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.


Story Source:

Materials provided by Penn State College of Medicine. Note: Content may be edited for style and length.

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

Creating a Life-Saving, Blood-Repellent Super Material – Revolutionizing Medical Implants: Colorado State University


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Briefly

  • Biomedical engineers and materials scientists have developed a “superhemophobic” surface treatment for titanium that repels liquids including blood, plasma, and water.
  • The result is a surface that completely repels any liquid with which it would come in contact – a material that could revolutionize medical implants.

GOODBYE REJECTION

Implanted medical devices like stents, catheters, and titanium rods are essential, life-saving tools for patients around the world. Still, having a foreign object in the human body does pose its own risks – chiefly, having the body reject the object or increasing the risk of dangerous blood clots. A new collaboration between two distinct scientific disciplines is working toward making those risks a concern of the past.

Biomedical engineers and materials scientists from Colorado State University (CSU) have developed a “superhemophobic” surface treatment for titanium that repels liquids including blood, plasma, and water. The titanium is essentially studded with nanoscale tubes treated with a non-stick chemical. The result is a surface that completely repels any liquid with which it would come in contact. The team’s findings are published in Advanced Healthcare Materials.

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Fluorinated nanotubes provided the best superhemophobic surfaces in the CSU researchers’ experiments. Credit: Kota lab/Colorado State University

AN END TO CLOTTING

In cases where a body does reject a medical implant, the patient’s immune system detects the foreign object and mounts a defense against it, which can lead to serious inflammation and other complications. The real trick to the team’s surface is that the body doesn’t even recognize that it’s there. According to Arun Kota, assistant professor of mechanical engineering and biomedical engineering at CSU, “We are taking a material that blood hates to come in contact with, in order to make it compatible with blood.”

Regarding clotting, patients with medical implants often need to stay on a regimen of blood-thinning drugs to decrease the risk. However, blood thinners are not guaranteed to work, and they also carry the risk of leading to excessive bleeding due to the prevention of even beneficial clotting near wounds. As Ketul Popat, associate professor of mechanical engineering and biomedical engineering at CSU explains, “The reason blood clots is because it finds cells in the blood to go to and attach.” He continues, “if we can design materials where blood barely contacts the surface, there is virtually no chance of clotting.”

This material is only in its earliest stages of development. Should the team’s findings hold up to further scrutinization, these life-saving medical devices could be given an unprecedented boost in safety.

Revolutionary Screening Method for the Impact of Biomedical Nanoparticles on the Immune System


Over the last several years, the application of nanoparticles, particles with at least one dimension within the size range of 1-100 nm, has become increasingly popular in a wide variety of practical industries.

Within the field of medicine, the use of nanoparticles as drug and gene delivery vehicles, particularly chemotherapeutic drugs, as well as fluorescent labels and contrast agents, has been particularly useful for its unique ability to specifically target organs and tissues of interest.

For example, gold nanoparticles have shown advantageous properties as a non-toxic chemotherapy drug for its ability to both enhance the efficacy of the drug and reduce systemic toxicity1.

Prior to their implementation in medical devices, nanoparticles must be proved to be both safe for the human body, and capable of bypassing the immune system in order to induce their desired clinical effect.


Nanoparticles show great promise for use in medicine. Image credit: Shutterstock / Kateryna Kon

Avoiding immune defense systems

Within the immune system are macrophages, which are cells present in almost all tissues of the body, whose responsibility is to act as a first line of defense for the immune system against foreign material. 

Through a process known as phagocytosis, macrophages engulf materials such as microorganisms, damaged cells and other particulate materials.

Through this function, macrophages are capable of mediating the clearance and biotransformation of nanoparticles from the body, which can therefore trigger an inflammatory reaction to occur.

While its potential is impressive, the use of nanoparticles in the clinical setting can be potentially unpredictable in regards to the possible consequences that could occur following exposure. 

As a result of this growing concern, researchers from the Universities of Geneva (UNIGE) and Fribourg (UNIFR) in Switzerland have developed a rapid screening method to select the most promising of nanoparticles and determine whether they are compatible with the human body.

Through this automated screening assay, researchers at UNIGE and UNIFR are capable of detecting the possible interactions between nanoparticles and macrophages by measuring the possible immune activating effects of nanoparticles on in vitro macrophages.

In their study, published in Nano Today, cytrate-stabilized gold nanoparticles and polymer-coated nanoparticles with and without Cy5 labeling were characterized and exposed to J774.1 murine macrophage cells for a 24 hour incubation period.

Following the incubation period, cell viability and macrophage activation were analyzed through flow cytometry and bright field microscopy, whereas cytokine secretion was analyzed by enzyme-linked immunosorbant assay (ELISA) techniques.

Screening for the least harmful nanoparticles

By utilizing these techniques, nanoparticle-related cytotoxicity, cellular reuptake of nanoparticles, and any proinflammatory activation upon exposure to nanoparticles was successfully analyzed.

Through flow cytometry techniques, researchers were able to distinguish whether the applied gold nanoparticles induced cell death by apoptosis or necrosis, which is an important marker in understanding whether an inflammatory reaction is expected to follow.

Apoptosis, a cellular death mechanism that does not generally promote inflammation, differs greatly from necrotic cell death, which will often lead to disruption of the cellular membrane and subsequent release of proinflmmatory molecules.

By screening nanoparticles that can potentially cause cytotoxicity through either of these mechanisms, researchers are able to quickly choose the least harmful treatment options more rapidly than before.

Further analysis of the cellular uptake of nanoparticles provides information regarding the potential rate of nanoparticle clearance from the body, which can determine the amount of time necessary for these particles to reach their target cells in the body before being captured by macrophages.

This novel approach in the development process of nanotechnology materials for biomedical purposes not only enables researchers to analyze the most promising particles quickly, but also limits the use of animal testing and increases the capability of personalizing treatment options for patients suffering from certain pathologies.

While further confirmation studies such as inductively coupled optical emission spectrometry (ICP-OES) have been suggested to fully quantify nanoparticle uptake, this standardized technique has the potential to quickly and easily screen the impact of nanoparticles and other materials on a variety of cell lines.

References

“Toxicological Considerations of Clinically Applicable Nanoparticles”, L. Yildirimer et al, Nano Today 2011. DOI:10.1016/j.nantod.2011.10.001

A Ground-breaking Method for Screening the Most Useful Nanoparticles for Medicine – University of Geneva Press Release

“A Rapid Screening Method to Evaluate the Impact of Nanoparticles on Macrophages”, I/ Mottas, Nanoscale 2017, DOI:10.1039/C6NR08194K

MIT: Nanoparticle screen could speed up drug development


mit-target-nano_0

A team of researchers from MIT, Georgia Tech, and the University of Florida has devised a way to rapidly test different nanoparticles to see where they go in the body. Image: Christine Daniloff/MIT

New test helps identify particles for gene delivery or RNA interference.

Many scientists are pursuing ways to treat disease by delivering DNA or RNA that can turn a gene on or off. However, a major obstacle to progress in this field has been finding ways to safely deliver that genetic material to the correct cells.

Encapsulating strands of RNA or DNA in tiny particles is one promising approach. To help speed up the development of such drug-delivery vehicles, a team of researchers from MIT, Georgia Tech, and the University of Florida has now devised a way to rapidly test different nanoparticles to see where they go in the body.

“Drug delivery is a really substantial hurdle that needs to be overcome,” says James Dahlman, a former MIT graduate student who is now an assistant professor at Georgia Tech and the study’s lead author. “Regardless of their biological mechanisms of action, all genetic therapies need safe and specific drug delivery to the tissue you want to target.”

This approach, described in the Proceedings of the National Academy of Sciences the week of Feb. 6, could help scientists target genetic therapies to precise locations in the body.

“It could be used to identify a nanoparticle that goes to a certain place, and with that information we could then develop the nanoparticle with a specific payload in mind,” says Daniel Anderson, an associate professor in MIT’s Department of Chemical Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

The paper’s senior authors are Anderson; Robert Langer, the David H. Koch Institute Professor at MIT and a member of the Koch Institute; and Eric Wang, a professor at the University of Florida. Other authors are graduate student Kevin Kauffman, recent MIT graduates Yiping Xing and Chloe Dlott, MIT undergraduate Taylor Shaw, and Koch Institute technical assistant Faryal Mir.

Targeting disease

Finding a reliable way to deliver DNA to target cells could help scientists realize the potential of gene therapy — a method of treating diseases such as cystic fibrosis or hemophilia by delivering new genes that replace missing or defective versions. Another promising approach for new therapies is RNA interference, which can be used to turn off overactive genes by blocking them with short strands of RNA known as siRNA.

Delivering these types of genetic material into body cells has proven difficult, however, because the body has evolved many defense mechanisms against foreign genetic material such as viruses.

To help evade these defenses, Anderson’s lab has developed nanoparticles, including many made from fatty molecules called lipids, that protect genetic material and carry it to a particular destination. Many of these particles tend to accumulate in the liver, in part because the liver is responsible for filtering blood, but it has been more difficult to find particles that target other organs.

“We’ve gotten good at delivering nanoparticles into certain tissues but not all of them,” Anderson says. “We also haven’t really figured out how the particles’ chemistries influence targeting to different destinations.”

To identify promising candidates, Anderson’s lab generates libraries of thousands of particles, by varying traits such as their size and chemical composition. Researchers then test the particles by placing them on a particular cell type, grown in a lab dish, to see if the particles can get into the cells. The best candidates are then tested in animals. However, this is a slow process and limits the number of particles that can be tried.

“The problem we have is we can make a lot more nanoparticles than we can test,” Anderson says.

To overcome that hurdle, the researchers decided to add “barcodes,” consisting of a DNA sequence of about 60 nucleotides, to each type of particle. After injecting the particles into an animal, the researchers can retrieve the DNA barcodes from different tissues and then sequence the barcodes to see which particles ended up where.

“What it allows us to do is test many different nanoparticles at once inside a single animal,” Dahlman says.

Tracking particles

The researchers first tested particles that had been previously shown to target the lungs and the liver, and confirmed that they did go where expected.

Then, the researchers screened 30 different lipid nanoparticles that varied in one key trait — the structure of a component known as polyethylene glycol (PEG), a polymer often added to drugs to increase their longevity in the bloodstream. Lipid nanoparticles can also vary in their size and other aspects of their chemical composition.

Each of the particles was also tagged with one of 30 DNA barcodes. By sequencing barcodes that ended up in different parts of the body, the researchers were able to identify particles that targeted the heart, brain, uterus, muscle, kidney, and pancreas, in addition to liver and lung. In future studies, they plan to investigate what makes different particles zero in on different tissues.

The researchers also performed further tests on one of the particles, which targets the liver, and found that it could successfully deliver siRNA that turns off the gene for a blood clotting factor.

Victor Koteliansky, director of the Skoltech Center for Functional Genomics, described the technique as an “innovative” way to speed up the process of identifying promising nanoparticles to deliver RNA and DNA.

“Finding a good particle is a very rare event, so you need to screen a lot of particles. This approach is faster and can give you a deeper understanding of where particles will go in the body,” says Kotelianksy, who was not involved in the research.

This type of screen could also be used to test other kinds of nanoparticles such as those made from polymers. “We’re really hoping that other labs across the country and across the world will try our system to see if it works for them,” Dahlman says.

The research was funded by an MIT Presidential Fellowship, a National Defense Science and Engineering Graduate Fellowship, a National Science Foundation Graduate Research Fellowship, the MIT Undergraduate Research Opportunities Program, the Koch Institute Frontier Research Program through the Kathy and Curt Marble Cancer Research Fund, and the National Institutes of Health.

U of Texas: Graphene-based sensor can track vital signs


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Researchers at the University of Texas have developed a graphene-based health sensor that attaches to the skin like a temporary tattoo and takes measurements with the same precision as bulky medical equipment. The graphene tattoos are said to be the thinnest epidermal electronics ever made. They can measure electrical signals from the heart, muscles, and brain, as well as skin temperature and hydration.

The research team hopes to integrate these sensors applications like consumer cosmetics, in addition to providing a more convenient replacement for existing medical equipment. The sensor takes advantage of graphene’s mechanical invisibility – when the sensor goes on the skin, it doesn’t just stay flat—it conforms to the microscale ridges and roughness of the epidermis.1-Brain Transparentgraphene1-640x353

The Texas researchers started by growing single-layer graphene on a sheet of copper. The 2D carbon sheet is then coated with a stretchy support polymer, and the copper is etched off. Next, the polymer-graphene sheet is placed on temporary tattoo paper, the graphene is carved to make electrodes with stretchy spiral-shaped connections between them, and the excess graphene is removed. Then the sensor is ready to be applied by placing it on the skin and wetting the back of the paper.

In their proof-of-concept work, the researchers used the graphene tattoos to take five kinds of measurements, and compared the data with results from conventional sensors. The graphene electrodes were able to pick up changes in electrical resistance caused by electrical activity in the tissue underneath. When worn on the chest, the graphene sensor detected faint fluctuations that were not visible on an EKG taken by an adjacent, conventional electrode. The sensor readouts for electroencephalography (EEG) and electromyography (EMG, which can be used to register electrical signals from muscles and is being incorporated into next-generation prosthetic arms and legs) were also of good quality. The sensors could also measure skin temperature and hydration, which could be useful for cosmetics companies.

Graphene’s conformity to the skin might be what enables the high-quality measurements. Air gaps between the skin and the relatively large, rigid electrodes used in conventional medical devices degrade these instruments’ signal quality. Newer sensors that stick to the skin and stretch and wrinkle with it have fewer airgaps, but because they’re still a few micrometers thick, and use gold electrodes hundreds of nanometers thick, they can lose contact with the skin when it wrinkles. The graphene in the Texas researchers’ device is 0.3-nm thick. Most of the tattoo’s bulk comes from the 463-nm-thick polymer support.

The next step is to add an antenna to the design so that signals can be transmitted from the device to a phone or computer.

Source:  spectrum.ieee

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