Nanoemulsion vaccines

A novel technique for vaccinating against a variety of infectious diseases – using an oil-based emulsion placed in the nose, rather than needles – has proved able to produce a strong immune response against smallpox and HIV in two new studies.

The results build on previous success in animal studies with a nasal nanoemulsion vaccine for influenza, reported by University of Michigan researchers in 2003.

Nanoemulsion vaccines developed at the Michigan Nanotechnology Institute for Medicine and the Biological Sciences at U-M are based on a mixture of soybean oil, alcohol, water and detergents emulsified into ultra-small particles smaller than 400 nanometers wide, or 1/200th the width of a human hair. These are combined with part or all of the disease-causing microbe to trigger the body’s immune response.

The surface tension of the nanoparticles disrupts membranes and destroys microbes but does not harm most human cells due to their location within body tissues. Nanoemulsion vaccines are highly effective at penetrating the mucous membranes in the nose and initiating strong and protective types of immune response, Baker says. U-M researchers are also exploring nasal nanoemulsion vaccines to protect against bioterrorism agents and hepatitis B.

The smallpox results, which appear in the February issue of Clinical Vaccine Immunology, could lead to an effective human vaccine against smallpox that is safer than the present live-vaccinia virus vaccine because it would use nanoemulsion-killed vaccinia virus, says Baker.

Anna U. Bielinska, Ph.D., a research assistant professor in internal medicine at the U-M Medical School, and others on Baker’s research team developed a killed-vaccinia virus nanoemulsion vaccine which they placed in the noses of mice to trigger an immune response. They found the vaccine produced both mucosal and antibody immunity, as well as Th1 cellular immunity, an important measure of protective immunity.

When the mice were exposed to live vaccinia virus to test the vaccine’s protective effect, all of them survived, while none of the unvaccinated control mice did. The researchers conclude that the nanoemulsion vaccinia vaccine offers protection equal to that of the existing vaccine, without the risk of using a live virus or the need for an inflammatory adjuvant such as alum hydroxide.

In antibody immunity, antibodies bind invading microbes as they circulate through the body. In cellular immunity, the immune system attacks invaders inside infected cells. There is growing interest in vaccines that induce mucosal immunity, in which the immune system stops and kills the invader in mucous membranes before it enters body systems.

A National Institutes of Health program, the Great Lakes Regional Centers of Excellence for Biodefense and Emerging Infectious Diseases, funded the research. If the federal government conducts further studies and finds the nanoemulsion smallpox vaccine effective in people, it could be a safer way to protect citizens and health care workers in the event of a bioterrorism attack involving smallpox, Baker says.

That would allay concerns about the current vaccine’s safety which arose in 2002. On the eve of the Iraq War, the Bush administration proposed a voluntary program to vaccinate military personnel and 500,000 health care workers with the existing vaccine to prepare for the possible use of smallpox virus as a biological weapon.

Silica nanoparticles more effectively deliver bacteria killing nitric oxide

Mark Schoenfisch and his lab of analytical chemists at UNC have created nano-scale scaffolds made of silica and loaded with nitric oxide (NO) which can be released in a precisely controlled way. Nitric Oxide can be used to kill bacteria.

Schoenfisch, Hetrick and their colleagues tested their silica scaffolds head-to-head with small molecules against the bacteria Pseudomonas aeruginosa, which is commonly found in burn and other wound infections.

NO delivered by both methods completely killed the bacteria. But the silica nanoparticles delivered the NO right to the bacteria’s doorstep. In contrast, the small molecules released NO indiscriminately, and the concentration of NO is lost as it makes its way toward bacterial cells.

“With the silica particles, more NO actually reached the inside of the cells, enhancing the efficacy of the nanoparticles compared to the small molecule. So, the overall amount of NO needed to kill bacteria is much less with silica nanoparticles,” Schoenfisch said. “And, with small molecules, you’re left with potentially toxic byproducts,” Schoenfisch said. Using mouse cells, they proved that the silica nanoparticles weren’t toxic to healthy cells, but the small molecules were.

Future research will include studying additional bacterial strains, active targeting, preferential uptake and biodistribution studies.

Nanomaterials used to localize and control drug delivery

Nanoscale polymer films, about four nanometers per layer, were used to build a sort of matrix or platform to hold and slowly release an anti-inflammatory drug. The films are orders of magnitude thinner than conventional drug deliver coatings, said Genhong Cheng, a researcher at UCLA’s Jonsson Comprehensive Cancer Center and one of the study’s authors. A nanometer is one billionth of a meter.

“Using this system, drugs could be released slowly and under control for weeks or longer,” said Cheng, a professor of microbiology, immunology and molecular genetics. “A drug that is given orally or through the bloodstream travels throughout the system and dissipates from the body much more quickly. Using a more localized and controlled approach could limit side effects, particularly with chemotherapy drugs.”

Researchers coated tiny chips with layers of the nanoscale polymer films, which are inert and helped provide a Harry Potter-like invisibility cloak for the chips, hiding them from the body’s natural defenses. They then added Dexamethasone, an anti-inflammatory drug, between the layers. The chips were implanted in mice, and researchers found that the Dexamethasone-coated films suppressed the expression of cytokines, proteins released by the cells of the immune system to initiate a response to a foreign invader. Mice without implants and those with uncoated implants were studied to compare immune response.

The uncoated implants generated an inflammatory response from the surrounding tissue, which ultimately would have led to the body’s rejection of the implant and the breakdown of its functionality. However, tissue from the mice without implants and the mice with the nano-cloaked implants were virtually identical, proving that the film-coated implants were effectively shielded from the body’s defense system, said Edward Chow, a former UCLA graduate student who participated in the study and is one of its authors.

The nanomaterial technology serves as a non-invasive and biocompatible platform for the delivery of a broad range of therapeutics, said Dean Ho, an assistant professor of biomedical and mechanical engineering with the McCormick School of Engineering and Applied Science, a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University and the study’s senior author.

The technology also may prove to be an effective approach for delivering multiple drugs, controlling the sequence of multi-drug delivery strategies and enhancing the life spans of commonly implanted devises such as cardiac stents, pacemakers and continuous glucose monitors

Magnetic Nanoparticles could be used to control uptake of drugs by cell receptors

For the first time, researchers have demonstrated a means of controlling cell functions with a physical, rather than chemical, signal. Immune cells coated with nanoparticles take up calcium in the presence of a magnetic field. Each nanoparticle measures approximately 30 nanometers in diameter.

In this image, yellow cells are taking up calcium in response to a localized magnetic field. Cells that are farther away from the field are shown in purple and do not take up calcium. Credit: Donald Ingber, Harvard Medical School

Using a magnetic field to pull together tiny beads targeted to particular cell receptors, Harvard researchers made cells take up calcium, and then stop, then take it up again.

This is another important step to cellular and molecular control to enable nanomedicine

Ingber's group demonstrated its method for biomagnetic control using a type of immune-system cell that mediates allergic reactions.

Targeted nanoparticles with iron oxide cores were used to mimic antigens in vitro. Each is attached to a molecule that in turn can attach to a single receptor on an immune cell. When Ingber exposes cells bound with these particles to a weak magnetic field, the nanoparticles become magnetic and draw together, pulling the attached cell receptors into clusters. This causes the cells to take in calcium. (In the body, this would initiate a chain of events that leads the cells to release histamine.) When the magnetic field is turned off, the particles are no longer attracted to each other, the receptors move apart, and the influx of calcium stops.

"It's not the chemistry; it's the proximity" that activates such receptors, says Ingber.

The approach could have a far-reaching impact, as many important cell receptors are activated in a similar way and might be controlled using Ingber's method.

"In recent years, there has been a realization that physical events, not just chemical events, are important" to cell function, says Shu Chien, a bioengineer at the University of California, San Diego. Researchers have probed the effects of physical forces on cells by, for example, squishing them between plates or pulling probes across their surfaces. But none of these techniques work at as fine a level of control as Ingber's magnetic beads, which act on single biomolecules.

Many drugs, from anticancer antibodies to hormones, work by activating cell receptors. Once a hormone is in the blood, however, there's no turning it on or off. "This shows that you can turn on and off the signal, and that you can do it instantly," says Christopher Chen, a bioengineer at the University of Pennsylvania. "That's something that's hard to do, for example, with an antibody."

Ingber has many ideas for devices that might integrate his method of cellular control. Magnetic pacemakers could use cells instead of electrodes to send electrical pulses to the heart. Implantable drug factories might contain many groups of cells, each of which makes a different drug when activated by a magnetic signal. Biomagnetic control might lead to computers that can take advantage of cells' processing power. "Cells do complex things like image processing so much better than computers," says Ingber. Ingber, who began the project in response to a call by the Defense Advanced Research Projects Agency for new cell-machine interfaces, acknowledges that his work is in its early stages. In fifty years, however, he expects that there will be devices that "seamlessly interface between living cells and machines."

FURTHER READING
Harvard Institute for Biologically Inspired Engineering.

Nanorobot drug delivery

Adriano Cavalcanti is CEO and chairman of CAN Center for Automation in Nanobiotech. Adriano and his coleagues have proposed a nanorobot platform should enable patient pervasive monitoring, and details are given in prognosis with nanorobots application for intracranial treatments. This integrated system also points towards precise diagnosis and smart drug delivery for cancer therapy.


nanorobot for nanomedicine drug delivery


Simulated nanorobot for drug delivery

Fully operational nanorobots for biomedical instrumentation should be achieved as a result of nanobioelectronics and proteomics integration. The proposed platform should enable patient pervasive monitoring, and details are given in prognosis with nanorobots application for intracranial treatments. This integrated system also points towards precise diagnosis and smart drug delivery for cancer therapy.

The methodologies and the implemented 3D simulation described in our study served as a test bed for molecular machine prototyping. The numerical analysis and advanced simulations provided a better understanding on how nanorobots should interact inside the human body. Hence, based on such information, we have proposed the innovative hardware architecture with a nanorobot model for use in common medical applications. The nanorobot takes chemical and thermal gradient changes as interaction choices for in vivo treatments. The use of mobile phones with RF is adopted in this platform as the most effective approach for control upload, helping to interface nanorobots communication and energy supply.

The next steps in our work can be defined as follows: (a) model manufacturing with CNT-CMOS biochip integration; (b) laboratory studies for in vivo tests; and (c) commercialization. The pipeline for development in the medical sector typically requires research and efforts to get new ideas out of laboratories and into the marketplace

FURTHER READING
Nanorobot design website

They have written many papers on this work. Robert Freitas is involved in some of them.

Nanorobot architecture for medical target identification.

The nanorobot interaction with the described workspace shows how time actuation is improved based on sensor capabilities. Therefore, our work addresses the control and the architecture design for developing practical molecular machines. Advances in nanotechnology are enabling manufacturing nanosensors and actuators through nanobioelectronics and biologically inspired devices. Analysis of integrated system modeling is one important aspect for supporting nanotechnology in the fast development towards one of the most challenging new fields of science: molecular machines. The use of 3D simulation can provide interactive tools for addressing nanorobot choices on sensing, hardware architecture design, manufacturing approaches, and control methodology investigation.

Earlier work was with CMOS versions of small robots

Hardware architecture for nanorobots

Freitas' nanomedicine site

Center for Automation in Nanobiotech website

Remote-control nanoparticles deliver drugs directly into tumors

MIT scientists have devised remotely controlled nanoparticles that, when pulsed with an electromagnetic field, release drugs to attack tumors.


Here, dark gray nanoparticles carry different drug payloads (one red, one green). A remotely generated five-minute pulse of a low-energy electromagnetic field releases the green drug but not the red. A five-minute pulse of a higher-energy electromagnetic field releases the red drug, which had been tethered using a DNA strand twice as long as the green tether, as measured in base pairs. Image courtesy / Bhatia/von Maltzahn, MIT. Derfus, UCSD

Toward cancer drugs that penetrate 10 times deeper into the brain

A new drug-delivery system for cancer of the brain — one of the most difficult cancers to treat — has the potential to carry anticancer drugs 10 times deeper into tumors than conventional medications, researchers in Connecticut and New York report.

In the new study, Mark Saltzman and colleagues showed that linking the anticancer drug campothecin (CPT) to the polymer polyethylene glycol (PEG), increased drug diffusion to more than a centimeter from the implant site.

They also identified a promising CPT-PET compound that could deliver 11 times more medication to the tumor than the plain drug alone. For patients, those advantages could substantially improve chances for successful treatment, the researchers indicate.