Gold Nanoparticles and Its Potential Applications in Cancer Research

2009 Spring Meeting of the NANOFANS Forum. Presented on May 1, 2009 from 11 am-2 pm in the Marcus Nanotechnology Building (Rooms 1116-1118) on the Georgia Tech campus.Cancer Nanotechnology: New Opportunities in Engineering and Medicine / Shuming Nie, Director, Center of Cancer Nanotechnology Excellence, Emory and Georgia Tech -- Magnetic Nanoparticles and Ovarian Cancer: A Potential New Direction in Therapeutic Intervention / John McDonald, Director, Ovarian Cancer Institute and Chair of the School of Biology at Georgia Tech -- Gold Nanoparticles and Its Potential Applications in Cancer Research / Mostafa El-Sayed, Director, Laser Dynamics Laboratory at the School of Chemistry & Biochemistry at Georgia Tech.Shuming Nie is the Wallace H. Coulter Distinguished Chair Professor in Biomedical Engineering at Emory University and the Georgia Institute of Technology. His research interest is broadly in biomolecular engineering and nanotechnology. John McDonald is taking an integrated systems approach to the study of cancer. This means that he views cancer not as a defect in any particular gene or protein, but as a de-regulated cellular/ inter-cellular process. Mostafa El-Sayed is the Julius Brown Chair and Regents Professor in the School of Chemistry and Biochemistry at Georgia Tech. He researches Nanoscience and also investigates how Nanoparticles can be used in Nanomedicine, Nano Catalysis, and Nanophotonics

Electron dynamics in gold and gold–silver alloy nanoparticles: The influence of a nonequilibrium electron distribution and the size dependence of the electron–phonon relaxation

©1999 American Institute of Physics. The electronic version of this article is the complete one and can be found online at: http://link.aip.org/link/?JCPSA6/111/1255/1DOI: 10.1063/1.479310Electron dynamics in gold nanoparticles with an average diameter between 9 and 48 nm have been studied by femtosecond transient absorption spectroscopy. Following the plasmon bleach recovery after low power excitation indicates that a non-Fermi electron distribution thermalizes by electron–electron relaxation on a time scale of 500 fs to a Fermi distribution. This effect is only observed at low excitation power and when the electron distribution is perturbed by mixing with the intraband transitions within the conduction band (i.e., when the excitation wavelength is 630 or 800 nm). However, exciting the interband transitions at 400 nm does not allow following the early electron thermalization process. Electron thermalization with the lattice of the nanoparticle by electron–phonon interactions occurs within 1.7 ps under these conditions, independent of the excitation wavelength. In agreement with the experiments, simulations of the optical response arising from thermalized and nonthermalized electron distributions show that a non-Fermi electron distribution leads to a less intense bleach of the plasmon absorption. Furthermore, the difference between the response from the two electron distributions is greater for small temperature changes of the electron gas (low excitation powers). No size dependence of the electron thermalization dynamics is observed for gold nanoparticles with diameters between 9 and 48 nm. High-resolution transmission electron microscopy (HRTEM) reveals that these gold nanoparticles possess defect structures. The effect of this on the electron–phonon relaxation processes is discussed. 18 nm gold–silver alloy nanoparticles with a gold mole fraction of 0.8 are compared to 15 nm gold nanoparticles. While mixing silver leads to a blue-shift of the plasmon absorption in the ground-state absorption spectrum, no difference is observed in the femtosecond dynamics of the system

Improvement of drought tolerance in five different cultivars of Vicia faba with foliar application of ascorbic acid or silicon

Aim of study: To explore the role of ascorbic acid (AsA) or silicon (Si) in improving drought tolerance in five faba bean cultivars under irrigation water deficit (IWD).Area of study: The experimental farm; 30° 36′ N, 32° 16′ E, Egypt.Material and methods: Three drip irrigation regimes (WW, well-watered, 4000 m3 water ha-1; MD, moderate drought, 3000 m3 water ha-1; and SD, severe drought, 2000 m3 water ha-1) were applied to plants, which were sprayed 25, 40, and 55 days after sowing with 1.5 mM AsA or 2.0 mM Si vs distilled water as a control.Main results: Drought negatively affected physiological attributes (photosynthetic pigments, gas exchange parameters, relative water content, membrane stability index, electrolyte leakage (EL), and lipid peroxidation), which restricted plant growth and yields, and stimulated alterations in both enzymatic and non-enzymatic antioxidant activities. However, AsA or Si application mitigated drought effects on physiological attributes, improving growth, yields and water use efficiency by raising antioxidant activities and suppressing lipid peroxidation and EL in stressful cultivars. The mitigating effects of AsA and Si were more pronounced under MD.Research highlights: ‘Nubaria-2’, ‘Giza-843’, and ‘Sakha-3’ were more tolerant than ‘Giza-716’ and ‘Sakha-4’, suggesting the use of AsA or Si to ameliorate the IWD effects on stressful cultivars. Certain physiological traits exhibited positive association with growth and seed yield, demonstrating their importance in enhancing seed yield under irrigation treatments

Diversity of inulinase-producing fungi associated with two Asteraceous plants, Pulicaria crispa (Forssk.) and Pluchea dioscoridis (L.) growing in an extreme arid environment

Inulinases are potentially valuable enzymes catalyze the hydrolysis of plant’s inulin into high fructose syrups as sweetening ingredients for food industry and ethanol production. The high demands for inulinase enzymes have promoted interest in microbial inulinases as the most suitable approach for biosynthesis of fructose syrups from inulin. Arid land ecosystem represents a valuable bioresource for soil microbial diversity with unique biochemical and physiological properties. In the present study, we explored the fungi diversity associated with the rhizosphere and rhizoplane of two desert medicinal plants namely Pluchea dioscoridis and Pulicaria crispa growing in the South-Eastern desert of Aswan, Egypt. A total of 180 fungal isolates were screened based on their ability to grow on potato dextrose agar medium supplemented with 1% inulin. The isolated fungal colonies were morphologically identified according to cultural characteristics and spore-bearing structure. In addition, the inulinase activity of the isolated fungi was examined spectrophotometrically. Among these, Aspergillus terreus var. terreus 233, Botrytis cinerea, Aspergillus aegyptiacus, Cochliobolus australiensis 447 and Cochliobolus australiensis exhibited high inulinase activity ranging from 5.05 to 7.26 U/ml. This study provides a promising source of microbial inulinase, which can be scaled up for industrial applications. DOI: http://dx.doi.org/10.5281/zenodo.120564

A Novel Approach in Pigment Printing Using Nano-keratin Based Binder

This study is devoted to preparation and characterization of nano-keratin based binder (NKBB) from cheap renewable natural resources, namely coarse Egyptian wool or feather. The prepared NKBB is utilized as a biodegradable, environment-friendly and relatively cheap binder in textile pigment printing of polyester, pure polyacrylic, viscose, polyester/viscose, and polyester/acrylic fabrics. Different concentrations of the prepared NKBB as well as its mixture with commercially produced one are used in the pigment printing paste. The colour strength of the printed fabrics as well as their fastness properties to light, washing, and perspiration are evaluated. The effect of the used binder on the bending stiffness of the printed fabrics is also assessed. Results show that the NKBB gives almost the same colour strength and fastness properties as the commercial binder with improved stiffness of the printed samples in relation to that printed with commercial one

Preoperative gemcitabine based chemo-radiotherapy in locally advanced non metastatic pancreatic adenocarcinoma

<p>Abstract</p> <p>Introduction</p> <p>Almost 30% of patients with pancreatic cancer have locally advanced tumours in absence of distant metastasis. Surgical resection is often contraindicated. The combination of gemcitabine with concurrent radiation therapy is a promising new approach that is being investigated for treating patients' unresectable pancreatic cancer. This work aims at assessing the efficacy of preoperative gemcitabine based chemo-radiotherapy in increasing the resectability rate for patients' locally advanced pancreatic cancer.</p> <p>Patients and methods</p> <p>From March 2006 to November 2007, 25 patients with locally advanced non metastatic pancreatic cancer were treated by preoperative gemcitabine based chemo-radiotherapy. The radiation dose was 54 Gray in 30 fractions over 6 weeks prescribed to the isocenter. Gemcitabine (300 mg/m2) was given through a 30 minute intravenous infusion. This was done 30 minutes before the radiation sitting on a weekly basis throughout the radiotherapy course.</p> <p>Approximately 6 weeks after the completion of chemo radiation, an evaluation was performed regarding tumour response and resectability as well as acute toxicity. Pancreaticoduodenectomy was performed for operable patients with surgical reconstruction.</p> <p>Results</p> <p>Patients who achieved complete resection (CR) numbered 2 (8%), while those achieving partial resection (PR) totalled 11 (44%); six of these patients were considered ro be operable. Thus Pancreaticoduodenectomy was performed on 8 patients (2 with CR and 6 with PR) with surgical reconstruction. Patients who had a stable disease numbered 4 (16%), and those with progressive diseases included a group of eight (32%). The postoperative 30 day mortality occurred only in one patient (12.5%). Acute toxicity of chemoradiation occurred in the form of grade I leucopoenia and thrombocytopenia. Hepatic toxicity, nausea, and vomiting were found in 8 patients (32%), 10 patients (40%) and 4 patients (16%), respectively. The postoperative 30 day mortality occurred only in 1 patient. Also, minor biliary leakage and leakage from gastrointestinal anaestomosis both occurred in a single patient. Out of the 8 patients who underwent radical surgical resection, only one developed local recurrence and simultaneous liver metastasis during the follow up period. The median survival of all patients was 12 months.</p> <p>Conclusion</p> <p>Preoperative gemcitabine based chemoradiation might benefit patients with locally advanced non metastatic pancreatic cancer by increasing the resectability without significant acute toxicity.</p

Metabolomic profile, anti-trypanosomal potential and molecular docking studies of <i>Thunbergia grandifolia</i>

Trypanosomiasis is a protozoan disease transmitted via Trypanosoma brucei. This study aimed to examine the metabolic profile and anti-trypanosomal effect of methanol extract of Thunbergia grandifolia leaves. The liquid chromatography-high resolution electrospray ionisation mass spectrometry (LC-HRESIMS) revealed the identification of fifteen compounds of iridoid, flavonoid, lignan, phenolic acid, and alkaloid classes. The extract displayed a promising inhibitory activity against T. brucei TC 221 with MIC value of 1.90 μg/mL within 72 h. A subsequent in silico analysis of the dereplicated compounds (i.e. inverse docking, molecular dynamic simulation, and absolute binding free energy) suggested both rhodesain and farnesyl diphosphate synthase as probable targets for two compounds among those dereplicated ones in the plant extract (i.e. diphyllin and avacennone B). The absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiling of diphyllin and avacennone were calculated accordingly, where both compounds showed acceptable drug-like properties. This study highlighted the antiparasitic potential of T. grandifolia leaves