Mayo Clinic Researchers develop new tumor-shrinking nanoparticle to fight breast cancer – prevent recurrence


Cancer New Nano Particle 58e378ef3aa34Credit: CC0 Public Domain

A Mayo Clinic research team has developed a new type of cancer-fighting nanoparticle aimed at shrinking breast cancer tumors, while also preventing recurrence of the disease. In the study, published today in Nature Nanotechnology, mice that received an injection with the nanoparticle showed a 70 to 80 percent reduction in tumor size. Most significantly, mice treated with these nanoparticles showed resistance to future tumor recurrence, even when exposed to cancer cells a month later.

The results show that the newly designed nanoparticle produced potent anti- immune responses to HER2-positive breast cancers. Breast cancers with higher levels of HER2 protein are known to grow aggressively and spread more quickly than those without the mutation.

“In this proof-of-concept study, we were astounded to find that the animals treated with these nanoparticles showed a lasting anti- effect,” says Betty Y.S. Kim, M.D., Ph.D., principal investigator, and a neurosurgeon and neuroscientist who specializes in brain tumors at Mayo Clinic’s Florida campus. “Unlike existing cancer immunotherapies that target only a portion of the immune system, our custom-designed nanomaterials actively engage the entire immune system to kill cancer , prompting the body to create its own memory system to minimize tumor recurrence. These nanomedicines can be expanded to target different types of cancer and other human diseases, including neurovascular and neurodegenerative disorders.”

Dr. Kim’s team developed the nanoparticle, which she has named “Multivalent Bi-specific Nano-Bioconjugate Engager,” a patented technology with Mayo Clinic Ventures, a commercialization arm of Mayo Clinic. It’s coated with antibodies that target the HER2 receptor, a common molecule found on 40 percent of breast cancers. It’s also coated with molecules that engage two distinct facets of the body’s immune system. The nanoparticle hones in on the tumor by recognizing HER2 and then helps the identify the tumor cells to attack them.

The molecules attached to the nanoparticle rev up the body’s nonspecific, clean-up cells (known as macrophages and phagocytes) in the immune system that engulf and destroy any foreign material. The design of the nanoparticle prompts these cells to appear in abundance and clear up abnormal cancer cells. These clean-up cells then relay information about the cancer cells to highly specialized T-cells in the immune system that help eradicate remaining , while maintaining a memory of these cells to prevent cancer recurrence. It’s the establishment of disease-fighting memory in the cells that makes the nanoparticle similar to a cancer vaccine. Ultimately, the body’s own cells become capable of recognizing and destroying recurrent tumors.

Since the late 1990s, the field of nanomedicine has focused on developing as simple drug delivery vehicles that can propel chemotherapy drugs to tumors. One pitfall is that the body tends to purge the particles before they reach their destination.

“Our study represents a novel concept of designing nanomedicine that can actively interact with the immune cells in our body and modulate their functions to treat human diseases,” says Dr. Kim. “It builds on recent developments in cancer immunotherapy, which have been successful in treating some types of tumors; however, most immunotherapy developed so far does not harness the power of the entire immune system. We’ve developed a new platform that reaches and also recruits abundant clean-up cells for a fully potent immune response.”

Future studies in the lab will explore the ability of the nanoparticle to prevent long-term recurrence of tumors, including metastases at sites distant from the primary tumor. What’s more, the nanoparticle is designed to be modular, meaning it can carry molecules to fight other types of disease. “This approach hopefully will open new doors in the design of new nanomedicine-based immunotherapies,” she says.

Explore further: Nanoparticles target and kill cancer stem cells that drive tumor growth

More information: Multivalent Bi-Specific Nano-Bioconjugate Engager for Targeted Cancer Immunotherapy, Nature Nanotechnology (2017). nature.com/articles/doi:10.1038/nnano.2017.69

 

MIT: Light-emitting particles (quantum dots) open new window for biological imaging


QD Bio Image V images

‘Quantum dots’ that emit infrared light enable highly detailed images of internal body structures

For certain frequencies of short-wave infrared light, most biological tissues are nearly as transparent as glass. Now, researchers have made tiny particles that can be injected into the body, where they emit those penetrating frequencies. The advance may provide a new way of making detailed images of internal body structures such as fine networks of blood vessels.

The new findings, based on the use of light-emitting particles called quantum dots, is described in a paper in the journal Nature Biomedical Engineering, by MIT research scientist Oliver Bruns, recent graduate Thomas Bischof PhD ’15, professor of chemistry Moungi Bawendi, and 21 others.

Near-infrared imaging for research on biological tissues, with wavelengths between 700 and 900 nanometers (billionths of a meter), is widely used, but wavelengths of around 1,000 to 2,000 nanometers have the potential to provide even better results, because body tissues are more transparent to that light. “We knew that this imaging mode would be better” than existing methods, Bruns explains, “but we were lacking high-quality emitters” — that is, light-emitting materials that could produce these precise wavelengths.

QD bio Image II imagesLight-emitting particles have been a specialty of Bawendi, the Lester Wolf Professor of Chemistry, whose lab has over the years developed new ways of making quantum dots. These nanocrystals, made of semiconductor materials, emit light whose frequency can be precisely tuned by controlling the exact size and composition of the particles.

The key was to develop versions of these quantum dots whose emissions matched the desired short-wave infrared frequencies and were bright enough to then be easily detected through the surrounding skin and muscle tissues. The team succeeded in making particles that are “orders of magnitude better than previous materials, and that allow unprecedented detail in biological imaging,” Bruns says. The synthesis of these new particles was initially described in a paper by graduate student Daniel Franke and others from the Bawendi group in Nature Communications last year.

The quantum dots the team produced are so bright that their emissions can be captured with very short exposure times, he says. This makes it possible to produce not just single images but video that captures details of motion, such as the flow of blood, making it possible to distinguish between veins and arteries.

QD Bio Image IV GAAlso Read About

Graphene Quantum Dots Expand Role In Cancer Treatment And Bio-Imaging

 

 

The new light-emitting particles are also the first that are bright enough to allow imaging of internal organs in mice that are awake and moving, as opposed to previous methods that required them to be anesthetized, Bruns says. Initial applications would be for preclinical research in animals, as the compounds contain some materials that are unlikely to be approved for use in humans. The researchers are also working on developing versions that would be safer for humans.QD Bio Image III 4260773298_1497232bef

 

The method also relies on the use of a newly developed camera that is highly sensitive to this particular range of short-wave infrared light. The camera is a commercially developed product, Bruns says, but his team was the first customer for the camera’s specialized detector, made of indium-gallium-arsenide. Though this camera was developed for research purposes, these frequencies of infrared light are also used as a way of seeing through fog or smoke.

Not only can the new method determine the direction of blood flow, Bruns says, it is detailed enough to track individual blood cells within that flow. “We can track the flow in each and every capillary, at super high speed,” he says. “We can get a quantitative measure of flow, and we can do such flow measurements at very high resolution, over large areas.”

Such imaging could potentially be used, for example, to study how the blood flow pattern in a tumor changes as the tumor develops, which might lead to new ways of monitoring disease progression or responsiveness to a drug treatment. “This could give a good indication of how treatments are working that was not possible before,” he says.

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The team included members from MIT’s departments of Chemistry, Chemical Engineering, Biological Engineering, and Mechanical Engineering, as well as from Harvard Medical School, the Harvard T.H. Chan School of Public Health, Raytheon Vision Systems, and University Medical Center in Hamburg, Germany. The work was supported by the National Institutes of Health, the National Cancer Institute, the National Foundation for Cancer Research, the Warshaw Institute for Pancreatic Cancer Research, the Massachusetts General Hospital Executive Committee on Research, the Army Research Office through the Institute for Soldier Nanotechnologies at MIT, the U.S. Department of Defense, and the National Science Foundation.

Additional background

ARCHIVE: A new contrast agent for MRI http://news.mit.edu/2017/iron-oxide-nanoparticles-contrast-agent-mri-0214

ARCHIVE: A new eye on the middle ear http://news.mit.edu/2016/shortwave-infrared-instrument-ear-infection-0822

ARCHIVE: Chemists design a quantum-dot spectrometer http://news.mit.edu/2015/quantum-dot-spectrometer-smartphone-0701

ARCHIVE: Running the color gamut http://news.mit.edu/2014/startup-quantum-dot-tv-displays-1119

ARCHIVE: Fine-tuning emissions from quantum dots http://news.mit.edu/2013/fine-tuning-emissions-from-quantum-dots-0602

MIT: New ‘Rubbery Nanowire” Fibers are Stretching the boundaries of neural implants ~ Hope for Spinal Cord Injuries


MIT-Stretch-Fiber-1_0Researchers have developed a rubber-like fiber, shown here, that can flex and stretch while simultaneously delivering both optical impulses, for optoelectronic stimulation, and electrical connections, for stimulation and monitoring. Image: Chi (Alice) Lu and Seongjun Park

Rubbery, multifunctional fibers could be used to study spinal cord neurons and potentially restore function.

Implantable fibers have been an enormous boon to brain research, allowing scientists to stimulate specific targets in the brain and monitor electrical responses. But similar studies in the nerves of the spinal cord, which might ultimately lead to treatments to alleviate spinal cord injuries, have been more difficult to carry out.

That’s because the spine flexes and stretches as the body moves, and the relatively stiff, brittle fibers used today could damage the delicate spinal cord tissue.

Now, researchers have developed a rubber-like fiber that can flex and stretch while simultaneously delivering both optical impulses, for optoelectronic stimulation, and electrical connections, for stimulation and monitoring. The new fibers are described in a paper in the journal Science Advances, by MIT graduate students Chi (Alice) Lu and Seongjun Park, Professor Polina Anikeeva, and eight others at MIT, the University of Washington, and Oxford University.

“I wanted to create a multimodal interface with mechanical properties compatible with tissues, for neural stimulation and recording,” as a tool for better understanding spinal cord functions, says Lu. But it was essential for the device to be stretchable, because “the spinal cord is not only bending but also stretching during movement.” The obvious choice would be some kind of elastomer, a rubber-like compound, but most of these materials are not adaptable to the process of fiber drawing, which turns a relatively large bundle of materials into a thread that can be narrower than a hair.

The spinal cord “undergoes stretches of about 12 percent during normal movement,” says Anikeeva, who is the Class of 1942 Career Development Professor in the Department of Materials Science and Engineering. “You don’t even need to get into a ‘downward dog’ [yoga position] to have such changes.” So finding a material that can match that degree of stretchiness could potentially make a big difference to research. “The goal was to mimic the stretchiness and softness and flexibility of the spinal cord,” she says. “You can match the stretchiness with a rubber. But drawing rubber is difficult — most of them just melt,” she says.

“Eventually, we’d like to be able to use something like this to combat spinal cord injury. But first, we have to have biocompatibility and to be able to withstand the stresses in the spinal cord without causing any damage,” she says.

 

 

 

 

 

 

 

 

 

The fibers are not only stretchable but also very flexible. “They’re so floppy, you could use them to do sutures, and do light delivery at the same time,” professor Polina Anikeeva says. (Video: Chi (Alice) Lu and Seongjun Park)

The team combined a newly developed transparent elastomer, which could act as a waveguide for optical signals, and a coating formed of a mesh of silver nanowires, producing a conductive layer for the electrical signals. To process the transparent elastomer, the material was embedded in a polymer cladding that enabled it to be drawn into a fiber that proved to be highly stretchable as well as flexible, Lu says. The cladding is dissolved away after the drawing process.

After the entire fabrication process, what’s left is the transparent fiber with electrically conductive, stretchy nanowire coatings. “It’s really just a piece of rubber, but conductive,” Anikeeva says. The fiber can stretch by at least 20 to 30 percent without affecting its properties, she says.

The fibers are not only stretchable but also very flexible. “They’re so floppy, you could use them to do sutures and deliver light  at the same time,” she says.

“We’re the first to develop something that enables simultaneous electrical recording and optical stimulation in the spinal cords of freely moving mice,” Lu says. “So we hope our work opens up new avenues for neuroscience research.” Scientists doing research on spinal cord injuries or disease usually must use larger animals in their studies, because the larger nerve fibers can withstand the more rigid wires used for stimulus and recording. While mice are generally much easier to study and available in many genetically modified strains, there was previously no technology that allowed them to be used for this type of research, she says.

“There are many different types of cells in the spinal cord, and we don’t know how the different types respond to recovery, or lack of recovery, after an injury,” she says. These new fibers, the researchers hope, could help to fill in some of those blanks.

The team included Alexander Derry, Chong Hou, Siyuan Rao, Jeewoo Kang, and professor Yoel Fink at MIT; Tom Richner and professor Chet Mortiz at the University of Washington; and Imogen Brown at Oxford University. The research was supported by the National Science Foundation, the National Institute of Neurological Disorders and Stroke, the U.S. Army Research Laboratory, and the U.S. Army Research Office through the Institute for Soldier Nanotechnologies at MIT.

Triple-threat cancer-fighting polymer capsules for guided drug delivery


drug delivery cancer 170330142230_1_540x360These micro-carriers may offer an entirely different approach to treating solid human tumors of numerous pathologic subtypes by delivering their encapsulated drug cargo to a tumor and protecting against collateral tissue damage.

Chemists at the University of Alabama at Birmingham have designed triple-threat cancer-fighting polymer capsules that bring the promise of guided drug delivery closer to preclinical testing.

These multilayer capsules show three traits that have been difficult to achieve in a single entity. They have good imaging contrast that allows detection with low-power ultrasound, they can stably and efficiently encapsulate the cancer drug doxorubicin, and both a low- and higher-power dose of ultrasound can trigger the release of that cargo.

These three features create a guided drug delivery system to target solid tumors. Therapeutic efficacy can be further improved through surface modifications to boost targeting capabilities. Diagnostic low-power ultrasound then could visualize the nanocapsules as they concentrated in a tumor, and therapeutic higher-dose ultrasound would release the drug at ground zero, sparing the rest of the body from dose-limiting toxicity.

This precise control of when and where doxorubicin or other cancer drugs are released could offer a noninvasive alternative to cancer surgery or systemic chemotherapy, the UAB researchers report in the journal ACS Nano, which has an impact factor of 13.3.

“We envision an entirely different approach to treating solid human tumors of numerous pathologic subtypes, including common metastatic malignancies such as breast, melanoma, colon, prostate and lung, utilizing these capsules as a delivery platform,” said Eugenia Kharlampieva, Ph.D., an associate professor in the Department of Chemistry, UAB College of Arts and Sciences. “These capsules can protect encapsulated therapeutics from degradation or clearance prior to reaching the target and have ultrasound contrast as a means of visualizing the drug release. They can release their encapsulated drug cargo in specific locations via externally applied ultrasound exposure.”

Kharlampieva — who creates her novel “smart” particles while working at the intersection of polymer chemistry, nanotechnology and biomedical science — says there is an urgent, and so far unmet, need for such an easily fabricated, guided drug delivery system.

The UAB researchers, led by Kharlampieva and co-first authors Jun Chen and Sithira Ratnayaka, use alternating layers of biocompatible tannic acid and poly(N-vinylpyrrolidone), or TA/PVPON, to build their microcarriers. The layers are formed around a sacrificial core of solid silica or porous calcium carbonate that is dissolved after the layers are complete.

By varying the number of layers, the molecular weight of PVPON or the ratio of shell thickness to capsule diameter, the researchers were able to alter the physical traits of the capsules and their sensitivity to diagnostic ultrasound, at power levels below the FDA maximum for clinical imaging and diagnosis.

For example, one-fourth of empty microcapsules made with four layers of TA/low-molecular weight PVPON were ruptured by three minutes of ultrasound, while capsules made of 15 layers of TA/low-molecular weight PVPON or capsules made from four layers of TA/high-molecular weight PVPON showed no rupture. The ruptured capsules had a lower mechanical rigidity that made them more sensitive to ultrasound pressure changes. Experiments showed that the ratio of the thickness of the capsule wall to the diameter of the capsule is a key variable for sensitivity to rupture.

To test the ultrasound imaging contrast of the microcapsules, the UAB researchers made capsules that were 5 micrometers wide, or about two times wider than the capsules used in the rupture experiments. This size is small enough to still pass through capillaries in the lung, while a larger size for various microparticles is known to greatly improve ultrasound contrast. Red blood cells, for a size comparison, have a diameter of about 6 to 8 micrometers.

Researchers found that 5-micrometer-wide, empty capsules that were made with eight layers of TA/low-molecular weight PVPON showed an ultrasound contrast comparable to the commercially available microsphere contrast agent Definity. When the UAB capsules — which have a shell thickness of about 50 nanometers — were loaded with doxorubicin, the ultrasound imaging contrast increased two- to eightfold compared to empty capsules, depending on the mode of ultrasound imaging used. These doxorubicin-loaded capsules were highly stable, with no change in ultrasound imaging contrast after six months of storage. Exposure to serum, known to deposit proteins on various microparticles, did not extinguish the ultrasound imaging contrast of the TA/PVPON microcapsules.

A therapeutic dose of ultrasound was able to rupture 50 percent of the 5-micrometer, doxorubicin-loaded microcapsules, releasing enough doxorubicin to induce 97 percent cytotoxicity in human breast adenocarcinoma cells in culture. Adenocarcinoma cells that were incubated with intact doxorubicin-loaded microcapsules remained viable.

Phenformin Nano Cancer Delivery id39449Thus, Kharlampieva says, these TA/PVPON capsules have strong potential as “theranostic” agents for efficient cancer therapy in conjunction with ultrasound. The term theranostic refers to nanoparticles or microcapsules that can double as diagnostic imaging agents and as therapeutic drug-delivery carriers.

The next important preclinical step, Kharlampieva says, in collaboration with Mark Bolding, Ph.D., assistant professor in the UAB Department of Radiology, and Jason Warram, Ph.D., assistant professor in the UAB Department of Otolaryngology, will be studies in animal models to explore how long the UAB capsules persist in blood circulation and where they distribute in the body.


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Materials provided by University of Alabama at Birmingham. Note: Content may be edited for style and length.


Journal Reference:

  1. Jun Chen, Sithira Ratnayaka, Aaron Alford, Veronika Kozlovskaya, Fei Liu, Bing Xue, Kenneth Hoyt, Eugenia Kharlampieva. Theranostic Multilayer Capsules for Ultrasound Imaging and Guided Drug Delivery. ACS Nano, 2017; 11 (3): 3135 DOI: 10.1021/acsnano.7b00151

Laser activated gold pyramids could deliver drugs, DNA into cells without harm


Harvard DNA Delivery 170323150417_1_540x360

Summary: The ability to deliver cargo like drugs or DNA into cells is essential for biological research and disease therapy but cell membranes are very good at defending their territory. Researchers have developed various methods to trick or force open the cell membrane but these methods are limited in the type of cargo they can deliver and aren’t particularly efficient. Harvard School of Engineering and Applied Sciences 

The ability to deliver cargo like drugs or DNA into cells is essential for biological research and disease therapy but cell membranes are very good at defending their territory. Researchers have developed various methods to trick or force open the cell membrane but these methods are limited in the type of cargo they can deliver and aren’t particularly efficient.

Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new method using gold microstructures to deliver a variety of molecules into cells with high efficiency and no lasting damage. The research is published in ACS Nano.

“Being able to effectively deliver large and diverse cargos directly into cells will transform biomedical research,” said Nabiha Saklayen, a PhD candidate in the Mazur Lab at SEAS and first author of the paper. “However, no current single delivery system can do all the things you need to do at once. Intracellular delivery systems need to be highly efficient, scalable, and cost effective while at the same time able to carry diverse cargo and deliver it to specific cells on a surface without damage. It’s a really big challenge.”

In previous research, Saklayen and her collaborators demonstrated that gold, pyramid-shaped microstructures are very good at focusing laser energy into electromagnetic hotspots. In this research, the team used a fabrication method called template stripping to make surfaces — about the size of a quarter — with 10 million of these tiny pyramids.

“The beautiful thing about this fabrication process is how simple it is,” said Marinna Madrid, coauthor of the paper and PhD candidate in the Mazur Lab. “Template-stripping allows you to reuse silicon templates indefinitely. It takes less than a minute to make each substrate, and each substrate comes out perfectly uniform. That doesn’t happen very often in nanofabrication.”

Harvard DNA Delivery 170323150417_1_540x360
A scanning-electron microscope image of chemically-fixed HeLa cancer cells on the substrate. The tips of the pyramids create tiny holes in the cell membranes, allowing molecular cargo to diffuse into the cells. Credit: Harvard SEAS

The team cultured HeLa cancer cells directly on top of the pyramids and surrounded the cells with a solution containing molecular cargo.

Using nanosecond laser pulses, the team heated the pyramids until the hotspots at the tips reached a temperature of about 300 degrees Celsius. This very localized heating — which did not affect the cells — caused bubbles to form right at the tip of each pyramid. These bubbles gently pushed their way into the cell membrane, opening brief pores in the cell and allowing the surrounding molecules to diffuse into the cell.

“We found that if we made these pores very quickly, the cells would heal themselves and we could keep them alive, healthy and dividing for many days,” Saklayen said.

Each HeLa cancer cell sat atop about 50 pyramids, meaning the researchers could make about 50 tiny pores in each cell. The team could control the size of the bubbles by controlling the laser parameters and could control which side of the cell to penetrate.

The molecules delivered into the cell were about the same size as clinically relevant cargos, including proteins and antibodies.

Next, the team plans on testing the methods on different cell types, including blood cells, stem cells and T cells. Clinically, this method could be used in ex vivo therapies, where unhealthy cells are taken out of the body, given cargo like drugs or DNA, and reintroduced into the body.

“This work is really exciting because there are so many different parameters we could optimize to allow this method to work across many different cell types and cargos,” said Saklayen. “It’s a very versatile platform.”

Harvard’s Office of Technology Development has filed patent applications and is considering commercialization opportunities.

“It’s great to see how the tools of physics can greatly advance other fields, especially when it may enable new therapies for previously difficult to treat diseases,” said Eric Mazur, the Balkanski Professor of Physics and Applied Physics and senior author of the paper.

This research was supported by the National Science Foundation and the Howard Hughes Medical Institute. It was coauthored by Marinus Huber, Marinna Madrid, Valeria Nuzzo, Daryl Inna Vulis, Weilu Shen, Jeffery Nelson, Arthur McClelland and Alexander Heisterkamp.


Story Source:

Materials provided by Harvard School of Engineering and Applied Sciences. Note: Content may be edited for style and length.


Journal Reference:

  1. Nabiha Saklayen, Marinus Huber, Marinna Madrid, Valeria Nuzzo, Daryl I. Vulis, Weilu Shen, Jeffery Nelson, Arthur A. McClelland, Alexander Heisterkamp, Eric Mazur. Intracellular Delivery Using Nanosecond-Laser Excitation of Large-Area Plasmonic Substrates. ACS Nano, 2017; DOI: 10.1021/acsnano.6b08162

Drug combination delivered by nanoparticles may help in melanoma treatment


Melenoma 170314140859_1_540x360Gavin Robertson, professor of pharmacology, pathology, dermatology, and surgery; director of the Penn State Melanoma and Skin Cancer Center and member of Penn State Cancer Institute, works with associates in the Melanoma Center.
Credit: Penn State College of Medicine

Summary: The first of a new class of medication that delivers a combination of drugs by nanoparticle may keep melanoma from becoming resistant to treatment, according to Penn State College of Medicine researchers.

CelePlum-777 combines a special ratio of the drugs Celecoxib, an anti-inflammatory, and Plumbagin, a toxin. By combining the drugs, the cells have difficulty overcoming the effect of having more than one active ingredient.

Celecoxib and Plumbagin work together to kill melanoma cells when used in a specific ratio. Researchers used microscopic particles called nanoparticles to deliver the drugs directly to the cancer cells. These particles are several hundred times smaller than the width of a hair and can be loaded with medications.

“Loading multiple drugs into nanoparticles is one innovative approach to deliver multiple cancer drugs to a particular site where they need to act and have them released at that optimal cancer cell killing ratio,” said Raghavendra Gowda, assistant professor of pharmacology, who is the lead author on the study. “Another advantage is that by combining the drugs, lower concentrations of each that are more effective and less toxic can be used.”

Celecoxib and Plumbagin cannot be taken by mouth because the drugs do not enter the body well this way and cannot be used together in the ratio needed because of toxicity.

CelePlum-777 can be injected intravenously without toxicity. Because of its small size, it also accumulates inside the tumors where it then releases the drugs to kill the cancer cells. Researchers report their results in the journals Molecular Cancer Therapeutics and Cancer Letters.

“This drug is the first of a new class, loaded with multiple agents to more effectively kill melanoma cells, that has potential to reduce the possibility of resistance development,” said senior author Gavin Robertson, professor of pharmacology, pathology, dermatology, and surgery; director of the Penn State Melanoma and Skin Cancer Center and member of Penn State Cancer Institute. “There is no drug like it in the clinic today and it is likely that the next breakthrough in melanoma treatment will come from a drug like this one.”

The researchers showed the results of CelePlum-777 on killing cancer cells growing in culture dishes and in tumors growing in mice following intravenous injection. The drug prevented tumor development in mice with no detectable side effects and also prevented proteins from enabling uncontrolled cancer cell growth.

More research is required by the Food and Drug Administration before CelePlum-777 can be tested in humans through clinical trials. Penn State has patented this discovery and licensed it to Cipher Pharmaceuticals, which will perform the next series of FDA-required tests.


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Florida State University Researchers take big step forward in nanotech-based drugs


Nanoparticle drug delivery F3.large

Florida State University Summary:New research takes a step forward in the understanding of nanoparticles and how they can best be used to deliver drugs.

Nanotechnology has become a growing part of medical research in recent years, with scientists feverishly working to see if tiny particles could revolutionize the world of drug delivery.

But many questions remain about how to effectively transport those particles and associated drugs to cells.

In an article published in Scientific Reports, FSU Associate Professor of Biological Science Steven Lenhert takes a step forward in the understanding of nanoparticles and how they can best be used to deliver drugs.

After conducting a series of experiments, Lenhert and his colleagues found that it may be possible to boost the efficacy of medicine entering target cells via a nanoparticle.

“We can enhance how cells take them up and make more drugs more potent,” Lenhert said.

Initially, Lenhert and his colleagues from the University of Toronto and the Karlsruhe Institute of Technology wanted to see what happened when they encapsulated silicon nanoparticles in liposomes — or small spherical sacs of molecules — and delivered them to HeLa cells, a standard cancer cell model.

The initial goal was to test the toxicity of silicon-based nanoparticles and get a better understanding of its biological activity.

Silicon is a non-toxic substance and has well-known optical properties that allow their nanostructures to appear fluorescent under an infrared camera, where tissue would be nearly transparent. Scientists believe it has enormous potential as a delivery agent for drugs as well as in medical imaging.

But there are still questions about how silicon behaves at such a small size.

“Nanoparticles change properties as they get smaller, so scientists want to understand the biological activity,” Lenhert said. “For example, how does shape and size affect toxicity?”

Scientists found that 10 out of 18 types of the particles, ranging from 1.5 nanometers to 6 nanometers, were significantly more toxic than crude mixtures of the material.

At first, scientists believed this could be a setback, but they then discovered the reason for the toxicity levels. The more toxic fragments also had enhanced cellular uptake. That information is more valuable long term, Lenhert said, because it means they could potentially alter nanoparticles to enhance the potency of a given therapeutic.

The work also paves the way for researchers to screen libraries of nanoparticles to see how cells react.

“This is an essential step toward the discovery of novel nanotechnology based therapeutics,” Lenhert said. “There’s big potential here for new therapeutics, but we need to be able to test everything first.”


Story Source:

Materials provided by Florida State University. Original written by Kathleen Haughney. Note: Content may be edited for style and length.


Journal Reference:

  1. Aubrey E. Kusi-Appiah, Melanie L. Mastronardi, Chenxi Qian, Kenneth K. Chen, Lida Ghazanfari, Plengchart Prommapan, Christian Kübel, Geoffrey A. Ozin, Steven Lenhert. Enhanced cellular uptake of size-separated lipophilic silicon nanoparticles. Scientific Reports, 2017; 7: 43731 DOI: 10.1038/srep43731

 

Graphene sheets capture individual cells leading to very low-cost diagnostic systems



A single cell can contain a wealth of information about the health of an individual. Now, a new method developed at MIT and National Chiao Tung University could make it possible to capture and analyze individual cells from a small sample of blood, potentially leading to very low-cost diagnostic systems that could be used almost anywhere.

The new system, based on specially treated sheets of graphene oxide, could ultimately lead to a variety of simple devices that could be produced for as little as $5 apiece and perform a variety of sensitive diagnostic tests even in places far from typical medical facilities.

The material used in this research is an oxidized version of the two-dimensional form of pure carbon known as graphene, which has been the subject of widespread research for over a decade because of its unique mechanical and electrical characteristics. The key to the new process is heating the graphene oxide at relatively mild temperatures. This low-temperature annealing, as it is known, makes it possible to bond particular compounds to the material’s surface.

These compounds in turn select and bond with specific molecules of interest, including DNA and proteins, or even whole cells. Once captured, those molecules or cells can then be subjected to a variety of tests.

Mild heating of graphene oxide sheets makes it possible to bond particular compounds to the sheets’ surface

Mild heating of graphene oxide sheets makes it possible to bond particular compounds to the sheets’ surface, a new study shows. These compounds in turn select and bond with specific molecules of interest, including DNA and proteins, or even whole cells. In this image the treated graphene oxide on the right is nearly twice as efficient at capturing cells as the untreated material on the left. (Image courtesy of the researchers)

The findings are reported in the journal ACS Nano (“Enhanced Cell Capture on Functionalized Graphene Oxide Nanosheets through Oxygen Clustering”).

Other researchers have been trying to develop diagnostic systems using a graphene oxide substrate to capture specific cells or molecules, but these approaches used just the raw, untreated material. Despite a decade of research, other attempts to improve such devices’ efficiency have relied on external modifications, such as surface patterning through lithographic fabrication techniques, or adding microfluidic channels, which add to the cost and complexity. The new finding offers a mass-producible, low-cost approach to achieving such improvements in efficiency.

The heating process changes the material’s surface properties, causing oxygen atoms to cluster together, leaving spaces of bare graphene between them. This makes it relatively easy to attach other chemicals to the surface, which can interact with specific molecules of interest. The new research demonstrates how that basic process could potentially enable a suite of low-cost diagnostic systems, for example for cancer screening or treatment follow-up.

For this proof-of-concept test, the team used molecules that can quickly and efficiently capture specific immune cells that are markers for certain cancers. They were able to demonstrate that their treated graphene oxide surfaces were almost twice as effective at capturing such cells from whole blood, compared to devices fabricated using ordinary, untreated graphene oxide, says Bardhan, the paper’s lead author.

The system has other advantages as well, Bardhan says. It allows for rapid capture and assessment of cells or biomolecules under ambient conditions within about 10 minutes and without the need for refrigeration of samples or incubators for precise temperature control. And the whole system is compatible with existing large-scale manufacturing methods, making it possible to produce diagnostic devices for less than $5 apiece, the team estimates. Such devices could be used in point-of-care testing or resource-constrained settings.

Existing methods for treating graphene oxide to allow functionalization of the surface require high temperature treatments or the use of harsh chemicals, but the new system, which the group has patented, requires no chemical pretreatment and an annealing temperature of just 50 to 80 degrees Celsius (122 to 176 F).

While the team’s basic processing method could make possible a wide variety of applications, including solar cells and light-emitting devices, for this work the researchers focused on improving the efficiency of capturing cells and biomolecules that can then be subjected to a suite of tests. They did this by enzymatically coating the treated graphene oxide surface with peptides called nanobodies — subunits of antibodies, which can be cheaply and easily produced in large quantities in bioreactors and are highly selective for particular biomolecules.

The researchers found that increasing the annealing time steadily increased the efficiency of cell capture: After nine days of annealing, the efficiency of capturing cells from whole blood went from 54 percent, for untreated graphene oxide, to 92 percent for the treated material.

The team then performed molecular dynamics simulations to understand the fundamental changes in the reactivity of the graphene oxide base material. The simulation results, which the team also verified experimentally, suggested that upon annealing, the relative fraction of one type of oxygen (carbonyl) increases at the expense of the other types of oxygen functional groups (epoxy and hydroxyl) as a result of the oxygen clustering. This change makes the material more reactive, which explains the higher density of cell capture agents and increased efficiency of cell capture.

“Efficiency is especially important if you’re trying to detect a rare event,” Belcher says. “The goal of this was to show a high efficiency of capture.” The next step after this basic proof of concept, she says, is to try to make a working detector for a specific disease model.

In principle, Bardhan says, many different tests could be incorporated on a single device, all of which could be placed on a small glass slide like those used for microscopy.

“I think the most interesting aspect of this work is the claimed clustering of oxygen species on graphene sheets and its enhanced performance in surface functionalization and cell capture,” says Younan Xia, a professor of chemistry and biochemistry at Georgia Institute of Technology who was not involved in this work. “It is an interesting idea.”

Source: By David L. Chandler, MIT

UC Berkeley: Magnetic nano-particle imaging Research May Lead to Early Cancer Detection


 

Magnetic particle imaging is a new, up-and-coming, safe and highly sensitive tracer imaging technique that works by detecting super-para-magnetic iron oxide nano-particles with high image contrast (that is, no background tissue signal). The technique, which does not use any ionizing radiation, can be used to image anywhere inside the body, which means that it could be promising for detecting and monitoring tumors. Researchers in the US are now the first to have used MPI to passively detect cancer by basically exploiting the abnormal leakiness of tumor blood vessels – a finding that bodes well for the early detection of cancers like breast cancer in patients at risk for the disease.

Biomedical imaging is important at every stage of diagnosing and treating cancer, beginning with initial screening, through to diagnosis, treatment planning and monitoring. The biggest challenge here is to be able to reliably distinguish tumour tissue from healthy tissue, something that is not as easy as it sounds.

“Conventional anatomical techniques, such as X-ray, X-ray computed tomography (CT), ultrasound and magnetic resonance imaging (MRI), are very useful for detecting the tissue architecture changes that generally accompany cancer, but the native contrast of tumours may not differ sufficiently from healthy tissue for a confident diagnosis, especially for metastatic or so-called diffuse tumours” explains lead author of the study Elaine Yu, who is completing her Bioengineering PhD in Steven Conolly’s lab at the University of California at Berkeley (UCB). “This is why exogenous contrast agents, such as iodine (for X-ray and CT) and gadolinium (for MRI) are often administered to highlight crucial vascular differences between normal and cancerous tissue for more precise screening.”

Exploiting the EPR effect

Contrast agents are all injected intravenously, but the way they highlight tumours differs considerably. Nanosized agents are better than conventional low molecular weight agents in one respect because they are not immediately excreted by the kidneys if designed to be large enough. They are thus able to circulate in the blood for extended periods of time. The naturally leaky vasculature of some tumours also allows nanosized particles to preferentially end up in tumour tissue, where they can be held. This is known as the enhanced permeability and retention (EPR) effect.

“Our work is the first to exploit the EPR effect with the high sensitivity and contrast afforded by magnetic particle imaging (MPI),” says Yu. “We have succeeded in imaging tumours in rats with vivid tumour-to-background contrast. “Thanks to its high sensitivity and good signal throughout the entire body, we were able to clearly capture the nanoparticle dynamics in the tumour: so-called rim enhancement, peak particle uptake at six hours after administration and eventual clearance beyond 48 hours.”

Synthesizing the SPIOscancer-shapeshiftin

The MPI-tailored superparamagnetic iron oxide nanoparticle (SPIO) tracers were synthesized by team members at LodeSpin Labs and by Kannan Krishnan’s lab at the University of Washington (UW), and were designed for optimal imaging resolution and long blood circulation time. “The iron oxide nanoparticles were made by thermolysis of iron III oleate in 1-octadcene, with subsequent oxidation to achieve the desired magnetic behaviour and coated with the biocompatible coating MPAO-PEG,” explains Yu.

The researchers injected the nanoparticles into the tail veins of rats and then performed a series of MPI scans as the nanoparticles travelled through the circulation. Thanks to the EPR effect, the particles preferentially accumulated in tumours and were retained there for up to six days.

Imaging the SPIO electronic moment

MPI was first developed by Philips Research in 2005 and is a tracer imaging technique that directly measures the location and concentration of SPIO nanoparticles in vivo. It images the SPIO electronic moment, which is 22 million times more intense than nuclear MRI moments. When a time-varying exciting field is applied, it causes the moments of the SPIOs to instantaneously “flip”, thereby inducing a signal in a receiver coil.

“The advantages of MPI are its superb contrast and sensitivity, which could very soon rival the dose-limited sensitivity of nuclear medicine techniques,” Conolly tells nanotechweb.org. “This is very exciting, since MPI does not rely on ionizing radiation. The scanner and iron oxide tracer are also thought to be safe for humans. Indeed, some SPIO agents are already FDA or EU safety approved for human use in other clinical applications.”

MPI tracers are excreted through the liver

Importantly, the MPI tracers are excreted through the liver, rather than through the kidneys, and there is evidence that SPIOs could be safer than iodine and gadolinium for patients with chronic kidney disease. “Given all these advantages, we are very hopeful that MPI could play an important role in early-stage cancer detection. Indeed, we are particularly focusing on early-stage breast cancer detection in the subpopulation of women with radiologically dense breast tissue and who are at high risk for cancer (because of, for example, BRCA1 or BRCA2 defects, or family history of the disease).”

Conolly says that he and his colleagues are now working hard to improve MPI in terms of resolution and sensitivity. “We are also studying MPI for stem-cell tracking, detecting pulmonary embolism, brain perfusion to detect and monitor strokes or traumatic brain injuries, and T-cell immunotherapy studies in collaboration with researchers at Berkeley, the University of California at San Francisco, UW, Case Western, Harvard and Stanford. We would also like to follow up on several promising demonstrations of MPI-guided magnetic fluid hyperthermia exploiting the unique ‘focusing’ capabilities of MPI to selectively heat tumours or to release chemotherapeutic agents specifically into a tumour. We are doing this work with University of Florida collaborators.”

The new MPI cancer imaging study is described in Nano Letters DOI: 10.1021/acs.nanolett.6b04865.

“Your Heart (Organ) on-a-chip” ~ mimics heart’s biomechanical properties (w/video)


Posted: Feb 23, 2017



The human heart beats more than 2.5 billion times in an average lifetime. Now scientists at Vanderbilt University have created a three-dimensional organ-on-a-chip that can mimic the heart’s amazing biomechanical properties.

“We created the I-Wire Heart-on-a-Chip so that we can understand why cardiac cells behave the way they do by asking the cells questions, instead of just watching them,” said Gordon A. Cain University Professor John Wikswo, who heads up the project. 

“We believe it could prove invaluable in studying cardiac diseases, drug screening and drug development, and, in the future, in personalized medicine by identifying the cells taken from patients that can be used to patch damaged hearts effectively.”

The device and the results of initial experiments demonstrating that it faithfully reproduces the response of cardiac cells to two different drugs that affect heart function in humans are described in an article published last month in the journal Acta Biomaterialia ~

(“I-Wire Heart-on-a-Chip I: Three-dimensional cardiac tissue constructs for physiology and pharmacology”). 

A companion article in the same issue presents a biomechanical analysis of the I-Wire platform that can be used for characterizing biomaterials for cardiac regenerative medicine.


I-Wire device with cardiac fiber shown in magnification window. (Image: VIIBRE / Vanderbilt)

The unique aspect of the new device, which represents about two millionths of a human heart, is that it controls the mechanical force applied to cardiac cells. 

This allows the researchers to reproduce the mechanical conditions of the living heart, which is continually stretching and contracting, in addition to its electrical and biochemical environment.

“Heart tissue, along with muscle, skeletal and vascular tissue, represents a special class of mechanically active biomaterials,” said Wikswo. “Mechanical activity is an intrinsic property of these tissues so you can’t fully understand how they function and how they fail without taking this factor into account.”

“Currently, we don’t have many models for studying how the heart responds to stress. Without them, it is very difficult to develop new drugs that specifically address what goes wrong in these conditions,” commented Charles Hong, associate professor of cardiovascular medicine at Vanderbilt’s School of Medicine, who didn’t participate in the research but is familiar with it. 

“This provides us with a really amazing model for studying how hearts fail.”

The I-Wire device consists of a thin thread of human cardiac cells 0.014 inches thick (about the size of 20-pound monofilament fishing line) stretched between two perpendicular wire anchors. 

The amount of tension on the fiber can be varied by moving the anchors in and out, and the tension is measured with a flexible probe that pushes against the side of the fiber.

The fiber is supported by wires and a frame in an optically clear well that is filled with liquid medium like that which surrounds cardiac cells in the body. The apparatus is mounted on the stage of a powerful optical microscope that records the fiber’s physical changes. 
The microscope also acts as a spectroscope that can provide information about the chemical changes taking place in the fiber. 
A floating microelectrode also measures the cells’ electrical activity.

According to the researchers, the I-Wire system can be used to characterize how cardiac cells respond to electrical stimulation and mechanical loads and can be implemented at low cost, small size and low fluid volumes, which make it suitable for screening drugs and toxins. Because of its potential applications, Vanderbilt University has patented the device.

Video taken through a microscope shows I-Wire heart fiber. left, beating at different frequencies. The black circle, right, is the flexible cantilever that measures the force of the fiber’s contractions. (Veniamin Sidorov / VIIBRE /Vanderbilt)

Unlike other heart-on-a-chip designs, I-Wire allows the researchers to grow cardiac cells under controlled, time-varying tension similar to what they experience in living hearts. 

As a consequence, the heart cells in the fiber align themselves in alternating dark and light bands, called sarcomeres, which are characteristic of human muscle tissue. The cardiac cells in most other heart-on-a-chip designs do not exhibit this natural organization.

In addition, the researchers have determined that their heart-on-a-chip obeys the Frank-Starling law of the heart. The law, which was discovered by two physiologists in 1918, describes the relationship between the volume of blood filling the heart and the force with which cardiac cells contract. The I-Wire is one of the first heart-on-a-chip devices to do so.

To demonstrate the I-Wire’s value in determining the effects that different drugs have on the heart, the scientists tested its response with two drugs known to affect heart function in humans: isoproterenol and blebbistatin. Isoproterenol is a medication used to treat bradycardia (slow heart rate) and heart block (obstruction of the heart’s natural pacemaker). Blebbistatin inhibits contractions in all types of muscle tissue, including the heart.

According to Veniamin Sidorov, the research assistant professor at the Vanderbilt Institute for Integrative Biosystems Research and Education (VIIBRE) who led its development, the device faithfully reproduces the response of cardiac cells in a living heart.

“Cardiac tissue has two basic elements: an active, contractile element and a passive, elastic element,” said Sidorov. “By separating these two elements with blebbistatin, we successfully characterized the elasticity of the artificial tissue. By exposing it to isoproterenol, we tested its response to adrenergic stimulation, which is one of the main systems responsible for regulation of heart contractions. 
We found that the relationship between these two elements in the cardiac fiber is consistent with that seen in natural tissue. 

This confirms that our heart-on-a-chip model provides us with a new way to study the elastic response of cardiac muscle, which is extremely complicated and is implicated in heart failure, hypertension, cardiac hypertrophy and cardiomyopathy.”

Source: Vanderbilt University

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