RESUMO
Phototherapy exhibits significant potential as a novel tumor treatment method, and the development of highly active photosensitizers and photothermal agents has drawn considerable attention. In this work, S and N atom co-doped carbon dots (S,N-CDs) with an absorption redshift effect were prepared by hydrothermal synthesis with lysine, o-phenylenediamine, and sulfuric acid as raw materials. The near-infrared (NIR) absorption features of the S,N-CDs resulted in two-photon (TP) emission, which has been used in TP fluorescence imaging of lysosomes and tumor tissue pH and real-time monitoring of apoptosis during tumor phototherapy, respectively. The obtained heteroatom co-doped CDs can be used not only as an NIR imaging probe but also as an effective photodynamic therapy/photothermal therapy (PDT/PTT) therapeutic agent. The efficiencies of different heteroatom-doped CDs in tumor treatment were compared. It was found that the S,N-CDs showed higher therapeutic efficiency than N-doped CDs, the efficiency of producing 1O2 was 27%, and the photothermal conversion efficiency reached 34.4%. The study provides new insight into the synthesis of carbon-based nanodrugs for synergistic phototherapy and accurate diagnosis of tumors.
Assuntos
Antineoplásicos/uso terapêutico , Corantes Fluorescentes/uso terapêutico , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Fármacos Fotossensibilizantes/uso terapêutico , Pontos Quânticos/uso terapêutico , Animais , Antineoplásicos/química , Antineoplásicos/efeitos da radiação , Apoptose/efeitos dos fármacos , Carbono/química , Carbono/efeitos da radiação , Corantes Fluorescentes/química , Corantes Fluorescentes/efeitos da radiação , Fluorometria , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Lisossomos/metabolismo , Camundongos Nus , Neoplasias/metabolismo , Nitrogênio/química , Nitrogênio/efeitos da radiação , Fótons , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/efeitos da radiação , Fototerapia , Pontos Quânticos/química , Pontos Quânticos/efeitos da radiação , Oxigênio Singlete/metabolismo , Enxofre/química , Enxofre/efeitos da radiaçãoRESUMO
Carbon dots (CDs) are photoluminescent nanomaterials with wide-ranging applications. Despite their photoactivity, it remains unknown whether CDs degrade under illumination and whether such photodegradation poses any cytotoxic effects. Here, we show laboratory-synthesized CDs irradiated with light degrade into molecules that are toxic to both normal (HEK-293) and cancerous (HeLa and HepG2) human cells. Eight days of irradiation photolyzes 28.6-59.8% of the CDs to <3 kilo Dalton molecules, 1431 of which are detected by high-throughput, non-target high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Molecular network and community analysis further reveal 499 cytotoxicity-related molecules, 212 of which contain polyethylene glycol, glucose, or benzene-related structures. Photo-induced production of hydroxyl and alkyl radicals play important roles in CD degradation as affected by temperature, pH, light intensity and wavelength. Commercial CDs show similar photodegraded products and cytotoxicity profiles, demonstrating that photodegradation-induced cytotoxicity is likely common to CDs regardless of their chemical composition. Our results highlight the importance of light in cytocompatibility studies of CDs.
Assuntos
Carbono/toxicidade , Citotoxinas/toxicidade , Pontos Quânticos/toxicidade , Derivados de Benzeno/química , Derivados de Benzeno/toxicidade , Carbono/química , Carbono/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Citotoxinas/química , Glucose/química , Glucose/toxicidade , Células HEK293 , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Radical Hidroxila/toxicidade , Cinética , Luz , Fotólise , Polietilenoglicóis/química , Polietilenoglicóis/toxicidade , Pontos Quânticos/química , Pontos Quânticos/efeitos da radiação , TemperaturaRESUMO
Silver nanoparticle (Ag NP)-coated carbon quantum dot (CQD) core-shell-structured nanocomposites (CQD@Ag NCs) were developed for fluorescent imaging of intracellular superoxide anion (O2â¢-). The morphology of CQD@Ag NCs was investigated by transmission electron microscopy, and the composition was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. CQDs display blue fluorescence with excitation/emission maxima at 360/440 nm, and the fluorescence was quenched by Ag NPs in CQD@Ag NCs. In the presence of O2â¢-, Ag NPs were oxide-etched and the fluorescence of CQDs was recovered. A linearity between the relative fluorescence intensity and O2â¢- solution concentration within the range 0.6 to 1.6 µM was found, with a detection limit of 0.3 µM. Due to their high sensitivity, selectivity, and low cytotoxicity, the as-synthesized CQD@Ag NCs have been successfully applied for imaging of O2â¢- in MCF-7 cells during the whole process of autophagy induced by serum starvation. In our perception, the developed method provides a cost-effective, sensitive, and selective tool in bioimaging and monitoring of intracellular O2â¢- changes, and is promising for potential biological applications. Graphical abstract Illustration of the synthesis of carbon quantum Dot@Silver nanocomposites (CQD@Ag NCs), and CQD@Ag NCs as a "turn-on" nanoprobe for fluorescent imaging of intracellular superoxide anion.
Assuntos
Corantes Fluorescentes/química , Nanocompostos/química , Pontos Quânticos/química , Superóxidos/análise , Carbono/química , Carbono/efeitos da radiação , Carbono/toxicidade , Corantes Fluorescentes/efeitos da radiação , Corantes Fluorescentes/toxicidade , Humanos , Limite de Detecção , Células MCF-7 , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Nanopartículas Metálicas/toxicidade , Microscopia de Fluorescência , Nanocompostos/efeitos da radiação , Nanocompostos/toxicidade , Pontos Quânticos/efeitos da radiação , Pontos Quânticos/toxicidade , Prata/química , Prata/efeitos da radiação , Prata/toxicidade , Raios UltravioletaRESUMO
Ferroptosis is an iron-dependent form of regulated cell death. In this study, a ratiometric fluorescent probe, gold carbon dots (GCDs) consisting of carbon skeleton and gold nanoclusters, was used for in situ imaging to monitor redox status in biothiols (glutathione and cysteine) and ferric metabolism of cancer cells in ferroptosis. The as-prepared GCDs can selectively respond to biothiols, interestingly, the fluorescence may be switched to sense ferric ions without interference by biothiols under proper conditions. The robust GCDs-probe exhibits excellent photobleaching resistance and can reversibly respond to intracellular biothiols/ferric ion with high temporal resolution. The 8 h real-time imaging of living cells was employed to track the fluctuation of biothiols, showing the change of redox status in ferroptosis. In addition, release of ferric ions in cells was monitored. The real-time imaging of depletion of biothiols and release of ferric ion in cells indicates the GCDs-probe can monitor how the ferroptosis regulates redox status in biothiols and ferric metabolism.
Assuntos
Cisteína/análise , Ferroptose/fisiologia , Corantes Fluorescentes/química , Glutationa/análise , Ferro/análise , Pontos Quânticos/química , Carbono/química , Carbono/efeitos da radiação , Linhagem Celular Tumoral , Cisteína/química , Cisteína/metabolismo , Ferroptose/efeitos dos fármacos , Corantes Fluorescentes/efeitos da radiação , Glutationa/química , Glutationa/metabolismo , Ouro/química , Ouro/efeitos da radiação , Humanos , Ferro/metabolismo , Luz , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Microscopia Confocal , Microscopia de Fluorescência , Neoplasias/metabolismo , Oxirredução , Piperazinas/farmacologia , Pontos Quânticos/efeitos da radiaçãoRESUMO
Controlled intracellular release of exogenous reactive oxygen species (ROS) is an innovative and efficient strategy for cancer treatment. Well-designed materials, which can produce ROS in targeted cells, minimizing side effects, still need to be explored as new generation nanomedicines. Here, red-emissive carbon nanodots (CNDs) with intrinsic theranostic properties are devised, and further modified with folic acid (FA) ligand through a controlled covalent functionalization for targeted cell imaging and intracellular production of ROS. We demonstrated that covalent functionalization is an effective strategy to prevent the aggregation of the dots, leading to superior colloidal stability, enhanced luminescence and ROS generation. Indeed, the functional nanodots possess a deep-red emission and good dispersibility under physiological conditions. Importantly, they show excellent targeting properties and generation of high levels of ROS under 660 nm laser irradiation, leading to efficient cell death. These unique properties enable FA-modified carbon nanodots to act as a multifunctional nanoplatform for simultaneous targeted imaging and efficient photodynamic therapy to induce cancer cell death.
Assuntos
Corantes Fluorescentes/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Pontos Quânticos/química , Espécies Reativas de Oxigênio/metabolismo , Carbono/química , Carbono/efeitos da radiação , Corantes Fluorescentes/química , Corantes Fluorescentes/efeitos da radiação , Ácido Fólico/química , Células HeLa , Humanos , Luz , Imagem Óptica , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/efeitos da radiação , Pontos Quânticos/efeitos da radiaçãoRESUMO
Carbon dots (CDs) emitting red fluorescence (610 nm) were synthesized by solvent thermal treatment of p-phenylenediamine in toluene. Upon 440 nm excitation, quercetin (QCT) alone endowed slight effects on the red fluorescence of CDs. Once Zn2+ was further introduced, the QCT-Zn2+ complex was quickly formed. This complex absorbs excitation light and emits bright green fluorescence at 480 nm. The red fluorescence of CDs was greatly quenched owing to the inner-filter effect. The ratio of fluorescence intensity at 480 nm and 610 nm (I480/I610) gradually increases with increasing concentration (c) of Zn2+. Al3+ exhibits the same phenomen like Zn2+. Fluoride ions form a more stable complex with Al3+ than QCT-Al3+ complex but have a negligible effect on the QCT-Zn2+ complex. The possible interference of Al3+ on Zn2+ can thus be avoided by adding certain amount of F-. The CD-QCT-F- system was constructed as a ratio-metric fluorescent nanoprobe toward Zn2+ with determination range of 0.14-30 µM and limit of detection (LOD) of 0.14 µM. Due to the stronger affinity of adenosine triphosphate (ATP) to Zn2+ than QCT, the I480/I610 value of CD-QCT-F--Zn2+ system gradually decreases with increasing cATP. The ratiometric fluorescent nanoprobe toward ATP was established with detection ranges of 0.55-10 and 10-35 µM and a LOD of 0.55 µM. The above two probes enable the quantitative determination of Zn2+ and ATP in tap and lake water samples with satisfactory recoveries. Graphical abstract Schematic representation of the ratiometric fluorescent nanoprobes based on the carbon dots (CDs)-quercetin (QCT) system towards Zn2+ and adenosine triphosphate (ATP) with high selectivity and sensitivity.
Assuntos
Trifosfato de Adenosina/análise , Corantes Fluorescentes/química , Pontos Quânticos/química , Quercetina/química , Espectrometria de Fluorescência/métodos , Zinco/análise , Carbono/química , Carbono/efeitos da radiação , Fluorescência , Corantes Fluorescentes/efeitos da radiação , Limite de Detecção , Pontos Quânticos/efeitos da radiação , Quercetina/efeitos da radiaçãoRESUMO
Carbon dots (CDs) as new fluorescent materials with excellent fluorescence properties have shown enormous potential applications, especially in anticounterfeiting and cell imaging. Herein, nitrogen-doped CDs (NCDs) with excellent biocompatibility were prepared by a simple thermal sintering method. An extremely large red shift (â¼130 nm) of the emission peak was observed when the excitation wavelength changes from 355 to 550 nm, indicating that NCDs are excellent fluorescent labeling materials for multiple cell imaging. On the other hand, NCDs showed obvious changes of emission intensity and peak position when the temperature increased from 223 to 323 K and the pH values changed from 1 to 13, respectively, which has been demonstrated by the "horse" pattern printed with NCD water-soluble fluorescent inks. The nontoxic NCDs dispersed in a multiple matrix are highly sensitive to excitation wavelength, temperature, and pH, indicating their great potential application in multiple anticounterfeiting and multiple cell imaging.
Assuntos
Corantes Fluorescentes/química , Fraude/prevenção & controle , Tinta , Pontos Quânticos/química , Alginatos/química , Carbono/química , Carbono/efeitos da radiação , Carbono/toxicidade , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Microscopia Confocal , Microscopia de Fluorescência , Nitrogênio/química , Nitrogênio/efeitos da radiação , Nitrogênio/toxicidade , Pontos Quânticos/efeitos da radiação , Pontos Quânticos/toxicidade , TemperaturaRESUMO
The adsorption with highly porous adsorbents is an efficient technique to trap the uncontrolled release of antibiotics in the environment, however, mere adsorption does not mineralize the discharged antibiotics. On the contrary, the regular photocatalysts completely mineralize the antibiotics, however suffers from high efficiency due to comparatively low surface area and porosity. In this work, a balance has been made between efficient adsorption followed by complete degradation of the adsorbed antibiotic over ZIF-8 derived ZnO/N-doped carbon composite. The nitrogen-doped carbon produced at 1000 °C showed a very high adsorption capacity of SMX, due to higher surface area, porosity and better surface interaction between adsorbate and adsorbent. The ZnO formed at 600 °C produced sufficient OH· that were responsible to show a very high rate of complete photocatalytic mineralization of SMX over the material. The ZnO/N-doped carbon composite showed a very high rate of photodegradation with a corresponding rate constant of 4.36 × 10-2 min-1. The complete degradation mechanism was proposed and rates were compared with existing literature.
Assuntos
Antibacterianos/química , Carbono/efeitos da radiação , Nanocompostos/efeitos da radiação , Nitrogênio/efeitos da radiação , Sulfametoxazol/química , Poluentes Químicos da Água/química , Óxido de Zinco/efeitos da radiação , Adsorção , Carbono/química , Catálise , Imidazóis/química , Estruturas Metalorgânicas/química , Nanocompostos/química , Nitrogênio/química , Fotólise , Zeolitas/química , Óxido de Zinco/químicaRESUMO
Efficient borylation reaction of diazonium salts in water is realized for the first time by using easily prepared, highly emissive and crystalline carbon dots. Electron-donating and electron-withdrawing groups on diazonium salts were well tolerated with moderate to good conversion efficiency. Compared with widely used metal complexes, organic dyes and quantum dots, the approach presented herein uses carbon dots, which are nontoxic and possess good biological and medicinal compatibility and high reactivity. Therefore, this approach presents a new prospective use for carbon dots in green chemistry.
Assuntos
Compostos de Boro/química , Carbono/química , Compostos de Diazônio/química , Carbono/efeitos da radiação , Catálise , Química Verde , Luz , SaisRESUMO
The emergence of more and more persistent organic molecules as contaminants in water simulates research towards the development of more advanced technologies, among which photocatalysis is a feasible choice. However, it is still challenging to design a photocatalyst that fulfills all the requirements for industrial application, i.e., active under visible-light irradiation, shape with handy convenience, highly uniform distribution of active sites, substrate with excellent electronic properties, etc. In this study, we report an attempt to solve these issues at once by designing a film-like photocatalyst with uniform distribution of nitrogen-doped ZnO nanoparticles along nitrogen-doped carbon ultrafine nanofibers with three-dimensional interconnected structure. Under visible-light irradiation, the product exhibited remarkable reactivity for the degradation of two model pollutants tetracycline hydrochloride and 2,4-dichlorophenol within 100 min. The cyclic experiments demonstrated only a slight loss (ca. 5 %) of reactivity after five consecutive photocatalytic reactions. We also investigated the detailed relationship between the structural features and the superior properties of this product, as well as the degradation mechanisms. The convenient shape of the product with excellent performances for the treatment of real polluted water increases its suitability for larger scale application. Our work provides a rational design of photocatalysts for environmental remediation.
Assuntos
Carbono/efeitos da radiação , Clorofenóis/química , Luz , Nanofibras/efeitos da radiação , Nitrogênio/efeitos da radiação , Tetraciclina/química , Poluentes Químicos da Água/química , Óxido de Zinco/efeitos da radiação , Carbono/química , Catálise , Óxidos N-Cíclicos/química , Nanofibras/química , Nitrogênio/química , Fotólise , Purificação da Água/métodos , Zeolitas/química , Óxido de Zinco/químicaRESUMO
The creation of a polymeric hydrogel from polyvinylpyrrolidone (PVP) cross-linked by Carbon Quantum Dots (CD) for the adsorption and photocatalytic degradation of both cationic and anionic dyes. PVP, an important biocompatible constituent and often surplus in cosmetic industry, was carboxylated through NaOH refluxing and covalently conjugated to surface amine functionality of CD derived from lemon juice and Cysteamine. The hybrid hydrogel was obtained from PVP-CD covalent conjugate by careful manipulation of pH and found to possess better rheological properties than only carboxylate-PVP. The monolayer physisorption of the dyes on the hydrogel was affected by hydrogen bonding, dispersion or inductive effect, and π-π interaction with the polymer backbone as well as the CD that followed pseudo-second-order kinetics. Degradation of the adsorbed dyes was instated by the unique Reactive Oxygen Species (ROS) generating ability of the CD embedded in the hydrogel matrix upon exposure to sunlight, the mechanism of which is also unveiled. The same CD-induced ROS was found to effectively annihilate both gram-positive and gram-negative bacteria in real polluted water in less than 10â¯min of photoexcitation of the hydrogel. The hydrogel was restored by mild acid wash that is able to perform dye adsorption and photo-degradation upto four cycles.
Assuntos
Carbono , Hidrogéis , Povidona , Pontos Quânticos , Purificação da Água/métodos , Carbono/administração & dosagem , Carbono/química , Carbono/efeitos da radiação , Corantes/química , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Hidrogéis/administração & dosagem , Hidrogéis/química , Hidrogéis/efeitos da radiação , Fotólise , Povidona/administração & dosagem , Povidona/química , Povidona/efeitos da radiação , Pontos Quânticos/administração & dosagem , Pontos Quânticos/química , Pontos Quânticos/efeitos da radiação , Espécies Reativas de Oxigênio/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Luz Solar , Águas Residuárias , Poluentes da Água/químicaRESUMO
In present work, we studied a novel Fe/C nanomaterial fabricated using Fe-based metal organic frameworks (MOFs) as precursors through thermal pyrolysis to catalyze gamma irradiation-induced degradation of antibiotics, cephalosporin C (CEP-C) and sulfamethazine (SMT) in aqueous solution. The MOFs-derived Fe/C nanomaterials (DMOFs) had the regular octahedrons structure of MOFs and contained element C, Fe and O, while Fe° with a fraction of Fe3O4 and Fe2O3 were identified. Results showed that DMOFs addition could accelerate the generation of OH during gamma irradiation, while the intermediates of bonds cleavages of antibiotic molecules and OH addition were identified. DMOFs were more effective to improve the decomposition of antibiotic having the higher adsorption capacity like SMT. The degradation rate of CEP-C and SMT increased by 1.3 times and 1.8 times, and TOC reduction at 1.0 kGy reached 42 % and 51 %, respectively by gamma/DMOFs treatment, while only 20.2 % (CEP-C) and 4.5 % (SMT) of TOC reduction were obtained by γ-irradiation alone. The crystal structure, functional groups and magnetism of DMOFs changed slightly after gamma irradiation, which made it possible to be reused. DMOFs were promising to enhance the degradation of antibiotics during gamma irradiation.
Assuntos
Antibacterianos/química , Estruturas Metalorgânicas/química , Nanoestruturas/química , Poluentes Químicos da Água/química , Adsorção , Carbono/química , Carbono/efeitos da radiação , Catálise/efeitos da radiação , Cefalosporinas/química , Ferro/química , Ferro/efeitos da radiação , Estruturas Metalorgânicas/efeitos da radiação , Nanoestruturas/efeitos da radiação , Radiação Ionizante , Sulfametazina/química , Purificação da Água/métodosRESUMO
A novel tubular graphitic carbon nitride (g-C3N4) modified with carbon quantum dots (CQDs) was fabricated and employed for the elimination of carbamazepine (CBZ) under visible light irradiation. The as-fabricated metal-free catalysts exhibited tubular morphologies due to the preforming of tubular protonated melamine with CQDs surface adsorption as the polymerization precursors. The surface bonded CQDs did not alter the band gap structure of g-C3N4, but greatly inhibited the charge recombination. Therefore, the CBZ degradation kinetics of tubular g-C3N4 were increased by over 5 times by the incorporation of CQDs. The main active species for CBZ degradation were found to be superoxide radical (O2-) and photo-generated holes (h+), which were further confirmed by electron spin resonance (ESR) analysis. In addition, the degradation pathways of CBZ were clarified via intermediates identification and quantum chemical computation using density functional theory (DFT) and wave function analysis. The olefinic double bond with the highest condensed Fukui index (f0 = 0.108) in CBZ molecule was found to be the most preferable sites for radical attack. Moreover, good stability of the as-prepared photocatalysts was observed in the consecutive recycling cycles, while the slight decline of photocatalytic activity was attributed to the minimal surface oxidation.
Assuntos
Carbamazepina/química , Carbono/química , Grafite/química , Compostos de Nitrogênio/química , Pontos Quânticos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Carbono/efeitos da radiação , Catálise , Teoria da Densidade Funcional , Grafite/efeitos da radiação , Luz , Compostos de Nitrogênio/efeitos da radiação , Fotólise , Pontos Quânticos/efeitos da radiaçãoRESUMO
Carbon dots (CDs) are a developing stable, conductive, and environmentally friendly fluorescent nanomaterial with potential applications in biomedicine and sensing. In this study, CDs with up- and down-conversion photoluminescence characteristics were prepared via a one-pot hydrothermal method using coffee beans as the sole raw material. Fourier transform infrared spectra and X-ray photoelectron spectroscopy showed the presence of nitrogen and oxygen functional groups on the CDs surfaces. Transmission electron microscopy showed that the CDs were spherical with an average size of 4.6 nm. The CDs precursor and synthesis process are environmentally benign, and the resulting CDs exhibit excellent photostability, reversible fluorescence response to temperature, and good ionic-strength tolerance. Moreover, these CDs can be used as efficient fluorescence probes in selective and sensitive Fe3+ detection by a dual-readout assay. The down- and up-conversion fluorescence measurements from the CDs were in the linear range for 0-0.10 mM Fe3+ with the detection limits of 15.4 and 16.3 nM, respectively. Furthermore, the CDs were successfully applied to intracellular sensing and imaging Fe3+ ions, indicating their potential use in bioscience applications.
Assuntos
Café/química , Corantes Fluorescentes/química , Ferro/análise , Pontos Quânticos/química , Sementes/química , Carbono/química , Carbono/efeitos da radiação , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Química Verde/métodos , Luz , Limite de Detecção , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Pontos Quânticos/efeitos da radiação , Solubilidade , Espectrometria de Fluorescência/métodos , Água/química , LevedurasRESUMO
Use of nanomaterials blessed with both therapeutic and diagnostic properties is a proficient strategy in the treatment of cancer in its early stage. In this context, our paper reports the synthesis of uniform size N-rich mesoporous carbon nanospheres of size 65-70 nm from pyrrole and aniline precursors using Triton-X as a structure-directing agent. Transmission electron microscopy reveals that these carbons spheres contain void spaces in which ultrasmall nitrogen-doped quantum dots (NCQD) are captured within the matrix. These mesoporous hollow NCQD captured carbon spheres (NCQD-HCS) show fluorescence quantum yield up to 14.6% under λex = 340 nm. Interestingly, samples calcined at >800 °C clearly absorb in the wavelength range 700-1000 nm and shows light-to-heat conversion efficiency up to 52%. In vitro experiments in human oral cancer cells (FaDu) show that NCQD-HCS are internalized by the cells and induce a substantial thermal ablation effect in FaDu cells when exposed under a 980 nm near-infrared laser.
Assuntos
Antineoplásicos/farmacologia , Corantes Fluorescentes/farmacologia , Pontos Quânticos/química , Antineoplásicos/síntese química , Antineoplásicos/efeitos da radiação , Apoptose/efeitos dos fármacos , Carbono/química , Carbono/efeitos da radiação , Linhagem Celular Tumoral , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Humanos , Hipertermia Induzida/métodos , Raios Infravermelhos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Neoplasias Bucais/tratamento farmacológico , Nitrogênio/química , Nitrogênio/efeitos da radiação , Fototerapia/métodos , Pontos Quânticos/efeitos da radiação , Nanomedicina Teranóstica/métodosRESUMO
A high quantum yield (QY) is the key requirement for implementing carbon dots (CDs) in nearly all applications. In this work, blue emissive N-doped CDs with a QY of 83% and orange emissive N-doped CDs with a QY of 47% were successfully prepared using resorcinol and phloroglucin as carbon resources in formamide by one-step microwave synthesis, respectively. Formamide not only plays a role as the solvent but also takes part in the formation of the high QY CDs. It is demonstrated that the as-prepared blue- and orange-emitting N-doped CDs with a high QY can be uniformly dispersed into glue and be fabricated as CD/glue fluorescent composites for fluorescent films and fingerprint imaging. Furthermore, these CDs also show excellent cellular imaging capability.
Assuntos
Carbono/química , Pontos Quânticos/química , Adesivos/química , Carbono/efeitos da radiação , Carbono/toxicidade , Cor , Dermatoglifia , Fluorescência , Humanos , Células MCF-7 , Membranas Artificiais , Microscopia de Fluorescência , Micro-Ondas , Floroglucinol/química , Pontos Quânticos/efeitos da radiação , Pontos Quânticos/toxicidade , Resorcinóis/química , SolubilidadeRESUMO
The current study proposes a fast one-pot microwave assisted synthesis of new carbon dots (CDs) based on glycerol and urea. The novel carbon nanoparticles (GUCDs) have been appropriately characterized and exhibited good luminescent properties with a quantum yield of about 9.8%. Interestingly, the GUCDs are able to selectively interact with tetracycline class antibiotics, which produce a decrease in the native fluorescence of the CDs. On the base of these features, a new analytical method has been developed for the determination of tetracycline. The proposed method has shown satisfactory analytical parameters, such as good linearity range -between 0.5 and 25⯵Mâ¯(R2â¯=â¯0.9997)- and an acceptable detection limit (165â¯nM). Moreover, the new method has been successfully applied for tetracycline determination in urine samples with good recoveries (94.7-103%) and precision (4.6 RSD%).
Assuntos
Carbono/química , Pontos Quânticos/química , Tetraciclina/urina , Carbono/efeitos da radiação , Fluorescência , Fluorometria/métodos , Glicerol/química , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Pontos Quânticos/efeitos da radiação , Raios Ultravioleta , Ureia/químicaRESUMO
Using chloroauric acid as precursor and ß-cyclodextrin (ß-CD) as reducing agent and stabilizer, ß-CD@AuNPs with negative charge were synthesized by one-step colloidal synthesis method. The positive charged carbon quantum dots (CQDs) were synthesized by one-step of sonication of cetylpyridinium chloride. Under the role of static electricity, the fluorescence resonance energy transfer (FRET) occurred between CQDs and ß-CD@AuNPs. CQDs and ß-CD@AuNPs served as the fluorescence energy donors and receptors, respectively, i.e., the fluorescence of CQDs was turned off by ß-CD@AuNPs. Based on the specific host-guest recognition between the inner cavity of ß-CD and cholesterol, CQDs was replaced by cholesterol, the FRET could be interrupted, and then the fluorescence of CQDs was turned on. A good linear relationship between cholesterol concentration (10-210⯵molâ¯L-1) and fluorescence intensity was obtained and the LOD was 343.48â¯nmolâ¯L-1. Because of excellent fluorescence quenching ability of FRET, the analytical performance (including LOD and linear scope) of such a turn off-on fluorescent nanosensor (e.g., CQDs/ß-CD@AuNPs) was better than nanosensor only via competitive host-guest recognition (e.g., ß-CD functionalized CQDs). The synergistic effect of competitive host-guest recognition and FRET was proved. Because of selective recognition, ultrasensitive, wide linear range, and strong anti-interference ability, CQDs/ß-CD@AuNPs as a turn off-on fluorescent nanosensor was developed to determine cholesterol in porcine serum.
Assuntos
Colesterol/sangue , Corantes Fluorescentes/química , Nanopartículas Metálicas/química , Pontos Quânticos/química , beta-Ciclodextrinas/química , Animais , Carbono/química , Carbono/efeitos da radiação , Fluorescência , Transferência Ressonante de Energia de Fluorescência/métodos , Ouro/química , Limite de Detecção , Tamanho da Partícula , Pontos Quânticos/efeitos da radiação , Suínos , Raios UltravioletaRESUMO
Glutamate mutase (GLM) is a coenzyme B12-dependent enzyme that catalyzes the conversion of S-glutamate to (2 S,3 S)-3-methyl aspartate. The initial step in the catalytic process is the homolytic cleavage of the coenzyme's Co-C bond upon binding of a substrate. Alternatively, the Co-C bond can be cleaved using light. To investigate the photolytic cleavage of the Co-C bond in GLM, we applied a combined density functional theory/molecular mechanics (DFT/MM) and time-dependent-DFT/MM method to scrutinize the ground and the low-lying excited states. Potential energy surfaces (PESs) were generated as a function of axial bond lengths to describe the photodissociation mechanism. The S1 PES was characterized as the crossing of two electronic states, metal-to-ligand charge transfer (MLCT), and ligand field (LF). In GLM, radical pairs generate from the LF state. Two pathways, path A and path B, were identified as possible channels to connect the MLCT and LF electronic states. The S1 PES in GLM was compared with the S1 PES for coenzyme B12-dependent ethanolamine ammonia lyase as well as the isolated AdoCbl cofactor. Finally, the theoretical insights related to the photodissociation mechanism were compared with transient absorption spectroscopy, electron paramagnetic resonance, and resonance Raman spectroscopy.
Assuntos
Carbono/química , Cobalto/química , Cobamidas/química , Transferases Intramoleculares/química , Carbono/efeitos da radiação , Clostridium/enzimologia , Cobalto/efeitos da radiação , Cobamidas/efeitos da radiação , Teoria da Densidade Funcional , Transferases Intramoleculares/efeitos da radiação , Luz , Modelos Químicos , Estrutura Molecular , FotóliseRESUMO
Due to the traditional therapies of cancer inducing huge pains to patients, the non-invasive photo-guided therapies are attracting massive attentions of researchers. Herein, the intelligent-designed carbon-dots/hemin nanoplatforms (HCDs NPs) were developed, owning high-authority photo-therapy for cancer. The fluorescence resonance energy transfer (FRET) effect enhanced the photo-thermal ability of HCDs NPs, endowing the synthesized nanoplatforms with photo-dynamic property simultaneously. Therefore, the obtained HCDs NPs could achieve synergetic photo-thermal and photo-dynamic therapies for cancer. Basing on the experimental results, the prepared HCDs NPs could induce the temperature enhancement high to ca 26⯰C under laser irradiation, also with the outstanding photo-dynamic efficacy. More than 90% of cancer cells die after 10â¯min laser treatment. Thus, the dual-modal photo-therapeutic HCDs NPs are promising and excellent nanomaterials for potential application in synergistic cancer therapy.