Posts Tagged ‘NANOPARTICLES’

Synthesis and optical properties of polyurethane foam modified with silver nanoparticles

This paper for the first time describes peculiarities of synthesis of polyurethane foam modified with silver nanoparticles as a potential material for optical sensors in analytical chemistry. We found that the unique sorptional properties of polyurethane foam gave an opportunity to perform such a synthesis by two different approaches. The first one was based on sorption of previously synthesized in-solution nanoparticles by polyurethane foam, the second one consisted in preparation of nanoparticles directly in polyurethane foam matrix. This possibility is novel and interesting for practical use because the nanoparticles in polyurethane foam are capable of surface plasmon resonance. The influence of different factors during the synthesis was investigated and the optimal conditions were found. The samples prepared were characterized by diffuse reflectance spectroscopy and scanning electron microscopy. On the basis of the results obtained we first suggested that this material is att…

First Master’s of Science in Nanomedicine degree program in US announced

We received this announcement of the new M.S. in Nanomedicine program from Radiological Technologies University – VT : Radiological Technologies University VT, located in South Bend, Indiana is pleased to announce the approval of the first Master’s of Science in Nanomedicine degree program in the country. The formal approval was granted today through the Indiana Commission for Postsecondary Proprietary Education. Nanomedicine is the medical application of Nanotechnology which focuses its work at the cellular level to do everything from repairing tissue, to cleaning arteries, to attacking cancer cells and viruses like AIDS. The RTU Nanomedicine program is the first of its kind in the country by combining Nanotechnology with an emphasis on Medical Physics. Radiological Technologies University offers degree programs ranging from a Bachelor’s degree in Medical Dosimetry to Master’s of Science degrees in Medical Dosimetry, Medical Physics, Medical Health Physics, and Nanomedicine. Although Foresight has no information about the details of this nanomedicine program, just one item from the NCI Alliance for Nanotechnology in Cancer news archive highlights the potential of nanomedicine, specifically the application of nanoparticles to cancer therapy. From “ Nanoparticles seek and destroy drug-resistant glioblastoma “: Glioblastoma is one of the most aggressive forms of brain cancer. Rather than presenting as a well-defined tumor, glioblastoma will often infiltrate the surrounding brain tissue, making it extremely difficult to treat surgically or with chemotherapy or radiation. Likewise, several mouse models of glioblastoma have proven completely resistant to all treatment attempts. In a new study, a team led by scientists at Sanford-Burnham Medical Research Institute (SBMRI) and the Salk Institute for Biological Studies developed a method to combine a tumor-homing peptide, a cell-killing peptide, and a nanoparticle that both enhances tumor cell death and allows the researchers to image the tumors. When used to treat mice with glioblastoma, this new nanosystem eradicated most tumors in one model and significantly delayed tumor development in another. These findings were published in the Proceedings of the National Academy of Sciences of the USA [ abstract ]. “This is a unique nanosystem for two reasons,” said project leader Erkki Ruoslahti of the SBMRI. “First, linking the cell-killing peptide to nanoparticles made it possible for us to deliver it specifically to tumors, virtually eliminating the killer peptide’s toxicity to normal tissues. Second, ordinarily researchers and clinicians are happy if they are able to deliver more drugs to a tumor than to normal tissues. We not only accomplished that, but were able to design our nanoparticles to deliver the killer peptide right where it acts, at the mitochondria, the cell’s energy-generating center.” The nanosystem developed in this study is made up of three elements. First, a nanoparticle acts as the carrier framework for an imaging agent and for two peptides. One of these peptides guides the nanoparticle and its payload specifically to cancer cells and the blood vessels that feed them by binding cell surface markers that distinguish them from normal cells. This same peptide also drives the whole system inside these target cells, where the second peptide wreaks havoc on the mitochondria, triggering cellular suicide through a process known as apoptosis. Together, these peptides and nanoparticles proved extremely effective at treating two different mouse models of glioblastoma. In the first model, treated mice survived significantly longer than untreated mice. In the second model, untreated mice survived for only eight to nine weeks. In sharp contrast, treatment with this nanosystem cured all but one of ten mice. What’s more, in addition to providing therapy, the nanoparticles could aid in diagnosing glioblastoma; they are made of iron oxide, which makes them and the tumors they target visible by magnetic resonance imaging. In a final twist, the researchers made the whole nanosystem even more effective by administering it to the mice in conjunction with a third peptide. Ruoslahti and his team previously showed that this peptide, known as iRGD, helps co-administered drugs penetrate deeply into tumor tissue. iRGD has been shown to substantially increase treatment efficacy of various drugs against human breast, prostate, and pancreatic cancers in mice, achieving the same therapeutic effect as a normal dose with one-third as much of the drug. Here, iRGD enhanced nanoparticle penetration and therapeutic efficacy. In this study, the researchers tested their nanoparticles on mice that developed glioblastomas with the same characteristics as observed in humans with the disease. Once the nanoparticles reached the tumors’ blood vessels, they delivered their payload directly to the cell’s power producer, the mitochondria. By destroying the blood vessels and also some surrounding tumor cells, the investigators found they were able to cure some mice and extend the lifespan of the rest.”

Hydrogen sensing properties of dielectrophoretically assembled SnO 2 nanoparticles on CMOS-compatible micro-hotplates

We fabricated nanoparticle-based gas through in situ ac dielectrophoretical assembling of drop-coated SnO 2 nanoparticles to bridge the gap between electrodes with high aspect ratio. While the conventional dielectrophoresis (DEP) adopts a microfluidic system for continuous flow of the solution during the process, we just drop-coated a small amount of solution onto the electrodes and executed in situ DEP for a very short time. This is a very simple, cost-effective, time-saving, and highly reproducible process. We fixed the duration time and applied voltage for the DEP at 1 s and 1 V respectively and changed the frequencies from 1 up to 500 kHz. I–V characteristics of the samples were checked and it was found that DEP samples fabricated at 1 s, 1 V and 150 kHz conditions showed considerably higher connectivity of the nanoparticles. This can be attributed to the excellent step coverage achieved by ac DEP under those conditions. The devices drop-coated …

The use of myristic acid as a ligand of polyethylenimine/DNA nanoparticles for targeted gene therapy of glioblastoma

To establish a gene delivery system for brain targeting, a low molecular weight polyethylenimine (PEI 10 K ) was modified with myristic acid (MC), and complexed with DNA, yielding MC-PEI 10 K / DNA nanoparticles successfully. The nanoparticles were observed to be successfully taken up by the brains of mice. The transfection efficiency of the nanoparticles was then investigated, and both the in vitro and in vivo gene expression of MC-PEI 10 K / DNA nanoparticles is significantly higher than that of unmodified PEI 10 K / DNA nanoparticles. The anti-glioblastoma effect of MC-PEI 10 K / pORF-hTRAIL was demonstrated by the survival time of intracranial U87 glioblastoma-bearing mice. The median survival time of the MC-PEI 10 K / pORF-hTRAIL group (28 days) was significantly longer than that of the PEI 10 K / pORF-hTRAIL group (24 days), the MC-PEI 10 K / pGL

Biocompatible transferrin-conjugated sodium hexametaphosphate-stabilized gold nanoparticles: …

The feasibility of using gold nanoparticles (AuNPs) for biomedical applications has led to considerable interest in the development of novel synthetic protocols and surface modification strategies for AuNPs to produce biocompatible molecular probes. This investigation is, to our knowledge, the first to elucidate the synthesis and characterization of sodium hexametaphosphate (HMP)-stabilized gold nanoparticles (Au–HMP) in an aqueous medium. The role of HMP, a food additive, as a polymeric stabilizing and protecting agent for AuNPs is elucidated. The surface modification of Au–HMP nanoparticles was carried out using polyethylene glycol and transferrin to produce molecular probes for possible clinical applications. In vitro cell viability studies performed using as-synthesized Au–HMP nanoparticles and their surface-modified counterparts reveal the biocompatibility of the nanoparticles. The transferrin-conjugated nanoparticles have significantly higher cellular uptake in J5 ce…

Cytoprotective properties of a fullerene derivative against copper

To delineate the complexity of the response of cells to nanoparticles we have performed a study on HT-29 human colon carcinoma cells exposed first to a fullerene derivative C 60 (OH) 20 and then to physiological copper ions. Our cell viability, proliferation, and intracellular reactive oxygen species (ROS) production assays clearly indicated that C 60 (OH) 20 suppressed cell damage as well as ROS production induced by copper, probably through neutralization of the metal ions by C 60 (OH) 20 in the extracellular space, as well as by adsorption and uptake of the nanoparticles surface-modified by the biomolecular species in the cell medium. This double-exposure study provides new data on the effects of nanoparticles on cell metabolism and may aid the treatment of oxidant-mediated diseases using nanomedicine.

Low-macroscopic field emission properties of wide bandgap copper aluminium oxide nanoparticles for low-power panel applications

Field emission properties of CuAlO 2 nanoparticles are reported for the first time, with a low turn-on field of approximately 2 V µm − 1 and field enhancement factor around 230. The field emission process follows the standard Fowler–Nordheim tunnelling of cold electron emission. The emission mechanism is found to be a combination of low electron affinity, internal nanostructure and large field enhancement at the low-dimensional emitter tips of the nanoparticles. The field emission properties are comparable to the conventional carbon-based field emitters, and thus can become alternative candidate for field emission devices for low-power panel applications.

Magnetic nanoparticle biodistribution following intratumoral administration

Recently, heat generated by iron oxide nanoparticles (IONPs) stimulated by an alternating magnetic field (AMF) has shown promise in the treatment of cancer. To determine the mechanism of nanoparticle-induced cytotoxicity, the physical association of the cancer cells and the nanoparticles must be determined. We have used transmission electron microscopy (TEM) to define the time dependent cellular uptake of intratumorally administered dextran-coated, core–shell configuration IONP having a mean hydrodynamic diameter of 100–130 nm in a murine breast adenocarcinoma cell line (MTG-B) in vivo . Tumors averaging volumes of 115 mm 3 were injected with iron oxide nanoparticles. The tumors were then excised and fixed for TEM at time 0.1–120 h post-IONP injection. Intracellular uptake of IONPs was 5.0, 48.8 and 91.1% uptake at one, 2 and 4 h post-injection of IONPs, respectively. This information is essential for the effective use of IONP hyperthermia in cancer treatment.

Synthesis, characterization and luminescent properties of Tb(III) doped Eu(III) complex nanoparticles

In recent years, considerable effort has been devoted to the development of transition metal complexes as novel luminescent materials that have potential application in the fluorescent labels for chemistry or biology. Among them, the nanostructured lanthanide complexes have been receiving much attention because of their excellent luminescence properties, which are attributed to the intramolecular energy transfer between the ligands and chelated lanthanide ions and their high solubility in water. This paper presents some results of the synthesis and characterization of the nanoparticles of Eu(III) and Tb(III) complexes with naphthoyl trifluoroacetone and tri-n-octylphosphineoxide. In addition, the influence of the dopant Tb(III) on the photophysical properties of the system of lanthanide complexes of Eu(III) and Tb(III) is also studied.

Nature Makes Silver Nanoparticles

Because they have a variety of useful properties, especially as antibacterial and antifungal agents, silver nanoparticles increasingly are being used in a wide variety of industrial and consumer products. This, in turn, has raised concerns about what happens to them once released into the environment. Now, a team of researchers from the Florida Institute of Technology ( FIT ), the State University of New York ( SUNY ) Buffalo, and the National Institute of Standards and Technology ( NIST ) reports that Nature may be making silver nanoparticles on her own. The researchers found that, given a source of silver ions, naturally occurring humic acid will synthesize stable silver nanoparticles. “Our colleague, Virender Sharma, had read an article in which they were using wine to form nanoparticles. He thought that, based on the similar chemistry, we should be able to produce silver nanoparticles with humic acids,” explains FIT chemist Mary Sohn. “First we formed them by traditional methods and then we tried one of our river sediment humic acids,” says Sohn. “We were really excited that we could see the characteristic yellow color of the nanoparticles.” Samples were sent to Sarbajit Banerjee at SUNY Buffalo and Robert MacCuspie at NIST for detailed analyses to confirm the presence of silver nanoparticles. “Humic acid” is a complex mixture of many organic acids that are formed during the decay of dead organic matter. Although the exact composition varies from place to place and season to season, humic acid is ubiquitous in the environment. Metallic nanoparticles, MacCuspie explains, have characteristic colors that are a direct consequence of their size.** Silver nanoparticles appear a yellowish brown. The team mixed silver ions with humic acid from a variety of sources at different temperatures and concentrations and found that acids from river water or sediments would form detectable silver nanoparticles at room temperature in as little as two to four days. Moreover, MacCuspie says, the humic acid appears to stabilize the nanoparticles by coating them and preventing the nanoparticles from clumping together into a larger mass of silver. “We believe it’s actually a similar process to how nanoparticles are synthesized in the laboratory,” he says, except that the lab process typically uses citric acid at elevated temperatures. “This caught us by surprise because a lot of our work is focused on how silver nanoparticles may dissolve when they’re released into the environment and release silver ions,” MacCuspie says. Many biologists believe the toxicity of silver nanoparticles, the reason for their use as an antibacterial or antifungal agent, is due to their high surface area that makes them an efficient source of silver ions, he says, but “this creates the idea that there may be some sort of natural cycle returning some of the ions to nanoparticles.” It also helps explain the discovery, over the past few years, of silver nanoparticles in locations like old mining regions that are not likely to have been exposed to man-made nanoparticles, but would have significant concentrations of silver ions. Read More Paper