Efficiency Of Reactive Oxygen Species Research Articles

Nanoarchitectonics of Bimetallic Cu-/Co-Doped Nitrogen-Carbon Nanozyme-Functionalized Hydrogel with NIR-Responsive Phototherapy for Synergistic Mitigation of Drug-Resistant Bacterial Infections.

Superbug infections and transmission have become major challenges in the contemporary medical field. The development of novel antibacterial strategies to efficiently treat bacterial infections and conquer the problem of antimicrobial resistance (AMR) is extremely important. In this paper, a bimetallic CuCo-doped nitrogen-carbon nanozyme-functionalized hydrogel (CuCo/NC-HG) has been successfully constructed. It exhibits photoresponsive-enhanced enzymatic effects under near-infrared (NIR) irradiation (808 nm) with strong peroxidase (POD)-like and oxidase (OXD)-like activities. Upon NIR irradiation, CuCo/NC-HG possesses photodynamic activity for producing singlet oxygen(1O2), and it also has a high photothermal conversion effect, which not only facilitates the elimination of bacteria but also improves the efficiency of reactive oxygen species (ROS) production and accelerates the consumption of GSH. CuCo/NC-HG shows a lower hemolytic rate and better cytocompatibility than CuCo/NC and possesses a positive charge and macroporous skeleton for restricting negatively charged bacteria in the range of ROS destruction, strengthening the antibacterial efficiency. Comparatively, CuCo/NC and CuCo/NC-HG have stronger bactericidal ability against methicillin-resistant Staphylococcus aureus (MRSA) and ampicillin-resistant Escherichia coli (AmprE. coli) through destroying the cell membranes with a negligible occurrence of AMR. More importantly, CuCo/NC-HG plus NIR irradiation can exhibit satisfactory bactericidal performance in the absence of H2O2, avoiding the toxicity from high-concentration H2O2. In vivo evaluation has been conducted using a mouse wound infection model and histological analyses, and the results show that CuCo/NC-HG upon NIR irradiation can efficiently suppress bacterial infections and promote wound healing, without causing inflammation and tissue adhesions.

Heavy-atom-free orthogonal configurative dye 1,7-di-anthra-aza-BODIPY for singlet oxygen generation

Spin-orbit, charge-transfer intersystem crossing (SOCT-ISC) can directly overcome the disadvantages of the traditional heavy-atom effect and improve the generation efficiency of reactive oxygen species (ROS). Since orthogonal molecular orbitals of donor-acceptor (D-A) pairs favor the SOCT-ISC transition, herein aza-borondipyrromethenes (aza-BODIPYs) with 1,7-di-anthracyl groups (An-azaBDP) was successfully prepared, owing to steric hindrance to produce a big dihedral angle between the two molecular orbital (MO) planes. Moreover, according to density functional theory (DFT) and time-dependent density functional theory (TDDFT), the energy difference between the S1-T1 orbitals of An-azaBDP is small and more inclined towards ISC. An-azaBDP can effectively generate singlet oxygen under light irradiation. An-azaBDP with light irradiation can induce apoptosis in SW620 cells, and can serve as a potential candidate for the treatment of cancer cells and tumors.

Amorphous 2D Mn-doped CoMo-layered double hydroxide nanosheets for magnetic resonance imaging-guided sonodynamic cancer therapy

Sonodynamic therapy (SDT) has attracted increasing attention owing to its superior tissue penetration compared with other therapies. However, the development of multifunctional sonosensitizers with imaging capability and high production efficiency of reactive oxygen species (ROS) is still a challenge for current sonodynamic cancer therapy. Herein, we report the design and preparation of amorphous 2D Mn-doped CoMo-layered double hydroxide (a-Mn-CoMo-LDH) nanosheets (NSs) through acid etching-induced crystalline-to-amorphous phase transformation as a highly active nano-agent for magnetic resonance imaging (MRI)-guided SDT. The a-Mn-CoMo-LDH NSs exhibit superior ROS production capacity compared with amorphous CoMo-LDH NSs (∼1.3 times) and crystalline Mn-CoMo-LDH NSs (∼3.9 times) under ultrasound (US) irradiation, which is ∼ 9.9 times of the previously reported TiO2 sonosensitizer. The doped Mn4+ in the a-Mn-CoMo-LDH NSs can not only decompose H2O2 into O2 to alleviate the hypoxia level in tumor microenvironment (TME), but also consume glutathione (GSH) to reduce its clearance of ROS, promoting the SDT performance synergistically. Importantly, the GSH consumption can partially reduce the Mn4+ to Mn2+ within the tumors, which can serve as an agent for T1-weighted MRI, thus endowing the a-Mn-CoMo-LDH NSs with excellent MRI capability. Therefore, the as-prepared a-Mn-CoMo-LDH NSs with polyethylene glycol modification can be used as an efficient nano-agent for MRI-guided SDT, which can effectively achieve apoptosis of cancer cells in vitro and eradication of tumors in vivo under US irradiation.

Esterase-triggered rapid release of succinic anhydride conjugated curcumin co-prodrug for osteosarcoma therapy

Osteosarcoma (OS) is one of the most common primary bone malignancies in children and adolescents worldwide. The serious side effects and multi-drug resistance of high-dose chemotherapy have become the major cause of the failure in OS treatment. Curcumin (Cur) is reported to selectively kill OS cells and has a low cytotoxicity on healthy osteoblasts, but its delivery remains a great challenge. Herein, a co-polymer-Cur prodrug (co-prodrug) was developed by polymerizing Cur with hydrophilic polymer modified by succinic anhydride (SA) to explore the physicochemical properties, drug release and potential biological effects for OS treatment. This design endowed the co-prodrug with excellent solubility and stability under different solution conditions (pH = 4.5, 7.4 and 8.5), and improved the release efficiency of reactive oxygen species. Interestingly, co-prodrug exhibited an esterase-triggered rapid drug release in a concentration-dependent manner rather than the well-known acid response. Moreover, co-prodrug could be internalized into cells through endocytosis and significantly inhibit the proliferation of OS cells. Additionally, co-prodrug had no obvious systemic toxicity, and could suppress the OS growth by promoting apoptosis, inhibiting proliferation activity and vascularization in vivo. Our research furnishes a fresh perspective for the formulation design of controlled release of insoluble and instable anticancer agents within tumor cells.

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping.

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4',4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing -SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of -SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation.

Linker Engineering for Reactive Oxygen Species Generation Efficiency in Ultra-Stable Nickel-Based Metal-Organic Frameworks.

Interfacial charge transfer on the surface of heterogeneous photocatalysts dictates the efficiency of reactive oxygen species (ROS) generation and therefore the efficiency of aerobic oxidation reactions. Reticular chemistry in metal-organic frameworks (MOFs) allows for the rational design of donor-acceptor pairs to optimize interfacial charge-transfer kinetics. Herein, we report a series of isostructural fcu-topology Ni8-MOFs (termed JNU-212, JNU-213, JNU-214, and JNU-215) with linearly bridged bipyrazoles as organic linkers. These crystalline Ni8-MOFs can maintain their structural integrity in 7 M NaOH at 100 °C for 24 h. Experimental studies reveal that linker engineering by tuning the electron-accepting capacity of the pyrazole-bridging units renders these Ni8-MOFs with significantly improved charge separation and transfer efficiency under visible-light irradiation. Among them, the one containing a benzoselenadiazole unit (JNU-214) exhibits the best photocatalytic performance in the aerobic oxidation of benzylamines with a conversion rate of 99% in 24 h. Recycling experiments were carried out to confirm the stability and reusability of JNU-214 as a robust heterogeneous catalyst. Significantly, the systematic modulation of the electron-accepting capacity of the bridging units in donor-acceptor-donor MOFs provides a new pathway to develop viable noble-metal-free heterogeneous photocatalysts for aerobic oxidation reactions.

ROS-responsive self-activatable photosensitizing agent for photodynamic-immunotherapy of cancer.

Photodynamic therapy (PDT), as a non-invasive and spatiotemporally controllable modality, exhibits great potential in cancer treatment. However, the efficiency of reactive oxygen species (ROS) production was restricted to the hydrophobic characteristics and aggregation-caused quenching (ACQ) of photosensitizers. Herein, we designed a ROS self-activatable nano system (denoted as PTKPa) based on poly(thioketal) conjugated with photosensitizers (PSs) pheophorbide A (Ppa) on the polymer side chains for suppressing ACQ and enhancing PDT. The process of self-activation is that ROS, which is derived from laser irradiated PTKPa, as an activating agent accelerates poly(thioketal) cleavage with the release of Ppa from PTKPa. This in turn generates abundant ROS, accelerates degradation of the remaining PTKPa and amplifies the efficacy of PDT with more tremendous ROS generated. Moreover, these abundant ROS can amplify PDT-induced oxidative stress, cause irreversible damage to tumor cells and achieve immunogenic cell death (ICD), thereby boosting the efficacy of photodynamic-immunotherapy. These findings provide new insights into ROS self-activatable strategy for enhancing cancer photodynamic- immunotherapy. STATEMENT OF SIGNIFICANCE: This work described an approach to utilize ROS-responsive self-activatable poly(thioketal) conjugated with pheophorbide A (Ppa) for suppressing aggregation-caused quenching (ACQ) and enhancing photodynamic-immunotherapy. The ROS, generated from the conjugated Ppa upon 660nm laser irradiation, as a triggering agent which initiates the release of Ppa with poly(thioketal) degradation. That in turn generates abundant ROS and facilitates degradation of the remaining PTKPa, resulting in oxidative stress to tumor cells and achieving immunogenic cell death (ICD). This work provides a promising solution to improve tumor photodynamic therapeutic effects.

Radiotherapy-mediated redox homeostasis-controllable nanomedicine for enhanced ferroptosis sensitivity in tumor therapy.

Ferroptosis has received increasing attentions in cancer therapy owing to its unique advantages over apoptosis. However, ferroptosis is governed by the efficiency of reactive oxygen species (ROS) production and the tumor cell antioxidant microenvironment that compromises therapeutic efficacy of ferroptosis. It is of great significance to develop a strategy that can both achieve high-efficiency ROS production and modulate tumor cell antioxidant microenvironment to amplify ferroptosis. However, until now, such a strategy has rarely been realized. Here, we, for the first time, reported a radiotherapy -mediated redox homeostasis-controllable nanomedicine for amplifying ferroptosis sensitivity in tumor therapy. The nanomedicine is constructed by co-assembling a ferroptosis inducer hemin and a thioredoxin 1 (Trx-1) inhibitor 1-methylpropyl 2-imidazolyl disulfide (PX-12) with human serum albumin. For our nanomedicine, hemin converts H2O2 to ROS via Fenton reaction to induce ferroptosis while PX-12 effectively inhibits the activity of antioxidant Trx-1 to suppress ROS depletion, resulting in amplified ferroptosis. Particularly, combining radiotherapy with the nanomedicine, radiotherapy depletes the other key antioxidant glutathione and generates additional radiotherapy-induced ROS, further boosting the ferroptosis effect. Therefore, our strategy can simultaneously ensure efficient ROS production and regulation of tumor cell antioxidant microenvironment, thereby enhancing efficacy of ferroptosis in tumor therapy. Our work offers an innovative approach to amplify ferroptosis sensitivity against tumors by simultaneously promoting ROS production and regulating redox homeostasis. STATEMENT OF SIGNIFICANCE: The antioxidants such as thioredoxin 1 (Trx-1) and glutathione (GSH) in tumor cells, are significantly upregulated by the innate cancer cellular redox homeostasis, severely restricting the reactive oxygen species (ROS)-based therapy and compromising the effect of Fenton reaction-induced ferroptosis against tumors. It is urgent to develop a strategy to simultaneously achieve Fenton reaction-induced ferroptosis and regulate the cancer cellular redox homeostasis against upregulated levels of Trx-1 and GSH. A radiotherapy-mediated redox homeostasis-regulatable nanomedicine was designed for amplifying ferroptosis sensitivity in tumor therapy, where the therapeutic efficacy of ferroptosis against tumors can be significantly amplified by integrating Fenton reaction-induced and radiotherapy-induced ferroptosis as well as PX-12-enabled inhibition of antioxidant Trx-1 and radiotherapy-induced downregulation of antioxidant GSH levels.

Recent Progress in Type I Aggregation-Induced Emission Photosensitizers for Photodynamic Therapy.

In modern medicine, precision diagnosis and treatment using optical materials, such as fluorescence/photoacoustic imaging-guided photodynamic therapy (PDT), are becoming increasingly popular. Photosensitizers (PSs) are the most important component of PDT. Different from conventional PSs with planar molecular structures, which are susceptible to quenching effects caused by aggregation, the distinct advantages of AIE fluorogens open up new avenues for the development of image-guided PDT with improved treatment accuracy and efficacy in practical applications. It is critical that as much of the energy absorbed by optical materials is dissipated into the pathways required to maximize biomedical applications as possible. Intersystem crossing (ISC) represents a key step during the energy conversion process that determines many fundamental optical properties, such as increasing the efficiency of reactive oxygen species (ROS) production from PSs, thus enhancing PDT efficacy. Although some review articles have summarized the accomplishments of various optical materials in imaging and therapeutics, few of them have focused on how to improve the phototherapeutic applications, especially PDT, by adjusting the ISC process of organic optics materials. In this review, we emphasize the latest advances in the reasonable design of AIE-active PSs with type I photochemical mechanism for anticancer or antibacterial applications based on ISC modulation, as well as discuss the future prospects and challenges of them. In order to maximize the anticancer or antibacterial effects of type I AIE PSs, it is the aim of this review to offer advice for their design with the best energy conversion.

Combined internal and external electric fields to promote photocarriers separation of TiO2 homogenous S-scheme composite for CIP photodegradation

The construction of internal and external electric fields is an effective collaborative way to boost the activity of photocatalyst. Herein, a face-to-face type of Fe-doped (FT) and Ag-loaded (AT) TiO2 ultra-thin nanosheet S-scheme composite (FT/AT (1:1)) has been synthesized for this aim. Introducing Fe3+ can extend light absorption and establish an internal electric field (IEF) inside TiO2. Combined with the external electric field (EEF) between FT and AT, photocarriers of the composite are efficiently separated according to the S-scheme way. EPR results indicate Ag can facilitate the oxygen reduction process so that the efficiently separated photogenerated electrons (e−) accumulated on Ag will generate lots of superoxide radicals (•O2−), while the photogenerated holes (h+) accumulated on the FT will oxidize water to generate vast hydroxyl radicals (•OH). Under the excellent generation efficiency of reactive oxygen species, FT/AT (1:1) plays a higher CIP photodegradation ability than FT and AT. This paper provides a simple and efficient preparation method of photocatalyst with IEF and EEF for water pollution remediation.

Dual-targeted nanoformulation with Janus structure for synergistic enhancement of sonodynamic therapy and chemotherapy

The accurate delivery of nanoparticles and organic small molecule drugs remains a serious challenge in nanoparticle-based tumor therapy. Dual-targeted therapy combining tumor cell targeting and organelle targeting is an effective solution. Here, an anticancer nanoformulation accurate delivery system was prepared using hyaluronic acid (HA) targeting CD44 receptors on the surface of tumor cells and IR780 iodine (IR780) targeting mitochondrial for delivery. The system is based on an ultra-small Janus structured inorganic sensitizer TiO2-x@NaGdF4 nanoparticles (TN NPs) prepared by one-step pyrolysis, further loaded with organic small molecule acoustic sensitizer IR780 and mitochondrial hexokinase II inhibitor lonidamine (LND), followed by encapsulation of HA. Ultra-small size nanoparticles exhibit strong tissue penetration, tumor inhibition and in vivo metabolism. Under ultrasound radiation, TN NPs and IR780 could produce a synergistic effect, effectively increased the efficiency of reactive oxygen species (ROS) production. Meanwhile, the released IR780 could smoothly target the mitochondria, and the ROS produced by IR780 can destroy the mitochondrial structure and disrupt the mitochondrial respiration. LND could inhibit the energy metabolism of tumor cells by reducing the activity of hexokinase II (HK II), which further accelerates the process of apoptosis. Furthermore, since the Janus structure allows the integration of multifunctional components into a single system, TN NPs can not only serve as an acoustic sensitizer to generate ROS, but the Gd element contained can also act as the nuclear magnetic resonance (MR) imaging contrast agent, suggesting that the nanoformulation can enable imaging-guided diagnosis and therapy. In conclusion, a new scheme to enhance sonodynamic therapy (SDT) and chemotherapy synergistically is proposed here based on ultra-small dual-targeted nanoformulation with Janus structure in the ultrasound radiation environment.

Conjugated‐Polymer‐Based Photodynamic Therapy

AbstractPhotodynamic therapy (PDT) is a promising method for cancer treatment owing to its high spatiotemporal precision and minimally invasive properties. The efficiency of reactive oxygen species (ROS) production by photosensitizers (PSs) directly affects PDT efficacy. Conjugated polymers (CPs) exhibit excellent light‐harvesting capabilities and effective intra‐ and intermolecular energy transfer between CPs and traditional PSs by the “molecular wire effect,” leading to a significant improvement in ROS generation efficiency when PSs are carefully paired with suitable CPs as energy donors. The recently proposed “polymerization‐enhanced photosensitization effect” further reveals that donor–acceptor type CPs can directly function as high‐performance PSs. Recently, two‐photon excitation and chemiluminescence excitation technologies are employed to enhance the penetration depth, a common challenge in phototherapy of CP‐based PDT systems. Furthermore, if precisely designed, CPs can endow the system with useful functions such as photothermal effects and drug‐delivery capacity, which can lead to a synergistic therapy with PDT. Here, recent advances are summarized in CP‐based PDT, including its underlying phenomena, mechanisms, and applications. Strategies for improving PDT performance are the focus of the discussions. In the conclusion, challenges and opportunities are discussed by considering further perspectives.

Tumor Microenvironment-Responsive Cu/CaCO3 -Based Nanoregulator for Mitochondrial Homeostasis Disruption-Enhanced Chemodynamic/Sonodynamic Therapy.

The efficiency of reactive oxygen species (ROS)-mediated cancer therapy is restrained by intrinsic characteristics in the tumor microenvironment (TME), such as overexpressed glutathione (GSH), hypoxia and limited efficiency of H2 O2 . In this work, intelligent copper-dropped calcium carbonate loading sonosensitizer Ce6 nanoparticles (Cu/CaCO3 @Ce6, CCC NPs) are established to realize TME-responsive self-supply of oxygen and successively Ca2+ -overloading-strengthened chemodynamic therapy/sonodynamic therapy (CDT/SDT). CCC NPs release Ca2+ , Cu2+ , and Ce6 in weakly acid and GSH-excessive TME. Released Cu2+ can not only consume GSH and turn into Cu+ via a redox reaction, but also provide CDT-creating hydroxyl radicals through the Fenton-like reaction. Under ultrasound irradiation, the intracellular oxidative stress is amplified profoundly relying on singlet oxygen outburst from SDT. Moreover, Ca2+ influx aggravates the mitochondrial disruption, which further accelerates the oxidation level. The facile and feasible design of the Cu-dropped CaCO3 -based nanoregulators will be further developed as a paradigm in ROS-contributed cancer therapy.

Inhibition of alanine-serine-cysteine transporter 2-mediated auto-enhanced photodynamic cancer therapy of co-nanoassembly between V-9302 and photosensitizer

The efficiency of reactive oxygen species (ROS)-based photodynamic therapy (PDT) is far from satisfactory, because cancer cells can adapt to PDT by upregulating glutathione (GSH) levels. The GSH levels in tumor cells are determined based on glutamine availability via alanine-serine-cysteine transporter 2 (ASCT2)-mediated entry into cells. Herein, we develop co-assembled nanoparticles (PPa/V-9302 NPs) of the photosensitizer pyropheophorbide a (PPa) and V-9302 (a known inhibitor of ASCT2) in a 1:1 M ratio using a one-step precipitation method to auto-enhance photodynamic therapy. The computational simulations revealed that PPa and V-9302 could self-assemble through different driving forces, such as π–π stacking, hydrophobic interactions, and ionic bonds. Such PPa/V-9302 NPs could disrupt the intracellular redox homeostasis due to enhanced ROS production via PPa-induced PDT and reduced GSH synthesis via inhibition of the ASCT2-mediated glutamine flux by V-9302. The in vivo assays reveal that PPa/V-9302 NPs could increase the drug accumulation in tumor sites and suppress tumor growth in BALB/c mice bearing mouse breast carcinoma (4 T1) tumor. Our findings provide a new paradigm for the rational design of the PDT-based combinational cancer therapy.

Self-redox reaction driven in situ formation of Cu2O/Ti3C2Tx nanosheets boost the photocatalytic eradication of multi-drug resistant bacteria from infected wound

BackgroundMXenes with interesting optical and electrical properties have been attractive in biomedical applications such as antibacterial and anticancer agents, but their low photogeneration efficiency of reactive oxygen species (ROS) and poor stability are major concerns against microbial resistance.MethodsWater-dispersible single layer Ti3C2Tx-based MXene through etching tightly stacked MAX phase precursor using a minimally intensive layer delamination method. After addition of Cu(II) ions, the adsorbed Cu(II) ions underwent self-redox reactions with the surface oxygenated moieties of MXene, leading to in situ formation of Cu2O species to yield Cu2O/Ti3C2Tx nanosheets (heterostructures).ResultsUnder NIR irradiation, the Cu2O enhanced generation of electron–hole pairs, which boosted the photocatalytic production of superoxide and subsequent transformation into hydrogen peroxide. Broad-spectrum antimicrobial performance of Cu2O/Ti3C2Tx nanosheets with sharp edges is attributed to the direct contact-induced membrane disruption, localized photothermal therapy, and in situ generated cytotoxic free radicals. The minimum inhibitory concentration of Cu2O/Ti3C2Tx nanosheets reduced at least tenfold upon NIR laser irradiation compared to pristine Cu2O/Ti3C2Tx nanosheets. The Cu2O/Ti3C2Tx nanosheets were topically administrated on the methicillin-resistant Staphylococcus aureus (MRSA) infected wounds on diabetic mice.ConclusionUpon NIR illumination, Cu2O/Ti3C2Tx nanosheets eradicated MRSA and their associated biofilm to promote wound healing. The Cu2O/Ti3C2Tx nanosheets with superior catalytic and photothermal properties have a great scope as an effective antimicrobial modality for the treatment of infected wounds.Graphical

Exogenous Melatonin Improves the Quality Performance of Rice under High Temperature during Grain Filling

With the increasing greenhouse effect, high temperature has become the most unfavorable environmental factor for the rice grain filling process, affecting rice yield and quality mainly through changing the composition and structure of starch in rice grains. Research has focused on the rational management of water and fertilizer, and spraying of exogenous chemicals, which have become important measures to alleviate high temperature stress of rice. As a multifunctional molecule, melatonin has the potential to improve plant stress resistance by enhancing the scavenging efficiency of reactive oxygen species (ROS), thus protecting plants from the adverse effects of abiotic stress. The present study used a typical japonica rice variety Nipponbare (NPB) as the experimental material, which was treated with high temperature and melatonin during grain-filling stages. The effects of exogenous melatonin on the rice growth and quality traits, as well as starch synthesis, in response to high temperature were analyzed systematically. Exogenous melatonin significantly increased the rice leaf photosynthetic and heat-resistance properties. Melatonin could alleviate the effects of high temperature on the key physicochemical properties related to rice quality. Furthermore, milled rice from NPB plants treated with melatonin had better endosperm appearance under high temperature. Further study found that exogenous melatonin could stabilize the chain length distribution of starch in NPB (especially amylopectin), which implied that melatonin could be used in rice cultivation to alleviate the effect of high temperature on quality, optimization of amylopectin synthesis can also improve rice quality. The results of the present study provide a new idea and research direction to alleviate high temperature stress of rice in the context of global warming.

The bifunctional Lewis acid site improved reactive oxygen species production: a detailed study of surface acid site modulation of TiO2 using ethanol and Br−

Modulation of surface acid sites (SAS) can effectively enhance the efficiency of reactive oxygen species (ROS) production.

Synthesis of red/black phosphorus-based composite nanosheets with a Z-scheme heterostructure for high-performance cancer phototherapy.

Two dimensional black phosphorus nanosheets (BP NSs) have attracted plenty of attention in the research field of cancer photonic therapy. However, the poor stability and relatively low efficiency of reactive oxygen species (ROS) generation of BP NSs limit their practical application. To address these drawbacks, herein we report a red/black phosphorus (RP/BP) composite nanosheet, M-RP/BP@ZnFe2O4, which was synthesized by (1) partially converting red phosphorus (RP) to black phosphorus (BP) followed by liquid-phase ultrasonic exfoliation to form RP/BP NSs, (2) in situ synthesis of ZnFe2O4 nanoparticles on the surface of RP/BP NSs, (3) and wrapping with the MCF-7 cell membrane. Due to the presence of RP, BP, ZnFe2O4 and the cell membrane, the M-RP/BP@ZnFe2O4 NSs exhibited high performance in cancer phototherapy with the following features: (i) a Z-scheme heterojunction structure was formed between RP/BP NSs thus enabling high separation efficiency of the photogenerated electrons and holes; (ii) the photoexcitation holes in the valence band of RP can break the tumor microenvironment by oxidizing glutathione; (iii) the NSs could decompose water to produce H2O2 and O2, which can be further converted to toxic ˙OH through the ZnFe2O4 catalyzed Fenton reaction and 1O2 through energy transfer, respectively; and (iv) the cell membrane wrapping improved the targeting of the composite NSs at the tumor site and photonic therapy can be finally triggered by a 660 nm laser to convert O2 to ˙O2- and 1O2. The in vitro cytotoxicity experiments showed that more than 90% cells were killed after photodynamic therapy (PDT) at 0.3 mg mL-1 M-RP/BP@ZnFe2O4 NSs, and the animal experiments with xenograft tumor model mice indicated that tumor growth was completely inhibited and the highest survival rate of 83.3% at 60 days post PDT was obtained.

Shape-Controllable Tellurium-Driven Heterostructures with Activated Robust Immunomodulatory Potential for Highly Efficient Radiophotothermal Therapy of Colon Cancer.

Tellurium (Te)-based semiconductor easily leads to the recombination of photogenerated electron-hole pairs (h+-e-) that severely limits the efficiency of reactive oxygen species (ROS) generation and further hinders its clinical application in biomedicine. With regard to these problems, herein we designed and synthesized a Te heterostructure (BTe-Pd-Au) by incorporating palladium (Pd) and gold (Au) elements to promote its radiosensitivity and photothermal performance, thus realizing highly efficient radiophotothermal tumor elimination by activating robust immunomodulatory potential. This shape-controllable heterostructure that coated by Pd on the surface of Te nanorods and Au in the center of Te nanorods was simply synthesized by using in situ synthesis method, which could promote the generation and separation of h+-e- pairs, thereby exhibiting superior ROS producing ability and photothermal conversion efficiency. Using a mouse model of colon cancer, we proved that BTe-Pd-Au-R-combined radiophotothermal therapy not only eradicated tumor but also elicited to a series of antitumor immune responses by enhancing the cytotoxic T lymphocytes, triggering dendritic cells maturation, and decreasing the percentage of M2 tumor-associated macrophages. In summary, our study highlights a facile strategy to design Te-driven heterostructure with versatile performance in radiosensitization, photothermal therapy, and immunomodulation and offers great promise for clinical translational treatment of colon cancer.

Sulfur-source dependent wet mechanochemical synthesis of pyrrhotite nanoparticles and evaluation of their sonocatalytic dye degradability

Sulfur-source dependent pyrrhotite nanoparticles (Fe1-XS (X 0–0.2)) were synthesized using ferric chloride and four different water-soluble sulfur sources, sodium thiosulphate, sodium sulfide, thiourea, and thioacetamide (referred to as IS-1, IS-2, IS-3, and IS-4, respectively), via a wet mechanochemical route without an inert atmosphere. Owing to the different dispersing sulfur environments and different bond energies of sulfur from different sources, pyrrhotite NPs with different shapes, sizes, band gap, and sulfur contents were obtained and that affects their catalytic activities. XPS of sulfur showed that the sulfide/polysulfide ratios of IS-1, IS-2, IS-3, and IS-4 were determined to be 3.48, 2.67, 1.29, and 1.94, respectively. Several classes of organic dyes, such as rhodamine B-RhB, methyl orange-MO, methylene blue-MB, Nile blue-NB, crystal violet-CV, and their mixtures, were used to explore the sonocatalytic dye degradation of the synthesized natural pyrrhotite NPs. The dye degradation efficiency was in the following sequence: IS-1 (highly active and reactive, 100% removal efficiency in 1 min) >> IS-2 (selective for RhB and MB) > IS-4 (moderately active) > IS-3 (inactive). The generation efficiency of reactive oxygen species using the pyrrhotite NPs under the sonocatalyic process was the same sequences of the sulfide/polysulfide ratio, which were the key factor affecting the sonocatalytic activity and stability during dyes degradation. Iron with different valence states allow faster electron transfer reaction and the presence of S2−/Sn2− redox couples improved the stability of the catalyst. Furthermore, the catalyst was reusable with similar reactivity and removal efficacy, even after five catalytic cycles.