Heart Attack on a Chip: Scientists Model Conditions of Ischemia on a Microfluidic Device

The microfluidic device containing HL-1 cardiac cells is capable of modeling conditions observed during a heart attack, including a reduction in levels of oxygen. Credit: Tufts University

Researchers led by biomedical engineers at Tufts University invented a microfluidic chip containing cardiac cells that is capable of mimicking hypoxic conditions following a heart attack—specifically when an artery is blocked in the heart and then unblocked after treatment.

The chip contains multiplexed arrays of electronic sensors placed outside and inside the cells that can detect the rise and fall of voltage across individual cell membranes, as well as voltage waves moving across the cell layer, which cause the cells to beat in unison in the chip, just as they do in the heart. After reducing levels of oxygen in the fluid within the device, the sensors detect an initial period of tachycardia (accelerated beat rate), followed by a reduction in beat rate and eventually arrhythmia which mimics cardiac arrest.

The research, published in Nano Letters, is a significant advance toward understanding the electrophysiological responses at the cellular level to ischemic heart attacks, and could be applied to future drug development. The paper was selected by the American Chemical Society as Editors’ Choice, and is available with open access.

Cardiovascular disease (CVD) remains the leading cause of death worldwide, with most patients suffering from cardiac ischemia—which occurs when an artery supplying blood to the heart is partially or fully blocked. If ischemia occurs over an extended period, the heart tissue is starved of oxygen (a condition called “hypoxia”), and can lead to tissue death, or myocardial infarction. The changes in cardiac cells and tissues induced by hypoxia include changes in voltage potentials across the cell membrane, release of neurotransmitters, shifts in gene expression, altered metabolic functions, and activation or deactivation of ion channels.

The biosensor technology used in the microfluidic chip combines multi-electrode arrays that can provide extracellular readouts of voltage patterns, with nanopillar probes that enter the membrane to take readouts of voltage levels (action potentials) within each cell. Tiny channels in the chip allow the researchers to continuously and precisely adjust the fluid flowing over the cells, lowering the levels of oxygen to about 1-4 percent to mimic hypoxia or raising oxygen to 21 percent to model normal conditions. The changing conditions are meant to model what happens to cells in the heart when an artery is blocked, and then re-opened by treatment.

“Heart-on-a-chip models are a powerful tool to model diseases, but current tools to study electrophysiology in those systems are somewhat lacking, as they are either difficult to multiplex or eventually cause damage to the cells,” said Brian Timko, assistant professor of biomedical engineering at Tufts University School of Engineering, and corresponding author of the study. “Signaling pathways between molecules and ultimately electrophysiology occur rapidly during hypoxia, and our device can capture a lot of this information simultaneously in real time for a large ensemble of cells.”

When tested, the extracellular electrode arrays provided a two-dimensional map of voltage waves passing over the layer of cardiac cells, and revealed a predictable wave pattern under normal (21 percent) oxygen levels. In contrast, the researchers observed erratic and slower wave patterns when the oxygen was reduced to 1 percent.

The intracellular nanoprobe sensors provided a remarkably accurate picture of action potentials within each cell. These sensors were arranged as an array of tiny platinum tipped needles upon which the cells rest, like a bed of nails. When stimulated with an electric field, the needles puncture through the cell membrane, where they can begin taking measurements at single cell resolution. Both types of devices were created using photolithography—the technology used to create integrated circuits—which allowed researchers to achieve device arrays with highly reproducible properties.

The extracellular and intracellular sensors together provide information of the eletro-physiological effects of a modeled ischemic attack, including a “time lapse” of cells as they become dysfunctional and then respond to treatment. As such, the microfluidic chip could form the basis of a high throughput platform in drug discovery, identifying therapeutics which help cells and tissues recover normal function more rapidly.

“In the future, we can look beyond the effects of hypoxia and consider other factors contributing to acute heart disease, such as acidosis, nutrient deprivation and waste accumulation, simply by modifying the composition and flow of the medium,” said Timko. “We could also incorporate different types of sensors to detect specific molecules expressed in response to stresses.”

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Study reveals how low oxygen levels in the heart predispose people to cardiac arrhythmias

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More information: Haitao Liu et al, Heart-on-a-Chip Model with Integrated Extra- and Intracellular Bioelectronics for Monitoring Cardiac Electrophysiology under Acute Hypoxia, Nano Letters (2020). DOI: 10.1021/acs.nanolett.0c00076

Journal information: Nano Letters

Researchers develop technique to create nanomaterials which may help detect cancer earlier – U of Central Florida

Assistant Professor Xiaohu Xia works in his chemistry lab at the University of Central Florida. Credit: UCF, Karen Norum

For the first time, a team of scientists at the University of Central Florida has created functional nanomaterials with hollow interiors that can be used to create highly sensitive biosensors for early cancer detection.

Xiaohu Xia, an assistant professor of chemistry with a joint appointment in the NanoScience Technology Center, and his team developed the new method and recently published their work in the journal ACS Nano.

“These advanced hollow nanomaterials hold great potential to enable high-performance technologies in various areas,” says Xia. “Potentially we could be talking about a better and less expensive diagnostic tool, sensitive enough to detect biomarkers at low concentrations, which could make it invaluable for early detection of cancers and infectious diseases.”

Because hollow nanomaterials made of gold and silver alloys display superior optical properties, they could be particularly good for developing better test strip technology, similar to over-the-counter pregnancy tests. Currently the technology used to indicate positive or negative symbols on the test stick is not sensitive enough to pick up markers that indicate certain types of cancer. But Xia’s new method of creating hollow nanomaterials could change that.

More advance warning could help doctors save more lives.

In conventional test strips, solid gold nanoparticles are often used as labels, where they are connected with antibodies and specifically generate color signal due to an optical phenomenon called localized surface plasmon resonance. Under Xia’s technique, metallic nanomaterials can be crafted with hollow interiors. Compared to the solid counterparts, these hollow nanostructures possess much stronger LSPR activities and thus offer more intense color signal. Therefore, when the hollow nanomaterials are used as labels in test strips they can induce sensitive color change, enabling the strips to detect biomarkers at lower concentrations.

“Test-strip technology gets upgraded by simply replacing solid gold nanoparticles with the unique hollow nanoparticles, while all other components of a test strip are kept unchanged,” says Xia. “Just like the pregnancy test, the new test strip can be performed by non-skilled persons, and the results can be determined with the naked eye without the need of any equipment. These features make the strip extremely suitable for use in challenging locations such as remote villages.”

The UCF study focused on prostate-specific antigen, a biomarker for prostate cancer. The new test strip based on hollow nanomaterials was able to detect PSA as low as 0.1 nanogram per milliliter (ng/mL), which is sufficiently sensitive for clinical diagnostics of prostate cancer. The published study includes electron microscope images of the metallic hollow nanomaterials.

“I hope that by providing a general and versatile platform to engineer functional hollow nanomaterials with desired properties, new research with the potential for other applications beyond biosensing can be launched,” Xia says.

Collaborators on the study include Zhuangqiang Gao, Zheng Xi, Haihang Ye, Zhiyuan Wei and Shikuan Shao from UCF’s chemistry department; Qingxiao Wang and Moon J. Kim from the University of Texas at Dallas, and Dianyong Tang from Chongqing University of Arts and Sciences in China.

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Test strips for cancer detection get upgraded with nanoparticle bling

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More information: Zhuangqiang Gao et al. Template Regeneration in Galvanic Replacement: A Route to Highly Diverse Hollow Nanostructures, ACS Nano (2020). DOI: 10.1021/acsnano.9b07781

Journal information: ACS Nano

Provided by University of Central Florida

New pulmonary fibrosis inhalation therapy shows promise in mouse model

Lung stem cell secretions – nanosized exosomes and secretomes – delivered via a nebulizer has been shown to help in the repair of lung injuries from pulmonary fibrosis in mice and rats in research led by a team from North Carolina State University (NC State; USA).

Pulmonary fibrosis is a fatal and incurable disease characterized by a thickening and scarring of healthy lung tissue, inflammation and replacement of lung cells with fibrotic tissue. The current treatment options for pulmonary fibrosis are severely limited and not very effective apart from highly invasive lung transplants. To rectify this, Ke Cheng of NC State led the research into developing spheroid-produced lung stem cells (LSCs) as a potential therapeutic.

“The mixture of cells in LSCs recreates the stem cells’ natural microenvironment – known as the stem cell niche – where cells secrete exosomes to communicate with each other just as they would inside your body,” Cheng explained. “LSCs secrete many beneficial proteins and growth factors known collectively as ‘secretome’ – exosomes and soluble proteins, which can reproduce the regenerative microenvironment of the cells themselves. In this work we took it one step further and tested the secretome and exosomes from our spheroid-produced stem cells against two models of pulmonary fibrosis.”

Cheng’s lab used mouse and rat models of chemically, silica- or particle-induced pulmonary fibrosis to test lung spheroid cell secretome (LSC-Sec) and lung spheroid cell exosomes (LSC-Exo) against commonly used mesenchymal stem cells (MSCs). The stem cell-derived therapeutics – proteins, small molecules and nanosized exosomes – were delivered via inhalation directly to the lungs by a nebulizer.

In the mouse model of chemically induced fibrosis, improvements were seen in all stem cell therapies compared to the control, with a 32.4% reduction in fibrosis with MSC-Sec treatment and nearly 50% reduction with LSC-Sec treatment.

In the silica-induced fibrosis mouse model LSC-Sec treatment led to a 26% reduction in fibrosis compared to 16.9% with MSC-Sec treatment.

“This work shows that lung spheroid cell secretome and exosomes are more effective than their mesenchymal stem cells counterparts in decreasing fibrotic tissue and inflammation in damaged lung tissue,” Cheng stated. “Hopefully we are taking our first steps toward an efficient, non-invasive and cost-effective way to repair damaged lungs.

“Given the therapy’s effectiveness in multiple models of lung fibrosis and inflammation, we are planning to expand the test into more pulmonary diseases, including chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS) and pulmonary hypertension (PH).”

“The finding that products released by lung stem cells can be just as efficacious, if not more so, than the stem cells themselves in treating pulmonary fibrosis can be a major finding that can have implications in many other diseases where stem cell therapy is being developed,” commented Kenneth Adler, Professor at NC State and a co-author of the paper.

SOURCE

• Dinh PC, Paudel D, Brochu H et al., Inhalation of lung spheroid cell secretome and exosomes promotes lung repair in pulmonary fibrosis. Nat. Commun. 11, 1064. (2020).

Innovative AI Breath Analyzer Diagnoses Diseases by “Smell” – AI System to Detect 17 Diseases from Exhaled Breath with 86% Accuracy

Re-Posted from Psychology Today: Author Cami Russo

Imagine being able to know if you have Parkinson’s disease, multiple sclerosis, liver failure, Crohn’s diseases, pulmonary hypertension, chronic kidney disease, or any number of cancers based on a simple, non-invasive test of your breath. Breath analyzers to detect alcohol have been around for well over half a century—why not apply the same concept to detect diseases? A global team of scientists from universities in Israel, France, Latvia, China and the United States have developed an artificial intelligence (AI) system to detect 17 diseases from exhaled breath with 86 percent accuracy.

The research team led by Professor Hassam Haick of the Technion-Israel Institute of Technology collected breath samples from 1404 subjects with either no disease (healthy control) or one of 17 different diseases. The disease conditions include lung cancer, colorectal cancer, head and neck cancer, ovarian cancer, bladder cancer, prostate cancer, kidney cancer, gastric cancer, Crohn’s disease, ulcerative colitis, irritable bowel syndrome, idiopathic Parkinson’s, atypical Parkinson ISM, multiple sclerosis, pulmonary hypertension, pre-eclampsia toxemia, and chronic kidney disease.

The concept is relatively simple—identify breath-prints of diseases, and compare it to human exhalation. What makes it complicated is the execution of the concept. For example, how to identify the breathprint of a disease? Is it unique like a fingerprint? To answer these questions requires a deeper look at the molecular composition of breath.

When we exhale, nitrogen, oxygen, carbon dioxide, argon, and water vapor are released. Human breath also contains volatile organic compounds (VOCs)–organic chemicals that are emitted as gases, and have a high vapor pressure at normal temperature. American biochemist Linus Pauling, one of the founders of modern quantum chemistry and molecular biology, and recipient of the 1954 Nobel Prize in Chemistry, and the 1962 Nobel Peace Prize, studied 250 human breath volatiles using a gas-liquid chromatogram in 1971. Pauling is widely regarded as a pioneer in modern breath analysis. Exhaled breath contains approximately over 3,500 components mostly comprised of VOCs in small quantities according to a 2011 study published in “Annals of Allergy, Asthma & Immunology.”

VOCs are the common factor in the smelling process for both breath analyzers and humans. When we inhale, the nose draws in odor molecules that typically contain volatile (easy to evaporate) chemicals. Once the odor molecules contact the olfactory epithelium tissue that lines the nasal cavity, it binds with the olfactory receptors and sends an electrical impulse to a spherical structure called the glomerulus in the olfactory bulb of the brain.

There are approximately 2,000 glomeruli near the surface of the olfactory bulb. Smell is the brain’s interpretation of the odorant patterns released from the glomerulus. The human nose can detect a trillion smells. In Haick’s researcher team, nanotechnology and machine learning replaces the biological brain in the smelling process.

Read More: AN ARTIFICIAL INTELLIGENCE “NOSE” TO SNIFF DISEASES

Haick’s team of scientists developed a system, aptly called “NaNose,” that uses nanotechnology-based sensors trained to detect volatile organic compounds associated with select diseases in the study. NaNose has two layers. One is an inorganic nanolayer with nanotubes and gold nanoparticles for electrical conductivity. The other is an organic sensing layer with carbon that controls the electrical resistance of the inorganic layer based on the incoming VOCs. The electrical resistance changes depending on the VOCs.

Artificial intelligence (AI) is used to analyze the data. Specifically, deep learning is used to identify patterns in the data in order to match incoming signals with the chemical signature of specific diseases. The AI system was then trained on more than 8,000 patients in clinics with promising results—the system detected gastric cancer with 92-94 percent accuracy in a blinded test. The researchers discovered that “each disease has its own unique breathprint.”

Efforts are underway to miniaturize and commercialize the innovative technology developed by Haick’s team in a project called “SniffPhone.”  In November 2018, the European Commission’s Horizon 2020 awarded the SniffPhone the “2018 Innovation Award” for the “Most Innovative Project.”

The market opportunity for medical breath analyzers is expected to grow. By 2024, the breath analyzer market is projected to increase to USD 11.3 billion globally according to figures published in Jun 2018 by Grand View Research—alcohol detection has a majority of the revenue share. Currently breath analyzers are used to detect alcohol, drugs, and to diagnose asthma and gastroenteric conditions. Clinical applications are projected to increase due to the introduction of “introduction of advanced technologies to detect nitric oxide and carbon monoxide in breath,” Grand View Research states. According to the study, the medical application segment is expected to grow due to ability of breath analyzers to detect volatile organic compounds (VOCs) that may help in “early diagnosis of conditions including cardiopulmonary diseases and lung and breast cancer,” and act as “biomarkers to assess disease progressions.”

By applying cross-disciplinary innovative technologies from the fields of artificial intelligence, nanotechnology, and molecular chemistry, diagnosing a wide variety of diseases may be as simple and non-invasive as a breath analysis using a handheld device in the not-so-distant future.

 

Nanoparticles used to Transport Anti-Cancer Agent to Cells – University of Cambridge

Cells with MOFs carrying siRNA. Credit: University of Cambridge

Scientists from the University of Cambridge have developed a platform that uses nanoparticles known as metal-organic frameworks to deliver a promising anti-cancer agent to cells.

Research led by Dr. David Fairen-Jimenez, from the Cambridge Department of Chemical Engineering and Biotechnology, indicates metal-organic frameworks (MOFs) could present a viable platform for delivering a potent anti-cancer agent, known as siRNA, to cells.

Small interfering ribonucleic acid (siRNA), has the potential to inhibit overexpressed cancer-causing genes, and has become an increasing focus for scientists on the hunt for new cancer treatments.

Fairen-Jimenez’s group used computational simulations to find a MOF with the perfect pore size to carry an siRNA molecule, and that would breakdown once inside a cell, releasing the siRNA to its target. Their results were published today in Cell Press journal, Chem.

Some cancers can occur when specific genes inside cells cause over-production of particular proteins. One way to tackle this is to block the gene expression pathway, limiting the production of these proteins.

SiRNA molecules can do just that—binding to specific gene messenger molecules and destroying them before they can tell the cell to produce a particular protein. This process is known as ‘gene knockdown’. Scientists have begun to focus more on siRNAs as potential cancer therapies in the last decade, as they offer a versatile solution to disease treatment—all you need to know is the sequence of the gene you want to inhibit and you can make the corresponding siRNA that will break it down. Instead of designing, synthesising and testing new drugs—an incredibly costly and lengthy process—you can make a few simple changes to the siRNA molecule and treat an entirely different disease.

One of the problems with using siRNAs to treat disease is that the molecules are very unstable and are often broken down by the cell’s natural defence mechanisms before they can reach their targets. SiRNA molecules can be modified to make them more stable, but this compromises their ability to knock down the target genes. It’s also difficult to get the molecules into cells—they need to be transported by another vehicle acting as a delivery agent.

Crystalline metal-organic framework. Credit: David Fairen-Jimenez

The Cambridge researchers have used a special nanoparticle to protect and deliver siRNA to cells, where they show its ability to inhibit a specific target gene.

Fairen-Jimenez leads research into advanced materials, with a particular focus on MOFs: self-assembling 3-D compounds made of metallic and organic building blocks connected together.

There are thousands of different types of MOFs that researchers can make—there are currently more than 84,000 MOF structures in the Cambridge Structural Database with 1000 new structures published each month—and their properties can be tuned for specific purposes. By changing different components of the MOF structure, researchers can create MOFs with different pore sizes, stabilities and toxicities, enabling them to design structures that can carry molecules such as siRNAs into cells without harmful side effects.

“With traditional cancer therapy if you’re designing new drugs to treat the system, these can have different behaviours, geometries, sizes, and so you’d need a MOF that is optimal for each of these individual drugs,” says Fairen-Jimenez. “But for siRNA, once you develop one MOF that is useful, you can in principle use this for a range of different siRNA sequences, treating different diseases.”

“People that have done this before have used MOFs that don’t have a porosity that’s big enough to encapsulate the siRNA, so a lot of it is likely just stuck on the outside,” says Michelle Teplensky, former Ph.D. student in Fairen-Jimenez’s group, who carried out the research. “We used a MOF that could encapsulate the siRNA and when it’s encapsulated you offer more protection. The MOF we chose is made of a zirconium based metal node and we’ve done a lot of studies that show zirconium is quite inert and it doesn’t cause any toxicity issues.”

Using a biodegradable MOF for siRNA delivery is important to avoid unwanted build-up of the structures once they’ve done their job. The MOF that Teplensky and team selected breaks down into harmless components that are easily recycled by the cell without harmful side effects. The large pore size also means the team can load a significant amount of siRNA into a single MOF molecule, keeping the dosage needed to knock down the genes very low.

“One of the benefits of using a MOF with such large pores is that we can get a much more localised, higher dose than other systems would require,” says Teplensky. “SiRNA is very powerful, you don’t need a huge amount of it to get good functionality. The dose needed is less than 5% of the porosity of the MOF.”

MOFs or other vehicles to carry small molecules into cells is that they are often stopped by the cells on the way to their target. This process is known as endosomal entrapment and is essentially a defence mechanism against unwanted components entering the cell. Fairen-Jimenez’s team added extra components to their MOF to stop them being trapped on their way into the cell, and with this, could ensure the siRNA reached its target.

The team used their system to knock down a gene that produces fluorescent proteins in the cell, so they were able to use microscopy imaging methods to measure how the fluorescence emitted by the proteins compared between cells not treated with the MOF and those that were. The group made use of in-house expertise, collaborating with super-resolution microscopy specialists Professors Clemens Kaminski and Gabi Kaminski-Schierle, who also lead research in the Department of Chemical Engineering and Biotechnology.

Using the MOF platform, the team were consistently able to prevent gene expression by 27%, a level that shows promise for using the technique to knock down cancer genes.

Fairen-Jimenez believes they will be able to increase the efficacy of the system and the next steps will be to apply the platform to genes involved in causing so-called hard-to-treat cancers.

“One of the questions we get asked a lot is ‘why do you want to use a metal-organic framework for healthcare?’, because there are metals involved that might sound harmful to the body,” says Fairen-Jimenez. “But we focus on difficult diseases such as hard-to-treat cancers for which there has been no improvement in treatment in the last 20 years. We need to have something that can offer a solution; just extra years of life will be very welcome.”

The versatility of the system will enable the team to use the same adapted MOF to deliver different siRNA sequences and target different genes. Because of its large pore size, the MOF also has the potential to deliver multiple drugs at once, opening up the option of combination therapy.

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High-tech gel aids delivery of drugs

MIT: Nanoparticles take a “Fantastic, (magnetic) Voyage” – Helping Drug-Delivery Nanoparticles Reach Their Targets (with Video)

MIT engineers have designed a magnetic microrobot that can help push drug-delivery particles into tumor tissue (left). They also employed swarms of naturally magnetic bacteria to achieve the same effect (right). Image courtesy of the researchers.

Tiny robots powered by magnetic fields could help drug-delivery nanoparticles reach their targets.

MIT engineers have designed tiny robots that can help drug-delivery nanoparticles push their way out of the bloodstream and into a tumor or another disease site. Like crafts in “Fantastic Voyage” — a 1960s science fiction film in which a submarine crew shrinks in size and roams a body to repair damaged cells — the robots swim through the bloodstream, creating a current that drags nanoparticles along with them.

The magnetic microrobots, inspired by bacterial propulsion, could help to overcome one of the biggest obstacles to delivering drugs with nanoparticles: getting the particles to exit blood vessels and accumulate in the right place.

“When you put nanomaterials in the bloodstream and target them to diseased tissue, the biggest barrier to that kind of payload getting into the tissue is the lining of the blood vessel,” says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical Engineering and Computer Science, a member of MIT’s Koch Institute for Integrative Cancer Research and the Institute for Medical Engineering and Science, and the senior author of the study.

“Our idea was to see if you can use magnetism to create fluid forces that push nanoparticles into the tissue,” adds Simone Schuerle, a former MIT postdoc and lead author of the paper, which appears in the April 26 issue of Science Advances.

In the same study, the researchers also showed that they could achieve a similar effect using swarms of living bacteria that are naturally magnetic. Each of these approaches could be suited for different types of drug delivery, the researchers say.

Tiny robots

Schuerle, who is now an assistant professor at the Swiss Federal Institute of Technology (ETH Zurich), first began working on tiny magnetic robots as a graduate student in Brad Nelson’s Multi-scale Robotics Lab at ETH Zurich. When she came to Bhatia’s lab as a postdoc in 2014, she began investigating whether this kind of bot could help to make nanoparticle drug delivery more efficient.

In most cases, researchers target their nanoparticles to disease sites that are surrounded by “leaky” blood vessels, such as tumors. This makes it easier for the particles to get into the tissue, but the delivery process is still not as effective as it needs to be.

The MIT team decided to explore whether the forces generated by magnetic robots might offer a better way to push the particles out of the bloodstream and into the target site.

The robots that Schuerle used in this study are 35 hundredths of a millimeter long, similar in size to a single cell, and can be controlled by applying an external magnetic field. This bio-inspired robot, which the researchers call an “artificial bacterial flagellum,” consists of a tiny helix that resembles the flagella that many bacteria use to propel themselves. These robots are 3-D-printed with a high-resolution 3-D printer and then coated with nickel, which makes them magnetic.

To test a single robot’s ability to control nearby nanoparticles, the researchers created a microfluidic system that mimics the blood vessels that surround tumors. The channel in their system, between 50 and 200 microns wide, is lined with a gel that has holes to simulate the broken blood vessels seen near tumors.

Using external magnets, the researchers applied magnetic fields to the robot, which makes the helix rotate and swim through the channel. Because fluid flows through the channel in the opposite direction, the robot remains stationary and creates a convection current, which pushes 200-nanometer polystyrene particles into the model tissue. These particles penetrated twice as far into the tissue as nanoparticles delivered without the aid of the magnetic robot.

This type of system could potentially be incorporated into stents, which are stationary and would be easy to target with an externally applied magnetic field. Such an approach could be useful for delivering drugs to help reduce inflammation at the site of the stent, Bhatia says.

Bacterial swarms

The researchers also developed a variant of this approach that relies on swarms of naturally magnetotactic bacteria instead of microrobots. Bhatia has previously developed bacteria that can be used to deliver cancer-fighting drugs and to diagnose cancer, exploiting bacteria’s natural tendency to accumulate at disease sites.

For this study, the researchers used a type of bacteria called Magnetospirillum magneticum, which naturally produces chains of iron oxide. These magnetic particles, known as magnetosomes, help bacteria orient themselves and find their preferred environments.

The researchers discovered that when they put these bacteria into the microfluidic system and applied rotating magnetic fields in certain orientations, the bacteria began to rotate in synchrony and move in the same direction, pulling along any nanoparticles that were nearby. In this case, the researchers found that nanoparticles were pushed into the model tissue three times faster than when the nanoparticles were delivered without any magnetic assistance.

This bacterial approach could be better suited for drug delivery in situations such as a tumor, where the swarm, controlled externally without the need for visual feedback, could generate fluidic forces in vessels throughout the tumor.

The particles that the researchers used in this study are big enough to carry large payloads, including the components required for the CRISPR genome-editing system, Bhatia says. She now plans to collaborate with Schuerle to further develop both of these magnetic approaches for testing in animal models.

The research was funded by the Swiss National Science Foundation, the Branco Weiss Fellowship, the National Institutes of Health, the National Science Foundation, and the Howard Hughes Medical Institute.

Washington State U – Bio-inspired nanoscale Research – Nano-Flowers may lead lead to more effective drug delivery and diagnostics for cancer and other illnesses

Schematic representation of the movement of the flower-like particle as it makes its way through a cellular trap to deliver therapeutic genes.

Credit: WSU

Washington State University researchers have developed a novel way to deliver drugs and therapies into cells at the nanoscale without causing toxic effects that have stymied other such efforts.

The work could someday lead to more effective therapies and diagnostics for cancer and other illnesses.

Led by Yuehe Lin, professor in WSU’s School of Mechanical and Materials Engineering, and Chunlong Chen, senior scientist at the Department of Energy’s Pacific Northwest National Laboratory (PNNL), the research team developed biologically inspired materials at the nanoscale that were able to effectively deliver model therapeutic genes into tumor cells. They published their results in the journal, Small.

Researchers have been working to develop nanomaterials that can effectively carry therapeutic genes directly into the cells for the treatment of diseases such as cancer. The key issues for gene delivery using nanomaterials are their low delivery efficiency of medicine and potential toxicity.

“To develop nanotechnology for medical purposes, the first thing to consider is toxicity — That is the first concern for doctors,” said Lin.

The flower-like particle the WSU and PNNL team developed is about 150 nanometers in size, or about one thousand times smaller than the width of a piece of paper. It is made of sheets of peptoids, which are similar to natural peptides that make up proteins. The peptoids make for a good drug delivery particle because they’re fairly easy to synthesize and, because they’re similar to natural biological materials, work well in biological systems.

The researchers added fluorescent probes in their peptoid nanoflowers, so they could trace them as they made their way through cells, and they added the element fluorine, which helped the nanoflowers more easily escape from tricky cellular traps that often impede drug delivery.

The flower-like particles loaded with therapeutic genes were able to make their way smoothly out of the predicted cellular trap, enter the heart of the cell, and release their drug there.

“The nanoflowers successfully and rapidly escaped (the cell trap) and exhibited minimal cytotoxicity,” said Lin.

After their initial testing with model drug molecules, the researchers hope to conduct further studies using real medicines.

“This paves a new way for us to develop nanocargoes that can efficiently deliver drug molecules into the cell and offers new opportunities for targeted gene therapies,” he said.

The WSU and PNNL team have filed a patent application for the new technology, and they are seeking industrial partners for further development.

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Story Source:

Materials provided by Washington State University. Note: Content may be edited for style and length.

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Journal Reference:

1. Yang Song, Mingming Wang, Suiqiong Li, Haibao Jin, Xiaoli Cai, Dan Du, He Li, Chun-Long Chen, Yuehe Lin. Efficient Cytosolic Delivery Using Crystalline Nanoflowers Assembled from Fluorinated Peptoids. Small, 2018; 14 (52): 1803544 DOI: 10.1002/smll.201803544

Healing Kidneys with Nanotechnology – ASU Researchers Explore a new horizon for DNA Nanotechnology

The illustration shows a diseased kidney on the left and a healthy kidney on the right, after rectangular DNA nanostructures migrated and accumulated in the kidney, acting to alleviate damage due to oxidative stress. Credit: Shireen Dooling

Each year, there are some 13.3 million new cases of acute kidney injury (AKI), a serious affliction. Formerly known as acute renal failure, the ailment produces a rapid buildup of nitrogenous wastes and decreases urine output, usually within hours or days of disease onset. Severe complications often ensue.

AKI is responsible for 1.7 million deaths annually. Protecting healthy kidneys from harm and treating those already injured remains a significant challenge for modern medicine.

In new research appearing in the journal Nature Biomedical Engineering, Hao Yan and his colleagues at the University of Wisconsin-Madison and in China describe a new method for treating and preventing AKI. Their technique involves the use of tiny, self-assembling forms measuring just billionths of a meter in diameter.

The triangular, tubular and rectangular shapes are designed and built using a method known as DNA origami. Here, the base pairing properties of DNA’s four nucleotides are used to engineer and fabricate DNA origami nanostructures (DONs), which self-assemble and preferentially accumulate in kidneys.

“The interdisciplinary collaboration between nanomedicine and the in-vivo imaging team led by professor Weibo Cai at the University of Wisconsin-Madison and the DNA nanotechnology team has led to a novel application—applying DNA origami nanostructures to treat acute kidney injury,” Yan says. “This represents a new horizon for DNA nanotechnology research.”

Experiments described in the new study—conducted in mice as well as human embryonic kidney cells—suggest that DONs act as a rapid and active kidney protectant and may also alleviate symptoms of AKI. The distribution of DONs was examined with positron emission tomography (PET). Results showed that the rectangular nanostructures were particularly successful, protecting the kidneys from harm as effectively as the leading drug therapy and alleviating a leading source of AKI known as oxidative stress.

The study is the first to explore the distribution of DNA nanostructures in a living system by means of quantitative imaging with PET and paves the way for a host of new therapeutic approaches for the treatment of AKI as well as other renal diseases.

“This is an excellent example of team science, with multidisciplinary and multinational collaboration,” Cai said. “The four research groups are located in different countries, but they communicate regularly and have synergistic expertise. The three equally-contributing first authors (Dawei Jiang, Zhilei Ge, Hyung-Jun Im) also have very different backgrounds, one in radiolabeling and imaging, one in DNA nanostructures, and the other in clinical nuclear medicine. Together, they drove the project forward.”

Vital organ

Kidneys perform essential roles in body, removing waste and extra water from the blood to form urine. Urine then flows from the kidneys to the bladder through the ureters. Wastes in the blood are produced from the normal breakdown of active muscle and from foods, which the body requires for energy and self-repair.

Acute kidney injury can range considerably in severity. In advanced AKI, kidney transplantation is required as well as supportive therapies including rehydration and dialysis. Contrast-induced AKI, a common form of the illness, is caused by contrast agents sometimes used to improve the clarity of medical imaging. An anti-oxidant drug known as N-acetylcysteine (NAC) is used clinically to protect the kidneys from toxic assault during such procedures, but poor bioavailability of the drug in the kidneys can limit its effectiveness. (Currently, there is no known cure for AKI.)

Nanomedicine—the engineering of atoms or molecules at the nanoscale for biomedical applications—represents a new and exciting avenue of medical exploration and therapy. Recent research in the field has driven advances leading to improved imaging and therapeutics for a range of diseases, including AKI, though the use of nanomaterials within living systems in order to treat kidney disease has thus far been limited.

Hao Yan directs the Biodesign Center for Molecular Design and Biomimetics and is the Martin D. Glick Distinguished Professor in the School of Molecular Sciences at ASU. Credit: The Biodesign Institute at Arizona State University

The base-pairing properties of nucleic acids like DNA and RNA enable the design of tiny programmable structures of predictable shape and size, capable of performing a multitude of tasks. Further, these nanoarchitectures are desirable for use in living systems due to their stability, low toxicity, and low immunogenicity.

New designs

The current study marks the first investigation of DNA origami nanostructures within living organisms, using quantitative imaging to track their behavior. The PET imaging used in the study allowed for a quantitative and reliable real-time method to study the circulation of DONs in a living organism and to assess their physiological distribution. Rectangular DONs were identified as the most effective therapeutic to treat AKI in mice, based on the PET analysis.

Yan and his colleagues prepared a series of DONs and used radio labeling to study their behavior in mouse kidney, using PET imaging. The PET scans showed that the DONs had preferentially accumulated in the kidneys of healthy mice as well as those with induced AKI. Of the three shapes used in the experiments, the rectangular DONs provided the greatest benefit in terms of protection and therapy and were comparable in their effect to the drug NAC, considered the gold standard treatment for AKI.

Patients with kidney disease often have accompanying maladies, including a high incidence of cardiovascular disease and malignancy. Acute kidney illness may be induced through the process of oxidative stress, which results from an increase in oxygen-containing waste products known as reactive oxygen species, that cause damage to lipids, proteins and DNA. This can occur when the delicate balance of free radicals and anti-oxidant defenses becomes destabilized, causing inflammation and accelerating the progression of renal disease. (Foods and supplements rich in antioxidants act to protect cells from the harmful effects of reactive oxygen species.)

Safeguarding kidneys with DNA geometry

The protective and therapeutic effects of the DONs described in the new study are due to the ability of the nanostructures to scavenge reactive oxygen species, thereby insulating vulnerable cells from damage due to oxidative stress. This effect was studied in human embryonic kidney cell lines as well as in living mice. The accumulation of the nanostructures in both healthy and diseased kidneys provided an increased therapeutic effect compared with traditional AKI therapy. (DONs alleviated oxidative stress within 2 hours of incubation with affected kidney cells.)

Improvement in AKI kidney function—comparable with high-dose administration of the drug NAC— was observed following the introduction of nanostructures. Examination of stained tissue samples further confirmed the beneficial effects of the DONs in the kidney.

The authors propose several mechanisms to account for the persistence in the kidneys of properly folded origami nanostructures, including their resistance to digestive enzymes, avoidance of immune surveillance and low protein absorption.

Levels of serum creatinine and blood urea nitrogen (BUN) were used to assess renal function in mice. AKI mice treated with rectangular DONs displayed improved kidney excretory function comparable to mice receiving treatment using the mainline drug NAC.

Further, the team established the safety of rectangular DONs, evaluating their potential to elicit an immune response in mice by examining blood levels of interleukin-6 and tumor necrosis factor alpha. Results showed the DONs were non-immunogenetic and tissue staining of heart, liver, spleen lungs and kidney revealed their low toxicity in primary organs, making them attractive candidates for clinical use in humans.

Based on the effective scavenging of reactive oxygen species by DONs in both human kidney cell culture and living mouse kidney, the study concludes that the approach may indeed provide localized protection for kidneys from AKI and may even offer effective treatment for AKI-damaged kidneys or other renal disorders.

The successful proof-of-concept study expands the potential for a new breed of therapeutic programmable nanostructures, engineered to address far-flung medical challenges, from smart drug delivery to precisely targeted organ and tissue repair.

 Explore further: YAP after acute kidney injury

More information: Dawei Jiang et al, DNA origami nanostructures can exhibit preferential renal uptake and alleviate acute kidney injury, Nature Biomedical Engineering (2018). DOI: 10.1038/s41551-018-0317-8

Journal reference: Nature Biomedical Engineering  

Provided by: Arizona State University

 

Our Bioelectronic Future: Smaller, Smarter, Connected – De Lange Conference at Rice University: Video

Bioelectronics, Our Bioelectronic Future: Smaller, Smarter, Connected

De Lange Conference XI | December 4-5, 2018 | Rice University De Lange Conference XI will bring together biologists, engineers, medical researchers, policy scholars, humanists, and industrial representatives from the nascent bioelectronics industry and federal agencies will serve to identify the grand challenges in the field, including technological, ethical, legal, and societal issues. The biennial De Lange Conferences, funded by the De Lange Endowment, were established by C.M. and Demaris Hudspeth in honor of Demaris’ parents, Albert and Demaris De Lange. For more information, visit delange.rice.edu

 

Read More About Graphene Applications for Bio-Electronics and Neuroprosthetics

The term bioelectronics, or bionics for short, describes a research field that is concerned with the integration of biological components with electronics; specifically, the application of biological materials and processes in electronics, and the use of electronic devices in living systems.

One day, bionics research could result in neural prostheses that augment or restore damaged or lost functions of the nervous system – restore vision, healing spinal cord injuries, and ameliorate neurodegenerative diseases such as Parkinson’s.

‘DNA-based’ nanocomposite hydrogel as a potent injectable drug delivery platform – A base matrix to form tissue engineering scaffolds and drug delivery platforms – U of Kansas

DNA is the carrier of genetic information of all living beings on earth. The nitrogenous base sequences along the DNA chain are responsible for the encoding and transmission of genetic information. Read More: Understanding DNA

Besides being a genetic material, DNA can also be considered as a chemical entity and hence can be exploited as a base matrix to form tissue engineering scaffolds and drug delivery platforms.

From a chemical perspective, DNA is a long chain polymer consisting of monomeric repeat units. Each repeat unit consists of a deoxyribose sugar molecule linked to a phosphate group. Every monomeric unit is also connected to one of the four nitrogenous bases.

The base pairing interactions between the DNA strands are highly specific. Together with the binding of other substances to the backbone, this can be exploited to construct three-dimensionally interconnected hydrogel networks.

Sayantani Basu, a PhD student from the lab of Professor Arghya Paul (BioIntel Research Group) at the University of Kansas, Lawrence, has been working on the utilization of DNA as a high molecular weight polymeric chain in order to form hydrogel networks for tissue regeneration and drug delivery applications.

They have designed shear thinning hydrogels, which can be passed through a 22-gauge syringe by taking advantage of the native chemical structure of DNA and its specific base pairing interactions.

“As a bio and nano-materials engineering lab we are constantly trying to explore the structural properties of different polymers and nanoparticles to design smart materials for diverse biomedical applications including regenerative medicine,” says Dr. Arghya Paul.

Previous studies from Paul’s BioIntel Research Group at the University of Kansas have shown the use of two-dimensional nanosilicates to form injectable hydrogels (Acta Biomaterialia, “Stem cell-inspired secretome-rich injectable hydrogel to repair injured cardiac tissue”)..

In their recent study (ACS Nano, “Harnessing the Noncovalent Interactions of DNA Backbone with 2D Silicate Nanodisks To Fabricate Injectable Therapeutic Hydrogels”), the group has investigated the potential of DNA to form self-assembled injectable hydrogels via physical crosslinking with silicate nanodisks.

DNA-based physically crosslinked hydrogels. (Reprinted with permission by American Chemical Society) (click on image to enlarge)

The DNA-nanosilicate hydrogel is formed by a combination of non-covalent network points without the need of any toxic chemical crosslinkers. DNA denaturation and rehybridization mechanism as well as attractive electrostatic interactions of nanosilicates with the DNA backbone are utilized to generate an interconnected network via a two-step gelation process.

Basu has also shown a sustained release of a model osteogenic drug dexamethasone from the nanoengineered hydrogels and confirmed the bioactivity of the released drugs under lab and preclinical settings to promote bone regeneration.

The animal work was done in collaboration with Professor Jinxi Wang, who directs the Harrington Laboratory for Molecular Orthopedics at University of Kansas Medical Center.

Future work from the research group will focus on the feasibility of the DNA based hydrogels for other more potent drug (small molecules, nucleic acids, growth factors) delivery, and cell delivery applications.

Provided by the University of Kansas as a Nanowerk exclusive.