1O2 Quantum Yield Research Articles

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.

Decoupling Optical Response and Photochemical Formation of Singlet Oxygen in Size Isolated Fractions of Ozonated Dissolved Organic Matter.

The complex effects of ozonation on the photophysical and size-based properties of dissolved organic matter (DOM) were investigated using two DOM isolates, Suwannee River Fulvic Acid (SRFA) and Pony Lake Fulvic Acid (PLFA). A size exclusion chromatography system paired with absorbance, fluorescence, and total organic carbon detection was used to determine the fluorescence quantum yield (Φf) as a function of the apparent molecular weight (AMW). Size-based fractions of each isolate were collected and irradiated to measure singlet oxygen (1O2) quantum yield (Φ1O2). Φf decreased with ozonation in low AMW fractions, while increasing in high AMW fractions. Φ1O2 increased with ozone dose in low AMW fractions from ∼2 to ∼7% and ∼3 to ∼11% for PLFA and SRFA, respectively, indicating that these are the most photoreactive fractions of DOM. Decreases in Φf and concomitant increases in Φ1O2 in low AMW fractions indicated that chemical transformations occurred, likely including the conversion of phenols to quinones, particularly in SRFA. Results further suggest that the photoactive and fluorescent fractions of DOM are likely independent pools of chromophores from different AMW fractions. In PLFA, a linear response in Φ1O2, specific UV absorbance at wavelength 254 nm (SUVA254), and Φf with ozonation indicated the equal distribution of ozone-reactive moieties.

A novel heavy-atom-free lysosome-targeted BODIPY as triplet photosensitizer based on SOCT-ISC mechanism for photodynamic therapy

As important organelles in biological cells, lysosomes are closely associated with cell signaling, necrosis and apoptosis. Herein, we report a novel lysosome-targeted boron dipyrromethene (BODIPY) photosensitizer, Lyso-BDP, which has the advantage of lower side effects and higher phototoxicity for 4T1 cells in photodynamic therapy (PDT). Lyso-BDP possesses the lysosomal targeting treatment through the production of the singlet oxygen under the light excitation at 600 nm. We combine the anthracenyl group and BODIPY to form a D-A binary compound. The orthogonal configuration is confirmed by density functional theory (DFT) and time-dependent density functional theory (TDDFT). The molecular orbitals and the energies of the triplet state explain the spin-orbit charge transfer inter-system crossing (SOCT-ISC) mechanism. Due to SOCT-ISC mechanism, Lyso-BDP has the high singlet oxygen (1O2) quantum yield of 62% in DCM without heavy atoms. In this way, the dark toxicity of photosensitizer can be reduced. Meanwhile, the 1O2 ″afterglow” can be achieved to enhance the phototherapeutic effect because of the anthracene group. Compared to classical photosensitizers, Lyso-BDP shows the low half maximum inhibitory concentration (IC50) of 2.5 μM for 4T1 cells in vitro cytotoxicity assays. Therefore, this work provides a strategy to solve the problem of high cellular dark toxicity and no organelle targeting of classical photosensitizers.

Singlet Molecular Oxygen Generation via Unexpected Emission Color-Tunable CdSe/ZnS Nanocrystals for Applications in Photodynamic Therapy

It is highly desirable in biomedical sciences to utilize the multifunctional nanoparticles of similar size with tunable emission. Since the optoelectronic properties of quantum dots (QDs) originate from size-dependent quantum confinement effects, we developed an alternate approach to synthesize color-tunable CdSe/ZnS QDs based on interfacial ion exchange (predominantly exchange of Se2– by S2– anions), using 1-dodecanethiol and oleylamine solvent systems as a sensitive parameter. The wide-range color-tunability (490–570 nm) was achieved unexpectedly as a result of interfacial alloying without inducing a significant change in the size (from 4.45 to 4.81 nm) of QDs. The local atomic structure order, chemical composition, and nature of alloying in QDs were unraveled by XAFS data analysis. Owing to the molecular-like sensitization behavior, the QDs were evaluated for singlet molecular oxygen (1O2) efficiency. They were further studied in RAW 264.7 macrophages for biocompatibility, bioimaging, and delivering pathways for use in future photodynamic therapy (PDT). The QDs demonstrated efficient singlet molecular oxygen (1O2) quantum yields (ΦQDs) of 14, 12, and 18% for QDs (I), QDs (II), and QDs (III), respectively. The QD-treated cells presented high cell viability above 85% and induced no cell activation. Fluorescence and transmission electron microscopy (TEM) images of cells manifested a considerable amount of QDs in the vicinity of the cell membrane and intracellular regions. The pathway-specific inhibition measurements revealed that the QDs were internalized by cells via energy-dependent endocytosis, predominantly macropinocytosis and other receptor-mediated endocytic pathways, and accumulated them presumably in endosome/lysosomes. This study will open new possibilities for engineering interfacial alloying-based tunable emission QDs and pathway-specific delivery of QD-based theranostics into a site of interest for simultaneous bioimaging and PDT.

Photoactive Oligomer with an Acceptor–Donor–Acceptor-Conjugated Structure for Single Near-Infrared Light-Triggered Photothermal/Photodynamic Synergistic Therapy of Tumors

Phototherapy is attracting increasing attention as a noninvasive, safe, and effective therapeutic modality for tumors. Especially, it is expected to achieve better therapeutic efficacy, fewer side effect, and deeper tissue penetration by the combination of photothermal (PTT) and photodynamic (PDT) under single near-infrared (NIR) light irradiation. For this purpose, herein, we develop a photoactive acceptor (A)–donor (D)–acceptor (A)-type conjugated oligomer (UF-TTOEH-2Cl). A NIR light-responsive nanoplatform (UTNPs) was fabricated based on UF-TTOEH-2Cl, and a folic acid-functionalized amphiphilic block copolymer (FA-PEG-PBLA10) was prepared as the polymer matrix through a nanoprecipitation method, which showed a high photothermal conversion efficiency (42%) and singlet oxygen (1O2) quantum yield (ΦΔ = 17.2%) under 880 nm laser irradiation. Furthermore, efficient UTNPs-based PDT/PTT synergistic therapy of tumors was demonstrated utilizing HeLa and SiHa cells as the models in vitro.

Near-infrared AIEgens with high singlet-oxygen yields for mitochondria-specific imaging and antitumor photodynamic therapy.

AIE-active photosensitizers (PSs) are promising for antitumor therapy due to their advantages of aggregation-promoted photosensitizing properties and outstanding imaging ability. High singlet-oxygen (1O2) yield, near-infrared (NIR) emission, and organelle specificity are vital parameters to PSs for biomedical applications. Herein, three AIE-active PSs with D-π-A structures are rationally designed to realize efficient 1O2 generation, by reducing the electron-hole distribution overlap, enlarging the difference on the electron-cloud distribution at the HOMO and LUMO, and decreasing the ΔEST. The design principle has been expounded with the aid of time-dependent density functional theory (TD-DFT) calculations and the analysis of electron-hole distributions. The 1O2 quantum yields of AIE-PSs developed here can be up to 6.8 times that of the commercial photosensitizer Rose Bengal under white-light irradiation, thus among the ones with the highest 1O2 quantum yields reported so far. Moreover, the NIR AIE-PSs show mitochondria-targeting capability, low dark cytotoxicity but superb photo-cytotoxicity, and satisfactory biocompatibility. The in vivo experimental results demonstrate good antitumor efficacy for the mouse tumour model. Therefore, the present work will shed light on the development of more high-performance AIE-PSs with high PDT efficiency.

Host-guest binding of tetracationic cyclophanes to photodynamic agents inhibits posttreatment phototoxicity and maintains antitumour efficacy.

In the past two decades, photodynamic therapy (PDT) has become an effective method for the treatment of cancer. However, the posttreatment residue of photodynamic agents (PDAs) causes long-term skin phototoxicity. Here, we apply naphthalene-derived, box-like tetracationic cyclophanes, named NpBoxes, to bind to clinically used porphyrin-based PDAs to alleviate their posttreatment phototoxicity by reducing their free content in skin tissues and 1O2 quantum yield. We show that one of the cyclophanes, 2,6-NpBox, could include the PDAs to efficiently suppress their photosensitivity for the generation of reactive oxygen species. A tumour-bearing mouse model study revealed that, when Photofrin, the most widely used PDA in clinic, was administrated at a dose corresponding to the clinical one, 2,6-NpBox of the same dose could significantly suppress its posttreatment phototoxicity on the skin induced by simulated sunlight irradiation, without imposing a negative influence on its PDT efficacy.

Development of water-soluble phenazine-2,3-diol-based photosensitizers for singlet oxygen generation.

Phenazine-2,3-diol-based dyes, KY-1Na and KY-2Na bearing one and two carboxylic acid sodium salts, respectively, have been newly developed as water-soluble photosensitizers (PSs) possessing the ability to generate singlet oxygen (1O2). In order to evaluate the solubility of KY-1Na and KY-2Na in water, the hydrophobicity/hydrophilicity of the two PSs was investigated by experimental measurement of the logarithms (log Po/w) of the 1-octanol/water partition coefficient (Po/w) for the PS. The log Po/w values of both KY-1Na and KY-2Na were determined to be -0.9, indicating that both the PSs are more hydrophilic than Rose Bengal (-0.6) and have hydrophilicity equivalent to methylene blue (-0.9). Both the PSs in water show a broad photoabsorption band in the range of 500 to 600 nm. Thus, we estimated the 1O2 quantum yields (ΦΔ) of KY-1Na and KY-2Na in water by using 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA) as a water-soluble 1O2 scavenger. It was found that in water the ΦΔ value (0.19) of KY-2Na is higher than that of KY-1Na (0.06). Density functional theory (DFT) calculations suggested that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distributions for the molecular structure of KY-2Na are adequately separated, leading to a decrease in the energy gap (ΔEST) between the singlet state (S1) and the triplet state (T1) that causes efficient intersystem crossing (ISC), compared to that for the molecular structure of KY-1Na. Indeed, time-dependent DFT (TD-DFT) calculations demonstrated that the ΔEST(S1-T1) value (0.82 eV) of KY-2Na is smaller than that (0.98 eV) of KY-1Na, resulting in a relatively high ΦΔ value of KY-2Na. Consequently, we demonstrate that phenazine-2,3-diol-based PSs bearing carboxylic acid salts possess high solubility and moderate 1O2 generation ability in water.

Light-triggered photosynthetic engineered bacteria for enhanced-photodynamic therapy by relieving tumor hypoxic microenvironment.

Background: Singlet oxygen (1O2) has received considerable research attention in photodynamic therapy (PDT) due to its cytotoxic solid features. However, the inherent hypoxic state of the tumor microenvironment (TME) leads to the meager 1O2 quantum yield of inorganic PDT reagents, and their application in vivo remains elusive. Methods: We developed a novel strategy to fabricate active photosynthetic bacteria/photosensitizer/photothermal agent hybrids for photosynthetic tumor oxygenation and PDT and PTT tumor therapy under different laser irradiation sources. Photosynthetic bacteria combined with Ce6 photosensitizer and Au NPs photothermal agent, the obtained Bac@Au-Ce6 effectively targets tumor tissues and further enhances the tumor accumulation of Au-Ce6. Results: The results showed that the Au-Ce6-loaded engineered bacteria (Bac@Au-Ce6) maintained the photosynthetic properties of Syne. After i.v. injection, Bac@Au-Ce6 efficiently aggregates at tumor sites due to the tumor-targeting ability of active Syne. With 660 nm laser irradiation at the tumor site, the photoautotrophic Syne undergoes sustained photosynthetic O2 release and immediately activates O2 to 1O2 via a loaded photosensitizer. PTT was subsequently imparted by 808 laser irradiations to enhance tumor killing further. Conclusions: This work provides a new platform for engineering bacteria-mediated photosynthesis to promote PDT combined with PTT multi-faceted anti-tumor.

Efficient wastewater disinfection by raised 1O2 yield through enhanced electron transfer and intersystem crossing via photocatalysis of peroxymonosulfate with CuS quantum dots modified MIL-101(Fe)

Peroxymonosulfate (PMS)-based photocatalysis is a promising alternative approach for wastewater disinfection. Singlet oxygen (1O2) is sensitive and efficient for bacterial inactivation. This study developed a 1O2-predominated PMS disinfection technique under visible light with CuS quantum dots (QDs) modified MIL-101(Fe) (CSQDs@MF). CuS QDs modification greatly enhanced the 1O2 quantum yield by 80% than that of MIL-101(Fe). Photoelectricity and photoluminescence tests demonstrated that both the enhanced electron transfer and energy transfer were responsible for improved 1O2 generation in Vis/PMS/CSQDs@MF system. The system took 60 min to inactivate 7.5-log E. coli, and it could be applied in a broad pH and dissolve oxygen range. Bacterial inactivation mechanism suggested that 1O2 attacked cell membrane first, then induced oxidative stress, up-regulated intracellular ROS level, eventually broke DNA strand. The system showed good disinfection performance on Gram-positive B. subtilis and fecal coliforms in practical wastewater, implying it is a promising alternative disinfection technology for wastewater treatment.

Self-Assembled BODIPY Derivative with A-D-A Structure as Organic Nanoparticles for Photodynamic/Photothermal Cancer Therapy.

Organic nanomaterials have attracted considerable attention in the area of photodynamic and photothermal therapy, owing to their outstanding biocompatibility, potential biodegradability, well-defined chemical structure, and easy functionalization. However, it is still a challenge to develop a single organic molecule that obtains both photothermal and photodynamic effects. In this contribution, we synthesized a new boron-dipyrromethene (BODIPY)-based derivative (DPBDP) with an acceptor-donor-acceptor (A-D-A) structure by coupling 3,6-di(2-thienyl)-2,5-dihydropyrrolo [3,4-c] pyrrole-1,4-dione (DPP) and BODIPY. To enhance the hydrophilicity of the BODIPY derivative, the polyethylene glycol (PEG) chains were introduced to the meso- position of BODIPY core. The amphiphilic DPBDP was then self-assembled into related nanoparticles (DPBDP NPs) with improved hydrophilicity and enhanced absorbance in the NIR region. DPBDP NPs could simultaneously generate the singlet oxygen (1O2) and heat under the irradiation of a single laser (690 nm). The 1O2 quantum yield and photothermal conversion efficiency (PCE) of DPBDP NPs were calculated to be 14.2% and 26.1%, respectively. The biocompatibility and phototherapeutic effect of DPBDP NPs were evaluated through cell counting kit-8 (CCK-8) assay. Under irradiation of 690 nm laser (1.0 W/cm2), the half maximal inhibitory concentration (IC50) of DPBDP NPs was calculated to be 16.47 µg/mL. Thus, the as-prepared DPBDP NPs could be acted as excellent candidates for synergistic photodynamic/photothermal therapy.

Novel BODIPY-Fluorene-Fullerene and BODIPY-Fluorene-BODIPY Conjugates: Synthesis, Characterization, Photophysical and Photochemical Properties.

Two new BODIPY-fluorene-fullerene (3) and BODIPY-fluorene-BODIPY (4) conjugates were designed, synthesized, and characterized for the first time. The structural properties of compounds were investigated with elemental analysis, mass, 1H, and 13C NMR techniques. Absorption and fluorescence spectroscopy were used to examine the photophysical (absorption and emission profiles, fluorescence quantum yields, and lifetimes) and photochemical (formation of singlet oxygen (1O2)) properties. It was observed that the novel compounds (3) and (4) showed high molar extinction coefficients and good 1O2 quantum yields. 1O2 formation ability of the BODIPY-fluorene-fullerene conjugate (3) was more efficient than that of the BODIPY-fluorene-BODIPY conjugate (4). Furthermore, photosensitization ability of both conjugate systems was more remarkable than some commonly used BODIPY based photosensitizers. The data presented in this work indicate that these two novel systems are effective 1O2 photosensitizers that might be used for various areas of applications such as photodynamic therapy and photocatalysis.

Photoinduced Carbene for Effective Photodynamic Therapy Against Hypoxic Cancer Cells

Photoinduced Carbene for Effective Photodynamic Therapy Against Hypoxic Cancer Cells

Multifunctional porphyrin-ionic liquid aggregate for highly sensitive electrochemical detection of protein

Herein, this paper describes a novel label-free and extensibility electrochemical sensing platform based on porphyrin-ionic liquid (Por-IL) aggregate for the detection of antibody. The Por-IL was synthesized with water-soluble porphyrins Zn(II) meso-tetrakis (4-sulfonatophenyl)porphyrin (ZnTPPS)) and the ionic liquid 1-decyl-alkyl-3-methylimidazolium bromide (C10mimBr) under room temperature, which exhibited high singlet oxygen (1O2) quantum yields and electrocatalytic activity toward hydrogen peroxide (H2O2). In the presence of antibody, the antibody could be introduced on the surface of the electrode on the basis of antigen-antibody biorecognition. Under light illumination, the 1O2 formed, then water and the formed 1O2 could be catalyzed by antibody via the antibody catalyzed water oxidation pathway to produce H2O2 which could be detected by the electrode, leading to the electrochemical signal for readout. Using anti-carcinoembryonic antigen (anti-CEA) as a model target, this method displayed a wide linear detection range and a lower detection limit. In particular, Por-IL demonstrated lower detection limit of 1.67 fg/mL. Furthermore, the Por-IL sensors were able to detect antibody in complex samples. The immunosensor platform has the features of label-free, sensitivity, only with air and on/off light switching and could be used to detect of a variety of antibody by using corresponding antigen, showing potential application in medical diagnosis.

Organic Theranostic Nanoplatform with Enhanced Fluorescence and Singlet Oxygen Quantum Yield for Tumor-Targeting Image-Guided Photodynamic/Photothermal Synergistic Therapy

The development of biocompatible therapeutic agents to achieve tumor-targeting photothermal/photodynamic synergistic therapy under imaging guidance is crucial for effective cancer phototherapy. Herein, we elaborately designed an organic theranostic nanoplatform, Ce6@HA-Cys-TTDTT nanoparticles (NPs), in which the active targeting moiety hyaluronic acid (HA) was conjugated with a hydrophobic conjugated oligomer TTDTT through the side chain of cystamine (Cys) to form an amphiphilic polymer, and then an excellent photosensitizer chlorin e6 (Ce6) was encapsulated by self-assembly. Bithiophenyl diketopyrrolopyrrole (TDPP) and triphenylamine were utilized as the acceptor (A) and donor (D), respectively, to construct the D–A–D molecule TTDTT, which served as an excellent photothermal agent with a moderate 1O2 quantum yield and quenched fluorescence (FL) in HA-Cys-TTDTT NPs. However, Ce6@HA-Cys-TTDTT NPs exhibited obviously higher 1O2 quantum yields (ΦΔ = 53.0%) and FL intensity than HA-Cys-TTDTT NPs (ΦΔ = 29.6%) and free Ce6 under laser irradiation at 635 nm and still maintained a high photothermal conversion efficiency (η = 37.7%). These results may be attributed to the efficient energy transfer from TTDTT to Ce6 in Ce6@HA-Cys-TTDTT NPs and the facilitation of the transition of singlet-to-triplet excited state via an intersystem crossing pathway. Ce6@HA-Cys-TTDTT NPs presented high tumor targeting capability in FL/thermal imaging in vivo and significant advantages over free Ce6 in long-term FL imaging in vivo. The remarkable antitumor efficacy of Ce6@HA-Cys-TTDTT NPs under a single wavelength laser irradiation was confirmed through in vitro and in vivo experiments. In this study, a multifunctional organic theranostic nanoplatform was designed to enhance the effect of tumor phototherapy, benefiting from the tumor-targeting multimodal imaging-guided photodynamic/photothermal synergistic therapy.

Locked and Loaded: β-Galactosidase Activated Photodynamic Therapy Agent Enables Selective Imaging and Targeted Treatment of Glioblastoma Multiforme Cancer Cells.

Selective detection and effective therapy of brain cancer, specifically, the very aggressive glioblastoma multiforme (GBM), remains one of the paramount challenges in clinical settings. While radiotherapy combined surgery is proposed as the main treatment course, it has several drawbacks such as complexity of the operation and common development of recurrent tumors in this course of patient care. Unique opportunities presented by photodynamic therapy (PDT) offer promising, effective, and precise therapy against GBM cells along with simultaneous imaging opportunities. However, activatable, theranostic molecular systems in PDT modality for GBM remained scarce. Specifically, even though elevated β-galactosidase (β-gal) activity in glioblastoma cells is well-documented, targeted, activatable therapeutic PDT agents have not been realized. Herein, we report a β-galactosidase (β-gal) activatable phototheranostic agent based on an iodinated resorufin core (RB-1) which was realized in only three steps with commercial reagents in 29% overall yield. RB-1 showed very high singlet oxygen (1O2) quantum yield (54%) accompanied by a remarkable turn-on response in fluorescence upon enzymatic activation. RB-1 was tested in different cell lines and revealed selective photocytotoxicity in U-87MG glioblastoma cells. Additionally, thanks to almost 7% fluorescence quantum yield (ΦF) despite extremely high 1O2 generation yield, RB-1 was also demonstrated as a successful agent for fluorescence imaging of U-87MG cells. Due to significantly lower (β-gal) activity in healthy cells (NIH/3T3), RB-1 stayed in a passive state and showed minimal photo and dark toxicity. RB-1 marks the first example of a β-gal activatable phototheranostic agent toward effective treatment of glioblastoma.

Substituted boron subphthalocyanines – Prospective compounds for theranostics: Synthesis, photochemical properties and in vitro cytotoxicity

Boron subphthalocyanines bearing a wide range of functional groups were tested as prospective photosensitizers and fluorophores. Synthetic protocols to novel 4-ethoxycarbonylphenoxy-substituted subphthalocyanine and phenoxy-substituted subphthalocyanine boron phenolate were presented. Differential triplet-triplet absorption spectra of subphthalocyanines were registered and triplet state lifetimes (τT = 0.6 ÷ 3.1 ms) were obtained. The results of flash photolysis measurements predicted the good ability of target subphthalocyanines to produce singlet oxygen and it was supported by the measurements of 1O2 quantum yields (ΦΔ = 0.47 ÷ 0.85). At the same time, satisfactory yields of fluorescence (Φf = 0.13 ÷ 0.50) were observed for most of the subphthalocyanines. The fluorescence decay kinetics were studied to determine the fluorescence lifetimes (τf = 0.30 ÷ 3.05 ns) and confirm the regularities obtained for fluorescence yields. Pronounced fluorescent properties allowed investigating the distribution of subphthalocyanines in the endoplasmic reticulum. In addition, the binding constants with human serum albumin were determined. tert-Butyl- and iodo-substituted subphthalocyanines demonstrated remarkable photocytotoxicity in human epidermoid carcinoma cells at micromolar concentrations. At the same time, target boron subphthalocyanines exhibited low dark cytotoxicity. All mentioned above make boron subphthalocyanines promising candidates as highly effective photosensitizers for photodynamic therapy and fluorescent labels for diagnostic.

Insights into the implication of halogen ions on the photoactivity of dissolved black carbon for the degradation of pharmaceutically active compounds

Although dissolved black carbon (DBC) is an important photosensitized substance and plays an irreplaceable role in the photodegradation of organic pollutants in freshwater, the photochemical activity of DBC in certain halogen ion enriched environments, such as estuaries, is unknown. Therefore, a halogen ions riched water environment was simulated in this study to investigate the effects of halogen ions on the photoactivity of DBC for the degradation of carbamazepine and 17β-estradiol as two representative pharmaceutically active compounds (PhACs). The results showed that the quantum yield coefficients of excited triplet state DBC (3DBC*) decreased along with halogen ions as compared to pure water, attributing to the ionic strength (IS) effect of halogen ions that inhibited the charge transfer (CT) of 3DBC* in its high/low-energy states. Nevertheless, no obvious change of singlet oxygen (1O2) quantum yield was observed in the presence of DBC with/without halogen ions. The 3DBC* formation rate (FT), loss rate constant (ks’), and steady-state concentration ([T]ss) with/without halogen ions were measured by a trimethylphenol probe method, suggesting that the elevation of [T]ss in the presence of halogen ions is attributed to the inhibition of ks’ by IS effect. In addition, we observed that the indirect photolysis of carbamazepine and 17β-estradiol were both inhibited by halogen ions. Radical scavenging experiments demonstrated that halogen ions were the dominant competitor to carbamazepine for 3DBC*, resulting in the retardation of indirect photolysis; whereas for 17β-estradiol, the presence of halogen ions inhibited DBC-mediated photodegradation due to the quenching of 3DBC* with halogen ions. These findings are helpful in understanding the photochemistry of DBC in estuaries and high salinity seawater and its effect on the phototransformation of PhACs.

A “donor–acceptor” structured semiconductor polymer for near infrared fluorescence imaging guided photodynamic therapy

Near infrared (NIR) fluorescence imaging guided photodynamic therapy (PDT) is a technique which has been developed in many clinical trials due to its advantage of real-time optical monitoring, specific spatiotemporal selectivity, and minimal invasiveness. For this, photosensitizers with NIR fluorescence emission and high 1O2 generation quantum yield are highly desirable. Herein, we designed and synthesized a “donor–acceptor” (D-A) structured semiconductor polymer (SP), which was then wrapped with an amphiphilic compound (Pluronic[Formula: see text] F127) to prepare water-soluble nanoparticles (F-SP NPs). The obtained F-SP NPs exhibit good water solubility, excellent particle size stability, strong absorbance at deep red region, and strong NIR fluorescent emission characteristics. The maximal mass extinction coefficient and fluorescence quantum yield of these F-SPs were calculated to be 21.7 L/(g[Formula: see text]cm) and 6.5%, respectively. Moreover, the 1O2 quantum yield of 89% for F-SP NPs has been achieved under 635 nm laser irradiation, which is higher than Methylene Blue, Ce6, and PpIX. The outstanding properties of these F-SP NPs originate from their unique D-A molecular characteristic. This work should help guide the design of novel semiconductor polymer for NIR fluorescent imaging guided PDT applications.

Eye-Visible Oxygen Sensing via In-Situ Synthesizing Blue-Emitting Cu(I) Cluster in Red-Emitting COF: Characterization and Performance.

Covalent organic frameworks (COFs) have shown virtues of well-defined and uniform pores with structural diversity, including the shape, size and even chemical nature of pores. These features are excellent for the application of O2 gas optical sensors. In this paper, two oxygen probes based on halogen-bridged Cu cluster were in-situ synthesized in the micropores of COFs, to allow a uniform distribution. The resulting composite samples were characterized in detail to confirm the successful probe loading. The doping level was determined as ~22%. The halogen-bridged Cu clusters showed blue emission peaking at ~440 nm, while COF host showed red emission peaking at 630 nm. These halogen-bridged Cu clusters had long emissive lifetime of ~6.7 μs and high emission quantum yield of 0.30 in pure N2 atmosphere. Given pure O2 atmosphere, lifetime and quantum yield were quenched to 2.5 μs and 0.11, showing oxygen-sensing possibility. A linear oxygen-sensing calibration curve was observed, with sensitivity of 12.25, response time of 13 s and recovery time of 38 s. Sample emission color was changed from blue to red when testing atmosphere was changed from pure N2 to pure O2, which was detectable by eyes.