Enhanced Reactive Oxygen Species Generation Research Articles

Green Synthesis and Characterization of Hydroxyapatite Nanorods with Enhanced Antibacterial and Anticancer Properties

This study reports the microwave synthesis of hydroxyapatite nanorods using Lantana camara L. flower extract (LCF-HA) and characterized by FTIR, XRD, TEM and SEM-EDX techniques. The extract coating on the hydroxyapatite nanorods improves the antibacterial efficacy against Gram-positive bacteria. The study also evaluates the mitochondrial membrane potential (MMP), generation of reactive oxygen species (ROS) and capacity to induce apoptosis of LCF-HA. It shows that LCF-HA efficiently inhibits the growth of osteosarcoma cells (MG-63) in a dose-dependent manner. The efficacy of LCF-HA in inducing apoptosis in osteosarcoma cells is established by dual acridine orange/ethidium bromide (AO/EB) fluorescence labelling. Additionally, LCF-HA induces an increase in reactive oxygen species (ROS) generation and a reduction in mitochondrial membrane potential (MMP) levels. The findings indicate that derived LCF-HA has significant anticancer efficacy by inducing apoptosis in osteosarcoma cells through enhanced ROS generation, suggesting that derived LCF-HA may serve as a promising therapeutic target for bone cancer cell lines. Furthermore, the study demostrates excellent compatibility with osteoblast cells, highlighting its potential for bone regeneration applications.

Enhancing Radiation-induced Reactive Oxygen Species Generation Through Mitochondrial Transplantation in Human Glioblastoma.

Glioblastoma (GBM) is the most aggressive primary brain malignancy in adults, with high recurrence rates and resistance to standard therapies. This study explores mitochondrial transplantation as a novel method to enhance the radiobiological effect (RBE) of ionizing radiation (IR) by increasing mitochondrial density in GBM cells, potentially boosting reactive oxygen species (ROS) production and promoting radiation-induced cell death. Using cell-penetrating peptides (CPPs), mitochondria were transplanted into GBM cell lines U3020 and U3035. Transplanted mitochondria were successfully incorporated into recipient cells, increasing mitochondrial density significantly. Mitochondrial chimeric cells demonstrated enhanced ROS generation post-irradiation, as evidenced by increased electron paramagnetic resonance (EPR) signal intensity and fluorescent ROS assays. The transplanted mitochondria retained functionality and viability for up to 14 days, with mitochondrial DNA (mtDNA) sequencing confirming high transfection and retention rates. Notably, mitochondrial transplantation was feasible in radiation-resistant GBM cells, suggesting potential clinical applicability. These findings support mitochondrial transplantation as a promising strategy to overcome therapeutic resistance in GBM by amplifying ROS-mediated cytotoxicity, warranting further investigation into its efficacy and mechanisms in vivo .

Boosting Reactive Oxygen Species Generation via Contact‐Electro‐Catalysis with FeIII‐Initiated Self‐cycled Fenton System

AbstractContact Electro‐Catalysis (CEC) using commercial dielectric materials in contact‐separation cycles with water can trigger interfacial electron transfer and induce the generation of reactive oxygen species (ROS). However, the inherent hydrophobicity of commercial dielectric materials limits the effective reaction sites, and the generated ROS inevitably undergo self‐combination to form hydrogen peroxide (H2O2). In typical CEC systems, H2O2 does not further decompose into ROS, leading to suboptimal reaction rates. Addressing the generation and activation of H2O2 is therefore crucial for advancing CEC. Here, we synthesized a catalyst by loading the dielectric material polytetrafluoroethylene (PTFE) onto ZSM‐5 (PTFE/ZSM‐5, PZ for short), achieving uniform dispersion of the catalyst in water for the first time. The introduction of an FeIII‐initiated self‐cycling Fenton system (SF‐CEC), with the synergistic effects of O2 activation and FeIII‐activated H2O2, further enhanced ROS generation. In the FeIII‐initiated SF‐CEC system, the synergistic effects of ROS and protonated azo dyes enabled nearly 99 % degradation of azo dyes within 10 minutes, a sixfold improvement compared to the CEC system. This represents the fastest degradation rate of methyl orange dye induced by ultrasound to date. Without extra oxidants, this system enabled stable dissolution of precious metals in weakly acidic solutions at room temperature, achieving 80 % gold dissolution within 2 hours, 2.5 times faster than similar CEC systems. This study also corrects the unfavorable perception of CEC applications under acidic conditions, providing new insights for the fields of dye degradation and precious metal recovery.

Two strategies of enhancing the therapeutic potential of a coumarin probe: Integration of a protonatable moiety and BSA-based nanoparticle formation

Photodynamic therapy (PDT) represents a promising non-invasive approach for cancer treatment, relying on photosensitizers (PSs) to generate reactive oxygen species (ROS) upon light activation. This study aims to enhance the therapeutic potential of a coumarin-based fluorescent probe by employing two strategic modifications: the integration of a protonatable lysosome-targeting moiety and the formation of bovine serum albumin (BSA)-based nanoparticles. The COM molecule was synthesized with a morpholine moiety to facilitate lysosome targeting and protonation in acidic environments, thereby enhancing ROS production and promoting lysosomal dysfunction for increased cancer cell apoptosis. Additionally, COM was encapsulated in BSA nanoparticles (COM-BSA NPs) to leverage hydrophobic interactions and hydrogen bonding, which enhance ROS generation by promoting the intersystem crossing (ISC) process. Comprehensive photophysical studies confirmed the enhanced ROS generation under acidic conditions and within BSA-based NPs. Cellular experiments demonstrated effective lysosome targeting and anticancer efficacy of both COM and COM-BSA NPs. These findings highlight the dual benefits of maintaining the bioimaging capabilities of coumarin while significantly improving its therapeutic efficacy in PDT applications.

Oxidative stress-modifying effects of TiO2 nanoparticles with varying content of Ti3+(Ti2+) ions

Nanoparticles (NPs) with reactive oxygen species (ROS)-regulating ability have recently attracted great attention as promising agents for nanomedicine. In the present study, we have analyzed the effects of TiO2defect structure related to the presence of stoichiometric (Ti4+) and non-stoichiometric (Ti3+and Ti2+) titanium ions in the crystal lattice and TiO2NPs aggregation ability on H2O2- and tert-butyl hydroperoxide (tBOOH)-induced ROS production in L929 cells. Synthesized TiO2-A, TiO2-B, and TiO2-C NPs with varying Ti3+(Ti2+) content were characterized by x-ray powder diffraction, transmission electron microscopy, small-angle x-ray scattering, x-ray photoelectron spectroscopy, and optical spectroscopy methods. Given the role of ROS-mediated toxicity for metal oxide NPs, L929 cell viability and changes in the intracellular ROS levels in H2O2- and tBOOH-treated L929 cells incubated with TiO2NPs have been evaluated. Our research shows that both the amount of non-stoichiometric Ti3+and Ti2+ions in the crystal lattice of TiO2NPs and NPs aggregative behavior affect their catalytic activity, in particular, H2O2decomposition and, consequently, the efficiency of aggravating H2O2- and tBOOH-induced oxidative damage to L929 cells. TiO2-A NPs reveal the strongest H2O2decomposition activity aligning with their less pronounced additional effects on H2O2-treated L929 cells due to the highest amount of Ti3+(Ti2+) ions. TiO2-C NPs with smaller amounts of Ti3+ions and a tendency to aggregate in water solutions show lower antioxidant activity and, consequently, some elevation of the level of ROS in H2O2/tBOOH-treated L929 cells. Our findings suggest that synthesized TiO2NPs capable of enhancing ROS generation at concentrations non-toxic for normal cells, which should be further investigated to assess their possible application in nanomedicine as ROS-regulating pharmaceutical agents.

Water-soluble AIE photosensitizer in short-wave infrared region for albumin-enhanced and self-reporting phototheranostics

Organic photosensitizers (PSs) play important roles in phototheranostics, and contribute to the fast development of precision medicine. However, water-soluble and highly emissive organic PSs, especially those emitting in the short-wave infrared region (SWIR), are still challenging. Also, it's difficult to prepare self-reporting PSs for visualizing the treatment via stimulated emission depletion (STED) nanoscopy. Thus, in this work, a water-soluble molecule of DTPAP-TBZ-I with aggregation-induced emission features is designed for the self-reporting photodynamic therapy (PDT) in an ultra-high resolution. In contrast to single molecule, its complex (DTPAP-TBZ-I@BSA) shows much enhanced fluorescence properties and reactive oxygen species (ROS) generation in SWIR window. Their photoluminescence quantum yield is determined to be ∼20.6 % and the enhancement of ROS generation is ∼18-fold. During the PDT, immigration of the complex from cytoplasm to nucleus is also observed via STED nanoscopy with a resolution of 66.11 nm, which allows self-report in the PDT treatment. DTPAP-TBZ-I@BSA is finally utilized for the imaging-guided PDT in vivo with a tumor inhibition rate of 84 %. This is the first work in albumin-enhanced water-soluble organic PSs in SWIR window for self-reporting phototheranostics at ultra-high resolutions, providing an ideal solution for the next generation of photosensitizers for precise medicine.

A dual-pathway pyroptosis inducer based on Au–Cu2-xSe@ZIF-8 enhances tumor immunotherapy by disrupting the zinc ion homeostasis

The regulation of intracellular ionic homeostasis to trigger antigen-specific immune responses has attracted extensive interest in tumor therapy. In this study, we developed a dual-pathway nanoreactor, Au-Cu2-xSe@ZIF-8@P18 NPs (ACS-Z-P NPs), which targets danger-associated molecular patterns (DAMPs) and releases Zn2+ and reactive oxygen species (ROS) within the tumor microenvironment (TME). Zn2+ released from the metal–organic frameworks (MOFs) was deposited in the cytoplasm, leading to aberrant transcription levels of intracellular zinc-regulated proteins and DNA damage, thereby inducing pyroptosis and immunogenic cell death (ICD) dependent on caspase1/gasdermin D (GSDMD) pathway. Furthermore, upon laser irradiation, ACS-Z-P NPs could break through the limitations of inherent defects of immunosuppression in TME, enhance ROS generation through a Fenton-like reaction cascade, which subsequently triggered the activation of inflammatory vesicles and the release of damage-associated molecular patterns (DAMPs). This cascade effect led to the amplification of pyroptosis and immunogenic cell death (ICD), thereby remodeling the immunosuppressed TME. Consequently, this process improved dendritic cell (DC) antigen presentation and augmented anti-tumor T-cell responses, effectively initiating antigen-specific immune responses and further enhancing pyroptosis and ICD. This study explores the therapeutic properties of these mechanisms in detail. Statement of significanceThe synthesized Au-Cu2-xSe@ZIF-8@P18 nanoparticles (ACS-Z-Ps) can effectively enhance the bodyʼs immune response by regulating zinc ion levels within cells. This regulation leads to abnormal levels of zinc-regulated protein transcription and DNA damage, which induces cellular pyroptosis. As a result, antigen presentation to dendritic cells (DCs) is improved, and anti-tumor T-cell responses are enhanced.The ACS-Z-P NPs overcome the limitations of ROS deficiency and immunosuppression in the tumor microenvironment by using H2O2 in the tumor microenvironment through a Fenton-like reaction. This leads to an increased production of ROS and O2, remodeling of the immunosuppressed tumor microenvironment, and enhanced induction of cell pyroptosis and immunogenic cell death.ACS-Z-P NPs targeted B16 cells using the photosensitizer P18 in combination with PDT treatment. This approach significantly inhibited the proliferation of B16 cells and effectively inhibited tumor growth.

3D Porous Gel from the Orthogonal-junction of Nanosheet Photosensitizers with Efficient and Selective Photosensitization

Photocatalysis waste decomposition is a promising candidate for efficient cleaning of volatile organic compounds (VOCs) with enhanced safety because of the self-degradation of toxic compounds by reactive oxygen species (ROS) under light irradiation. However, the complete removal of pollutants remains challenging due to the inert characteristics of their inactivity in the presence of electrophilic ROS. Herein, a new strategy for efficient degradation of inert VOCs such as benzaldehyde has been proposed, basing on the synergism of selective adsorption and chemical activation by the construction of 3D porous gel through an orthogonal-junction of nanosheet-shaped photosensitizers. The key to the success of the combination is the use of hierarchically assembled hydrogen bonded laminates (HBLs) as gelation scaffolds. The backbone could integrate organic photosensitizers (PSs) into robust gel skeleton with enhanced ROS generation, which promotes the photocatalytic degradation. Especially, the backbone is able to directionally recognize glue clusters by hydrogen bonding to result in orthogonal 3D gel, giving remarkable selective adsorption for inert aromatic aldehydes. The synergistic integration of chemical activation and selective entrapment gives rise to unusual rapid photo-degradation for carbonyl compounds, resulting in efficient removal of inert pollutants from the environment without any adverse effect.

Two-Dimensional Atomically Thin Piezoelectric Nanosheets for Efficient Pyroptosis-Dominated Sonopiezoelectric Cancer Therapy.

Sonopiezocatalytic therapy is an emerging therapeutic strategy that utilizes ultrasound irradiation to activate piezoelectric materials, inducing polarization and energy band bending to facilitate the generation of reactive oxygen species (ROS). However, the efficient generation of ROS is hindered by the long distance of charge migration from the bulk to the material surface. Herein, atomically thin Bi2O2(OH)(NO3) (AT-BON) nanosheets are rationally engineered through disrupting the weaker hydrogen bonds within the [OH] and [NO3] layer in the bulk material. The ultrathin structure of AT-BON piezocatalytic nanosheets shortens the migration distance of carriers, expands the specific surface area, and accelerates the charge transfer efficiency, showcasing a natural advantage in ROS generation. Importantly, the non-centrosymmetric polar crystal structure grants the nanosheets the ability to separate electron-hole pairs. Under ultrasonic mechanical stress, Bi2O2(OH)(NO3) nanosheets with the remarkable piezoelectric feature exhibit the desirable in vivo antineoplastic outcomes in both breast cancer model and liver cancer model. Especially, the AT-BON-induced ROS bursts lead to the activation of the Caspase-1-driven pyroptosis pathway. This study highlights the beneficial impact of bulk material thinning on enhancing ROS generation efficiency and anti-cancer effects.

Interleukin-37 Inhibits Interleukin-1β-Induced Articular Chondrocyte Apoptosis by Suppressing Reactive Oxygen Species.

Objective: Chondrocyte apoptosis has been considered a crucial mechanism that is responsible for cartilage destruction in osteoarthritis (OA). The mechanism of interleukin-37 (IL-37) on chondrocyte apoptosis has not been clearly determined in the pathogenesis of OA. Here, we explored the role of IL-37 in the regulation of cellular apoptosis in rat chondrocytes stimulated by IL-1β. Methods: Rat chondrocytes were used in in vitro study, and were stimulated with IL-1β (10 ng/mL) and/or recombinant IL-37 (rIL-37; 100 ng/mL) after cytotoxicity assessments using these cytokines were conducted. After rIL-37 treatment of chondrocytes stimulated with IL-1β, the cell proliferation assay, apoptosis assays, including expression of mitochondrial apoptosis-related markers, flow cytometry analysis of annexin V-FITC/propidium iodide (PI), cell cycle analysis, and Hoechst 33342 staining, and reactive oxygen species (ROS) measurement were used. Results: IL-1β induced expression of inflammatory cytokines and triggered degradation of the extracellular matrix of rat chondrocytes, but this effect was significantly attenuated by rIL-37 treatment. Enhanced ROS generation following IL-1β stimulation was reduced in a dose-dependent manner after stimulation with rIL-37. IL-1β induced pro-apoptotic markers and suppressed anti-apoptotic markers in rat chondrocytes. Flow cytometry using annexin V-FITC/PI revealed that IL-1β increased the apoptosis rate of rat chondrocytes, and that this effect was markedly reversed by treatment with rIL-37. Conclusions: IL-37 potently attenuated IL-1β-mediated apoptosis of rat chondrocytes by blocking ROS production. This study suggests that IL-37 can serve as a novel anti-cytokine therapy in OA by blocking chondrocyte apoptosis.

Low oxygen adsorption energy barrier architectures to facilitate microenvironmental photocatalytic disinfection in Wei River

Photocatalytic disinfection is an eco-friendly strategy that uses solar energy to purify bacteria-contaminated water. However, improvements in photocatalysts tend to focus on thermodynamics while neglecting kinetic interactions that involve oxygen. Here, we propose the MOF-on-MOF heterojunction NR-HKUST-1@Cu/ZIF-8 (NH@CZ) for kinetic photocatalytic disinfection; the heterojunction reduced bacterial load by nearly 8-log within 20 min. The NH@CZ structure exhibits a high specific surface area with Cu2O8 and CuN4 sites that provide substantial oxygen storage capacity and binding sites. In vitro experiments demonstrated the effective delivery of oxygen to photocatalytic reactions via NH@CZ, leading to enhanced superoxide radical (·O2-) generation. Experimental analysis and theoretical calculations confirm that the formation of heterojunctions in NH@CZ provides an efficient pathway for oxygen reduction by reducing the energy barrier associated with oxygen adsorption. Mechanistic studies show that reactive oxygen species (ROS) disrupt bacterial cell membranes, resulting in the release of cellular contents (e.g., potassium ions and macromolecular proteins) and subsequent cell death. Furthermore, the oxygen-carrying NH@CZ killed all microorganisms in Wei River water samples within 45 min. The MOF-on-MOF heterojunction offers a promising pathway to enhance ROS generation and provides valuable insights into advances in water disinfection technology.

Flexible roles of TiO2 in enhancing carrier separation for the high photocatalytic performance of water treatment under different spectrum sunlight

Construction of heterogeneous-photocatalysts is an effective mean for enhancing charge separation, however, the specific roles of the individual components have not been thoroughly explored. In this article, a heterogeneous-photocatalyst, TiO2/MoO3-x, was constructed, revealing that the two components, TiO2 and MoO3-x, play varying roles under different light spectra. Under full spectrum light, an S-scheme mechanism was achieved, which preserved the high oxidizing and reducing property of MoO3-x and TiO2, facilitating an augmented generation of reactive oxygen species (ROS). Under visible light, the MoO3-x functioned as the donor of hot electrons and the TiO2 served as the receptor platform for these electrons. The presence of the interfacial electric field enabled the transfer of hot electrons, leading to an enhanced ROS generation. Consequently, the TiO2/MoO3-x achieved high photocatalytic activity under both full spectrum and visible light. The optimized TiO2/MoO3-x catalyst demonstrated outstanding antibacterial efficacy, achieving eradication rates of 98.1 % for Staphylococcus aureus, and 99.6 % for Escherichia coli respectively. Additionally, it exhibited substantial degradation activity with a rate of 0.028 min−1 for Rhodamine B (50 mg/L). Furthermore, the TiO2/MoO3-x membrane removed approximately 81.2 % of bacteria from surface water, underscoring the potential of the designed membrane in water purification systems. This article explored the distinct roles and corresponding charge transfer mechanisms of the TiO2 and MoO3-x under full spectrum or visible light, offering innovative ideas for the design of full-spectrum photocatalysts with high efficiency. The straightforward design of membrane-based filtering device demonstrated wide applications for treating wastewater for the removal of dye and bacterial contamination.

Tumor microenvironment ameliorative and adaptive nanoparticles with photothermal-to-photodynamic switch for cancer phototherapy

The notorious tumor microenvironment (TME) usually becomes more deteriorative during phototherapeutic progress that hampers the antitumor efficacy. To overcome this issue, we herein report the ameliorative and adaptive nanoparticles (TPASIC-PFH@PLGA NPs) that simultaneously reverse hypoxia TME and switch photoactivities from photothermal-dominated state to photodynamic-dominated state to maximize phototherapeutic effect. TPASIC-PFH@PLGA NPs are designed by incorporating oxygen-rich liquid perfluorohexane (PFH) into the intraparticle microenvironment to regulate the intramolecular motions of AIE photosensitizer TPASIC. TPASIC exhibits a unique aggregation-enhanced reactive oxygen species (ROS) generation feature. PFH incorporation affords TPASIC the initially dispersed state, thus promoting active intramolecular motions and photothermal conversion efficiency. While PFH volatilization leads to nanoparticle collapse and the formation of tight TPASIC aggregates with largely enhanced ROS generation efficiency. As a consequence, PFH incorporation not only currently promotes both photothermal and photodynamic efficacies of TPASIC and increases the intratumoral oxygen level, but also enables the smart photothermal-to-photodynamic switch to maximize the phototherapeutic performance. The integration of PFH and AIE photosensitizer eventually delivers more excellent antitumor effect over conventional phototherapeutic agents with fixed photothermal and photodynamic efficacies. This study proposes a new nanoengineering strategy to ameliorate TME and adapt the treatment modality to fit the changed TME for advanced antitumor applications.

Boosting Reactive Oxygen Species Generation via Contact-Electro-Catalysis with FeIII-Initiated Self-cycled Fenton System.

Contact Electro-Catalysis (CEC) using commercial dielectric materials in contact-separation cycles with water can trigger interfacial electron transfer and induce the generation of reactive oxygen species (ROS). However, the inherent hydrophobicity of commercial dielectric materials limits the effective reaction sites, and the generated ROS inevitably undergo self-combination to form hydrogen peroxide (H2O2). In typical CEC systems, H2O2 does not further decompose into ROS, leading to suboptimal reaction rates. Addressing the generation and activation of H2O2 is therefore crucial for advancing CEC. Here, we synthesized a catalyst by loading the dielectric material polytetrafluoroethylene (PTFE) onto ZSM-5 (PTFE/ZSM-5, PZ for short), achieving uniform dispersion of the catalyst in water for the first time. The introduction of an FeIII-initiated self-cycling Fenton system (SF-CEC), with the synergistic effects of O2 activation and FeIII-activated H2O2, further enhanced ROS generation. In the FeIII-initiated SF-CEC system, the synergistic effects of ROS and protonated azo dyes enabled nearly 99 % degradation of azo dyes within 10 minutes, a sixfold improvement compared to the CEC system. This represents the fastest degradation rate of methyl orange dye induced by ultrasound to date. Without extra oxidants, this system enabled stable dissolution of precious metals in weakly acidic solutions at room temperature, achieving 80 % gold dissolution within 2 hours, 2.5 times faster than similar CEC systems. This study also corrects the unfavorable perception of CEC applications under acidic conditions, providing new insights for the fields of dye degradation and precious metal recovery.

Synergistic Activation of LEPR and ADRB2 Induced by Leptin Enhances ROS Generation in TNBC Cells.

Leptin interacts not only with leptin receptor (LEPR) but also engages with other receptors. While the pro-oncogenic effects of the adrenergic receptor β2 (ADRB2) are well-established, the role of leptin in activating ADRB2 in triple-negative breast cancer (TNBC) remains unclear. The pro-carcinogenic effects of LEPR were investigated using murine TNBC cell lines, 4T1 and EMT6, and a tumor-bearing mouse model. Expression levels of LEPR, NOX4, and ADRB2 in TNBC cells and tumor tissues were analyzed via Western blot and qPCR. Changes in reactive oxygen species (ROS) levels were assessed using flow cytometry and MitoSox staining, while immunofluorescence double-staining confirmed the co-localization of LEPR and ADRB2. LEPR activation promoted NOX4-derived ROS and mitochondrial ROS production, facilitating TNBC cell proliferation and migration, effects which were mitigated by the LEPR inhibitor Allo-aca. Co-expression of LEPR and ADRB2 was observed on cell membranes, and bioinformatics data revealed a positive correlation between the two receptors. Leptin activated both LEPR and ADRB2, enhancing intracellular ROS generation and promoting tumor progression, which was effectively countered by a specific ADRB2 inhibitor ICI118551. In vivo, leptin injection accelerated tumor growth and lung metastases without affecting appetite, while treatments with Allo-aca or ICI118551 mitigated these effects. This study demonstrates that leptin stimulates the growth and metastasis of TNBC through the activation of both LEPR and ADRB2, resulting in increased ROS production. These findings highlight LEPR and ADRB2 as potential biomarkers and therapeutic targets in TNBC.

Novel insights into the factors influencing rhizosphere reactive oxygen species production and their role in polycyclic aromatic hydrocarbons transformation

Reactive oxygen species (ROS) are recognised as pivotal biogeochemical process drivers. However, the factors influencing ROS production in the rhizosphere and their role in pollutant transformation remain elusive. We investigated ROS with a focus on spatiotemporal variations in superoxide radicals (O2•−), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH) in the rhizosphere of maize during root development, and elucidated the impact of environmental conditions on ROS production. In-situ visualisation by fluorescence imaging showed that ROS hotspots gradually shifted from seminal to lateral roots during maize growth, indicating that newly developed roots are the major contributors to ROS production. The three types of ROS contents changed with root growth, suggesting that root development regulates ROS production. The ROS contents reached a maximum at 25 °C and 45% maximum field capacity. Both ambient temperature and soil moisture indirectly influenced ROS production by regulating the release of root exudates to induce changes in water-soluble phenols and dissolved organic carbon (DOC). In contrast, ROS content gradually increased with oxygen availability, which directly mediated ROS generation by acting as a precursor. More interestingly, the presence of polycyclic aromatic hydrocarbons (PAHs) significantly enhanced ROS generation, which further promoted PAH removal with a contribution of 31.4–43.3%. These findings provide new insights into the occurrence, distribution, and environmental effects of ROS in the rhizosphere.

Vidarabine as a novel antifungal agent against Candida albicans: insights on mechanism of action.

Around 1.5 million mortality cases due to fungal infection are reported annually, posing a massive threat to global health. However, the effectiveness of current antifungal therapies in the treatment of invasive fungal infections is limited. Repurposing existing antifungal drugs is an advisable alternative approach for enhancing their effectiveness. This study evaluated the antifungal efficacy of the antiviral drug vidarabine against Candida albicans ATCC 90028. Antifungal susceptibility testing was performed by microbroth dilution assay and further processed to find the minimum fungicidal concentration. Investigation on probable mode of vidarabine action against C. albicans was assessed by using the ergosterol reduction assay, reactive oxygen species (ROS) accumulation, nuclear condensation, and apoptosis assay. Results revealed that C. albicans was susceptible to vidarabine action and exhibited minimum inhibitory concentration at 150µg/ml. At a concentration of 300µg/ml, vidarabine had fungicidal activity against C. albicans. 300µg/ml vidarabine-treated C. albicans cells demonstrated 91% reduced ergosterol content. Annexin/FITC/PI assay showed that vidarabine (150µg/ml) had increased late apoptotic cells up to 31%. As per the fractional inhibitory concentration index, vidarabine had synergistic activity with fluconazole and caspofungin against this fungus. The mechanism underlying fungicidal action of vidarabine was evaluated at the intracellular level, and probably because of increased nuclear condensation, enhanced ROS generation, and cell cycle arrest. In conclusion, this data is the first to report that vidarabine has potential to be used as a repurposed antifungal agent alone or in combination with standard antifungal drugs, and could be a quick and safe addition to existing therapies for treating fungal infections.

Engineering Heterostructured Piezoelectric Nanorods with Rich Oxygen Vacancy‐Mediated Piezoelectricity for Ultrasound‐Triggered Piezocatalytic Cancer Therapy

AbstractUsing piezoelectric bionanomaterials to promote the generation of reactive oxygen species (ROS) is being increasingly recognized in ultrasound (US)‐triggered tumor treatments. The mechanism underlying this innovative treatment involves US irradiation, which activates the built‐in electric field (BIEF) and induces energy‐band bending in piezoelectric materials (PEMs). In this study, Sr0.5Ba0.5Nb2O6 (SBN) nanorods (NRs) are synthesized using a molten salt method. Subsequently, oxygen‐vacancy (OV)‐rich SBN/Sr2Nb2O7 (SBN/SNO) heterojunction nanocomposites (NCs) are fabricated via H2 annealing of the SBN NRs. The engineering strategy focused on enhancing ROS generation, thereby augmenting the piezoelectric catalytic activity of the NCs. This configuration ensures that the BIEF and heterojunction‐induced field act synergistically to provide a sustained driving force for the separation of electron‐hole (e−‐h+) pairs. Importantly, the OVs on the surfaces of the H2‐annealed SBN NRs create electron‐rich sites, which substantially enhance their piezocatalytic capabilities. In vitro and in vivo analyses of hepatocellular carcinoma (HCC) models demonstrate the significant cytotoxic and tumor‐inhibitory capabilities of this rich OV‐mediated sonopiezoelectric therapy (SPT) and illustrate its potential as a promising therapeutic approach against cancer.

SILAR deposited Antiviral silver-doped Ceria nano-films

Amid the COVID-19 global pandemic, ceria nanomaterials (CN) have garnered renewed interest as potential antiviral agents due to their ability to generate reactive oxygen species (ROS) on their surfaces. Enhancing ROS generation through precise defect engineering is key to improving these antiviral properties. This can be achieved through various methods, such as altering nano-dimensions and doping. In this context, we report on silver-doped ceria thin films. We have employed a cost-effective SILAR (Successive Ionic Layer Adsorption and Reaction) method for ceria nano-film deposition, which offers excellent control over film thickness. Utilizing an Arduino-controlled layer-by-layer (LBL) setup, we achieved precise control over the deposition process. This method facilitated the easy doping of ceria nano-films with silver ions. The silver-doped SILAR ceria thin films of varying thicknesses were subjected to antibacterial testing against E. coli bacteria. The samples with the highest antibacterial activity were further tested for antiviral efficacy against Feline calicivirus. The 80 SILAR Layers Ag-Ceria sample exhibited the best activity, completely deactivating the viral titer (105). This sample, when further tested against OC43 coronavirus, demonstrated a >99% reduction in virus titer. The mechanisms underlying these antimicrobial properties were investigated using antioxidative testing assays.

Self-Oxygenated Hydrogel Enhances Immune Cell Response and Infiltration Via Triggering Dual DNA Damage to Activate cGAS-STING and Inhibiting CAFs.

Immune checkpoint inhibitors (ICIs) offer promise in breaking through the treatment and survival dilemma of triple-negative breast cancer (TNBC), yet only immunomodulatory subtype and ≈5% TNBC patients respond as monotherapy due to lack of effector immune cells (internal problem) and physical barrier (external limitation) formed by cancer-associated fibroblasts (CAFs). A hydrogel drug-delivery platform, ALG@TBP-2/Pt(0)/nintedanib (ALG@TPN), is designed to induce strong immune functions and the dual elimination of the internal and external tumor microenvironment (TME). Activated by white light, through type I and II photodynamic therapy (PDT), TBP-2 generates large amounts of reactive oxygen species (ROS) intracellularly, oxidizing mitochondrial DNA (mtDNA). The unique catalase activity of Pt(0) converts endogenous H2O2 to O2, reducing the anoxia-limiting PDT and enhancing ROS generation efficacy. Abundant ROS can oxidize Pt(0) to cytotoxic Pt(II), damaging the nuclear DNA (nDNA). Dual damage to mtDNA and nDNA might bi-directionally activate the cGAS/STING pathway and enhance the immune cell response. Besides, nintedanib demonstrates a significant inhibitory effect on CAFs, weakening the immune barrier and deepening immune cell infiltration. Overall, the study provides a self-oxygenating hydrogel with the "PDT/chemotherapy/anti-CAFs" effect, triggering the cGAS/STING pathway to reshape the TME. Both internal and external interventions increase anti-TNBC immune responses.