Reactive Oxygen Species Generation Efficiency Research Articles

Polycyclic naphthalenediimide-based nanoparticles for NIR-II fluorescence imaging guided phototherapy

Optical imaging and phototherapy in the second near-infrared window (NIR-II, 900–1700 nm) can reduce tissue auto-fluorescence and photon scattering, which facilitates higher spatial resolution and deeper tissue penetration depth for solid tumor theranostics. Herein, a polycyclic naphthalenediimide (NDI) based chromophore 13-amino-4,5-dibromo-2,7- di(dodecan-6-yl)-1H-isoquinolino[4,5,6-fgh]naphtho[1,8-bc][1,9]phenanthroline-1,3,6,8(2H,7H,9H)-tetraone (NDI-NA) was designed and synthesized. With large polycyclic π-systems, NDI-NA molecule possesses broad near-infrared (NIR) absorption (maximum at 777 nm) and emission (maximum at 921 nm). By nanoprecipitation, NDI-NA nanoparticles (NPs) were formed in aqueous solution with J-aggregative state, which showed huge red-shift in both absorption spectrum (maximum at 904 nm) and emission spectrum (maximum at 1,020 nm), endowing NDI-NA NPs efficient NIR-II fluorescence imaging capability. Besides, the NPs present effective tumor-targeting capability in vivo based on the enhanced permeation and retention (EPR) effect. More importantly, NDI-NA NPs simultaneously have high photothermal conversion efficiency (30.8%) and efficient reactive oxygen species generation ability, making them remarkably phototoxic to cancer cells. The polycyclic chromophore based multifunctional NDI-NA NPs as NIR-II phototheranostic agents possess bright future for clinical NIR-II imaging-guided cancer phototherapy.

Mesoporous Rod‐Like Metal‐Organic Framework with Optimal Tumor Targeting Properties for Enhanced Activatable Photodynamic Therapy

AbstractNanoscale metal‐organic frameworks (nMOFs) have shown great potential in the highly effective delivery of exogenous drugs and imaging agents for biomedical applications, and rod‐like nanomaterials with superb loading capability have demonstrated broad versatility to tumor imaging and tumor‐targeted drug delivery. However, owing to difficulties in their fabrication, nMOFs with both rod‐like shape and mesoporosity for tumor imaging or tumor‐targeted cargo delivery are largely unexplored. Herein, a nanoscale rod‐like [{Cu2(ndc)2(dabco)]n (Cu‐MOF), a copper(II) nMOF, is successfully endowed with mesoporosity via defect engineering. Owing to the mesopores, the as‐synthesized defective rod‐like Cu‐MOF is able to load an aggregation‐induced‐emission (AIE) photosensitizer (PS) with inhibited sensitization at high loading weight percentage. In vitro and in vivo experiments demonstrate that the rod‐like Cu‐MOF can afford the AIE PS payload with enhanced tumor targeting specificity and penetration depth. After optimal tumor enrichment and cancer cell uptake, Cu(II) in the defective Cu‐MOF efficiently depletes intracellular glutathione and causes dissociation of the Cu‐MOF to release the PS payload and recover its efficient reactive oxygen species generation. Concomitantly, bright fluorescence is afforded by the AIE PS during delivery, contributing to image‐guided cancer‐cell‐activated photodynamic therapy with enhanced therapeutic effects.

Synthesis of Water-Soluble Thioglycosylated trans-A2B2 Type Porphyrins: Cellular Uptake Studies and Photodynamic Efficiency.

The synthesis of water-soluble thioglycosylated A2B2 type porphyrins and their zinc(II) complexes is reported. The water-soluble trans-A2B2 porphyrins were synthesized in two steps, via [2+2] condensation between thioglycosylated dipyrromethanes and aromatic aldehydes in 15-21% yields. The thioglycosylated trans-A2B2 porphyrins showed decent in vitro singlet oxygen generation, which was supported by the intracellular DCFDA study. The in vitro cellular investigations of thioglycosylated A2B2 porphyrins were carried out in lung cancer cells (A549) to test their photodynamic therapeutic (PDT) activity. The PDT study revealed significant cytotoxicities of porphyrins with IC50 values between 23.3 and 44.2 μM in the dark, whereas, after visible light exposure, the photosensitizers exhibited IC50 values around 11.1-23.8 μM. The water-soluble thioglycosylated zinc(II) porphyrins having two meso-N-butylcarbazole groups exhibited an excellent degree of photocytotoxicity (IC50 = 4.6-8.8 μM). The flow cytometry analysis revealed that cellular uptake and ROS (reactive oxygen species) generation efficiency of water-soluble thioglycosylated zinc(II) porphyrins were considerably higher than nonmetalated porphyrins. Confocal microscopy images displayed substantial distribution in the endoplasmic reticulum with partial colocalization in mitochondria and lysosomes of water-soluble thioglycosylated zinc(II) porphyrins in A549 cells.

Experimental investigation of effect of ultrasonic duty cycle on generation of reactive oxygen species for highly efficient sonodynamic treatment

Sonodynamic treatment (SDT) is a non-invasive treatment of cancer, combining ultrasound, reactive oxygen species (ROS), and sonosensitizer. When cavitation bubbles generated by ultrasound oscillate and collapse, ROS are generated due to the high temperature and high pressure inside the bubble. By generating cavitation bubbles in a target tissue, it can be treated by the cytotoxicity of ROS, which can be further enhanced by a sonosensitizer. In SDT, the small treatment region by a single shot of HIFU results in a long treatment time, which needs to be reduced by improving the efficiency of ROS generation. ROS can be visualized by the sonochemiluminescence of luminol. In this study, a polyacrylamide gel soaked with luminol solution is used as a target of ultrasonic exposure. The effect of the duty cycle of HIFU exposure on ROS generation was investigated by capturing sonochemiluminescent light emission, and high-speed photography of cavitation bubbles.

An open source and reduce expenditure ROS generation strategy for chemodynamic/photodynamic synergistic therapy

The therapeutic effect of reactive oxygen species (ROS)-involved cancer therapies is significantly limited by shortage of oxy-substrates, such as hypoxia in photodynamic therapy (PDT) and insufficient hydrogen peroxide (H2O2) in chemodynamic therapy (CDT). Here, we report a H2O2/O2 self-supplying nanoagent, (MSNs@CaO2-ICG)@LA, which consists of manganese silicate (MSN)-supported calcium peroxide (CaO2) and indocyanine green (ICG) with further surface modification of phase-change material lauric acid (LA). Under laser irradiation, ICG simultaneously generates singlet oxygen and emits heat to melt the LA. The exposed CaO2 reacts with water to produce O2 and H2O2 for hypoxia-relieved ICG-mediated PDT and H2O2-supplying MSN-based CDT, acting as an open source strategy for ROS production. Additionally, the MSNs-induced glutathione depletion protects ROS from scavenging, termed reduce expenditure. This open source and reduce expenditure strategy is effective in inhibiting tumor growth both in vitro and in vivo, and significantly improves ROS generation efficiency from multi-level for ROS-involved cancer therapies.

Silver-Laden Black Phosphorus Nanosheets for an Efficient In Vivo Antimicrobial Application.

Nanobactericides represent one of the most efficient and promising strategies for eliminating bacterial infection considering the increasing resistance threats of conventional antibiotics. Black phosphorus (BP) is the most exciting postgraphene layered 2D nanomaterial with convincing physiochemical properties, yet the study of BP-based antibiotics is still in its infancy. Here, a compact silver nanoparticle (AgNP)-doped black phosphorus nanosheet (BPN) is constructed to synergistically enhance solar disinfection through the promoted reactive oxygen species (ROS) photogeneration, which is attributed to the improved electron-hole separation and recombination of BPNs as revealed from the systematic experimental studies. An in-depth density functional theory (DFT) calculation confirms that the integrated AgNPs provide a preferred site for facilitating the adsorption and activation of O2 , thus promoting the more efficient and robust ROS generation on BPN-AgNP nanohybrids. Besides the enhanced photoinduced ROS, the anchored AgNPs simultaneously lead to a dramatically increased affinity toward bacteria, which facilitates a synergetic pathogen inactivation. Significantly, the convincing antimicrobial BPN-AgNP contributes to the prominent wound healing and antimicrobial ability in vivo with minimized biological burden. This sophisticated design of new 2D nanohybrids opens a new avenue for further exploiting BP-based nanohybrids in portable bandage and broad-spectrum disinfection applications.

Upconversion Nanoparticle-Induced Multimode Photodynamic Therapy Based on a Metal-Organic Framework/Titanium Dioxide Nanocomposite.

Photodynamic therapy (PDT) possesses two pathways depending on the type of high-toxicity reactive oxygen species (ROS), superoxide anion radical (O2·-) and hydroxyl radical (·OH) generated through Type I and singlet oxygen (1O2) generated through Type II, inducing cancer cell apoptosis. However, the low efficiency of ROS generation and poor biocompatibility are the limitations of the traditional photosensitizers for PDT. Herein, inspired by photochemical reactions of titanium dioxide and porphyrin-based metal-organic frameworks, we developed a nanoplatform by covering ultrasmall titanium dioxide nanoparticles on a heterodimer made up of upconversion nanoparticles and metal-organic frameworks, realizing a multimode PDT through Type I and Type II mechanisms. Once irradiated by a near-infrared light, upconversion nanoparticles could generate ultraviolet and visible lights, which were not only able to stimulate different photochemical reactions of titanium dioxide and porphyrin but also accomplish deep penetration photodynamic therapy. Our photosensitive agent exhibited good biocompatibility and an effective multimode PDT performance, which could meet the needs of different situations of photodynamic therapy in the future.

Nanoscale ZnO-based photosensitizers for photodynamic therapy.

Due to the ability to induce the generation of reactive oxygen species (ROS) under light irradiation, ZnO nanoparticles show great potential in photodynamic therapy (PDT). Photo-triggered ROS production by ZnO nanoparticles and the resulting phototoxicity are efficient in killing cancer cells. This review highlights the recent exciting progress on the nanoscale ZnO-based photosensitizers (PSs) for PDT. Both the semplice ZnO nanoparticles as the PSs and the various chemicals (organic PS, dopant, metal and chemotherapeutic drugs) modified ZnO nanoparticles as the PSs show good ROS generation efficiency. The productive rate of ROS, the wavelength of exciting lights, and the therapeutic effect can be altered by doping different chemicals into ZnO nanoparticles at will. Additionally, we give some outlook on the design and functionalization of next-generation ZnO nanoparticles for more effective anti-cancer applications.

Multifunctional theranostic agents based on prussian blue nanoparticles for tumor targeted and MRI—guided photodynamic/photothermal combined treatment

The independence of photodynamic or photothermal modality create difficulties in the success of tumor therapy. In this current study, a multifunctional nanotheranostic agent of PDE-Ce6-HA was developed for tumor targeted and MRI-guided photodynamic/photothermal combined therapy (PDT/PTT). For this purpose, the near-infrared-absorbing nanoparticles of prussian blue were coated with polydopamine and successively conjugated with chlorin e6 (Ce6) for reactive oxygen species (ROS) generation. The resultant nanoparticles, denoted as PDE-Ce6, were then modified with hyaluronic acid (HA) through electrostatic interaction to yield the final therapeutic agent of PDE-Ce6-HA NPs. PDE-Ce6-HA NPs not only exhibited high colloid stability, good biocompatibility and suitable transverse relaxation rate (0.54 mM−1 s−1), but also high photothermal conversion efficiency (40.4%) and excellent ROS generation efficiency under NIR light irradiation. The confocal microscopy images demonstrated a selective uptake of PDE-Ce6-HA by CD44 overexpressed HeLa cells via HA-mediated endocytosis. Meanwhile, in vitro anti-cancer evaluation verified the significant photodynamic and photothermal combined effects of PDE-Ce6-HA on cancer cells. Moreover, PDE-Ce6-HA led to an increase of T1-MRI contrast in tumor site. Furthermore, in vivo anti-tumor evaluation proved that the PDE-Ce6-HA under both 808 and 670 nm laser showed significantly high tumor growth inhibition effects compared with individual PTT or PDT. Hence, PDE-Ce6-HA is applicable in tumor targeted and MRI-guided photodynamic/photothermal combined treatment.

A boronic acid-functionalized phthalocyanine with an aggregation-enhanced photodynamic effect for combating antibiotic-resistant bacteria.

Most existing photosensitizers (e.g., porphyrins) are often aggregated in aqueous solution because of their large conjugated molecular structures. This aggregation usually results in a lack or low levels of reactive oxygen species (ROS) generation due to aggregation-caused quenching, which severely hampers the application of photosensitizers in photodynamic therapy (PDT). Herein, we make an interesting finding that a boronic acid-functionalized phthalocyanine (PcN4-BA) displays an uncommon phenomenon, an aggregation-enhanced photodynamic effect. The combination of the ability to form uniform nanostructured self-assemblies in water, highly efficient ROS generation and boronic acid-induced targeting give PcN4-BA excellent performances in antimicrobial PDT.

Stereotactic Photodynamic Therapy Using a Two-Photon AIE Photosensitizer.

Two-photon photodynamic therapy (TP-PDT) is emerging as a powerful strategy for stereotactic targeting of diseased areas, but ideal photosensitizers (PSs) are currently lacking. This work reports a smart PS with aggregation-induced emission (AIE) feature, namely DPASP, for TP-PDT with excellent performances. DPASP exhibits high affinity to mitochondria, superior photostability, large two-photon absorption cross section as well as efficient reactive oxygen species generation, enabling it to achieve photosensitization both in vitro and in vivo under two-photon excitation. Moreover, its capability of stereotactic ablation of targeted cells with high-precision is also successfully demonstrated. All these merits make DPASP a promising TP-PDT candidate for accurate ablation of abnormal tissues with minimal damages to surrounding areas in the treatment of various diseases.

Ultrafast discrimination of Gram-positive bacteria and highly efficient photodynamic antibacterial therapy using near-infrared photosensitizer with aggregation-induced emission characteristics

With the increase of bacterial infections in clinical practice, it becomes a public health problem which has aroused worldwide attention. Fluorescence imaging-guided photodynamic antibiosis has recently emerged as a promising protocol to solve this problem. However, developing a super powerful fluorescent material allowing facile preparation, long emission wavelength, rapid bacterial discrimination, washing-free staining, and high photodynamic antibacterial efficiency in a single entity, is highly desirable but remains challenging. In this study, we utilize for the first time a water-soluble near-infrared (NIR) emissive luminogen with aggregation-induced emission (AIE) characteristics, namely TTVP, for simultaneous dual applications of Gram-positive bacteria discrimination and photodynamic antibiosis. TTVP is able to selectively target Gram-positive bacteria over Gram-negative bacteria through a washing-free procedure after only 3 s incubation period, which is at least 100-fold shorter than those of previously reported protocols, implying ultrafast bacterial discrimination features. Meanwhile, TTVP exhibits extremely high reactive oxygen species generation efficiency, which is far superior to that of most popularly used photosensitizers, representing one of the best candidates for photodynamic antibiosis. In vitro and in vivo results demonstrate that TTVP provides extraordinary performance on photodynamic antibacterial therapy. This study thus offers a blueprint for the next generation of antibacterial materials.

Evaluation of Structure-Function Relationships of Aggregation-Induced Emission Luminogens for Simultaneous Dual Applications of Specific Discrimination and Efficient Photodynamic Killing of Gram-Positive Bacteria.

Bacterial infectious diseases, especially those caused by Gram-positive bacteria, have been seriously threatening human health. Preparation of a multifunctional system bearing both rapid bacterial differentiation and effective antibacterial effects is highly in demand, but remains a severe challenge. Herein, we rationally designed and successfully developed a sequence of aggregation-induced emission luminogens (AIEgens) with orderly enhanced D-A strength. Evaluation of structure-function relationships reveals that AIEgens having intrinsic positive charge and proper ClogP value are able to stain Gram-positive bacteria. Meanwhile, one of the presented AIEgens (TTPy) can generate reactive oxygen species (ROS) in extraordinarily high efficiency under white light irradiation due to the smaller singlet-triplet energy gap. Thanks to the NIR emission, excellent specificity to Gram-positive bacteria, and effective ROS generation efficiency, TTPy has been proved to perform well in selective photodynamic killing of Gram-positive bacteria in vitro, such as S. aureus and S. epidermidis, even in S. aureus-infected rat wounds.

Tuning Organelle Specificity and Photodynamic Therapy Efficiency by Molecular Function Design.

Efficient organic photosensitizers (PSs) have attracted much attention because of their promising applications in photodynamic therapy (PDT). However, guidelines on their molecular design are rarely reported. In this work, a series of PSs are designed and synthesized based on a triphenylamine-azafluorenone core. Their structure-property-application relationships are systematically studied. Cationization is an effective strategy to enhance the PDT efficiency of PSs by targeting mitochondria. From the molecularly dispersed state to the aggregate state, the fluorescence and the reactive oxygen species generation efficiency of PSs with aggregation-induced emission (AIE) increase due to the restriction of the intramolecular motions and enhancement of intersystem crossing. Cationized mitochondrion-targeting PSs show higher PDT efficiency than that of nonionized ones targeting lipid droplets. The ability of AIE PSs to kill cancer cells can be further enhanced by combination of PDT with radiotherapy. Such results should trigger research enthusiasm for designing and synthesizing AIE PSs with better PDT efficiency and properties.

Light-Induced Production of Reactive Oxygen Species by a Novel Water-Soluble Benzophenone Derivative Containing Quaternary Ammonium Groups and Its Assembly on the Protein Fiber Surface.

Developing an efficient antimicrobial surface has important significance in the field of advanced biomaterials. A novel water-soluble benzophenone tetracarboxylamine derivative containing two quaternary ammonium groups, 3,3'-[4,4'-carbonyl-diphthalimide-]-bis(N-benzyl-N,N-dimethyl-N-propyl-1-aminium)dichloride (BPTCA-N), as a photoactive antibacterial agent was designed and synthesized. The ability of BPTCA-N to generate reactive oxygen species (ROS) in solution was investigated by light-induced activity. Its antibacterial activity in a dark environment or UV exposure was tested on Staphylococcus aureus and Escherichia coli. The influences of different solvents and the pH values on the ability of BPTCA-N to generate ROS were also discussed. BPTCA-N possessed high photoactivity and efficient ROS generation ability. The generation of hydroxyl radicals could be greatly affected by addition of other solvents and H+ or OH-. For the BPTCA-N solution at a concentration of 0.2 mmol/L, the reduction of S. aureus and E. coli could all reach 99.99%. The BPTCA-N compound was assembled onto wool protein fibers. The modified protein fabrics also showed excellent photoactivity and antibacterial property against S. aureus and E. coli. For the wool fabric modified with 30 g/L of BPTCA-N, the reduction of S. aureus could reach 99.91% and that of E. coli was 91.23%. BPTCA-N had the synergistic antibacterial effect of quaternary ammonium salt and benzophenones. It has potential application in the biomedical field as highly effective antimicrobial agent or antimicrobial biomaterial.

Effect of inter-focal distance and interval time in focus scanning of high-intensity focused ultrasound on efficiency of reactive oxygen generation

Sonodynamic treatment (SDT) is a non-invasive cancer treatment using ultrasound, reactive oxygen species (ROS) generated by acoustic cavitation bubbles, and sonodynamically active antitumor agents. When cavitation bubbles collapse, they generate ROS, which can attack cancer cells by their cytotoxicity. For SDT, both localization and efficiency of generating ROS are important. In this study, high-intensity focused ultrasound (HIFU) was employed for localization and “Trigger HIFU” sequence was further employed for generating cavitation and ROS efficiently even under the progressive wave condition. A polyacrylamide gel containing luminol was employed to visualize the region of ROS generation by utilizing sonochemiluminescence of luminol. Focus scanning methods were thereby tested to further improve the ROS generation efficiency. In focus scanning irradiation, the time interval considering the bubble lifetime and the inter-focal distance considering the sidelobes were found to be important for efficient generation of ROS.

Photosensitizers for Photodynamic Therapy.

As an emerging clinical modality for cancer treatment, photodynamic therapy (PDT) takes advantage of the cytotoxic activity of reactive oxygen species (ROS) that are generated by light irradiating photosensitizers (PSs) in the presence of oxygen (O2 ). However, further advancements including tumor selectivity and ROS generation efficiency are still required. Substantial efforts are devoted to design and synthesize smart PSs with optimized properties for achieving a desirable therapeutic efficacy. This review summarizes the recent progress in developing intelligent PSs for efficient PDT, ranging from single molecules to delicate nanomaterials. The strategies to improve ROS generation through optimizing photoinduced electron transfer and energy transfer processes of PSs are highlighted. Moreover, the approaches that combine PDT with other therapeutics (e.g., chemotherapy, photothermal therapy, and radiotherapy) and the targeted delivery in cancer cells or tumor tissue are introduced. The main challenges for the clinical application of PSs are also discussed.

Probing the Formation of Reactive Oxygen Species by a Porous Self-Assembled Benzophenone Bis-Urea Host.

Herein, we examine the photochemical formation of reactive oxygen species (ROS) by a porous benzophenone-containing bis-urea host (1) to investigate the mechanism of photooxidations that occur within the confines of its nanochannels. UV irradiation of the self-assembled host in the presence of molecular oxygen generates both singlet oxygen and superoxide when suspended in solution. The efficiency of ROS generation by the host is lower than that of benzophenone (BP), which could be beneficial for reactions carried out catalytically, as ROS species react quickly and often unselectively. Superoxide formation was detected through reaction with 5,5-dimethyl-1-pyrroline N-oxide in the presence of methanol. However, it is not detected in CHCl3, as it reacts rapidly with the solvent to generate methaneperoxy and chloride anions, similar to BP. The lifetime of airborne singlet oxygen (τΔairborne) was examined at the air–solid outer surface of the host and host·quencher complexes and suggests that quenching is a surface phenomenon. The efficiency of the host and BP as catalysts was compared for the photooxidation of 1-methyl-1-cyclohexene in solution. Both the host and BP mediate the photooxidation in CHCl3, benzene, and benzene-d6, producing primarily epoxide-derived products with low selectivity likely by both type I and type II photooxidation processes. Interestingly, in CHCl3, two chlorohydrins were also formed, reflecting the formation of chloride in this solvent. In contrast, UV irradiation of the host·guest crystals in an oxygen atmosphere produced no epoxide and appeared to favor mainly the type II processes. Photolysis afforded high conversion to only three products: an enone, a tertiary allylic alcohol, and a diol, which demonstrates the accessibility of the encapsulated reactants to oxygen and the influence of confinement on the reaction pathway.

Self-Assembled Responsive Bilayered Vesicles with Adjustable Oxidative Stress for Enhanced Cancer Imaging and Therapy.

In the present study, we report the development of magnetic-plasmonic bilayer vesicles assembled from iron oxide-gold Janus nanoparticles (Fe3O4-Au JNPs) for reactive oxygen species (ROS) enhanced chemotherapy. The amphiphilic Fe3O4-Au JNPs were grafted with poly(ethylene glycol) (PEG) on the Au surface and ROS-generating poly(lipid hydroperoxide) (PLHP) on the Fe3O4 surface, respectively, which were then assembled into vesicles containing two closely attached Fe3O4-Au NPs layers in opposite directions. The self-assembly mechanism of the bilayered vesicles was elucidated by performing a series of numerical simulations. The enhanced optical properties of the bilayered vesicles were verified by the calculated results and experimental data. The vesicles exhibited enhanced T2 relaxivity and photoacoustic properties over single JNPs due to the interparticle magnetic dipole interaction and plasmonic coupling. In particular, the vesicles are pH responsive and disassemble into single JNPs in the acidic tumor environment, activating an intracellular biochemical reaction between the grafted PLHP and released ferrous ions (Fe2+) from Fe3O4 NPs, resulting in highly efficient local ROS generation and increased intracellular oxidative stress. In combination with the release of doxorubicin (DOX), the vesicles combine ROS-mediated cytotoxicity and DOX-induced chemotherapy, leading to greatly improved therapeutic efficacy than monotherapies. High tumor accumulation efficiency and fast vesicle clearance from the body were also confirmed by positron emission tomography (PET) imaging of radioisotope 64Cu-labeled vesicles.

Efficient evolution of reactive oxygen species over the coordinated π-delocalization g-C3N4 with favorable charge transfer for sustainable pollutant elimination

Reactive oxygen species (ROS) as efficient and green oxidants can be generated through various catalytic methods, which is important for environmental chemistry and chemical engineering. Here we construct an efficient photocatalytic system to evolve ROS for environmental purification. In the work, the coordinated g-C3N4 photocatalysts (Cu/C3N4) are designed by interacting N 2p lone electrons at vacancy site of tri-s-triazine polymer with 3d orbits of Cu2+, resulting in the extended π-delocalization structure of g-C3N4. Experimental and theoretical calculations confirm that the extended π-delocalization structure of Cu/C3N4 strengthens the light capturing capability from ultraviolet to near infrared light, favors the charge transfer from N 2p of C3-N to the linked C, and Cu atoms. As a result, the efficient evolution of ROS including O2− (13 μmol L−1 h−1), and H2O2 (550 μmol L−1 h−1) can be completed over Cu/C3N4 photocatalysts. Cu/C3N4 photocatalysts results in a highly efficient generation of ROS and also exhibited a sustainable removal efficiency for NO, and HCHO, which demonstrates a promising application in the field of environmental purification.