I watched this the other day on tv. I knew how they were using nano particles to target cancer. I didn't know anything about the people that developed it.
http://www.hybridmed....com/60min.html
It's well worth watching.
Posted 23 April 2008 - 12:45 AM
Posted 23 April 2008 - 01:36 AM
Posted 26 April 2008 - 10:32 PM
Posted 26 April 2008 - 11:56 PM
Posted 27 April 2008 - 02:20 AM
Posted 27 April 2008 - 04:45 AM
Posted 31 July 2008 - 07:48 PM
A compound called Photofrin is the only photosensitizer currently approved by the FDA. Photofrin is absorbed by cancer cells and, upon exposure to light, becomes active and kills cells. It is currently used to treat certain kinds of shallowly located tumors, but Yang and his colleagues realized that combing Photofrin with quantum dots could create an efficient method to kill even deeply seated cancer cells.
Upon exposure to high doses of radiation, the dots become luminescent and emit light; that light triggers the cancer-killing activity of the Photofrin. In theory, the process, which so far has been studied only in cancer cells grown in culture, could work on tumors located too deep within the body to be reached by an external light source.
Posted 01 August 2008 - 06:00 PM
Yet another nanotech cancer treatment with potential (and another Imminst discussion about the RF heat treatment)
A compound called Photofrin is the only photosensitizer currently approved by the FDA. Photofrin is absorbed by cancer cells and, upon exposure to light, becomes active and kills cells. It is currently used to treat certain kinds of shallowly located tumors, but Yang and his colleagues realized that combing Photofrin with quantum dots could create an efficient method to kill even deeply seated cancer cells.
Upon exposure to high doses of radiation, the dots become luminescent and emit light; that light triggers the cancer-killing activity of the Photofrin. In theory, the process, which so far has been studied only in cancer cells grown in culture, could work on tumors located too deep within the body to be reached by an external light source.
Posted 04 August 2008 - 10:19 AM
Posted 04 August 2008 - 01:36 PM
UVA (my undergraduate alma mater!) researchers announced a new breakthrough method to combat cancer:
http://www.physorg.c...s136556803.html
I noted especially the following: "In tests on human lung carcinoma cells, the process resulted in a 2-6 times lower tumor cell survival compared to radiation alone, but with minimal toxicity to nearby cells."
Posted 11 August 2008 - 07:39 PM
One of the fundamental challenges in radiation therapy is to destroy tumors with irradiation while preserving healthy tissue. With hadrontherapy, the use of fast ions as ionizing particles offers a major advantage because they deposit most of their energy in the tissue at the end of their range. This method enables tumors to be destroyed in a targeted manner by adjusting the initial energy of the particles. Also, the ions used in this technique are more effective in destroying cancerous tissue than conventional treatments (X-rays, for example).
In this work, the researchers combined, for the first time, ionic radiation with platinum-enriched cells, using agents such as cis-platinum(2), similar to molecules used in medicine. The impact of the incident ions (protons, carbon) and the electrons ejected along the way causes the platinum atoms to become highly ionized. The process of electron capture and emission that ensues significantly increases damage to surrounding molecules and considerably enhances cell death rate. In the presence of platinum, the effectiveness of ions at their end point is increased by at least 50 percent, thus improving how well the tumor can be targeted.
Posted 10 September 2008 - 08:08 PM
"What we found that was unexpected was within each oil droplet there was also a water droplet — a double emulsion," said Timothy Deming, professor and chair of the UCLA Department of Bioengineering and a member of both the California NanoSystems Institute (CNSI) at UCLA and UCLA's Jonsson Cancer Center. "We have a water droplet inside of an oil droplet, in water."
"If we have water-soluble drugs, we can load them inside," Deming said. "If we have water-insoluble drugs, we can load them inside as well. We can deliver them simultaneously."
"Here, you effectively combine both types of drug molecules in the same delivery package," Mason said. "This approach could be used for a combination therapy where you want to deliver two drugs simultaneously at a fixed ratio into the same location."
Posted 13 September 2008 - 01:30 AM
Posted 18 September 2008 - 08:24 PM
Over the past several years, researchers have had great success using antibodies and other molecules to target drugs to cells of particular tissue types. But once a drug gets inside the right cell, it's easy for it to get lost. Drugs are tiny compared with cells, and their charge, weight, and tendency to interact with water all determine where in the cell a drug ends up. "You have to design it such that it finds its way," says Volkmar Weissig, a professor of pharmacology at the Midwestern University College of Pharmacy, in Glendale, AZ, who developed the new targeted therapy with Vladimir Torchillin, director of the Center for Pharmaceutical Biotechnology and Nanomedicine, at Northeastern University, in Boston.
Subcellular targeting "is one of the biggest promises nanotechnology offers," says Jerry Lee, a project manager at the National Cancer Institute's Alliance for Nanotechnology in Cancer. The new research, he says, "offers early proof of concept of being able to target not only to cancer cells, but to pick and choose where in the cell to target."
Posted 18 September 2008 - 08:30 PM
The drug in this study specifically targets Akt3 and the mutant B-Raf and does therefore not affect normal cells, added Robertson, who is also director of the Foreman Foundation Melanoma Therapeutics Program at the Penn State College of Medicine Cancer Institute.
However, while knocking out specific genes may seem like a straightforward task, delivering the siRNA drug to cancerous cells is another story, because protective layers in the skin not only keep drugs out, but chemicals in the skin quickly degrade the siRNA.
To clear these two hurdles, Robertson and his team engineered hollow nano-sized particles -- nanoliposomes -- from globes of fatty acids into which they packed the siRNA. Next, the researchers used a portable ultrasound device to temporarily create microscopic holes in the surface of the skin, allowing the drug-filled particles to leak into tumor cells beneath.
"Think of it as tiny basketballs that each protect the siRNA inside from getting degraded by the skin," explained Robertson. "These basketballs fall through the holes created by the ultrasound and are taken up by the tumor cells, thereby delivering the siRNA drug into the tumor cells."
When the researchers exposed lab-generated skin -- made from human connective tissue -- containing early cancerous lesions to the treatment 10 days after the skin was created, the siRNA reduced the ability of cells containing the mutant B-Raf to multiply by nearly 60 to 70 percent, and more than halved the size of lesions after three weeks.
"This is essentially human skin with human melanoma cells, which provides an accurate picture of how the drug is acting," said Robertson.
Mice with melanoma that underwent the same treatment had their tumors shrink by nearly 30 percent when only the mutant B-Raf was targeted. There was no difference in the development of melanoma when the Akt3 gene alone was targeted, though existing tumors shrank by about 10 to 15 percent in two weeks.
However, when the researchers targeted both the Akt3 and the mutant B-Raf at the same time, they found that tumors in the mice shrank about 60 to 70 percent more than when either gene was targeted alone.
"If you knock down each of these two genes separately, you are able to reduce tumor development somewhat," Robertson said. "But knocking them down together leads to synergistic reduction of tumor development."
While human clinical trials could be years away, Robertson says the findings show the promise of personalized medicine, where patients could receive treatments designed to specifically target the errant genes or proteins for their disease.
Posted 18 September 2008 - 09:59 PM
Posted 01 October 2008 - 06:46 AM
Posted 01 October 2008 - 11:50 PM
Public release date: 1-Oct-2008
[ Print Article | E-mail Article | Close Window ]
Contact: Judith Barra Austin
jbaustin@purdue.edu
765-494-2432
Purdue University
Researchers use nanoparticles to deliver treatment for brain, spinal cord injuries
WEST LAFAYETTE, Ind. - Purdue University researchers have developed a method of using nanoparticles to deliver treatments to injured brain and spinal cord cells.
A team led by Richard Borgens of the School of Veterinary Medicine's Center for Paralysis Research and Welden School of Biomedical Engineering coated silica nanoparticles with a polymer to target and repair injured guinea pig spinal cords. That research is being published in the October edition of the journal Small.
The team then used the coated nanoparticles to deliver both the polymer and hydralazine to cells with secondary damage from a naturally produced toxin. That research was published in August by the journal Nanomedicine.
Borgens' group had previously shown benefits of the polymer polyethylene glycol, or PEG, to treat rats with brain injuries and dogs with spinal cord injuries. PEG specifically targets damaged cells and seals the injured area, reducing further damage. It also helps restore cell function, Borgens said.
(excerpt)
Posted 06 October 2008 - 08:14 PM
Posted 17 October 2008 - 03:29 AM
Jefferson scientists deliver toxic genes to effectively kill pancreatic cancer cells
New 'suicide gene' delivery approach offers potential for novel therapy
PHILADELPHIA – A research team, led by investigators at the Department of Surgery at Jefferson Medical College of Thomas Jefferson University and the Kimmel Cancer Center at Jefferson, has achieved a substantial "kill" of pancreatic cancer cells by using nanoparticles to successfully deliver a deadly diphtheria toxin gene. The findings – set to be published in the October issue of Cancer Biology & Therapy – reflect the first time this unique strategy has been tested in pancreatic cancer cells, and the success seen offers promise for future pre-clinical animal studies, and possibly, a new clinical approach.
The researchers found that delivery of a diphtheria toxin gene inhibited a basic function of pancreatic tumor cells by over 95 percent, resulting in significant cell death of pancreatic cancer cells six days after a single treatment. They also demonstrated that the treatment targets only pancreatic cancer cells and leaves normal cells alone, thus providing a potential 'therapeutic window.' Further, they are targeting a molecule that is found in over three-quarters of pancreatic cancer patients.
"For the pancreatic cancer world, this is very exciting," says the study's lead author, molecular biologist Jonathan Brody, Ph.D., assistant professor, Department of Surgery at Jefferson Medical College of Thomas Jefferson University, who works closely with the Samuel D. Gross Professor and Surgeon, Charles J. Yeo, M.D. "There are no effective targeted treatments for pancreatic cancer, aside from surgery for which only a minority of patients qualify. We are in great need of translating the plethora of molecular information we know about this disease to novel therapeutic ideas."
Pancreatic cancer is the fourth leading cause of cancer-related mortality in the U.S., reflecting the generally short survival time of patients - often less than a year from diagnosis.
This approach was originally developed in ovarian cancer cells by study co-author Janet Sawicki, Ph.D., a member of the Kimmel Cancer Center, and professor at the Lankenau Institute for Medical Research in Wynnewood, Pennsylvania. She and her group had recent success in reducing the size of ovarian tumors following treatment with diphtheria toxin nanoparticles.
The strategy is based on the fact that both ovarian and pancreatic cancer cells significantly over-express a protein found on the cell membrane, called mesothelin. The function of that molecule is unknown, but it is found in the majority of pancreatic tumors and ovarian cancer tumors. Other solid tumors also express mesothelin, but not at such a high rate.
"We don't know completely why cancer cells repeatedly turn on mesothelin genes to produce these membrane proteins, but it gives us a way to fool the cell and hijack its machinery, to trick it into making other more potent genes that will be detrimental to the cancer cells," Brody says.
To do that, the researchers devised an agent that consists of a bit of mesothelin DNA connected to the gene that produces the toxin from diphtheria, a highly contagious and potentially deadly bacteria, which is now controlled through childhood DPT vaccination. "Naked" DNA is then coated in a polymer to form nanoparticles that are taken up by the cancer cells.
Inside the cells, the agent performs its trickery. The nanoparticles biodegrade and the cell machinery senses genetic material from mesothelin. It activates the diphtheria toxin gene, which then turns on production of the toxin which allows the toxin to then do its work on the cancer cells, Brody says. Within 24 hours of delivery, the toxin disrupted production of protein machinery by over 95 percent, and within six days, a number of cancer cells die or are arrested.
"The cancer thinks it is turning on mesothelin and once it gets started reading that genetic code, it can't stop," he says. "So it will read the bacteria's DNA and produce the toxin which shuts down protein production in the cancer cells."
"It worked well in our cell culture models and now we are moving into pre-clinical experiments," Brody says.
The agent will not attack normal cells because the molecular machinery needed to turn on mesothelin is not found in normal cells, Brody says. Additionally, Sawicki has modified the diphtheria DNA to ensure that toxin that might be released from dying cancer cells is not taken up by healthy, normal cells.
But the researchers are now perfecting even more stringent measures to ensure safety, he says. "We can't help being hopeful," he says. "Our findings suggest that such a strategy will work in the clinical setting against the majority of pancreatic tumors."
Posted 28 October 2008 - 02:35 PM
Seeing Nanotubes Targeting Tumors In Vivo
Carbon nanotubes have significant potential for delivering both imaging and therapeutic agents to tumors, but there is still a need to better quantify how well these rolled-up sheets of graphite can target tumors. Now, thanks to the development of a microscope capable of measuring Raman spectroscopic signals from living mice, researchers have a noninvasive tool to study where carbon nanotubes travel once they are injected into the blood stream.
Reporting its work in the journal Nano Letters, a team of investigators led by Sanjiv Gambhir, M.D., Ph.D., principal investigator of the Center for Cancer Nanotechnology Excellence Focused on Therapy Response (CCNE-TR), based at Stanford University, and Hongjie Dai, Ph.D., also a member of the CCNE-TR, described its use of an optimized Raman microscope to track two different sets of carbon nanotubes as they transited through the body of living mice. One of the nanotubes was covered with the tumor-targeting peptide known as RGD; the other set was used without any added functionality.
Although other investigators have used positron emission tomography (PET) to follow radioactively labeled nanotubes as they move through the body, this technique requires the use of expensive radioisotopes and scanning instruments. To overcome these limitations, the CCNE-TR team took advantage of the fact that carbon nanotubes generate a characteristic Raman emission peak. Earlier this year (click here to see story), Dr. Gambhir and his colleagues described a new type of Raman microscope designed specifically for use in bioimaging studies.
Using this Raman microscope, the investigators were able to track differences in nanotube trafficking between the targeted and untargeted nanotubes. Although both sets of nanotubes showed an initial spike in tumor accumulation, the concentration of untargeted nanotubes in tumors began dropping as early as 20 minutes after injection. In contrast, the tumor concentration of the targeted nanotubes remained elevated for at least 72 hours after injection. In animals treated with the targeted nanotubes, tumors were readily visible as early as 2 hours postinjection and for at least 72 hours. The investigators noted that their results are consistent with those obtained using radioactively labeled nanotubes and PET imaging.
This work, which is detailed in the paper “Noninvasive Raman Spectroscopy in Living Mice for Evaluation of Tumor Targeting With Carbon Nanotubes,” was supported by the NCI Alliance for Nanotechnology in Cancer, a comprehensive initiative designed to accelerate the application of nanotechnology to the prevention, diagnosis, and treatment of cancer. An abstract of this paper is available at the journal’s Web site.
View abstract
Posted 29 October 2008 - 03:20 AM
a cancer article http://health.usnews...code.html?msg=1
Edited by bobscrachy, 29 October 2008 - 03:22 AM.
Posted 01 November 2008 - 02:38 PM
Nanoparticles Target Multiple Cancer Genes, Shrink Tumors More Effectively
Nanoparticles filled with small interfering RNA (siRNA) molecules targeting two genes that trigger melanoma have shown that they can inhibit the development of melanoma, the most dangerous type of skin cancer. The nanoparticles, administered in conjuction with ultrasound irradiation, exerted their effects only on malignant tissue, leaving healthy tissue alone.
“It is a very selective and targeted approach,” said Gavin Robertson, Ph.D., who led the team of researchers from the Penn State College of Medicine. “And unlike most other cancer drugs that inadvertently affect a bunch of proteins, we are able to knock out single genes.”
The Penn State researchers speculated that siRNA could turn off the two cancer-causing genes and potentially treat the deadly disease more effectively. “siRNA checks the expression of the two genes, which then lowers the abnormal levels of the cancer causing proteins in cells,” explained Dr. Robertson. This research appears in the journal Cancer Research.
In recent years, researchers have zeroed in on two key genes—B-Raf and Akt3—that play key roles in the development of melanoma. Mutations in the B-Raf gene, the most frequently mutated gene in melanoma, lead to the production of a mutant form of the B-Raf protein, which then helps mole cells survive and grow. B-Raf mutations alone, however, do not trigger melanoma development. That event requires a second protein, called Akt3, that regulates the activity of the mutated B-Raf, which aids the development of melanoma. The siRNA agents used in this study specifically target Akt3 and the mutant B-Raf and therefore do not affect normal cells.
However, although knocking out specific genes may seem like a straightforward task, delivering the siRNA drug to cancerous cells is another story, because not only do protective layers in the skin keep drugs out but also chemicals in the skin quickly degrade the siRNA. To clear these two hurdles, Dr. Robertson and his team engineered lipid-based nanoparticles that can incorporate siRNA into their hollow interiors. The researchers then used a portable ultrasound device to temporarily create microscopic holes in the surface of the skin, allowing the drug-filled particles to leak into tumor cells beneath.
When the researchers exposed lab-generated skin containing early cancerous lesions to the treatment 10 days after the skin was created, the siRNA reduced the ability of cells containing the mutant B-Raf to multiply by nearly 60 to 70 percent and more than halved the size of lesions after 3 weeks. “This is essentially human skin with human melanoma cells, which provides an accurate picture of how the drug is acting,” said Dr. Robertson.
Mice with melanoma that underwent the same treatment had their tumors shrink by nearly 30 percent when only the mutant B-Raf was targeted. There was no difference in the development of melanoma when the Akt3 gene alone was targeted, although existing tumors shrank by about 10 to 15 percent in 2 weeks. However, when the researchers targeted both Akt3 and mutant B-Raf at the same time, they found that tumors in the mice shrank about 60 to 70 percent more than when either gene was targeted alone.
“If you knock down each of these two genes separately, you are able to reduce tumor development somewhat,” Dr. Robertson said. “But knocking them down together leads to synergistic reduction of tumor development.”
This work, which was supported in part by the National Cancer Institute, was detailed in the paper “Targeting V600EB-Raf and Akt3 Using Nanoliposomal-Small Interfering RNA Inhibits Cutaneous Melanocytic Lesion Development.” An abstract of this paper is available at the journal’s Web site.
Posted 01 December 2008 - 07:55 PM
Carbon Nanotubes Improve Protein Array Detection Limits a thousand fold
To detect cancer as early as possible, dozens of research groups are developing methods to detect trace levels of cancer-related proteins and genes in blood or other biological samples. Those efforts should get a boost thanks to new research results showing that carbon nanotubes can serve as incredibly sensitive optical labels for use in a wide variety of assay systems.
Reporting its work in the journal Nature Biotechnology, a research team headed by Hongjie Dai, Ph.D., Stanford University and the Center for Cancer Nanotechnology Excellence Focused on Therapeutic Response, describes a new type of coating developed specifically for attaching any number of different types of targeting agents to the surface of single-walled carbon nanotubes. This coating, a branched form of the biocompatible polymer poly(ethylene glycol) (PEG), enabled the investigators to readily couple antibodies to carbon nanotubes. In the experiments reported in their current paper, the antibodies were designed to identify specific proteins immobilized on a standard protein array microchip.
Carbon nanotubes can function as bright Raman optical tags that are readily detected when irradiated with light. Experiments comparing the lower limits of protein detection using an antibody-labeled carbon nanotube tag and a standard fluorescence tag showed that the carbon nanotube-enabled assay was at least 1,000 times more sensitive than the fluorescence assay. At least part of this improvement resulted from the almost total elimination of background fluorescence that can confound other detection schemes. In addition, the investigators found that the Raman tags were useful over a larger range of concentrations, ranging from 10 nanomoles to 1 femtomoles. The investigators note in their paper that the coating they developed also should enable them to create Raman tags that can detect nucleic acids and other types of biomolecules.
Meanwhile, a second group of investigators, led by Beatrice Knudsen, M.D., Ph.D., Fred Hutchinson Cancer Research Center, and Selena Chan, Ph.D., Intel Corporation, has developed a mathematical technique for analyzing the specific spectral output of different Raman probes, making it possible to create highly multiplexed assays using these probes. Unlike traditional fluorescent labels that typically absorb and emit light in a very narrow band of frequencies, Raman probes generate complex frequency spectra that are chock-full of information.
The Knudsen-Chan team, which published its results in the journal ACS Nano, developed a method for sorting out the various spectral peaks associated with individual nanoscale Raman probes that were part of a mixture of these probes. Each probe was designed to bind to a different biomolecule. In one experiment, the investigators were able to decipher a complex Raman spectrum that included the optical emission from three different Raman probes and thereby determine the amount of each probe in the mixture. The researchers note that their method for spectral analysis is exceedingly simple to conduct and is amenable to high-throughput analysis in any type of multiplexed assay system.
The work by Dr. Dai and his colleagues, which is detailed in the paper “Protein microarrays with carbon nanotubes as multicolor Raman labels,” was supported by the NCI Alliance for Nanotechnology in Cancer, a comprehensive initiative designed to accelerate the application of nanotechnology to the prevention, diagnosis, and treatment of cancer. An investigator from Tsinghua University in Beijing, China, also participated in this study. An abstract of this paper is available at the journal’s Web site.
View abstract
The work led by Drs. Knudsen and Chan, which is detailed in the paper “Spectral analysis of multiplex Raman probe signatures,” was supported by the National Cancer Institute (NCI). An abstract of this paper is available at the journal’s Web site.
Posted 16 December 2008 - 11:28 PM
In the new study, Mark Kester, James Adair and colleagues at Penn State's Hershey Medical Center and University Park campus point out that certain nanoparticles have shown promise as drug delivery vehicles. However, many of these particles will not dissolve in body fluids and are toxic to cells, making them unsuitable for drug delivery in humans. Although promising as an anti-cancer agent, ceramide also is insoluble in the blood stream making delivery to cancer cells difficult.
The scientists report a potential solution with development of calcium phosphate nanocomposite particles (CPNPs). The particles are soluble and with ceramide encapsulated with the calcium phosphate, effectively make ceramide soluble. With ceramide encapsulated inside, the CPNPs killed 95 percent of human melanoma cells and was "highly effective" against human breast cancer cells that are normally resistant to anticancer drugs, the researchers say.
Penn State Research Foundation has licensed the calcium phosphate nanocomposite particle technology known as "NanoJackets" to Keystone Nano, Inc. MK and JA are CMO and CSO, respectively.
Posted 24 December 2008 - 12:50 PM
Posted 05 January 2009 - 07:44 PM
The biochip uses giant magnetoresistive sensors like those that read data in disk drives. Instead of sensing magnetic bits, the sensors detect magnetic nanoparticles attached to protein molecules. The biochip captures protein biomarkers that indicate cancer and attaches magnetic nanoparticles to them.
The magnetic sensors can detect as few as 10 magnetic nanoparticles, which allows the biochip to detect small concentrations of the cancer-indicating proteins.
Posted 02 February 2009 - 06:59 AM
Antibodies that target epidermal growth factor receptor (EGFR) have proven themselves as potent anticancer drugs. Now, a team of investigators led by Shuming Nie, Ph.D., and Lily Yang, Ph.D., both at the Emory University School of Medicine and members of the Emory-Georgia Tech Nanotechnology Center for Personalized and Predictive Oncology, is aiming to capitalize on this targeting ability, using a modified anti-EGFR antibody to delivery nanoparticles into tumor cells.
Reporting its work in the journal Small, the Emory team describes its use of a so-called single-chain antibody to mimic the tumor-targeting properties of a standard anti-EGFR antibody. Standard antibodies are large biomolecules comprising two pairs of two peptide chains known as heavy and light chains. In part because of their large size, antibodies are difficult to work with and often have difficulty accessing the deeper regions of a solid tumor. To overcome these problems, the investigators built an artificial antibody comprising portions of a single heavy chain and a light chain hooked together. This construct is less than 20% of the size and weight of a full antibody, but it retains the larger molecule’s binding abilities for EGFR.
With their artificial antibody in hand, the investigators used it as a tumor-targeting agent for two types of nanoparticles—quantum dots, which can be seen using fluorescence imaging, and iron oxide nanoparticles, which can be imaged using standard magnetic resonance imaging (MRI) instruments. The Emory team attached the targeting agent to the nanoparticles using a novel linking technology they developed for this purpose.
With the two types of antibody-linked nanoparticles in hand, the investigators conducted a series of experiments to determine whether these nanoscale constructs would target tumors and whether tumor cells would take up take the antibody-nanoparticle combos. Indeed, targeted nanoparticles homed in quickly on tumors when injected into tumor-bearing mice, whereas untargeted nanoparticles accumulated primarily in the liver and spleen. The targeted nanoparticles also gained rapid entry into tumor cells, whereas the untargeted nanoparticles did not. The nanoparticles were visible using both fluorescence imaging and MRI.
This work, which was detailed in the paper “Single chain epidermal growth factor receptor antibody conjugated nanoparticles for in vivo tumor targeting and imaging,” was supported in part by the NCI Alliance for Nanotechnology in Cancer, a comprehensive initiative designed to accelerate the application of nanotechnology to the prevention, diagnosis, and treatment of cancer. Investigators from Ocean NanoTech, LLC, the Fox Chase Cancer Center, and the University of Washington in Seattle also participated in this study. An abstract of this paper is available at the journal’s Web site.
Posted 02 February 2009 - 06:58 PM
In the mouse model, fluorescent tagging showed that the plain hollow gold nanospheres only accumulated near the tumor's blood vessels, while the targeted nanospheres were found throughout the tumor.
"There are many biological barriers to effective use of nanoparticles, with the liver and spleen being the most important," Li said. The body directs foreign particles and defective cells to those organs for destruction.
Most of the targeted nanospheres in the treated mice gathered in the tumor, with smaller amounts found in the liver and spleen. Most of the untargeted nanospheres gathered in the spleen, then in the liver and then the tumor, demonstrating the selectivity and importance of targeting.
In another group of mice, near-infrared light beamed into tumors with targeted nanospheres destroyed 66 percent of the tumors, but only destroyed 7.9 percent of tumors treated with untargeted nanospheres.
The researchers used F-18-labeled glucose to monitor tumor activity by observing how much glucose it metabolized. This action "lights up" the tumor for positron emission tomography (PET) imaging. Tumors treated with targeted shells largely went dark.
"Clinical implications of this approach are not limited to melanoma," Li said. "It's also a proof of principle that receptors common to other cancers can also be targeted by a peptide-guided hollow gold nanosphere. We've also shown that non-invasive PET can monitor early response to treatment."
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