Photodynamic Activity Research Articles

AIE donor-dependent photosensitizer for enhance photodynamic antibacterial interface

Although photosensitizers (PSs) with aggregation-induced emission (AIE) effect (AIE-PSs) can realize strong fluorescence and high production of reactive oxygen species (ROS), the effect of different AIE electron donors in AIE-PSs structure on it has rarely been reported. Herein, we explore the effect of two kinds of AIE-PSs (TPEBT-Py and TPABT-Py) with triphenylamine (TPA) and tetraphenylethylene (TPE) as AIE electron donors on their ROS generation and photodynamic antibacterial interface. Interestingly, the photodynamic activity for 1O2 generation in TPABT-Py is significantly greater than that of TPEBT-Py, indicating the photodynamic performance of AIE-PSs is affected by their AIE donors. According to the density functional theory (DFT) calculation, the singlet-triplet energy gap (△ES1T1) of TPABT-Py is smaller than that of TPEBT-Py, suggesting TPA as an electron donor is more prone to intersystem crossing (ISC) and promotes the generation of 1O2. Therefore, the utilization of TPABT-Py as a photosensitizer for photodynamic antibacterial yields much superior performance.

Photoantimicrobial and photocatalytic hydrogen evolution activities of seleno-Chevrel phases

Chevrel phases are triclinic crystal structures consisting of a refractory metals and chalcogenides, which present unique properties in many applications. Herein, structural, mechanical, dynamical and electronic properties of Fe2Mo6Se8 and Cu2Mo6Se8 seleno-Chevrel phases were theoretically and experimentally investigated. The theoretical studies revealed the mechanical and dynamical stabilities of these phases that lead to the experimental synthesis. These seleno-Chevrel phases were used for photothermal and photodynamic antibacterial and antibiofilm applications, in the absence and presence of near infrared (NIR) and white light-emitting diode (LED) illuminations on Staphylococcus aureus (S. aureus) and Escherichia coli (E.coli) strains. Fe2Mo6Se8 and Cu2Mo6Se8 displayed enhanced antibacterial activities (73.1% and 60.0%, respectively) and biofilm inhibition effects (93.9% and 88.7%, respectively) on S. aureus. For E. coli bacterium, Fe2Mo6Se8 and Cu2Mo6Se8 showed also antibacterial effects (60.0% and 67.5%, respectively) and biofilm inhibition activities (88.7% and 78.1%, respectively). The increased photothermal and photodynamic activities of Fe2Mo6Se8 and Cu2Mo6Se8 can be attributed to the enhanced ROS production, which triggered probably the denaturation of bacterial proteins and nucleic acids by producing photoinduced electrons to obtain super oxide anion (•O₂̄) radical under light irradiation. Therefore, seleno-Chevrel phases could be a good alternative for medical antibacterial surface applications. Moreover, Fe2Mo6Se8 and Cu2Mo6Se8 were also used as catalysts for photocatalytic hydrogen evolution reactions. Fe2Mo6Se8 showed 1.8-fold higher photocatalytic hydrogen evolution rate than that of Cu2Mo6Se8, which can be explained by the bonding properties of catalysts. This article paves the way that Chevrel phases can be effectively used for different photocatalytic and photoantimicrobial applications.

The First Report of In Vitro Antifungal and Antibiofilm Photodynamic Activity of Tetra-Cationic Porphyrins Containing Pt(II) Complexes against Candida albicans for Onychomycosis Treatment.

Onychomycosis is a prevalent nail fungal infection, and Candida albicans is one of the most common microorganisms associated with it. One alternative therapy to the conventional treatment of onychomycosis is antimicrobial photoinactivation. This study aimed to evaluate for the first time the in vitro activity of cationic porphyrins with platinum(II) complexes 4PtTPyP and 3PtTPyP against C. albicans. The minimum inhibitory concentration of porphyrins and reactive oxygen species was evaluated by broth microdilution. The yeast eradication time was evaluated using a time-kill assay, and a checkerboard assay assessed the synergism in combination with commercial treatments. In vitro biofilm formation and destruction were observed using the crystal violet technique. The morphology of the samples was evaluated by atomic force microscopy, and the MTT technique was used to evaluate the cytotoxicity of the studied porphyrins in keratinocyte and fibroblast cell lines. The porphyrin 3PtTPyP showed excellent in vitro antifungal activity against the tested C. albicans strains. After white-light irradiation, 3PtTPyP eradicated fungal growth in 30 and 60 min. The possible mechanism of action was mixed by ROS generation, and the combined treatment with commercial drugs was indifferent. The 3PtTPyP significantly reduced the preformed biofilm in vitro. Lastly, the atomic force microscopy showed cellular damage in the tested samples, and 3PtTPyP did not show cytotoxicity against the tested cell lines. We conclude that 3PtTPyP is an excellent photosensitizer with promising in vitro results against C. albicans strains.

Antimicrobial activity of photosensitizers: arrangement in bacterial membrane matters.

Porphyrins are well-known photosensitizers (PSs) for antibacterial photodynamic therapy (aPDT), which is still an underestimated antibiotic-free method to kill bacteria, viruses, and fungi. In the present work, we developed a comprehensive tool for predicting the structure and assessment of the photodynamic efficacy of PS molecules for their application in aPDT. We checked it on a series of water-soluble phosphorus(V) porphyrin molecules with OH or ethoxy axial ligands and phenyl/pyridyl peripheral substituents. First, we used biophysical approaches to show the effect of PSs on membrane structure and their photodynamic activity in the lipid environment. Second, we developed a force field for studying phosphorus(V) porphyrins and performed all-atom molecular dynamics simulations of their interactions with bacterial lipid membranes. Finally, we obtained the structure-activity relationship for the antimicrobial activity of PSs and tested our predictions on two models of Gram-negative bacteria, Escherichia coli and Acinetobacter baumannii. Our approach allowed us to propose a new PS molecule, whose MIC50 values after an extremely low light dose of 5J/cm2 (5.0 ± 0.4μg/mL for E. coli and 4.9 ± 0.8μg/mL for A. baumannii) exceeded those for common antibiotics, making it a prospective antimicrobial agent.

The synthesis of novel water-soluble zinc (II) phthalocyanine based photosensitizers and exploring of photodynamic therapy activities on the PC3 cancer cell line.

In this study, Schiff base substituted phthalocyanine complexes (Zn1c, Zn2c) and their quaternized derivatives (Q-Zn1c, Q-Zn2c) were synthesized for the first time. Their structures have been characterized by FT-IR, 1H-NMR, UV-Vis, mass spectrometry and elemental analysis as well as. The photophysicochemical properties (fluorescence, singlet oxygen and photodegradation quantum yield) of these novel complexes were investigated in dimethylsulfoxide (DMSO) for both non-ionic and quaternized cationic phthalocyanine complexes and in aqueous solution for quaternized cationic phthalocyanine complexes. Water soluble cationic phthalocyanine compounds gave good singlet oxygen quantum yield (0.65 for Q-Zn1c, 0.66 for Q-Zn2c in DMSO; 0.65 for Q-Zn2c in aqueous solution). The binding of Q-Zn1c and Q-Zn2c to BSA/DNA was studied by using UV-Vis and fluorescence spectroscopy and these. Studies indicate that the mechanism of BSA quenching by quaternized zinc(II) phthalocyanines was static quenching. Quaternized zinc(II) phthalocyanines interacted with ct-DNA by intercalation. Quaternized zinc(II) phthalocyanines caused a decrease in cell viability and triggered apoptotic cell death after PDT was applied at a concentration that did not have a toxic effect on their own. Q-Zn1c and Q-Zn2c mediated PDT reduced the activity of SOD, CAT, GSH while increased MDA level in the prostate cancer cells. Furthermore, expression of apoptotic proteins after PDT was examined. The results revealed that the synthesized water soluble quaternized zinc(II) phthalocyanine complexes (Q-Zn1c and Q-Zn2c) are promising potential photosensitizers for PDT.

Deep-red Emitting Ir(III) Complexes as Type-I Photosensitizers for Lipid Droplets Targeted Photodynamic Therapy.

Photodynamic therapy (PDT) relying on photosensitizer-induced production of reactive oxygen species (ROS) for killing cancer cells has emerged as a non-invasive anti-cancer strategy. Compared with oxygen-dependent type-II photosensitizers (PSs) for PDT, the development of intrinsic oxygen-independent type-I ones is highly desired but remains a challenge. In this work, two netural Ir(III) complexes that can produce type-I reactive oxygen species, namely MPhBI-Ir-BIQ (Ir-1) and NPhBI-Ir-BIQ (Ir-2), were synthesized. Bright deep-red emitting nanoparticles with moderate particle size are beneficial for imaging-guided PDT. In in vitro experiments, importantly, the excellent biocompatibility, the targeting of lipid droplets (LDs), and the type-I ⋅OH and O2 ⋅- generation promoted effective photodynamic activity. This work will guide the building of type-I Ir(III) complexes PSs and can provide advantages for potential clinical applications under hypoxic conditions.

Spectroscopic study of methylene blue in vivo: effects on tissue oxygenation and tumor metabolism

Methylene blue (MB) is a promising photosensitizer (PS) for the treatment of pathological neoplasms, since it has both photodynamic activity (under laser irradiation) and redox and catalytic properties (in the absence of light). In the framework of this work, using spectroscopic methods, the effect of intravenous administration of MB on tissue oxygenation of hemoglobin in small animals in vivo in tumor and normal tissues was analyzed. The influence of MB on cell metabolism was analyzed. It has been shown that the use of MB promotes an increase in oxygen consumption by the tumor, and also leads to a shift in metabolism towards oxidative phosphorylation. It was shown that the use of MB contributes to an increase in oxygen consumption by the tumor, and also leads to a shift in metabolism towards oxidative phosphorylation.

Carbon dots for long-term near-infrared afterglow imaging and photodynamic therapy

Imaging-guided photodynamic therapy (PDT) has the features of precise location and non-invasiveness. However, most of the photosensitizers (PSs) for PDT are poor fluorescent emitters, and the inadequate fluorescence is usually interfered by tissue auto-fluorescence. The afterglow phosphorescence could ideally address the issues of fluorescence imaging. Therefore, it is of double benefit to design phosphorescentCDs for enhanced near-infrared (NIR) phototheranostics. Hereon, we synthesized CDs with excellent biosafety, outstanding stability, good water dispersibility and effective photodynamic activity. CDs could emit NIR luminescence with long lifetime over 2 h, which afforded large tissue penetration (10 mm) and high SNR (98.4) for deep-tissue and long-term in vivo persistent luminescent imaging. Moreover, abundant reactive oxygen species generated by CDs enabled NIR afterglow imaging-guided PDT to effectively inhibit tumor growth. This work demonstrates the enormous potential of CDs as multifunctional nanoplatforms for biomedical application.

Near-Infrared Photodynamic Chemiluminescent Probes for Cancer Therapy and Metastasis Detection.

There is growing interest in the development of chemiluminescence (CL) probes for phototheranostics because of their minimized tissue autofluorescence. However, due to a lack of near-infrared (NIR)-absorbing chemiluminophores, current probes for NIR CL-guided phototherapy are based on nanoparticles made up of multiple components. We report bright unimolecular chemiluminophores with NIR absorptions and emissions, long CL half-lives and ideal photodynamic efficiency. One luminophore is modified into an activatable probe, DBPOL , with a turn-on CL signal and photodynamic activity that are specific to a cancer biomarker. The highly sensitive DBPOL allows CL-guided photodynamic therapy which completely inhibits tumor growth and lung metastasis in mouse models, and can be applied for noninvasive monitoring of lung metastasis. We provide molecular guidelines for NIR-absorbing CL probes for imaging-guided phototherapy.

Near‐Infrared Photodynamic Chemiluminescent Probes for Cancer Therapy and Metastasis Detection

AbstractThere is growing interest in the development of chemiluminescence (CL) probes for phototheranostics because of their minimized tissue autofluorescence. However, due to a lack of near‐infrared (NIR)‐absorbing chemiluminophores, current probes for NIR CL‐guided phototherapy are based on nanoparticles made up of multiple components. We report bright unimolecular chemiluminophores with NIR absorptions and emissions, long CL half‐lives and ideal photodynamic efficiency. One luminophore is modified into an activatable probe, DBPOL, with a turn‐on CL signal and photodynamic activity that are specific to a cancer biomarker. The highly sensitive DBPOL allows CL‐guided photodynamic therapy which completely inhibits tumor growth and lung metastasis in mouse models, and can be applied for noninvasive monitoring of lung metastasis. We provide molecular guidelines for NIR‐absorbing CL probes for imaging‐guided phototherapy.

Cupric-ion-promoted fabrication of oxygen-replenishing nanotherapeutics for synergistic chemo and photodynamic therapy against tumor hypoxia.

Mixing a glutathione (GSH)-responsive carboxy zinc(II) phthalocyanine (ZnPc*) and CuSO4·5H2O in water with or without the presence of the anticancer drug SN38 resulted in the formation of self-assembled nanotherapeutics labeled as ZnPc*/Cu/SN38@NP and ZnPc*/Cu@NP, respectively. The Cu2+ ions not only promoted the self-assembly of the carboxy phthalocyanine through metal complexation, but also catalyzed the transformation of H2O2 to oxygen via a catalase-like reaction, rendering an oxygen-replenishing property to the nanosystems. Both nanosystems exhibited high stability in aqueous media, but the nanoparticles disassembled gradually in an acidic or GSH-enriched environment and inside human colorectal adenocarcinoma HT29 cells, releasing the encapsulated therapeutic components. The disassembly process together with the activation by the intracellular GSH led to relaxation of the intrinsic quenching of the nanophotosensitizers and restoration of the photoactivities of ZnPc*. Under a hypoxic condition, ZnPc*/Cu/SN38@NP could attenuate the intracellular hypoxia level and maintain the photodynamic activity due to its Cu2+-promoted oxygen-replenishing ability. The photodynamic effect of ZnPc* and the anticancer effect of SN38 worked cooperatively, causing substantial apoptotic cell death. The dual therapeutic actions could also effectively inhibit the tumor growth in HT29 tumor-bearing nude mice without initiating notable adverse effects to the mice. STATEMENT OF SIGNIFICANCE: The oxygen-dependent nature of photodynamic therapy generally reduces its efficacy against tumor hypoxia, which is a common characteristic of advanced solid tumors and usually leads to resistance toward various anticancer therapies. We report herein a facile approach to assemble a glutathione-responsive carboxy phthalocyanine-based photosensitizer and an anticancer drug in aqueous media, in which Cu(II) ions were used to promote the self-assembly through metal complexation and catalyze the conversion of H2O2 to oxygen through a catalase-like reaction, making the resulting nanoparticles possessing an oxygen-replenishing property that could promote the photodynamic effect against hypoxic cancer cells and tumors. The use of Cu(II) ions to achieve the aforementioned dual functions in the fabrication of advanced nano-photosensitizing systems has not been reported.

Rational Design of Mesoporous Coordination Polymer Nanophotosensitizers for Photodynamic Tumor Ablation

Effective clinical practice of precise photodynamic therapy (PDT) is severely impeded by the inherent drawbacks and aggregation propensity of conventional photosensitizers. An all-in-one approach is highly desired to optimize structural features, photophysical properties, and pharmacokinetic behaviors of photosensitizers. Herein, we have fabricated mesoporous boron dipyrromethene-bridged coordination polymer nanophotosensitizers (BCP-NPs) for high-performance PDT via a unique solvent-assisted assembly strategy. Distinctive photophysical and structural characteristics of BCP-NPs confer enhanced photodynamic activities, together with high cellular uptake and ultrahigh stability. Moreover, BCP-NPs showed excellent tumor accumulation and prolonged tumor retention, achieving eradication of the triple-negative breast cancer (TNBC) model under low-power-density LED irradiation. This work has provided a valuable paradigm for the construction of mesoporous photoactive nanomaterials for biophotonic applications.

Vaterite microparticle-loaded methylene blue for photodynamic activity in macrophages infected with Leishmania braziliensis.

Calcium carbonate (CaCO3) exhibits a variety of crystalline phases, including the anhydrous crystalline polymorphs calcite, aragonite, and vaterite. Developing porous calcium carbonate microparticles in the vaterite phase for the encapsulation of methylene blue (MB) as a photosensitizer (PS) for use in photodynamic therapy (PDT) was the goal of this investigation. Using an adsorption approach, the PS was integrated into the CaCO3 microparticles. The vaterite microparticles were characterized by scanning electron microscopy (SEM) and steady-state techniques. The trypan blue exclusion method was used to measure the biological activity of macrophages infected with Leishmania braziliensis in vitro. The vaterite microparticles produced are highly porous, non-aggregated, and uniform in size. After encapsulation, the MB-loaded microparticles kept their photophysical characteristics. The carriers that were captured allowed for dye localization inside the cells. The results obtained in this study indicated that the MB-loaded vaterite microparticles show promising photodynamic activity in macrophages infected with Leishmania braziliensis.

Photodynamic Activity of Acridine Orange in Keratinocytes under Blue Light Irradiation

Acridine orange (AO) is a metachromatic fluorescent dye that stains various cellular compartments, specifically accumulating in acidic vacuoles (AVOs). AO is frequently used for cell and tissue staining (in vivo and in vitro), mainly because it marks different cellular compartments with different colors. However, AO also forms triplet excited states and its role as a photosensitizer is not yet completely understood. Human immortalized keratinocytes (HaCaT) were incubated for either 10 or 60 min with various concentrations (nanomolar range) of AO that were significantly lower than those typically used in staining protocols (micromolar). After incubation, the cells were irradiated with a 490 nm LED. As expected, cell viability (measured by MTT, NRU and crystal violet staining) decreased with the increase in AO concentration. Interestingly, at the same AO concentration, altering the incubation time with HaCaT substantially decreased the 50% lethal dose (LD50) from 300 to 150 nM. The photoinduced cell death correlated primarily with lysosomal disfunction, and the correlation was stronger for the 60 min AO incubation results. Furthermore, the longer incubation time favored monomers of AO and a distribution of the dye to intracellular sites other than lysosomes. Studies with mimetic systems indicated that monomers, which have higher yields of fluorescence emission and singlet oxygen generation, are favored in acidic environments, consistent with the more intense emission from cells submitted to the longer AO incubation period. Our results indicate that AO is an efficient PDT photosensitizer, with a photodynamic efficiency that is enhanced in acidic environments when multiple intracellular locations are targeted. Consequently, when using AO as a probe for live cell tracking and tissue staining, care must be taken to avoid excessive exposure to light to avoid undesirable photosensitized oxidation reactions in the tissue or cell under investigation.

Coupling probiotics with 2D CoCuMo-LDH nanosheets as tumor microenvironment-responsive platform for precise NIR-II photodynamic therapy.

Photodynamic therapy (PDT) has become a promising cancer treatment approach with superior advantages. However, it remains a ground challenge to develop tumor microenvironment (TME)-responsive photosensitizers (PSs) for tumor-targeting precise PDT. Herein, we report the coupling Lactobacillus acidophilus probiotics with 2D CoCuMo-layered double hydroxide nanosheets (LA&LDH) as a TME-responsive platform for precise NIR-II PDT. The CoCuMo-LDH nanosheets loaded on LA can be transformed from crystalline into amorphous one through etching by the LA metabolite-enabled low pH and over-expressed glutathione. The TME-induced in-situ amorphization of CoCuMo-LDH nanosheets can boost its photodynamic activity for singlet oxygen (1 O2 ) generation under 1270nm laser irradiation with the relative 1 O2 quantum yield of 1.06, which is the highest among previously reported NIR-excited PSs. In vitro and in vivo assays prove that the LA&LDH can effectively achieve complete cell apoptosis and tumor eradication under 1270nm laser irradiation. This study proves that the probiotics can be used as a tumor-targeting platform for highly efficient precise NIR-II PDT. This article is protected by copyright. All rights reserved.

Near-infrared photodynamic antibacterial enhanced superhydrophobic electrospun membrane surfaces

Superhydrophobic surfaces have attracted great attention as effective antimicrobial platforms due to the superb repellency against various microbial biofouling. However, due to the lack of intrinsic antimicrobial activity, some bacteria still have the opportunity to adhere and survive on superhydrophobic surfaces, inevitably causing serious bacterial contamination. Herein, a poly(vinylidene) fluoride (PVDF) based nanocomposite membrane with both superhydrophobic property and near-infrared (NIR) light triggered photodynamic antibacterial activity has been prepared by a facile electrospinning method. Among those, the silicon dioxide nano-scale particles were introduced in the membrane to increase the roughness of the electrospun fibres, while the zinc phthalocyanine (ZnPC) as the NIR photosensitizer was also involved. Owing to the stable Cassie-Baxter model superhydrophobic properties, the resultant membrane demonstrated strong bacterial repellent performances for both Gram-positive and Gram-negative bacteria (~8.9 % reduction for S. aureus and ~9.4 % for E. coli). After being exposed to NIR light illumination (808 nm, 2.0 mW) for 10 min, the membrane surface showed further enhanced antimicrobial efficiency and no surviving bacteria were observed, which is extremely difficult to achieve by relying on either superhydrophobic repellency or NIR photodynamic sterilization alone. Furthermore, this nanocomposite membrane displays no detectable cytotoxicity to L929 cells, even suffered from NIR light irradiation, and the surface also shows no significant activation on red blood cells as well as good liquid-repellency against whole blood adhesion. These results conclusively show that the nanocomposite membranes exhibit great potential applications in a wide range of antimicrobial-related fields.

Antimicrobial activity of Emodin in combination with visible light against Escherichia coli and Staphylococcus aureus: Applications for food safety technology

In order to promote the application of natural photosensitizer, the photodynamic antibacterial effect of emodin combined with visible light on Escherichia coli and Staphylococcus aureus were studied in this work. The results showed that emodin mediated photodynamic antibacterial activity was dependent on concentration, light time and pH. Confocal microscopy and scanning electron microscopy confirmed that emodin can produce reactive oxygen species to kill bacteria under visible light irradiation. After treatment with emodin and visible intermittent radiation, S. aureus inoculated on the surface of fresh-cut apples was significantly reduced to 1.5 Log CFU/mL during 5 days of storage, and the storage method had no significant effect on the weight and appearance of apples. The results indicate that photodynamic inactivation of foodborne pathogens by combining emodin with visible light is a potential food safety technology.

Photodynamic Activity of TMPyP4/TiO2 Complex under Blue Light in Human Melanoma Cells: Potential for Cancer-Selective Therapy.

The combination of TiO2 nanoparticles (NPs) and photosensitizers (PS) may offer significant advantages in photodynamic therapy (PDT) of melanoma, such as improved cell penetration, enhanced ROS production, and cancer selectivity. In this study, we aimed to investigate the photodynamic effect of 5,10,15,20-(Tetra-N-methyl-4-pyridyl)porphyrin tetratosylate (TMPyP4) complexes with TiO2 NPs on human cutaneous melanoma cells by irradiation with 1 mW/cm2 blue light. The porphyrin conjugation with the NPs was analyzed by absorption and FTIR spectroscopy. The morphological characterization of the complexes was performed by Scanning Electron Microscopy and Dynamic Light Scattering. The singlet oxygen generation was analyzed by phosphorescence at 1270 nm. Our predictions indicated that the non-irradiated investigated porphyrin has a low degree of toxicity. The photodynamic activity of the TMPyP4/TiO2 complex was assessed on the human melanoma Mel-Juso cell line and non-tumor skin CCD-1070Sk cell line treated with various concentrations of the PS and subjected to dark conditions and visible light-irradiation. The tested complexes of TiO2 NPs with TMPyP4 presented cytotoxicity only after activation by blue light (405 nm) mediated by the intracellular production of ROS in a dose-dependent manner. The photodynamic effect observed in this evaluation was higher in melanoma cells than the effect observed in the non-tumor cell line, demonstrating a promising potential for cancer-selectivity in PDT of melanoma.

Bacteria-triggered photodynamic nano-system based on hematoporphyrin-modified chitosan for sustainable plant disease control

Faced with increasingly serious drug resistance and environmental pollution, there is an urgent necessity to develop green and efficient pesticides with new mechanisms of action. A novel antibacterial nano-system for plant protection based on photodynamic action was prepared by grafting hematoporphyrin (HP) onto modified chitosan through ester bonding. The self-quenching effect caused by aggregation of grafted HP could effectively inhibit its photodegradation, thus enhancing its photostability. The breakage of ester bonds induced by enzyme stimulation at the sites of bacterial infection could trigger HP release exerting an efficient photodynamic effect. The antibacterial experiments showed that the nanoparticles (NPs) have good photodynamic antibacterial activity, and the inhibition rate was as high as 96 % after 60 min of light exposure. Adhesion and safety studies have shown that the NPs are well retained on plant foliage without causing damage to the crop. Thus, NPs have great potential in sustainable plant disease management.

Specific Chemiluminescence Imaging and Enhanced Photodynamic Therapy of Bacterial Infections by Hemin-Modified Carbon Dots.

Antibacterial photodynamic therapy (aPDT) is a promising antibiotics-alternative strategy for bacterial infectious diseases, which features broad-spectrum antibacterial activity with a low risk of inducing bacterial resistance. However, clinical applications of aPDT are still hindered by the hydrophobicity-caused inadequate photodynamic activity of conventional photosensitizers and the hypoxic microenvironment of bacterial infections. To address these problems, herein, a promising strategy is developed to achieve specific chemiluminescence (CL) imaging and enhanced PDT of bacterial infections using hemin-modified carbon dots (H-CDs). The H-CDs can be facilely prepared and exhibit favorable water solubility, augmented photodynamic activity, and unique peroxidase-mimicking capacity. Compared with the free CDs, the photodynamic efficacy of H-CDs is significantly augmented due to the increased electron-hole separation efficiency. Moreover, the peroxidase catalytic performance of H-CDs enables not only infection identification via bacterial infection microenvironment-responsive CL imaging but also oxygen self-supplied aPDT with hypoxia-relief-enhanced bacteria inactivation effects. Finally, the enhanced aPDT efficiencies of H-CDs are validated in both in vivo abscess and infected wound models. This work may provide an effective antibacterial platform for the selective imaging-guided treatment of bacterial infections.