Extrinsic Point Defects in TiO2-Acetylacetone Charge-Transfer Complex and Their Effects on Optical and Photochemical Properties.

TiO2-based visible-light-sensitive nanomaterials are widely studied for photocatalytic applications under UV-Vis radiation. Among the mechanisms of visible-light sensitization, extrinsic oxygen vacancies have been introduced into TiO2 and charge-transfer complexes (CTCs) have been formed between chelating ligands, such as acetylacetone, and nanocrystalline TiO2 (TiO2-ACAC). However, the influence of extrinsic oxygen vacancies on the photocatalytic performance of TiO2-based CTCs is unknown. In this work, surface/bulk extrinsic oxygen vacancies were introduced into TiO2-ACAC through calcination at 270 °C under static air, argon, and hydrogen atmospheres. TiO2-ACAC CTCs were characterized by X-ray powder diffraction, thermogravimetric analysis, diffuse-reflectance spectroscopy, photoluminescence, electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy techniques. The correlation between EPR-spin trapping and tetracycline (TC) photodegradation, using scavengers, highlighted the key role of the superoxide radical in TC degradation by TiO2-ACAC CTCs under low-power visible-light radiation. The increased extrinsic oxygen vacancies concentration was not beneficial for the photocatalytic performance of TiO2 CTCs, since bulk extrinsic oxygen vacancies additionally act as recombination centers. In fact, the TiO2-ACAC CTC with the lowest extrinsic oxygen vacancies concentration exhibited the highest photocatalytic performance for TC degradation due to an adequate distribution of extrinsic bulk oxygen vacancies, which led to the trapped electrons undergoing repeated hopping, reducing the recombination rates and improving the efficiency in superoxide radicals production. Our findings indicated that TiO2-ACAC CTCs are able to degrade pollutants via interactions with electronic holes and principally superoxide radicals and also, provided fundamental information about the influence of surface/bulk extrinsic oxygen vacancies on the photocatalytic performance, lattice parameters, and optical and photochemical properties of TiO2-based CTCs.

Extrinsic Point Defects in Low-Positive Thermal Expansion Al2W3O12 and Their Effects on Thermal and Optical Properties.

A2M3O12-type ceramics are potentially useful in a variety of applications due to their peculiar thermal and mechanical properties. In addition, their intrinsic coefficients of thermal expansion can be finely tuned through different mechanisms. Despite the great influence of extrinsic point defects on physical properties, only a few reports have dealt with their relationship to thermal expansion and thermal conductivity. Extrinsic oxygen vacancies in orthorhombic Al2W3O12, in different concentrations, were formed through heat treatments in argon or hydrogen atmospheres. X-ray powder diffraction, diffuse reflectance spectroscopy, and Raman and electron paramagnetic resonance spectroscopies were used to study the as-formed vacancies, and X-ray photoelectron spectroscopy was employed to propose a charge compensation mechanism. It was found that the intrinsic coefficient of thermal expansion of orthorhombic Al2W3O12 was severely affected by extrinsic oxygen vacancies. Thermal expansion was decreased up to 40% (from 25 to 400 °C) with respect to the extrinsic-point-defect-free counterpart. Unit-cell volumes of defective orthorhombic Al2W3O12 were larger, while their W-O bonds were weaker, likely leading to higher lattice flexibility and enhanced low-energy transverse acoustic modes. Extrinsic oxygen vacancies could be an additional mechanism for fine-tuning the intrinsic coefficients of thermal expansion in A2M3O12-type ceramics and in other framework structures built through two or threefold linkages.

Initialization and read-out of intrinsic spin defects in a van der Waals crystal at room temperature.

Optically addressable spins in wide-bandgap semiconductors are a promising platform for exploring quantum phenomena. While colour centres in three-dimensional crystals such as diamond and silicon carbide were studied in detail, they were not observed experimentally in two-dimensional (2D) materials. Here, we report spin-dependent processes in the 2D material hexagonal boron nitride (hBN). We identify fluorescence lines associated with a particular defect, the negatively charged boron vacancy ([Formula: see text]), showing a triplet (S = 1) ground state and zero-field splitting of ~3.5 GHz. We establish that this centre exhibits optically detected magnetic resonance at room temperature and demonstrate its spin polarization under optical pumping, which leads to optically induced population inversion of the spin ground state-a prerequisite for coherent spin-manipulation schemes. Our results constitute a step forward in establishing 2D hBN as a prime platform for scalable quantum technologies, with potential for spin-based quantum information and sensing applications.

Photophysical and electrochemical properties of two trans-A2B-corroles: differences between phenyl or pyrenyl groups at the meso-10 position.

The present study reports on the optical and photophysical properties of trans-A2B-corroles possessing pyrenyl units attached at the meso-10-position and compares them with those of model trans-A2B-corroles having phenyl substituents at that position. In contrast to the model meso-substituted corrole, the new pyrenyl-corrole shows slightly red-shifted absorption bands and blue-shifted emission, slightly higher fluorescence quantum yield, and more importantly, it shows better photo-stability under white-light illumination. Theoretical calculations were used to determine the electronic transitions and geometries of the singlet and triplet excited states (TD-DFT and NTO). Moreover, we demonstrate that the pyrenyl-corrole in analogy to previously studied model corroles is able to generate reactive oxygen species (ROS) under visible light using photo-degradation of 1,3-diphenylisobenzofuran (DBPF), a singlet oxygen quencher, and EPR spectroscopy allied with the spin-trapping method is used for identifying singlet oxygen species. The results show that the pyrenyl unit attached at the meso-10-position of the corrole increases the photo-stability and efficiency in ROS generation compared to the phenyl substituent.

The reduction of oxidative stress by nanocomposite Fullerol decreases mucositis severity and reverts leukopenia induced by Irinotecan.

Irinotecan is a useful chemotherapeutic agent for the treatment of several solid tumors. However, this therapy is associated with side effects, including leukopenia and mucositis. Reactive oxygen species (ROS) activate inflammatory pathways and contribute to Irinotecan-induced mucositis. Fullerol is a nanocomposite with anti-oxidant properties that may reduce tissue damage after inflammatory stimuli. In this paper, the effects of Fullerol and mechanisms of protection were investigated in a model of Irinotecan-induced mucositis. Mucositis was induced by an injection of Irinotecan per 4 days in C57BL/6. Fullerol or a vehicle was injected every 12h. On day 7, the intestines were removed to evaluate histological changes, leukocyte influx, and the production of cytokines and ROS. Irinotecan therapy resulted in weight loss, an increased clinical score and intestinal injury. Treatment with Fullerol attenuated weight loss, decreased clinical score and intestinal damage. Irinotecan also induced increased ROS production in enterocytes, oxidative stress, IL-1ß production, neutrophil and eosinophil influx in the ileum. Fullerol treatment decreased production of ROS in the enterocytes, oxidative stress, IL-1ß production, neutrophil and eosinophil influx in the ileum. Irinotecan therapy also induced leukopenia in an ROS-dependent manner because leukopenia reverted in WT mice treated with Fullerol or Apocynin or in Gp91phox(-/-) mice. Mice treated with Irinotecan presented less melanoma tumor growth compared to the control group. Fullerol does not interfere in the anti-tumor action of Irinotecan. Fullerol has a great pharmacology potential to decreases the severity of mucositis and of leukopenia during chemotherapy treatment.

Unravelling the mechanisms of reactive oxygen species formation in nanohybrid systems of porphyrins and enriched (6,5) single-walled carbon nanotubes for photosensitization.

Nanohybrids of enriched (6,5) single-walled semiconducting carbon nanotubes (E-SWCNTs) and porphyrin can be used synergistically as photodynamic therapy (PDT) agents. The efficiency of different porphyrins within the nanohybrids was investigated and compared with results obtained from porphyrins in previous studies. Reactive oxygen species singlet oxygen (1)O2 and for the first time hydroxyl radical ˙OH generation by the nanohybrids under illumination were detected by electron paramagnetic resonance using spin trapping molecules TEMP and PBN. Based on the analysis, we improve the modelling of charge transport within the nanohybrids, which is also detected by Raman scattering. It is shown that the 5,10,15,20-tetrakis(4-trimethylammoniumphenyl)porphyrin [H2TTMAPP(OTs)4] and E-SWCNT form very efficient nanohybrids for PDT applications in the visible spectral range.

Exploring electronic, structural and dynamics parameters of phenylbenzothiazole complexes with Mn2+, Cu2+ and Zn2+ for designing new magnetic resonance imaging (MRI) probes: congruence between computation and spectroscopic data.

Cancer is one of the leading causes of human death worldwide, being one of the most serious problems faced by mankind. For the diagnosis, Magnetic Resonance Imaging (MRI), through effective contrast agents (Cas), has greatly helped in the diagnosis at the initial stages. However, it is necessary to include new compounds more effective and selective for cancer diagnosis. The complexes with Mn2+, Cu2+ and Zn2+ have received great attention due to their applications as CAs for MRI. Those materials can shorten the T2 and T2* transverse relaxation times. Thus, the representative structures for hyperfine coupling constants (HFCCs) were selected from docking results by frequency of occupancy calculations. From the Multivariate Analysis to obtain the PCA graphs in the choice of a representative conformations. it is possible to notice that the variable energy does not present a high correlation with the other variables, and structural factors, such as the spatial positions of the metal atoms, seem to be important in the reactivity of the complexes. Structural factors, such as the spatial positions of the metal atoms, seem to be important in the reactivity of the complexes. Theoretical findings suggest that the compounds are capable of increasing the Aiso values of the water molecules, but the complex [Zn(H2O)(NNO)] shows a greater influence, being more sensitive to the Electron paramagnetic resonance parameters than the complexes [CuCl(H2O)NNO] and [MnCl2(H2O)(NNO)] with the explicit solvent and the enzyme. MRI contrast agents have generated various problems due to their high toxicity. In this perspective, this compound may be a promising alternative for transporting the CAs into diseased tissue.Communicated by Ramaswamy H. Sarma.

Photophysical, photobiological, and biomolecule-binding properties of new tri-cationic meso-tri(2-thienyl)corroles with Pt(II) and Pd(II) polypyridyl derivatives.

We report the synthesis and characterization of new tri-cationic corrole derivatives, containing Pt(II) or Pd(II) complexes attached at the peripheral position of thienyl moieties. Corrole derivatives were characterized through microanalysis, electrochemical, spectrometry and spectroscopy analysis. Singlet and triplet excited-states are investigated by photophysical/theoretical calculation methods and photobiological parameters were also evaluated spectroscopic techniques (UV-Vis and EPR). Also, the binding capacity of each corrole derivative with nucleic acids (DNA) and human serum albumin (HSA) was determined by UV-Vis, steady-state, and time-resolved fluorescence spectroscopy, combined with molecular docking analysis. Moreover, the new corroles containing peripheral complexes improve their interactions with biomacromolecules, generate reactive oxygen species under light source irradiation studied and has potential for application in photodynamic therapeutic processes.

Nanozymes with Peroxidase-like Activity for Ferroptosis-Driven Biocatalytic Nanotherapeutics of Glioblastoma Cancer: 2D and 3D Spheroids Models.

Glioblastoma (GBM) is the most common primary brain cancer in adults. Despite the remarkable advancements in recent years in the realm of cancer diagnosis and therapy, regrettably, GBM remains the most lethal form of brain cancer. In this view, the fascinating area of nanotechnology has emerged as an innovative strategy for developing novel nanomaterials for cancer nanomedicine, such as artificial enzymes, termed nanozymes, with intrinsic enzyme-like activities. Therefore, this study reports for the first time the design, synthesis, and extensive characterization of innovative colloidal nanostructures made of cobalt-doped iron oxide nanoparticles chemically stabilized by a carboxymethylcellulose capping ligand (i.e., Co-MION), creating a peroxidase-like (POD) nanozyme for biocatalytically killing GBM cancer cells. These nanoconjugates were produced using a strictly green aqueous process under mild conditions to create non-toxic bioengineered nanotherapeutics against GBM cells. The nanozyme (Co-MION) showed a magnetite inorganic crystalline core with a uniform spherical morphology (diameter, 2R = 6-7 nm) stabilized by the CMC biopolymer, producing a hydrodynamic diameter (HD) of 41-52 nm and a negatively charged surface (ZP~-50 mV). Thus, we created supramolecular water-dispersible colloidal nanostructures composed of an inorganic core (Cox-MION) and a surrounding biopolymer shell (CMC). The nanozymes confirmed the cytotoxicity evaluated by an MTT bioassay using a 2D culture in vitro of U87 brain cancer cells, which was concentration-dependent and boosted by increasing the cobalt-doping content in the nanosystems. Additionally, the results confirmed that the lethality of U87 brain cancer cells was predominantly caused by the production of toxic cell-damaging reactive oxygen species (ROS) through the in situ generation of hydroxyl radicals (·OH) by the peroxidase-like activity displayed by nanozymes. Thus, the nanozymes induced apoptosis (i.e., programmed cell death) and ferroptosis (i.e., lipid peroxidation) pathways by intracellular biocatalytic enzyme-like activity. More importantly, based on the 3D spheroids model, these nanozymes inhibited tumor growth and remarkably reduced the malignant tumor volume after the nanotherapeutic treatment (ΔV~40%). The kinetics of the anticancer activity of these novel nanotherapeutic agents decreased with the time of incubation of the GBM 3D models, indicating a similar trend commonly observed in tumor microenvironments (TMEs). Furthermore, the results demonstrated that the 2D in vitro model overestimated the relative efficiency of the anticancer agents (i.e., nanozymes and the DOX drug) compared to the 3D spheroid models. These findings are notable as they evidenced that the 3D spheroid model resembles more precisely the TME of "real" brain cancer tumors in patients than 2D cell cultures. Thus, based on our groundwork, 3D tumor spheroid models might be able to offer transitional systems between conventional 2D cell cultures and complex biological in vivo models for evaluating anticancer agents more precisely. These nanotherapeutics offer a wide avenue of opportunities to develop innovative nanomedicines for fighting against cancerous tumors and reducing the frequency of severe side effects in conventionally applied chemotherapy-based treatments.

Selective methane photooxidation into methanol under mild conditions promoted by highly dispersed Cu atoms on crystalline carbon nitrides.

Here we report a photocatalytic system based on crystalline carbon nitrides (PHI) and highly dispersed transition metals (Fe, Co and Cu) for controlled methane photooxidation to methanol under mild conditions. The Cu-PHI catalyst showed a remarkable methanol production (2900 µmol g-1) in 4 hours, with a turnover number of 51 moles of oxygenated liquid product per mole of Cu. To date, this result is the highest value for methane oxidation under mild conditions (1 bar, 25 °C).

Post-synthetic modification of aluminum trimesate and copper trimesate with TiO2 nanoparticles for photocatalytic applications.

Organic pollutants have been a significant source of concern in recent years due to their facile dissemination and harmful effects. In this work, two different metal-organic frameworks (MOFs) were initially prepared by hydrothermal treatment, namely aluminum trimesate (MIL-100(Al)) and copper trimesate (HKUST-1). These materials were subsequently submitted to a post-synthetic modification step to grow titania nanoparticles on their surface. Anatase nanoparticles with sizes around 5 nm were successfully anchored on MIL-100(Al), and the concentration of TiO2 in this sample was about 68 wt.%. This is the first time that this composite (TiO2@MIL-100(Al)) is reported in the literature. It showed an improved photocatalytic activity, removing 90% of methylene blue (k app = 1.29 h-1), 55% of sodium diclofenac (k app = 0.21 h-1), and 62% of ibuprofen (k app = 0.37 h-1) after four hours of illumination with UV-A light. A significant concentration (14 µM) of reactive oxygen species (ROS) was detected for this composite. HKUST-1 showed a structural collapse during its post-synthetic modification, leading to a non-porous material and providing fewer sites for the heterogeneous nucleation of titania. This behavior led to a low concentration of rutile nanoparticles on HKUST-1 (9 wt.%). However, the obtained composite (TiO2@HKUST) also showed an improved photoactivity compared to HKUST-1, increasing the photodegradation rates evaluated for methylene blue (0.05 h-1 vs. 0.29 h-1), sodium diclofenac (negligible vs. 0.03 h-1), and ibuprofen (0.01 h-1 vs. 0.02 h-1). This work brings new insights concerning the preparation of photocatalysts by growing semiconductor nanoparticles on trimesate-based MOFs.

Hybrid polymer aerogels containing porphyrins as catalysts for efficient photodegradation of pharmaceuticals in water.

Polymer aerogels of poly(acrylic acid)/poly(vinyl alcohol) (labeled as CPA) were prepared and tested as support materials for different cationic porphyrin organocatalysts (denoted as TMPyP, TMPyPZn, or TMPyPMn). The hybrid aerogels were characterized by various techniques, while their catalytic activity was investigated towards the photodegradation of amoxicillin (AMX), caffeine (CAF), and naproxen (NPX) under artificial visible light. Photodegradation experiments revealed that the CPA-TMPyPMn aerogel shows superior catalytic potential when compared to the others aerogels or the "free" TMPyPMn porphyrin. All pharmaceuticals were quickly degraded (before 60 min) and high COD removal rates (greater than95%) were achieved at pH 7.0 and room temperature. The CG-MS data confirm the complete degradation of all tested pharmaceuticals catalyzed by CPA-TMPyPMn. Recycling experiments revealed that this hybrid aerogel keeps its photocatalytic efficiency for at least 15 reuse runs. In short, this original photocatalytic system is promising to mediate the removal of pharmaceutical contaminants from the aqueous medium.

Photophysical, photooxidation, and biomolecule-interaction of meso-tetra(thienyl)porphyrins containing peripheral Pt(II) and Pd(II) complexes. Insights for photodynamic therapy applications.

We report the synthesis and characterization of two novel tetra-cationic porphyrins, containing Pt(II) or Pd(II) polypyridyl complexes attached at the peripheral position of N4-macrocycle. Compounds were characterized through elemental analysis, molar conductivity, cyclic voltammetry, and spectroscopy analysis. Photophysical and photobiological parameters were also evaluated. Also, the binding capacity of each porphyrin with human serum albumin (HSA) was determined by UV-Vis, steady-state, and time-resolved fluorescence spectroscopy, combined with molecular docking calculations. The results suggest that the interaction of these compounds is spontaneous, weak to moderate, and probably occurs at site III (subdomain IB) by non-covalent forces, including van der Waals and H-bonding. Moreover, porphyrins containing peripheral complexes improve their interactions with biomolecules, show good photostability, generate reactive oxygen species under white light studied by electron paramagnetic resonance (EPR) analysis, and promote photo-damage of HSA.

Detection of singlet oxygen by EPR: The instability of the nitroxyl radicals.

The use of spin traps and redox probes coupled with electron paramagnetic resonance (EPR) is a method frequently applied in the evaluation of the efficiency of photosensitizers and photocatalysts in phototherapeutic and photocatalytic processes that involve reactive oxygen species. In this way, the method helps to clarify the mechanism behind photo-induced reactions. Hydroxy-TEMP is a very specific redox probe for selectively identifying and quantifying singlet oxygen (1O2). In this work, the kinetics of radical generated by the oxidation products of the Hydroxy-TEMP redox probe was analyzed from EPR spectra in aqueous solutions of several water-soluble porphyrins ([H2T4MPyP](OTs)4, Na4[H2T4SPP], [H2T2MPyP](OTs)4, [ZnT4MyPyP](OTs)4, [MnT4MyPyP](OTs)5, H2T4CPP, and [H2T4TriMAPP](OTs)4) under white light illumination. Different factors such as the concentration of the redox probe, pH of the medium, and photostability of the porphyrins were evaluated. A systematic study was carried out to reveal the factors associated with stable radical degradation (TEMPOL) by illumination in the visible spectral region in systems containing photosensitizer (porphyrin) and redox probe (Hydroxy-TEMP). With the aid of EPR and gas chromatography coupled with mass spectroscopy (GC-MS) techniques, the mechanism of the radical degradation and the photobleaching of porphyrins were investigated. After successive interactions with the porphyrin in its excited state, in alkaline aqueous solution (pH > 10), the free radical TEMPOL is transformed into TEMPONE until the final diamagnetic product Phorone. A protocol was elaborated to identify and quantify the generation of 1O2 by Hydroxy-TEMP reliably, to avoid possible errors in the interpretation of efficiency of photosensitizers.

Tunable magnetothermal properties of cobalt-doped magnetite-carboxymethylcellulose ferrofluids: smart nanoplatforms for potential magnetic hyperthermia applications in cancer therapy.

Magnetite nanoparticles are one of the most promising ferrofluids for hyperthermia applications due to the combination of unique physicochemical and magnetic properties. In this study, we designed and produced superparamagnetic ferrofluids composed of magnetite (Fe3O4, MION) and cobalt-doped magnetite (Co x -MION, x = 3, 5, and 10% mol of cobalt) nanoconjugates through an eco-friendly aqueous method using carboxymethylcellulose (CMC) as the biocompatible macromolecular ligand. The effect of the gradual increase of cobalt content in Fe3O4 nanocolloids was investigated in-depth using XRD, XRF, XPS, FTIR, DLS, zeta potential, EMR, and VSM analyses. Additionally, the cytotoxicity of these nanoconjugates and their ability to cause cancer cell death through heat induction were evaluated by MTT assays in vitro. The results demonstrated that the progressive substitution of Co in the magnetite host material significantly affected the magnetic anisotropy properties of the ferrofluids. Therefore, Co-doped ferrite (Co x Fe(3-x)O4) nanoconjugates enhanced the cell-killing activities in magnetic hyperthermia experiments under alternating magnetic field performed with human brain cancer cells (U87). On the other hand, the Co-doping process retained the pristine inverse spinel crystalline structure of MIONs, and it has not significantly altered the average nanoparticle size (ca.∼7.1 ± 1.6 nm). Thus, the incorporation of cobalt into magnetite-polymer nanostructures may constitute a smart strategy for tuning their magnetothermal capability towards cancer therapy by heat generation.

Peroxidation and photo-peroxidation of pantoprazole in aqueous solution using silver molybdate as catalyst.

In this study, silver molybdate was used as a catalyst in different oxidation processes to degrade pantoprazole (PAN) from aqueous suspension. The catalyst was synthesized using a controlled precipitation method and characterized by XRD, FTIR spectroscopy, BET analysis, Zeta potential, FEG-SEM/EDS, DRS and EPR. The α- and ß-phases of Ag2MoO4 were identified as crystalline structure of the butterfly-shaped particles. The metastable α-phase could be completely converted into ß-Ag2MoO4 by thermal treatment at 300 °C. The band gap energy of ß-Ag2MoO4 (Eg = 3.25 eV) is slightly higher than for as-prepared catalyst (α-Ag2MoO4 + ß-Ag2MoO4) (Eg = 3.09 eV), suggesting that as-prepared catalyst should be active under visible light. PAN is sensible to UV light irradiation, and the addition of H2O2 as electron acceptor enhanced the mineralization rate. In the catalytic UV-based reactions, high PAN oxidation efficiencies were obtained (>85%) but with low mineralization (32-64%). Catalytic peroxidation and photo-catalytic peroxidation under visible light showed the highest PAN oxidation efficiency, leading to its almost complete mineralization (>95%), even under dark conditions (98% in 120 min). Several degradation byproducts were identified and three mechanistic routes of PAN decomposition were proposed. The identified byproducts are less toxic than the parent compound. EPR coupled with the spin trapping method identified •OH radicals as the main ROS species in both photocatalytic and catalytic peroxidation reactions. Ag2MoO4 showed to be a promising catalyst to promote the decomposition of hydrogen peroxide into ROS.1.

Amoxicillin photodegradation under visible light catalyzed by metal-free carbon nitride: An investigation of the influence of the structural defects.

Herein, the structural defects of metal-free polymeric carbon nitrides were controlled by making use of different precursors in their syntheses, i.e. melamine (CN-M) and thiourea (CN-T), as well as a 1:1 mixture of them (CN-1M:1 T). By controlling the structural defects, the electronic, morphological and chemical properties were modified. Additionally, the activities of synthesized PCNs were evaluated for amoxicillin photodegradation under visible light irradiation (16 mW cm-2). The results of photocatalytic tests showed that CN-T material has better efficiency (100 % removal within 48 h), which is directly related to the greater number of defects present in its structure with consequent improvement of electron-hole pairs separation efficiency. The CN-T material showed excellent stability with only 13 % decrease in its photocatalytic activity after the third cycle. A mechanism for amoxicillin degradation by CN-T was proposed based on the ESI-MS and the in situ EPR allied with spin trapping method investigations.

Anti-inflammatory and antioxidant effects of the nanocomposite Fullerol decrease the severity of intestinal inflammation induced by gut ischemia and reperfusion.

Intestinal ischemia is a vascular emergency that arises when blood flow to the intestine is compromised. Reperfusion is necessary to restore intestinal function but might lead to local and systemic inflammatory responses and bacterial translocation, with consequent multiple organ dysfunction syndrome (MODS). During reperfusion occurs production of reactive oxygen species. These species contribute to intestinal injury through direct toxicity or activation of inflammatory pathways. Fullerol is a nanacomposite which has been shown to act as reactive oxygen species and reactive nitrogen species (RNS) scavengers. Thus, our aim was to evaluate whether Fullerol confer anti-inflammatory activity during intestinal ischemia and reperfusion (IIR). Intestinal ischemia was induced by total occlusion of the superior mesenteric artery. Groups were treated with vehicle or Fullerol 10 min before reperfusion. Mice were euthanized after 6 h of reperfusion, and small intestines were collected for evaluation of plasma extravasation, leukocyte influx, cytokine production and histological damage. Bacterial translocation to the peritoneal cavity and reactive oxygen and nitrogen species production by lamina propria cells were also evaluated. Our results showed that treatment with Fullerol inhibited bacterial translocation to the peritoneal cavity, delayed and decreased the lethality rates and diminished neutrophil influx and intestinal injury induced by IIR. Reduced severity of reperfusion injury in Fullerol-treated mice was associated with blunted reactive oxygen and nitrogen species production in leukocytes isolated from gut lamina propria and decreased production of pro-inflammatory mediators. Thus, the present study shows that Fullerol is a potential therapy to treat inflammatory bowel disorders associated with bacterial translocation, such as IIR.

Photophysical, photodynamical, redox properties and BSA interactions of novel isomeric tetracationic peripheral palladium(II)-bipyridyl porphyrins.

New isomeric tetra-cationic porphyrins containing peripheral [Pd(bpy)Cl]+ units attached to pyridyl substituents were synthesized and fully characterized. The porphyrins present an intense Soret band located in the blue spectral region and an additional four weaker red-shifted Q bands in the visible spectral region (about 500-700 nm). The obtained Strickler-Berg parameters indicate fully spin and symmetry allowed transitions for all the observed absorption bands. Both porphyrins present two fluorescence emission bands, an intense one located around 650 nm and an additional weak red-shifted emission at ∼710 nm. Fluorescence decay time profiles were obtained showing bi-exponential decay. The interaction of the porphyrins with bovine serum albumin (BSA) was studied in detail by a fluorescence quenching method and molecular docking analysis. In addition, the photodynamical activity of the porphyrins in the photooxidation of BSA was determined and compared with the light-induced formation of reactive oxygen species (ROS) by electron paramagnetic resonance (EPR) allied with the spin trapping method. The results show that the Pd(ii)-bypyridyl tetra-cationic porphyrins are promising candidates for the photooxidation of biological substrates used in photodynamic therapy (PDT).

Supramolecular magnetonanohybrids for multimodal targeted therapy of triple-negative breast cancer cells.

Despite the undeniable advances in recent decades, cancer remains one of the deadliest diseases of the current millennium, where the triple-negative breast cancer (TNBC) is very aggressive, extremely metastatic, and resistant to conventional chemotherapy. The nanotheranostic approach focusing on targeting membrane receptors often expressed at abnormal levels by cancer cells can be a strategic weapon for fighting malignant tumors. Herein, we introduced a novel "all-in-one nanosoldier" made of colloidal hybrid nanostructures, which were designed for simultaneously targeting, imaging, and killing TNBC cells. These nanohybrids comprised four distinct components: (a) superparamagnetic iron oxide nanoparticles, as bi-functional nanomaterials for inducing ferroptosis via inorganic nanozyme-mediated catalysis and magnetotherapy by hyperthermia treatment; (b) carboxymethyl cellulose biopolymer, as a water-soluble capping macromolecule; (c) folic acid, as the membranotopic vector for targeting folate receptors; (d) and doxorubicin (DOX) drug for chemotherapy. The results demonstrated that this novel strategy was highly effective for targeting and killing TNBC cells in vitro, expressing high levels of folate membrane-receptors. The results evidenced that three integrated mechanisms triggered the deaths of the cancer cells in vitro: (a) ferroptosis, by magnetite nanoparticles inducing a Fenton-like reaction; (b) magneto-hyperthermia effect by generating heat under an alternate magnetic field; and (c) chemotherapy, through the DOX intracellular release causing DNA dysfunction. This "all-in-one nanosoldier" strategy offers a vast realm of prospective alternatives for attacking cancer cells, combining multimodal therapy and the delivery of therapeutic agents to diseased sites and preserving healthy cells, which is one of the most critical clinical challenges faced in fighting drug-resistant breast cancers.