RESUMEN

Food allergy is increasing in prevalence, posing aheavier social and financial burden. At present, there is still no widely accepted treatment for it. Methods to reduce or eliminate the allergenicity of trigger foods are urgently needed. Technological processing contributes to producing some hypoallergenic foods. Among the processing methods, the Maillard reaction (MR) is popular because neither special chemical materials nor sophisticated equipment is needed. MR may affect the allergenicity of proteins by disrupting the conformational epitope, disclosing the hidden epitope, masking the linear epitope, and/or forming a new epitope. Changes in the allergenicity of foods after processing are affected by various factors, such as the characteristics of the allergen, the processing parameters, and the processing matrix, and they are therefore variable and difficult to predict. This paper reviews the effects of MR on the allergenicity of each allergen group from common allergenic foods.

RESUMEN

PURPOSE: To investigate the possibility of bridging long ureteral defects by longitudinal clipping and mucosal stripping of the pedicled segment of ileum (CMSPI). MATERIALS AND METHODS: Ten beagle dogs (five males and females aged 2-3 years) were used to model a defect of the entire ureter. An ileal segment was selected, and half of the intestinal segment was longitudinally resected, without mesenteric resection. The intestinal mucosa was removed. Then, the ileum was sutured to form a tube connecting the renal pelvis to the bladder. A 5F ureter stent was inserted into the ileum and removed 4 weeks after surgery. Intravenous urography (IVU) was used to observe the reconstructed ureters at 6 and 12 weeks after the operation. Blood samples were collected before surgery and during each radiological examination to assess electrolyte and renal function. Five dogs were randomly euthanized after each IVU. After macroscopic analysis, hematoxylin-eosin (H&E) staining was performed to observe the microscopic changes in the reconstructed ureter. RESULTS: All dogs were in good condition after surgery. Changes in blood electrolyte and renal function after surgery were not significant (Cl- P = .595; Ur P = .852). IVU demonstrated no ureteral obstruction or extravasation of the contrast agent; however, mild hydronephrosis were observed in three dogs. Macroscopic analysis indicated that the reconstructed ureter was intact without strictures. H&E showed that no mucosal structure was present on the luminal surface. CONCLUSION: CMSPI is feasible for bridging long ureteral defects and has shown good efficacy in this preliminary study.

Asunto(s)

Anastomosis Quirúrgica/métodos , Íleon/cirugía , Procedimientos de Cirugía Plástica/métodos , Uréter , Enfermedades Ureterales/cirugía , Animales , Perros , Femenino , Pruebas de Función Renal , Masculino , Modelos Anatómicos , Modelos Animales , Evaluación de Resultado en la Atención de Salud , Recuperación de la Función , Estructuras Creadas Quirúrgicamente , Uréter/diagnóstico por imagen , Uréter/cirugía , Urografía/métodos

RESUMEN

To study the effect of fluorine on the oxidative stress in coal-burning fluorosis, we investigated the environmental characteristics of coal-burning endemic fluorosis combined with fluorine content surveillance in air, water, food, briquette, and clay binder samples from Bijie region, Guizhou Province, southwest of China. The activities of antioxidant enzymes including copper/zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and level of lipid peroxidation such as malondialdehyde (MDA) were measured in serum samples obtained from subjects residing in the Bijie region. Expression of the Cu/Zn-SOD gene was assessed by quantitative reverse transcriptase PCR (qRT-PCR). Our results showed that people suffering from endemic fluorosis (the high and low exposure groups) had much higher MDA level. Their antioxidant enzyme activities and Cu/Zn-SOD gene expression levels were lower when compared to healthy people (the control group). Fluorosis can decrease the activities of antioxidant enzymes, which was associated with exposure level of fluorine. Down-regulation of Cu/Zn-SOD expression may play an important role in the aggravation of oxidative stress in endemic fluorosis.

Asunto(s)

Carbón Mineral , Exposición a Riesgos Ambientales/análisis , Enzimas/sangre , Fluorosis Dental/enzimología , Fluorosis Dental/genética , Superóxido Dismutasa/genética , Adolescente , Adulto , Contaminantes Atmosféricos/análisis , Estudios de Casos y Controles , Catalasa/sangre , China/epidemiología , Minas de Carbón , Agua Potable/análisis , Agua Potable/química , Exposición a Riesgos Ambientales/efectos adversos , Femenino , Fluoruros/análisis , Flúor/efectos adversos , Flúor/orina , Fluorosis Dental/epidemiología , Glutatión Peroxidasa/sangre , Humanos , Peroxidación de Lípido , Masculino , Malondialdehído/sangre , Persona de Mediana Edad , Estrés Oxidativo , Adulto Joven

RESUMEN

The medicinal fungus Ganoderma lucidum has been shown to have hepatoprotective effects. G. lucidum contains triterpenes and polysaccharides, and the Sporoderm-broken G. lucidum powder is particular beneficial. This study utilized G. lucidum spore to examine its effect on [Cd(II)]-induced hepatotoxicity in mice and the mechanism of the protection. Mice were pretreated with G. lucidum spore (0.1, 0.5, and 1.0 g/kg, po, for 7 days), and subsequently challenged with a hepatotoxic dose of Cd(II) (3.7 mg/kg, ip). Liver injury was evaluated 8h later. G. lucidum spore protected against Cd(II)-induced liver injury in a dose-dependent manner, as evidenced by serum alanine aminotransferase, aspartate aminotransferase and histopathology. To examine the mechanism of protection, subcellular distribution of Cd(II) was determined. G. lucidum spore decreased Cd(II) accumulation in hepatic nuclei, mitochondria, and microsomes, but increased Cd(II) distribution to the cytosol, where Cd(II) is sequestered by metallothionein, a protein against Cd(II) toxicity. Indeed, G. lucidum spore induced hepatic metallothionein-1 mRNA 8-fold, and also increased metallothionein protein as determined by the Cd(II)/hemoglobin assay. Cd(II)-induced oxidative stress was also decreased by G. lucidum spore, as evidenced by decreased formation of malondialdehyde. In summary, G. lucidum spore is effective in protection against Cd(II)-induced hepatotoxicity, and this effect is due, at least in part, to the induction of hepatic metallothionein to achieve beneficial effects.

Asunto(s)

Enfermedad Hepática Inducida por Sustancias y Drogas/tratamiento farmacológico , Sustancias Protectoras/farmacología , Reishi , Esporas Fúngicas , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , Cadmio/farmacocinética , Cadmio/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Citosol/efectos de los fármacos , Citosol/metabolismo , Relación Dosis-Respuesta a Droga , Masculino , Malondialdehído/metabolismo , Metalotioneína/genética , Metalotioneína/metabolismo , Ratones , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Mitocondrias Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Polvos

RESUMEN

Enhancing chemotherapeutic efficiency through improved drug delivery would facilitate treatment of chemoresistant cancers, such as recurrent mammary tumors and liver cancer. One way to improve drug delivery is through the use of nanodiamond (ND) therapies, which are both scalable and biocompatible. Here, we examined the efficacy of an ND-conjugated chemotherapeutic in mouse models of liver and mammary cancer. A complex (NDX) of ND and doxorubicin (Dox) overcame drug efflux and significantly increased apoptosis and tumor growth inhibition beyond conventional Dox treatment in both murine liver tumor and mammary carcinoma models. Unmodified Dox treatment represents the clinical standard for most cancer treatment regimens, and NDX had significantly decreased toxicity in vivo compared to standard Dox treatment. Thus, ND-conjugated chemotherapy represents a promising, biocompatible strategy for overcoming chemoresistance and enhancing chemotherapy efficacy and safety.

Asunto(s)

Antineoplásicos/administración & dosificación , Portadores de Fármacos , Nanoestructuras , Neoplasias Experimentales/tratamiento farmacológico , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Antineoplásicos/farmacocinética , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Diamante , Doxorrubicina/administración & dosificación , Doxorrubicina/farmacocinética , Sistemas de Liberación de Medicamentos , Resistencia a Antineoplásicos , Femenino , Humanos , Neoplasias Hepáticas Experimentales/tratamiento farmacológico , Neoplasias Hepáticas Experimentales/metabolismo , Neoplasias Hepáticas Experimentales/patología , Neoplasias Mamarias Experimentales/tratamiento farmacológico , Neoplasias Mamarias Experimentales/metabolismo , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Endogámicos BALB C , Nanomedicina , Nanotecnología , Neoplasias Experimentales/metabolismo , Neoplasias Experimentales/patología

RESUMEN

OBJECTIVE: To study astrocytes cellular cycle and the activities of SDH, 5'-NT and ACP in rat cerebral cortex astrocytes by NaF in vitro. METHODS: Astrocytes of rat cerebral cortex were purified and cultured in vitro to obtain the highly purified cells (identified by immunochemistry of anti-GFAP). The constituent ratio of cell cycle was analyzed by FCM after the cells were cultured with different levels of NaF for different time span. Activities of SDH, 5'-NT and ACP were tested by UV colorimetry. RESULTS: Cell cycle arrest transited from S phase to G2/M phase and subG1 cells increased in 1-5 mmol/L in the astrocyte cycle treated with different levels of NaF for different time span by using FCM. There was inverse correlation between the relative amount of the subG1 DNA and activities of SDH and ACP respectively (SDH: r = -0.84148, P < 0.05; ACP: r = -0.90416, P < 0.01) that were inhibited by NaF and 5 mmol/L NaF can inactivate 5'-NT in astrocytes. CONCLUSION: NaF can induce cell cycle arrest from S to G2/M and inhibit activities of 5'-NT,SDH and ACP in astrocytes.

Asunto(s)

Apoptosis/efectos de los fármacos , Astrocitos/citología , Ciclo Celular/efectos de los fármacos , Corteza Cerebral/citología , Fluoruros/toxicidad , Animales , Astrocitos/enzimología , Células Cultivadas , Femenino , Masculino , Ratas , Ratas Wistar , Fluoruro de Sodio/toxicidad

RESUMEN

The fabrication of biologically amenable interfaces in medicine bridges translational technologies with their surrounding biological environment. Functionalized nanomaterials catalyze this coalescence through the creation of biomimetic and active substrates upon which a spectrum of therapeutic elements can be delivered to adherent cells to address biomolecular processes in cancer, inflammation, etc. Here, we demonstrate the robust functionalization of ultrananocrystalline diamond (UNCD) with type I collagen and dexamethasone (Dex), an anti-inflammatory drug, to fabricate a hybrid therapeutically active substrate for localized drug delivery. UNCD oxidation coupled with a pH-mediated collagen adsorption process generated a comprehensive interface between the two materials, and subsequent Dex integration, activity, and elution were confirmed through inflammatory gene expression assays. These studies confer a translational relevance to the biofunctionalized UNCD in its role as an active therapeutic network for potent regulation of cellular activity toward applications in nanomedicine.

Asunto(s)

Materiales Biocompatibles/química , Colágeno/química , Diamante/química , Adsorción , Animales , Antiinflamatorios/administración & dosificación , Línea Celular , Diseño de Fármacos , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Ratones , Microscopía de Fuerza Atómica/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Temperatura

RESUMEN

Enhanced specificity in drug delivery aims to improve upon systemic elution methods by locally concentrating therapeutic agents and reducing negative side effects. Due to their robust physical properties, biocompatibility and drug loading capabilities, nanodiamonds serve as drug delivery platforms that can be applied towards the elution of a broad range of therapeutically-active compounds. In this work, bovine insulin was non-covalently bound to detonated nanodiamonds via physical adsorption in an aqueous solution and demonstrated pH-dependent desorption in alkaline environments of sodium hydroxide. Insulin adsorption to NDs was confirmed by FT-IR spectroscopy and zeta potential measurements, while both adsorption and desorption were visualized with TEM imaging, quantified using protein detection assays and protein function demonstrated by MTT and RT-PCR. NDs combined with insulin at a 4:1 ratio showed 79.8+/-4.3% adsorption and 31.3+/-1.6% desorption in pH-neutral and alkaline solutions, respectively. Additionally, a 5-day desorption assay in NaOH (pH 10.5) and neutral solution resulted in 45.8+/-3.8% and 2.2+/-1.2% desorption, respectively. MTT viability assays and quantitative RT-PCR (expression of Ins1 and Csf3/G-csf genes) reveal bound insulin remains inactive until alkaline-mediated desorption. For applications in sustained drug delivery and therapy we have developed a therapeutic protein-ND complex with demonstrated tunable release and preserved activity.

Asunto(s)

Diamante/química , Portadores de Fármacos/química , Insulina/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Proteínas/química , Células 3T3 , Animales , Bovinos , Supervivencia Celular/efectos de los fármacos , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Ratones , Tamaño de la Partícula , Proteínas/administración & dosificación

RESUMEN

A broad array of water-insoluble compounds has displayed therapeutically relevant properties toward a spectrum of medical and physiological disorders, including cancer and inflammation. However, the continued search for scalable, facile, and biocompatible routes toward mediating the dispersal of these compounds in water has limited their widespread application in medicine. Here we demonstrate a platform approach of water-dispersible, nanodiamond cluster-mediated interactions with several therapeutics to enhance their suspension in water with preserved functionality, thereby enabling novel treatment paradigms that were previously unrealized. These therapeutics include Purvalanol A, a highly promising compound for hepatocarcinoma (liver cancer) treatment, 4-hydroxytamoxifen (4-OHT), an emerging drug for the treatment of breast cancer, as well as dexamethasone, a clinically relevant anti-inflammatory that has addressed an entire spectrum of diseases that span complications from blood and brain cancers to rheumatic and renal disorders. Given the scalability of nanodiamond processing and functionalization, this novel approach serves as a facile, broadly impacting and significant route to translate water-insoluble compounds toward treatment-relevant scenarios.

RESUMEN

Nanodiamonds are rapidly emerging as promising carriers for next-generation therapeutics and drug delivery. However, developing future nanoscale devices and arrays that harness these nanoparticles will require unrealized spatial control. Furthermore, single-cell in vitro transfection methods lack an instrument that simultaneously offers the advantages of having nanoscale dimensions and control and continuous delivery via microfluidic components. To address this, two modes of controlled delivery of functionalized diamond nanoparticles are demonstrated using a broadly applicable nanofountain probe, a tool for direct-write nanopatterning with sub-100-nm resolution and direct in vitro single-cell injection. This study demonstrates the versatility of the nanofountain probe as a tool for high-fidelity delivery of functionalized nanodiamonds and other agents in nanomanufacturing and single-cell biological studies. These initial demonstrations of controlled delivery open the door to future studies examining the nanofountain probe's potential in delivering specific doses of DNA, viruses, and other therapeutically relevant biomolecules.

Asunto(s)

Diamante , Portadores de Fármacos , Nanoestructuras

RESUMEN

Parylene is a biologically inert material capable of being deposited in conformal nanoscale layers on virtually any surface, making it a viable structural material for the fabrication of drug delivery devices, as well as implant coatings, sensors, and other biomedical technologies. Here we explore its novel drug delivery applications by using parylene to package the polymethyloxazoline-polydimethylsiloxane-polymethyloxazoline (PMOXA-PDMS-PMOXA) block copolymer membrane of a nanoscale thickness (approximately 4 nm/layer) mixed with a therapeutic element, creating an active parylene-encapsulated copolymeric (APC) membrane for slow release drug delivery of dexamethasone (Dex), a potent anti-inflammatory and immunosuppressant synthetic glucocorticoid. Given current needs for localized therapeutic release for conditions such as cancer, post-surgical inflammation, wound healing, regenerative medicine, to name a few, this stand-alone and minimally invasive implantable technology may impact a broad range of medical scenarios. To evaluate the applicability of the APC membrane as a biocompatible drug delivery system, real-time polymerase chain reaction (RT-PCR) was performed to investigate the expression of cytokines that regulate cellular stress and inflammation as a result of in vitro RAW264.7 macrophage cell growth on the APC membrane. Significant decreases in relative mRNA levels of IL-6, TNF-alpha, and iNOS were observed. Dex functionalized APC membranes were further found to effectively slow-elute the drug via confocal microscopy, with a confirmed extended elution capability over a period of several days, undergoing phosphate buffered saline washes between time points. In addition, we examined the membrane surface through atomic force microscopy (AFM) to examine Dex/copolymer deposition, and to characterize the surface of the APC membrane. Furthermore, we evaluated the effects of incubation with the APC membrane in solution on macrophage growth behavior and cellular adhesion, including the physical properties of parylene and the copolymer to elucidate the anti-adhesive responses we observed. The results of this study will provide insight into ultra-thin and flexible devices of parylene-encapsulated copolymer membranes as platform drug delivery technologies capable of localized and precision therapeutic drug elution.

Asunto(s)

Preparaciones de Acción Retardada/administración & dosificación , Preparaciones de Acción Retardada/química , Membranas Artificiales , Nanoestructuras/administración & dosificación , Nanoestructuras/química , Polímeros/química , Xilenos/química , Nanoestructuras/ultraestructura , Tamaño de la Partícula

RESUMEN

OBJECTIVE: To observe the expressions of CXC chemokine receptor 4 (CXCR4) in muscle satellite cells in situ of normal and cardiotoxin-intoxicated muscle tissues so as to further investigate the molecular mechanism involving in muscle regeneration such as progressing muscular dystrophy (PMD) for seeking the way to cure muscle retrogression. METHODS: The muscle injured model of 12 C57 male mice was made by injecting cardiotoxin (5 microg per mouse) in left quadriceps femoris, their right quadriceps femoris was used as control without any injection. The histological, immunohistochemical analysis and RT-PCR were done to investigate the expression of CXCR4 in the quadriceps femoris in situ after 1 day, 4 days, 1 week, 2 weeks, 4 weeks and 6 weeks. RESULTS: HE staining results demonstrated that the muscle tissues experienced the process from muscle injury, repair to regeneration. The result of immunohistochemistry showed that the expressions of CXCR4 in injured muscle tissue were 1955.6 +/- 150.3, 2223.2 +/- 264.3, 2317.6 +/- 178.7, 3066.5 +/- 269.6, 1770.9 +/- 98.7 and 1505.7 +/- 107.1 at 1 day, 4 days, 1 week, 2 weeks, 4 weeks and 6 weeks after injection of cardiotoxin, there was significant difference when compared with normal muscle (640.3 +/- 124.0, P < 0.00 1). The RT-PCR showed that the expressions of CXCR4 mRNA in injured muscle tissue were 0.822 +/- 0.013, 0.882 +/- 0.025, 1.025 +/- 0.028, 1.065 +/- 0.041, 0.837 +/- 0.011 and 0.777 +/- 0.015 at 1 day, 4 days, 1 week, 2 weeks, 4 weeks and 6 weeks after injection of cardiotoxin, there was significant difference when compared with normal muscle (0.349 +/- 0.006, P < 0.001). CONCLUSION: CXCR4 may be the critical protein in the process of muscle impairment and reparation.

Asunto(s)

Enfermedades Musculares/metabolismo , Receptores CXCR4/biosíntesis , Células Satélite del Músculo Esquelético/metabolismo , Traumatismos de los Tejidos Blandos/metabolismo , Animales , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Enfermedades Musculares/patología

RESUMEN

Nanodiamonds (NDs) of 2-8 nm diameters physically bound with the chemotherapeutic agent doxorubicin hydrochloride (DOX) were embedded within a parylene C polymer microfilm through a facile and scalable process. The microfilm architecture consists of DOX-ND conjugates sandwiched between a base and thin variable layer of parylene C which allows for modulation of release. Successive layers of parylene and the DOX-ND conjugates were characterized through atomic force microscopy (AFM) images and drug release assays. Elution rates were tested separately over a period of 8 days and up to one month in order to illustrate the release characteristics of the microfilms. The microfilms displayed the stable and continuous slow-release of drug for at least one month due to the powerful sequestration abilities of the DOX-ND complex and the release-modulating nature of the thin parylene layer. Since the fabrication process is devoid of any destructive steps, the DOX-ND conjugates are unaffected and unaltered. A DNA fragmentation assay was performed to illustrate this retained activity of DOX under biological conditions. Specifically, in this work we have conferred the ability to tangibly manipulate the NDs in a polymer-packaged microfilm format for directed placement over diseased areas. By harnessing the innate ND benefits in a biostable patch platform, extended targeted and controlled release, possibly relevant toward conditions such as cancer, viral infection, and inflammation, where complementary alternatives to systemic drug release enabled by the microfilm devices, can allow for enhanced treatment efficacy.

Asunto(s)

Líquidos Corporales/química , Preparaciones de Acción Retardada/química , Diamante/química , Doxorrubicina/química , Membranas Artificiales , Nanoestructuras/administración & dosificación , Nanoestructuras/química , Difusión , Doxorrubicina/administración & dosificación

RESUMEN

Aqueous dispersible detonation nanodiamonds (NDs) with a diameter of 2-8 nm were assembled into a closely packed ND multilayer nanofilm with positively charged poly-L-lysine via the layer-by-layer deposition technique. The innate biocompatibility of the NDs in both free-floating and thin-film forms was confirmed via cellular gene expression examination by real-time polymerase chain reaction as well as MTT and DNA fragmentation assays. The highly biologically amenable ND nanofilm was successfully integrated with therapeutic molecules, and the functionality of the composite drug-ND material was assessed via interrogation of the suppression of inflammatory cytokine release. Knockdown of lipopolysaccharide-mediated inflammation was observed through the potent attenuation of tumor necrosis factor-alpha, interleukin-6, and inducible nitric oxide synthase levels following ND nanofilm interfacing with RAW 264.7 murine macrophages. Furthermore, basal cytokine secretion levels were assessed to examine innate material biocompability, revealing unchanged cellular inflammatory responses which strongly supported the relevance of the NDs as effective treatment platforms for nanoscale medicine. In addition to the easy preparation, robustness, and fine controllability of the film structures, these hybrid materials possess enormous potential for biomedical applications such as localized drug delivery and anti-inflammatory implant coatings and devices, as demonstrated in vitro in this work.

Asunto(s)

Materiales Biocompatibles/química , Cristalización/métodos , Diamante/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Polilisina/química , Hidrogeles/química , Sustancias Macromoleculares/química , Ensayo de Materiales , Membranas Artificiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de Superficie

RESUMEN

Nanodiamond materials can serve as highly versatile platforms for the controlled functionalization and delivery of a wide spectrum of therapeutic elements. In this work, doxorubicin hydrochloride (DOX), an apoptosis-inducing drug widely used in chemotherapy, was successfully applied toward the functionalization of nanodiamond materials (NDs, 2-8 nm) and introduced toward murine macrophages as well as human colorectal carcinoma cells with preserved efficacy. The adsorption of DOX onto the NDs and its reversible release were achieved by regulating Cl- ion concentration, and the NDs were found to be able to efficiently ferry the drug inside living cells. Comprehensive bioassays were performed to assess and confirm the innate biocompatibility of the NDs, via real-time quantitative polymerase chain reaction (RT-PCR), and electrophoretic DNA fragmentation as well as MTT analysis confirmed the functional apoptosis-inducing mechanisms driven by the DOX-functionalized NDs. We extended the applicability of the DOX-ND composites toward a translational context, where MTT assays were performed on the HT-29 colon cancer cell line to assess DOX-ND induced cell death and ND-mediated chemotherapeutic sequestering for potential slow/sustained released capabilities. These and other medically relevant capabilities enabled by the NDs forge its strong potential as a therapeutically significant nanomaterial.

Asunto(s)

Antineoplásicos/administración & dosificación , Diamante , Sistemas de Liberación de Medicamentos , Nanopartículas/química , Nanotecnología/métodos , Neoplasias/tratamiento farmacológico , Animales , Apoptosis , Materiales Biocompatibles , Línea Celular Tumoral , Neoplasias del Colon/tratamiento farmacológico , Doxorrubicina/administración & dosificación , Humanos , Macrófagos/efectos de los fármacos , Ratones , Espectrofotometría Ultravioleta/métodos , Sales de Tetrazolio/farmacología , Tiazoles/farmacología

RESUMEN

Finely divided carbon particles, including charcoal, lampblack, and diamond particles, have been used for ornamental and official tattoos since ancient times. With the recent development in nanoscience and nanotechnology, carbon-based nanomaterials (e.g., fullerenes, nanotubes, nanodiamonds) attract a great deal of interest. Owing to their low chemical reactivity and unique physical properties, nanodiamonds could be useful in a variety of biological applications such as carriers for drugs, genes, or proteins; novel imaging techniques; coatings for implantable materials; and biosensors and biomedical nanorobots. Therefore, it is essential to ascertain the possible hazards of nanodiamonds to humans and other biological systems. We have, for the first time, assessed the cytotoxicity of nanodiamonds ranging in size from 2 to 10 nm. Assays of cell viability such as mitochondrial function (MTT) and luminescent ATP production showed that nanodiamonds were not toxic to a variety of cell types. Furthermore, nanodiamonds did not produce significant reactive oxygen species. Cells can grow on nanodiamond-coated substrates without morphological changes compared to controls. These results suggest that nanodiamonds could be ideal for many biological applications in a diverse range of cell types.

Asunto(s)

Diamante/química , Nanopartículas , Carbono/química , Línea Celular Tumoral , Supervivencia Celular , Relación Dosis-Respuesta a Droga , Fulerenos/química , Humanos , Nanopartículas del Metal/química , Microscopía Electrónica de Transmisión , Microscopía Fluorescente , Mitocondrias/metabolismo , Nanotubos/química , Tamaño de la Partícula , Especies Reactivas de Oxígeno

RESUMEN

Upon laser irradiation in air, metallic single-walled carbon nanotubes (SWNTs) in carbon nanotube thin film can be destroyed in preference to their semiconducting counterparts when the wavelength and power intensity of the irradiation are appropriate and the carbon nanotubes are not heavily bundled. Our method takes advantage of these two species' different rates of photolysis-assisted oxidation, creating the possibility of defining the semiconducting portions of carbon nanotube (CNT) networks using optical lithography, particularly when constructing all-CNT FETs (without metal electrodes) in the future.

RESUMEN

While it is well-known that tube-tube interaction causes changes (peak red-shift and suppression) in the optical absorption of single-walled carbon nanotubes (SWNTs), we found in this work that, upon bundling, the optical absorption of metallic SWNTs (M11) is less affected compared to their semiconducting counterparts (S11 or S22), resulting in enhanced absorbance ratio of metallic and semiconducting SWNTs (A(M)/A(S)). Annealing of the SWNTs increases this ratio due to the intensified tube-tube interaction. We have also found that the interaction between SWNTs and the surfactant Triton X-405 has a similar effect. The evaluation of SWNT separation by types (metallic or semiconducting) based on the optical absorption should take these effects into account.

RESUMEN

N@C60 has a lower photochemical reactivity toward disilirane than C60, although N@C60 does not differ from C60 in its thermal reactivity; theoretical calculations reveal that N@C60 and C60 have the same orbital levels and that N@3C60* has a shorter lifetime than 3C60*.

RESUMEN

The initial relaxation dynamics of the photoexcited fullerenes C60, C70, C76, C84, C86, and C90 were investigated by dispersion-free femtosecond pump-probe spectroscopy. Under identical excitation conditions, the formation of the lowest excited state slows down for the larger fullerenes. This trend in dynamics, monitored throughout the visible and NIR range, is found to correlate with the number of isomers in accordance with the isomerization mechanism suggested by Stone and Wales. The Stone-Wales isomerization was calculated as thermally inaccessible but photoinduced barrierless. The energy difference of the isomers is in the 1 meV range, and back-isomerization is observed on the picosecond time scale. The characteristic spectrally broad transient absorption of the investigated fullerenes is promising for fast optical gating applications.