant Pemphigus and the Burden of Multiple Comorbidities.

Pemphigus vulgaris is a chronic autoimmune disease of the skin caused by the production of autoantibodies targeting desmogleins 1 and 3 usually presenting in individuals with an average age of onset of approximately 40 years. A 35-year-old obese, diabetic woman presented with fluid-filled lesions over her body for three months along with erosions and painful ulcers in her mouth and genital area for two months. Based on clinical and histopathological studies, the patient was diagnosed as a case of pemphigus vulgaris. She was started on conventional treatment with oral corticosteroids followed by pulse therapy and mycophenolate mofetil. Rituximab infusion was scheduled but could not be administered due to elevated D-dimer values. The patient underwent screening for deep vein thrombosis (DVT) and received subcutaneous enoxaparin and oral rivaroxaban. She developed severe sepsis for which she was treated with systemic antibiotics. She subsequently developed acute renal failure and underwent hemodialysis. The patient's clinical condition further deteriorated, which necessitated therapeutic plasma exchange (TPE). Collagen, colloidal silver, and silicone foam dressings were done to hasten wound healing. Two distinct approaches were employed to eliminate the pseudomembrane on the wounds. One portion was treated with hydrogen peroxide (H2O2), while the other was with hyaluronidase. The hyaluronidase treatment resulted in considerable improvement of the lesions. Intravenous immunoglobulin (IVIG) infusion was scheduled. However, the treatment could not be administered as the patient succumbed to death due to pulmonary thromboembolism (PTE) secondary to DVT.

Validating ΔΔG Selectivity Descriptor for Electrosynthesis of H2O2 from Oxygen Reduction Reaction.

Understanding selectivity trends is a crucial hurdle in the developing innovative catalysts for generating hydrogen peroxide through the two-electron oxygen reduction reaction (2e-ORR). The identification of selectivity patterns has been made more accessible through the introduction of a newly developed selectivity descriptor derived from thermodynamics, denoted as ΔΔG introduced in Chem Catal. 2023, 3(3), 100568. To validate the suitability of this parameter as a descriptor for 2e-ORR selectivity, we utilize an extensive library of 155 binary alloys. We validate that ΔΔG reliably depicts the selectivity trends in binary alloys reported for their high activity in the 2e-ORR. This analysis also enables the identification of nine selective 2e-ORR catalysts underscoring the efficacy of ΔΔG as 2e-ORR selectivity descriptor. This work highlights the significance of concurrently considering both selectivity and activity trends. This holistic approach is crucial for obtaining a comprehensive understanding in the identification of high-performance catalyst materials for optimal efficiency in various applications.

In-Plane Topological-Defect-Enriched Graphene as an Efficient Metal-Free Catalyst for pH-Universal H2O2 Electrosynthesis.

Developing efficient metal-free catalysts to directly synthesize hydrogen peroxide (H2O2) through a 2-electron (2e) oxygen reduction reaction (ORR) is crucial for substituting the traditional energy-intensive anthraquinone process. Here, in-plane topological defects enriched graphene with pentagon-S and pyrrolic-N coordination (SNC) is synthesized via the process of hydrothermal and nitridation. In SNC, pentagon-S and pyrrolic-N originating from thiourea precursor are covalently grafted onto the basal plane of the graphene framework, building unsymmetrical dumbbell-like S─C─N motifs, which effectively modulates atomic and electronic structures of graphene. The SNC catalyst delivers ultrahigh H2O2 productivity of 8.1, 7.3, and 3.9 mol gcatalyst -1 h-1 in alkaline, neutral, and acidic electrolytes, respectively, together with long-term operational stability in pH-universal electrolytes, outperforming most reported carbon catalysts. Theoretical calculations further unveil that defective S─C─N motifs efficiently optimize the binding strength to OOH* intermediate and substantially diminish the kinetic barrier for reducing O2 to H2O2, thereby promoting the intrinsic activity of 2e-ORR.

Fluorescence-Recovered Wearable Hydrogel Patch for In Vitro Detection of Glucose Based on Rare-Earth Nanoparticles.

The physiological state of the human body can be indicated by analyzing the composition of sweat. In this research, a fluorescence-recovered wearable hydrogel patch has been designed and realized which can noninvasively monitor the glucose concentration in human sweat. Rare-earth nanoparticles (RENPs) of NaGdF4 doped with different elements (Yb, Er, and Ce) are synthesized and optimized for better luminescence in the near-infrared second (NIR-II) and visible region. In addition, RENPs are coated with CoOOH of which the absorbance has an extensive peak in the visible and NIR regions. The concentration of H2O2 in the environment can be detected by the fluorescence recovery degree of CoOOH-modified RENPs based on the fluorescence resonance energy transfer effect. For in vivo detection, the physiological state of oxidative stress at tumor sites can be visualized through its fluorescence in NIR-II with low background noise and high penetration depth. For the in vitro detection, CoOOH-modified RENP and glucose oxidase (GOx) were doped into a polyacrylamide hydrogel, and a patch that can emit green upconversion fluorescence under a 980 nm laser was prepared. Compared with the conventional electrochemical detection method, the fluorescence we presented has higher sensitivity and linear detection region to detect the glucose. This improved anti-interference sweat patch that can work in the dark environment was obtained, and the physiological state of the human body is conveniently monitored, which provides a new facile and convenient method to monitor the sweat status.

Can atypical response in endothelial dysfunction-related genes and microRNAs arise from low hydrogen peroxide exposure?

OBJECTIVE: Vascular endothelium is a tissue in which several vasoactive substances are produced and secreted. Reactive oxygen species can cause endothelial dysfunction (ED). miRNAs can be implicated in the oxidative stress-related ED during vascular disease pathogeneses. Our aim is to investigate effect of H2O2-induced oxidative stress on expression levels of genes and miRNAs that are key players in ED. METHODS: H2O2 effect on cell viability of human umbilical-vein endothelial cells (HUVEC) at 24-hour was measured with MTT. Low sub-cytotoxic H2O2 concentrations (25, 50 µM) were selected to analyze their oxidative stress-inducing capacities with MDA assay and their effects on EDN1, NOS3, VCAM1, SERPINE1, miR21, miR22, miR126, and miR146a levels with RT-qPCR. RESULTS: Each tested H2O2 concentration reduced HUVEC cell viability. Fifty µM H2O2 augmented cellular MDA levels. Intriguingly, EDN1, VCAM1, and SERPINE1 and all analyzed miRNAs' levels attenuated upon H2O2 treatment whereas there was no change in NOS3 levels compared to control. There was a positive correlation between miR-21 and VCAM1. CONCLUSION: Rather than individual alterations in analyzed parameters, consistent changes in our findings i.e., parallel decreases in EDN1, VCAM1, SERPINE1 mRNA levels as well as miRNAs, suggests that H2O2 concentration-dependent modulation of expression patterns can bring about various impacts on ED (Tab. 1, Fig. 5, Ref. 63).

Hydrogen peroxide induced changes in the levels of disease-resistant substances and activities of disease-resistant enzymes in relation to the storability of longan fruit.

The influences of hydrogen peroxide (H2O2) on the storability and metabolism of disease-resistant substances in fresh longan were investigated. Compared to the control samples, H2O2-treated longan exhibited a higher index of fruit disease, pericarp browning, and pulp breakdown, a higher rate of fruit weight loss, but lower chromaticity values (L*, a* and b*) in pericarp appearance, and a lower commercially acceptable fruit rate. Additionally, H2O2-treated longan showed a lower lignin content, lower activities of enzymes including phenylalnine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumaryl coenzyme A ligase (4-CL), cinnamate dehydrogenase (CAD), peroxidase (POD), chitinase (CHI), and ß-1,3-glucanase (GLU). These data collectively suggest that H2O2 negatively impacted the storability of fresh longan. This can be attributed to H2O2's role in reducing the levels of disease-resistant substances and suppressing the activities of disease-resistant enzymes, implying that H2O2 reduced the postharvest storability of longan by compromising its disease resistance.

Effect of different oxygen precursors on alumina deposited using a spatial atomic layer deposition system for thin-film encapsulation of perovskite solar cells.

An atmospheric-pressure spatial atomic layer deposition system operated in atmospheric-pressure spatial chemical vapor deposition conditions is employed to deposit alumina (AlOx) thin films using trimethylaluminum and different oxidants, including water (H2O), hydrogen peroxide (H2O2), and ozone (O3). The impact of the oxygen precursor on the structural properties of the films and their moisture-barrier performance is investigated. The O3-AlOxfilms, followed by H2O2-AlOx, exhibit higher refractive indexes, lower concentrations of OH- groups, and lower water-vapor-transmission rates compared to the films deposited using water (H2O-AlOx). The AlOxfilms are then rapidly deposited as thin-film-encapsulation layers on perovskite solar cells at 130 °C without damaging the temperature-sensitive perovskite and organic materials. The stability of thep-i-nformamidinium methylammonium lead iodide solar cells under standard ISOS-D-3 testing conditions (65 °C and 85% relative humidity) is significantly enhanced by the encapsulation layers. Specifically, the O3-AlOxand H2O2-AlOxlayers result in a six-fold increase in the time required for the cells to degrade to 80% of their original efficiency compared to un-encapsulated cells.

Peroxymonosulfate-Based Electrochemical Advanced Oxidation: Complication by Oxygen Reduction Reaction.

Peroxymonosulfate (PMS)-based electrochemical advanced oxidation processes (EAOPs) have received widespread attention in recent years, but the precise nature of PMS activation and its impact on the overall process performance remain poorly understood. This study presents the first demonstration of the critical role played by the oxygen reduction reaction in the effective utilization of PMS and the subsequent enhancement of overall pollutant remediation. We observed the concurrent generation of H2O2 via oxygen reduction during the cathodic PMS activation by a model nitrogen-doped carbon nanotube catalyst. A complex interplay between H2O2 generation and PMS activation, as well as a locally increased pH near the electrode due to the oxygen reduction reaction, resulted in a SO4•-/•OH-mixed oxidation environment that facilitated pollutant degradation. The findings of this study highlight a unique dependency between PMS-driven and H2O2-driven EAOPs and a new perspective on a previously unexplored route for further enhancing PMS-based treatment processes.

A pilot study comparing the disinfecting effects of commercialized stable ClO2 solution (free of activation) with conventional H2O2 on dental unit waterlines in the dental practice setting.

Disinfection of dental unit waterlines (DUWLs) plays a key role in control and prevention of nosocomial infection in a dental clinic. The most conventional disinfectant is hydrogen peroxide (H2O2), while chlorine dioxide (ClO2) has been considered however was limited by the "activation" procedures. With the availability of commercialized stable ClO2 solution (free of activation), direct application of ClO2 in the dental practice became possible. This study was designed to compare the disinfecting effects of stable 5 ppm of ClO2 solution with conventional 0.24% of H2O2 on DUWLs in dental practice. Studies of colony-forming units (CFUs), confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM) were employed for evaluation. In CFUs studies, we found that the efficiency of ClO2 was no less than those of H2O2. In the morphological studies, the stronger disinfecting effects of ClO2 was verified by both CLSM and SEM studies for removal and prevention of biofilm. Importantly, ClO2 solution achieved a better disinfecting efficiency not only at the surface of bacterial biofilm, but also, it has penetrating effects, presented disinfecting effects from the surface to the bottom of the biofilm. This pilot study provided evidence regarding the efficiency of stable ClO2 solution on disinfection of DUWLs in the dental practice setting. Application of stable ClO2 solution in dental practice is therefore become possible.

Research Progress of SERS Sensors Based on Hydrogen Peroxide and Related Substances.

Hydrogen peroxide (H2O2) has an important role in living organisms, and its detection is of great importance in medical, chemical, and food safety applications. This review provides a comparison of different types of Surface-enhanced Raman scattering (SERS) sensors for H2O2 and related substances with respect to their detection limits, which are of interest due to high sensitivity compared to conventional sensors. According to the latest research report, this review focuses on the sensing mechanism of different sensors and summarizes the linear range, detection limits, and cellular applications of new SERS sensors, and discusses the limitations in vivo and future prospects of SERS technology for the detection of H2O2.

Inhibition of human cervical cancer development through p53-dependent pathways induced by the specified triple helical ß-glucan.

This study demonstrates that the purified ß-glucan (LNT) with a triple helix and relatively narrow molecular weight distribution, extracted and purified from artificially cultured Lentinus edodes, showed a significant cervical cancer inhibition with little cytotoxicity against normal cells in vitro and in vivo. From the in vitro data, the potential mechanism of anti-cervical cancer was preliminarily revealed as follows: LNT was firstly recognized by the human cervical cancer cell line of Hela and induced cell proliferation inhibition through p21 and apoptosis via a mitochondrion-dependent pathway by targeting the tumor suppressor of p53, indicated by an increase in reactive oxygen species (ROS) generation and a loss of mitochondrial membrane potential (Δψm), in a significant dosage-dependent manner. Meanwhile, LNT repressed tumor growth with an inhibition ratio of 61.2 % and induced tumor cell apoptosis through endogenous MDM2/p53/Bax/mitochondrion signal pathway by up-regulating the expression of p53, Bax, Cyt. c, caspase 9, and caspase 3, as well as down-regulating Bcl-2, MDM2, and PARP1 levels in Hela cells-transplanted BALB/c nude mice. This study provides a scientific basis for the clinical treatment of cervical cancer with LNT as a potential drug candidate characterized by the triple helix and specified molecular weight with a relatively narrow distribution.

Synthesis of Multifunctional Polymersomes Prepared by Polymerization-Induced Self-Assembly.

Polymersomes are an exciting modality for drug delivery due to their structural similarity to biological cells and their ability to encapsulate both hydrophilic and hydrophobic drugs. In this regard, the current work aimed to develop multifunctional polymersomes, integrating dye (with hydrophobic Nile red and hydrophilic sulfo-cyanine5-NHS ester as model drugs) encapsulation, stimulus responsiveness, and surface-ligand modifications. Polymersomes constituting poly(N-2-hydroxypropylmethacrylamide)-b-poly(N-(2-(methylthio)ethyl)acrylamide) (PHPMAm-b-PMTEAM) are prepared by aqueous dispersion RAFT-mediated polymerization-induced self-assembly (PISA). The hydrophilic block lengths have an effect on the obtained morphologies, with short chain P(HPMAm)16 affording spheres and long chain P(HPMAm)43 yielding vesicles. This further induces different responses to H2O2, with spheres fragmenting and vesicles aggregating. Folic acid (FA) is successfully conjugated to the P(HPMAm)43, which self-assembles into FA-functionalized P(HPMAm)43-b-P(MTEAM)300 polymersomes. The FA-functionalized P(HPMAm)43-b-P(MTEAM)300 polymersomes entrap both hydrophobic Nile red (NR) and hydrophilic Cy5 dye. The NR-loaded FA-linked polymersomes exhibit a controlled release of the encapsulated NR dye when exposed to 10 mM H2O2. All the polymersomes formed are stable in human plasma and well-tolerated in MCF-7 breast cancer cells. These preliminary results demonstrate that, with simple and scalable chemistry, PISA offers access to different shapes and opens up the possibility of the one-pot synthesis of multicompartmental and responsive polymersomes.

A Flexible and Transparent PtNP/SWCNT/PET Electrochemical Sensor for Nonenzymatic Detection of Hydrogen Peroxide Released from Living Cells with Real-Time Monitoring Capability.

We developed a transparent and flexible electrochemical sensor using a platform based on a network of single-walled carbon nanotubes (SWCNTs) for the non-enzymatic detection of hydrogen peroxide (H2O2) released from living cells. We decorated the SWCNT network on a poly(ethylene terephthalate) (PET) substrate with platinum nanoparticles (PtNPs) using a potentiodynamic method. The PtNP/SWCNT/PET sensor synergized the advantages of a flexible PET substrate, a conducting SWCNT network, and a catalytic PtNP and demonstrated good biocompatibility and flexibility, enabling cell adhesion. The PtNP/SWCNT/PET-based sensor demonstrated enhanced electrocatalytic activity towards H2O2, as well as excellent selectivity, stability, and reproducibility. The sensor exhibited a wide dynamic range of 500 nM to 1 M, with a low detection limit of 228 nM. Furthermore, the PtNP/SWCNT/PET sensor remained operationally stable, even after bending at various angles (15°, 30°, 60°, and 90°), with no noticeable loss of current signal. These outstanding characteristics enabled the PtNP/SWCNT/PET sensor to be practically applied for the direct culture of HeLa cells and the real-time monitoring of H2O2 release by the HeLa cells under drug stimulation.