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1.
Inorg Chem ; 58(16): 10778-10790, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31386351

RESUMO

A new family of cyclometalated ruthenium(II) complexes [Ru(N^N)2(C^N)]+ derived from the π-extended benzo[h]imidazo[4,5-f]quinolone ligand appended with thienyl groups (n = 1-4, compounds 1-4) was prepared and its members were characterized for their chemical, photophysical, and photobiological properties. The lipophilicities of 1-4, determined as octanol-water partition coefficients (log Po/w), were positive and increased with the number of thienyl units. The absorption and emission bands of the C^N compounds were red-shifted by up to 200 nm relative to the analogous Ru(II) diimine systems. All of the complexes exhibited dual emission with the intraligand fluorescence (1IL, C^N-based) shifting to lower energies with increasing n and the metal-to-ligand charge transfer phosphorescence (3MLCT, N^N-based) remaining unchanged. Compounds 1-3 exhibited excited state absorption (ESA) profiles consistent with lowest-lying 3MLCT states when probed by nanosecond transient absorption (TA) spectroscopy with 532 nm excitation and had contributions from 1IL(C^N) states with 355 nm excitation. These assignments were supported by the lifetimes observed (<10 ns for the 1IL states and around 20 ns for the 3MLCT states) as well as a noticeable ESA for 3 with 355 nm excitation that did not occur with 532 nm excitation. Compound 4 was the only member of the family with two 3MLCT emissive lifetimes (15, 110 ns), and the TA spectra collected with both 355 and 532 nm excitation was assigned to the 3IL state, which was corroborated by its 4-6 µs lifetime. The ESA for 4 had a rise time of approximately 10 ns and an initial decay of 110 ns, which suggests a possible 3MLCT-3IL excited state equilibrium that results in delayed emission from the 3MLCT state. Compound 4 was nontoxic toward human skin melanoma cells (SKMEL28) in the dark (EC50 = >300 µM); 1-3 were cytotoxic and yielded EC50 values between 1 and 20 µM. The photocytotoxicites with visible light ranged from 87 nM with a phototherapeutic index (PI) of 13 for 1 to approximately 1 µM (PI = >267) for 4. With red light, EC50 values varied from 270 nM (PI = 21) for 3 to 12 µM for 4 (PI = >25). The larger PIs for 4, especially with visible light, were attributed to the much lower dark cytotoxicity for this compound. Because the dark cytotoxicity contributes substantially to the observed photocytotoxicity for 1-3, it was not possible to assess whether the 3IL state of 4 led to a much more potent phototoxic mechanism in the absence of dark toxicity. There was no stark contrast in cellular uptake and accumulation by laser scanning confocal and differential interference contrast microscopy to explain the large differences in dark toxicities between 1-3 and 4. Nevertheless, the study highlights a new family of Ru(II) C^N complexes where π-conjugation beyond a certain point results in low dark cytotoxicity with high photocytotoxicity, opposing the notion that cyclometalated Ru(II) systems are too toxic to be phototherapeutic agents.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Quinolonas/farmacologia , Rutênio/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ligantes , Luz , Estrutura Molecular , Processos Fotoquímicos , Fotoquimioterapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Quinolonas/química , Rutênio/química
2.
Phys Chem Chem Phys ; 21(32): 17971-17977, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31384846

RESUMO

The electron-hole injection from a family of spiropyran photoswitches into A/T-duplex DNA has been investigated at the molecular level for the first time. Multiscale computations coupled with automatized quantitative wavefunction analysis reveal a pronounced directionality and regioselectivity towards the template strand of the duplex DNA. Our findings suggest that this directional and regioselective photoinduced electron-hole transfer could thus be exploited to tailor the charge transport processes in DNA in specific applications.


Assuntos
Benzopiranos/química , DNA/química , Indóis/química , Substâncias Intercalantes/química , Nitrocompostos/química , Transporte de Elétrons , Luz , Modelos Moleculares , Conformação de Ácido Nucleico , Oxirredução , Processos Fotoquímicos , Prótons , Termodinâmica
3.
Chem Commun (Camb) ; 55(69): 10192-10213, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31411602

RESUMO

Light is unsurpassed in its ability to modulate biological interactions. Since their discovery, chemists have been fascinated by photosensitive molecules capable of switching between isomeric forms, known as photoswitches. Photoswitchable peptides have been recognized for many years; however, their functional implementation in biological systems has only recently been achieved. Peptides are now acknowledged as excellent protein-protein interaction modulators and have been important in the emergence of photopharmacology. In this review, we briefly explain the different classes of photoswitches and summarize structural studies when they are incorporated into peptides. Importantly, we provide a detailed overview of the rapidly increasing number of examples, where biological modulation is driven by the structural changes. Furthermore, we discuss some of the remaining challenges faced in this field. These exciting proof-of-principle studies highlight the tremendous potential of photocontrollable peptides as optochemical tools for chemical biology and biomedicine.


Assuntos
Descoberta de Drogas , Peptídeos/química , Peptídeos/farmacologia , Sequência de Aminoácidos , Animais , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Morte Celular/efeitos dos fármacos , Descoberta de Drogas/métodos , Humanos , Isomerismo , Luz , Modelos Moleculares , Ácidos Nucleicos/metabolismo , Peptídeos/metabolismo , Processos Fotoquímicos , Mapas de Interação de Proteínas/efeitos dos fármacos
4.
Chem Commun (Camb) ; 55(70): 10380-10383, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31397448

RESUMO

A strategy for the photoelectrochemical detection of miRNA with ultra-low background noise was developed using tungsten diselenide-cysteine-dopamine (WSe2/Cys/DA) as a nanoprobe coupled with mismatched catalytic hairpin assembly target recycling. A superior detection limit of 3.3 aM toward miRNA-221 was achieved.


Assuntos
Cisteína/química , Dopamina/química , Técnicas Eletroquímicas/métodos , MicroRNAs/análise , Sondas Moleculares/química , Nanoestruturas , Processos Fotoquímicos , Selênio/química , Tungstênio/química , Técnicas Biossensoriais , Catálise , Humanos , Limite de Detecção , MicroRNAs/sangue , Estudo de Prova de Conceito
5.
Chem Commun (Camb) ; 55(62): 9108-9111, 2019 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-31298230

RESUMO

Inhibition of myostatin is an attractive treatment for muscular dystrophy and other amyotrophic diseases. A myostatin-binding peptide was functionalized by equipped with an on/off switchable photo-oxygenation catalyst. This peptide induces a selective oxygenation of myostatin under near-infrared light, resulting in inactivation of myostatin. This peptide shows several orders of magnitude greater inhibitory effect than the original peptide.


Assuntos
Miostatina/efeitos dos fármacos , Miostatina/efeitos da radiação , Oxigênio/química , Oxigênio/efeitos da radiação , Peptídeos/farmacologia , Processos Fotoquímicos/efeitos da radiação , Catálise/efeitos dos fármacos , Catálise/efeitos da radiação , Humanos , Raios Infravermelhos , Modelos Moleculares , Estrutura Molecular , Miostatina/metabolismo , Peptídeos/química
6.
J Chem Phys ; 151(1): 014104, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31272170

RESUMO

Many important open quantum systems, such as light harvesting systems irradiated with natural incoherent light, present challenging computational problems. Specifically, such systems are characterized by multiple time scales over many orders of magnitude. We describe and apply an efficient approach to determine rates and dynamics in such systems. As an example, we present a theoretical and computational analysis of retinal isomerization under incoherent solar excitation using a minimal retinal model. Solar- and bath-induced Fano coherences are shown to have a small but non-negligible effect on the reaction dynamics, and the effect of Fano coherences on the reaction rate is shown to depend strongly upon the form and strength of the system-bath coupling. Using the isomerization probability to obtain the time-dependent cellular hyperpolarization, we show that the effect of coherence on hyperpolarization dynamics is small compared to the effect of natural variations in the solar intensity.


Assuntos
Luz , Teoria Quântica , Retina/fisiologia , Isomerismo , Cinética , Processos Fotoquímicos
8.
Chem Commun (Camb) ; 55(66): 9769-9772, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31329196

RESUMO

We report the accelerated photoisomerization of amphiphilic lophine dimers based on the inner environments of molecular assemblies and rapid control of the interfacial properties of aqueous solution with photoirradiation. This novel photoisomerization system enables on-demand controlled release of drugs, perfumes, and other active compounds.


Assuntos
Imidazóis/química , Dimerização , Sistemas de Liberação de Medicamentos , Isomerismo , Processos Fotoquímicos , Espectrofotometria Ultravioleta , Tensão Superficial
9.
J Chem Theory Comput ; 15(8): 4526-4534, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31314524

RESUMO

We investigate the photoinduced ultrafast charge migration phenomenon in the glycine molecule using a recently proposed nonequilibrium Green's functions (NEGF) approach. We first consider the dynamics resulting from the sudden removal of an electron in the valence shells, finding a satisfactory agreement with available data. Then we explicitly simulate the laser-induced photoionization process and study the evolution of the system after the pulse. We disentangle polarization and correlation effects in the electron dynamics and assign the main frequencies to specific elements of the reduced one-particle density matrix. We show that electronic correlations renormalize the bare frequencies, redistribute the spectral weights, and give rise to new spectral features.


Assuntos
Elétrons , Glicina/química , Íons/química , Lasers , Modelos Moleculares , Processos Fotoquímicos
10.
Chem Commun (Camb) ; 55(56): 8076-8078, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31225560

RESUMO

We developed a novel "signal-on" photoelectrochemical (PEC) aptasensor with a near-zero background signal by using AgVO3 as a single photoactive material for the sensitive detection of vascular endothelial growth factor (VEGF165).


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas/métodos , Óxidos/química , Processos Fotoquímicos , Prata/química , Compostos de Vanádio/química , Fator A de Crescimento do Endotélio Vascular/análise , Humanos , Limite de Detecção
11.
Phys Chem Chem Phys ; 21(24): 12818-12825, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31165817

RESUMO

Optimizing the heterojunction structure of semiconductor photocatalysts is vital for utilizing their abilities in organic matter degradation. Herein, a novel fabrication of a Z-scheme system with inverse opal g-C3N4 and BiOBr via a reflux process is developed. On the one hand, the unique inverse opal construction, formed by using silica (SiO2) photonic crystals as the template, not only provides a larger surface area for adsorption of antibiotics but also improves the separation and transfer efficiency of photogenerated electrons and holes as well as visible light absorption ability. On the other hand, by imitating natural photosynthesis, the artificial Z-scheme system with an inverse opal g-C3N4-BiOBr nanojunction further promotes the separation of photogenerated electrons and holes. The obtained IO CN/BiOBr catalyst exhibits superior photocatalytic performance for antibiotics degradation under visible light irradiation. In a typical test, almost complete degradation of levofloxacin (LVX) (10 mg L-1) could be achieved within 50 min due to the proper bandgap match between inverse opal g-C3N4 and BiOBr as well as enhanced surface area and light absorption. The present work provides an alternative strategy for construction of novel visible-light-driven Z-scheme photocatalysts and offers some new insights into the methods of waste water treatment.


Assuntos
Antibacterianos/química , Bismuto/química , Levofloxacino/química , Poluentes Químicos da Água/química , Adsorção , Catálise , Luz , Processos Fotoquímicos , Dióxido de Silício/química , Propriedades de Superfície
12.
J Environ Sci (China) ; 83: 183-194, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221381

RESUMO

The photocatalytic activity of Fe-doped TiO2 nanoparticles is significantly increased by an acid-treatment process. The photocatalyst nanoparticles were prepared using sol-gel method with 0.5 mol% ratio of Fe:Ti in acidic pH of 3. The nanoparticles were structurally characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). It was observed that the photocatalytic activity suffered from an iron oxide contaminating layer deposited on the surface of the nanoparticles. This contamination layer was removed using an HCl acid-treatment process. The photocatalytic activity using 500 mg/L of Fe0.5-TiO2 in a 10 mg/L of phenol solution increased significantly from 33% to 57% (about 73% increase in the performance), within 90 min of reaction time under visible light irradiation. This significant improvement was achieved by removing the iron oxide contamination layer from the surface of the nanoparticles and adjusting pH to mild acidic and basic pHs.


Assuntos
Modelos Químicos , Fenol/química , Processos Fotoquímicos , Catálise , Luz , Fenóis , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Titânio/química , Difração de Raios X
13.
Environ Pollut ; 249: 1106-1114, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31146316

RESUMO

Graphene oxide (GO) has been demonstrated to be key component for diverse applications. However, their potential environmental reactivity, fate and risk have not been fully evaluated to date. In this study, we investigated the photochemical reactivity of four types of GO with different oxidation degrees in aqueous environment, and their related toxicity to two bacterial models Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was further compared. After UV-irradiation, a large amount of oxygen functional groups on GO were reduced and the electronic conjugations within GO were restored as indicated by UV-visible absorption spectra, X-ray photoelectron spectroscopy and Raman spectroscopy analysis. Moreover, the higher the oxidation degree of the pristine GO was, the more obvious of the photo-transformation changes were. In order to further reveal the photochemical reactivity mechanisms, the reactive oxygen species (ROS) generation of GO was monitored. The quantity of ROS including singlet oxygen (1O2), superoxide anions (O2·-), and hydroxyl radicals (·OH) increased with increasing oxidation degree of GO, which was in accordance with the previous characterization results. Scanning electron microscopy and cell growth analyses of E. coli and S. aureus showed that the photochemical transformation enhanced the toxicity of GO, which might be due to an increase in functional group density. The higher conductivity of the reduced graphene oxide (RGO) was responsible for its stronger toxicity than GO through membrane damage and oxidative stress to bacteria. This study revealed that the oxidation degrees play important roles in photochemical transformation and the resulting toxicity of GO, which is helpful for understanding the environmental behaviors and risks of GO in aquatic environments.


Assuntos
Escherichia coli/efeitos dos fármacos , Grafite/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Escherichia coli/crescimento & desenvolvimento , Grafite/efeitos da radiação , Oxirredução , Processos Fotoquímicos , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/crescimento & desenvolvimento , Poluentes Químicos da Água/efeitos da radiação
14.
Chemosphere ; 232: 140-151, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31152898

RESUMO

Catalytic oxidative degradation of acetaminophen (ACT) was evaluated using magnetic mesoporous carbon (MNPs@C) coupled with UV light and peroxymonosulfate (PMS). The performance of hybrid system (i.e., MNPs@C/UV/PMS) was assessed as a function of some operational factors (e.g., reaction time and different concentrations of catalyst, PMS and ACT) in a batch system. MNPs@C represented a high magnetic response and was easily recovered from aqueous solution via an external magnet. A significant synergistic effect was observed among the applied techniques in MNPs@C/UV/PMS system for ACT degradation. After 40 min reaction, the removal efficiencies of 97.4 and 63.5% were obtained for ACT and TOC, respectively. Both adsorption and oxidation mechanisms were responsible simultaneously for ACT removal in MNPs@C/UV/PMS system. Under optimum conditions, the removal rates of ACT and TOC were reduced slightly to 91.7 and 49.4% after five consecutive catalyst uses, which indicates the excellent reusing potential of MNPs@C. In addition, a high stability was detected for as-prepared catalyst during recycling tests, since the quantity of leached Fe was <0.2 mg/L. Methanol and tert-butyl alcohol showed a strong quenching effect on the performance of MNPs@C/UV/PMS system, demonstrating the dominant role of SO4•- and HO radicals in ACT degradation process. MNPs@C in comparison with ferrous ions, as a homogeneous catalyst, showed a better performance in the activation of PMS and ACT degradation. Integration of MNPs@C, UV and PMS exhibited an excellent performance into ACT removal over 40 min reaction, which can be utilized as an effective and promising technique for the efficient decontamination of polluted waters.


Assuntos
Acetaminofen/química , Peróxidos/química , Processos Fotoquímicos , Carbono/química , Catálise , Ferro , Magnetismo , Imãs , Oxirredução , Reciclagem
15.
Chemosphere ; 232: 287-295, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31154190

RESUMO

Enols are an important group of photochemical precursors of atmospheric carbonyl compounds. However, the transformation mechanism is not fully understood. In this study, the photo-induced transformation of a typical enol, allyl alcohol, to carbonyl compounds on TiO2 (P25) and aluminum reduced TiO2 (P25, rutile and anatase TiO2) were investigated. Intermediate results confirmed that a total of seven carbonyl compounds, including four monocarbonyl compounds (acetone, glycolaldehyde, 1,3-dihydroxyacetone and acrolein) and three dicarbonyl compounds (glyoxal, methylglyoxal and dimethylglyoxal), were formed on studied TiO2. This is the first time to report the transformation of allyl alcohol to dicarbonyl compounds on TiO2. The same byproducts formation indicated negligible effects of reduction treatment and crystal phase to the composition of carbonyl intermediates. However, the relative content ratio of dicarbonyl compounds to monocarbonyl ones on reduced P25 is ca. 4.1 times higher than that on P25, suggesting reduction treatment significantly accelerated the transformation of allyl alcohol or monocarbonyl compounds to dicarbonyl ones. Furthermore, both rutile and anatase crystal phases were found beneficial for the dicarbonyl compounds generation within enough reaction time, especially for anatase. The enhanced •OH was responsible for all accelerations. Furthermore, the intermediate results together with quantum chemical calculations confirmed that •OH addition and O2 oxidation preferred converting allyl alcohol to dicarbonyl compounds rather than monocarbonyl ones. The present work could provide a deep insight into the transformation of allyl alcohol to carbonyl compounds, and efficiently replenish atmospheric transformation fate of enols.


Assuntos
Modelos Químicos , Processos Fotoquímicos , Propanóis/química , Luz Solar , Compostos Orgânicos , Oxirredução , Titânio/química
16.
Phys Chem Chem Phys ; 21(25): 13467-13473, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31187825

RESUMO

This work scrutinizes the relaxation mechanism of 2-oxopurine. Contrary to its ancestor, purine, which is a UVC chromophore, 2-oxopurine shows a red-shifted absorption spectrum centered in the UVA region. In 2-oxopurine, relaxation along the ππ* spectroscopic state directs the population from the Franck-Condon (FC) region towards a minimum, which acts as a crossroad for the further decay of the system either to triplet states or, alternatively, to the ground state through a C6-puckered S1/S0 funnel. A comparison of the optical properties and excited state potential energy surfaces of purine, 2-oxopurine, 2-aminopurine, 6-oxopurine and adenine, allows establishing how the position and nature of substituent tune the photophysics of purine. For this series, we conclude that both C2 and C6 substitution redshift the absorption spectrum of purine, with 2-oxo substitution exhibiting the largest shift. An important exception is the canonical nucleobase adenine, which presents a blue shifted absorption spectrum. The topography of purine's ππ* potential energy surface experiences major changes when functionalized at the C6 position. In particular, the disappearance of the minimum along the ππ* potential energy surface efficiently funnels the excited state population from the FC region to the ground state and increases the photostability of 6-aminopurine (adenine) and 6-oxopurine (hypoxanthine) nucleobases.


Assuntos
Purinonas/química , 2-Aminopurina/química , Adenina/química , Modelos Moleculares , Estrutura Molecular , Processos Fotoquímicos , Teoria Quântica , Espectrofotometria , Termodinâmica , Raios Ultravioleta
17.
Phys Chem Chem Phys ; 21(25): 13474-13485, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31204732

RESUMO

Isoguanine is an alternative nucleobase that has been proposed as a component of expanded genetic codes. It has also been considered as a molecule with potential relevance to primordial informational polymers. Here, we scrutinize the photodynamics of isoguanine, because photostability has been proposed as a critical criterion for the prebiotic selection of biomolecular building blocks on an early Earth. We discuss resonance-enhanced multiphoton ionization, IR-UV double resonance spectroscopy and pump-probe measurements performed for this molecule to track the excited-state behaviour of its different tautomeric forms in the gas phase. These experiments, when confronted with highly accurate quantum chemical calculations and nonadiabatic dynamics simulations provide a complete mechanistic picture of the tautomer-specific photodynamics of isoguanine. Our results indicate that UV-excited enol tautomers of isoguanine are relatively short lived and therefore photostable. In contrast, the biologically more relevant keto forms are trapped in dark nπ* states which are sufficiently long lived to participate in destructive photochemistry. The resulting lower photostability compared to canonical nucleobases may have been one of the reasons why isoguanine was not incorporated into DNA and RNA.


Assuntos
DNA/química , Guanina/química , Modelos Moleculares , Cinética , Oxirredução , Processos Fotoquímicos , Teoria Quântica , Termodinâmica
18.
Chemosphere ; 231: 478-486, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31151007

RESUMO

Secondary organic aerosol (SOA) is a complex mixture consisting of a variety of oxidation products. In this study, the role of relative humidity (RH) on SOA formation with different [H2O2]0/[cyclohexene]0 was investigated in a smog chamber. It was found that the cyclohexene SOA yield increases with increasing initial OH concentration at both high and low RH conditions. The increased rate of SOA formation was lower at wet conditions than that at dry conditions. For [H2O2]0/[cyclohexene]0 = 0.4 and 0.8, the SOA yield increased from 1.5% to 8% at dry condition to 7% and 12% at wet condition, respectively. In contrast, at high RH the SOA yield fell from 54% to 52% for [H2O2]0/[cyclohexene]0 = 1.3. The SOA mass loss was higher at high RH at the same OH exposure. The chemical composition of SOA was characterized using hybrid quadrupole-orbitrap mass spectrometer equipped with electrospray ionization (ESI-Q-Orbitrap-HRMS). Oligomers, which were responsible for the increase of the SOA yield, were detected in the SOA formed at high RH conditions. The esterification reaction between dicarboxylic acids and HOC6H10-O-O-C6H10OH was the pathway of oligomers formation. All the oligomers have cyclic molecular structures. For [H2O2]0/[cyclohexene]0 = 1.3, the relative intensity of both low and high molecular weight substances reduced more at wet conditions. This indicates that at sufficient OH level, the inhibition of oligomers formation and the further reaction of SOA with OH result in a slightly lower SOA yield at wet condition.


Assuntos
Aerossóis/química , Poluentes Atmosféricos/química , Cicloexenos/química , Umidade , Peróxido de Hidrogênio , Modelos Químicos , Estrutura Molecular , Oxirredução , Ozônio/química , Processos Fotoquímicos
19.
Chem Commun (Camb) ; 55(43): 6002-6005, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31041951

RESUMO

Electronic migration can be tailored by carefully manipulating the local electron donating and withdrawing nature of carbon nitride for charge separation and red-shift emission. A high yield of H2 (5 mmol h-1 g-1) with an apparent quantum yield of 20.98% at 420 nm and a preliminary study on phototherapy by labeling cell membranes are simultaneously provided.


Assuntos
Nitrilos/química , Processos Fotoquímicos , Fototerapia , Catálise , Membrana Celular/metabolismo , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica
20.
Chem Commun (Camb) ; 55(44): 6165-6168, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31049495

RESUMO

Tau amyloid formation and deposition are responsible for the onset of Alzheimer's disease. In particular, the seeding activity of the tau protein plays an important role in the spreading of tau pathology via its propagation in the human brain. Here we demonstrate that catalytic photo-oxygenation markedly suppresses tau seeding activity, resulting in the inhibition of amyloid formation, both in vitro and in cultured cells.


Assuntos
Oxigênio/metabolismo , Processos Fotoquímicos , Proteínas tau/antagonistas & inibidores , Proteínas tau/biossíntese , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Proteínas Amiloidogênicas/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Catálise , Reação de Cicloadição , Células HEK293 , Humanos
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