Detecting single molecules and diagnosing diseases with a smartphone

Ludwig-Maximilians-Universitaet (LMU) in Munich researchers show that the light emitted by a single molecule can be detected with a low-cost optical setup. Their prototype could facilitate medical diagnostics.

Biomarkers play a central role in the diagnosis of disease and assessment of its course. Among the markers now in use are genes, proteins, hormones, lipids and other classes of molecules. Biomarkers can be found in the blood, in cerebrospinal fluid, urine and various types of tissues, but most of them have one thing in common: They occur in extremely low concentrations, and are therefore technically challenging to detect and quantify.

Many detection procedures use molecular probes, such as antibodies or short nucleic-acid sequences, which are designed to bind to specific biomarkers. When a probe recognizes and binds to its target, chemical or physical reactions give rise to fluorescence signals. Such methods work well, provided they are sensitive enough to recognize the relevant biomarker in a high percentage of all patients who carry it in their blood. In addition, before such fluorescence-based tests can be used in practice, the biomarkers themselves or their signals must be amplified. The ultimate goal is to enable medical screening to be carried out directly on patients, without having to send the samples to a distant laboratory for analysis.

Molecular antennas amplify fluorescence signals

Philip Tinnefeld, who holds a Chair in Physical Chemistry at LMU, has developed a strategy for determining levels of biomarkers present in low concentrations. He has succeeded in coupling DNA probes to tiny particles of gold or silver. Pairs of particles (‘dimers’) act as nano-antennas that amplify the fluorescence signals. The trick works as follows: Interactions between the nanoparticles and incoming light waves intensify the local electromagnetic fields, and this in turn leads to a massive increase in the amplitude of the fluorescence. In this way, bacteria that contain antibiotic resistance genes and even viruses can be specifically detected.

“DNA-based nano-antennas have been studied for the last few years,” saysKateryna Trofymchuk, joint first author of the study. “But the fabrication of these nanostructures presents challenges.” Philip Tinnefeld’s research group has now succeeded in configuring the components of their nano-antennas more precisely, and in positioning the DNA molecules that serve as capture probes at the site of signal amplification. Together, these modifications enable the fluorescence signal to be more effectively amplified. Furthermore, in the minuscule volume involved, which is on the order of zeptoliters (a zeptoliter equals 10-21of a liter), even more molecules can be captured.

The high degree of positioning control is made possible by DNA nanotechnology, which exploits the structural properties of DNA to guide the assembly of all sorts of nanoscale objects—in extremely large numbers. “In one sample, we can simultaneously produce billions of these nano-antennas, using a procedure that basically consists of pipetting a few solutions together,” says Trofymchuk.

Routine diagnostics on the smartphone

“In the future,” says Viktorija Glembockyte, also joint first author of the publication, “our technology could be utilized for diagnostic tests even in areas in which access to electricity or laboratory equipment is restricted. We have shown that we can directly detect small fragments of DNA in blood serum, using a portable, smartphone-based microscope that runs on a conventional USB power pack to monitor the assay.” Newer smartphones are usually equipped with pretty good cameras. Apart from that, all that’s needed is a laser and a lens—two readily available and cheap components. The LMU researchers used this basic recipe to construct their prototypes.

They went on to demonstrate that DNA fragments that are specific for antibiotic resistance genes in bacteria could be detected by this set-up. But the assay could be easily modified to detect a whole range of interesting target types, such as viruses. Tinnefeld is optimistic: “The past year has shown that there is always a need for new and innovative diagnostic methods, and perhaps our technology can one day contribute to the development of an inexpensive and reliable diagnostic test that can be carried out at home.”

Covid-19 Diagnostic Based on MIT Technology to be Tested on Patients Soon

This scanning electron microscope image shows SARS-CoV-2 (yellow)—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient, emerging from the surface of cells (blue/pink) cultured in the lab. Image: NIAID-RML

A variety of MIT research projects could aid efforts to detect and prevent the spread of coronavirus.

As more Covid-19 cases appear in the United States and around the world, the need for fast, easy-to-use diagnostic tests is becoming ever more pressing. A startup company spun out from MIT is now working on a paper-based test that can deliver results in under half an hour, based on technology developed at MIT’s Institute for Medical Engineering and Science (IMES).

Cambridge-based E25Bio, which developed the test, is now preparing to submit it to the FDA for “emergency use authorization,” which would grant temporary approval for using the device on patient samples during public health emergencies.

Elsewhere around MIT, several other research groups are working on projects that may help further scientists’ understanding of how coronaviruses are transmitted and how infection may be prevented. Their work touches on fields ranging from diagnostics and vaccine development to more traditional disease prevention measures such as social distancing and handwashing.

Faster diagnosis

The technology behind the new E25Bio diagnostic was developed by Lee Gehrke, the Hermann L.F. von Helmholtz Professor at IMES, and other members of his lab, including Irene Bosch, a former IMES research scientist who is now the CTO of E25Bio.

For the past several years, Gehrke, Bosch, and others in the lab have been working on diagnostic devices that work similar to a pregnancy test but can identify viral proteins from patient samples. The researchers have used this technology, known as lateral flow technology, to create tests for Ebola, dengue fever, and Zika virus, among other infectious diseases.

The tests consist of strips of paper that are coated with antibodies that bind to a specific viral protein. A second antibody is attached to specialized nanoparticles, and the patient’s sample is added to a solution of those particles. The test strip is then dipped in this solution. If the viral protein is present, it attaches to the antibodies on the paper strip as well as the nanoparticle-bound antibodies, and a colored spot appears on the strip within 20 minutes.

Currently, there are two primary types of Covid-19 diagnostics available. One such test screens patient blood samples for antibodies against the virus. However, antibodies are often not detectable until a few days after symptoms begin. Another type of test looks for viral DNA in a sputum sample. These tests can detect the virus earlier in the infection, but they require polymerase chain reaction (PCR), a technology that amplifies the amount of DNA to detectable levels and takes several hours to perform.

“Our hope is that, similar to other tests that we’ve developed, this will be usable on the day that symptoms develop,” Gehrke says. “We don’t have to wait for antibodies to the virus to come up.”

If the U.S. Food and Drug Administration grants the emergency authorization, E25Bio could start testing the diagnostic with patient samples, which they haven’t been able to do yet. “If those are successful, then the next step would be to talk about using it for actual clinical diagnosis,” Gehrke says.

Another advantage of this approach is that the paper tests can be easily and inexpensively manufactured in large quantities, he adds.

RNA vaccines

On Feb. 24, only about a month after the first U.S. case of coronavirus was reported, the Cambridge-based biotech company Moderna announced it had an experimental vaccine ready to test. That speedy turnaround is due to the unique advantages of RNA vaccines, says Daniel Anderson, an MIT professor of chemical engineering, who also works on such vaccines, though not specifically for coronavirus.

“A key advantage of messenger RNA is the speed with which you can identify a new sequence and use it to come up with a new vaccine,” Anderson says.

Traditional vaccines consist of an inactivated form of a viral protein that induces an immune response. However, these vaccines usually take a long time to manufacture, and for some diseases, they are too risky. Vaccines that consist of messenger RNA are an appealing alternative because they induce host cells to produce many copies of the proteins they encode, provoking a stronger immune response than proteins delivered on their own.

RNA vaccines can also be quickly reprogrammed to target different viral proteins, as long as the sequence encoding the protein is known. The main obstacle to developing such vaccines so far has been finding effective and safe ways to deliver them. Anderson’s lab has been working on such strategies for several years, and in a recent study he showed that packing such vaccines into a special type of lipid nanoparticles can enhance the immune response that they produce.

“Messenger RNA can encode the viral antigens, but in order to work, we need to find a way to deliver these antigens to the correct part of the body so that they get expressed and generate an immune response. We also need to make sure that the vaccine causes appropriate immune stimulation to get a strong response,” Anderson says.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), has estimated that it will take at least 12 to 18 months to fully test any potential Covid-19 vaccine for safety and effectiveness.

Keep your distance

Over the last decade, Lydia Bourouiba, an associate professor directing the Fluid Dynamics of Disease Transmission Laboratory at MIT, has focused on characterizing and modeling infectious disease dynamics and transmission at various scales. Through experiments in the lab and clinical environment, she has reported that when a person coughs or sneezes, they do not emit a spray of individual droplets that quickly fall to the ground and evaporate, as scientists had once thought. Instead, they produce a complex cloud of hot and moist air that traps droplets of all sizes together, propelling them much further through the air than any individual droplet would travel on its own.

On average, her experiments have revealed that a cough can transmit droplets up to 13 to 16 feet, while a sneeze can eject them up to 26 feet away. Surrounding air conditions can act to further disperse the residual droplets in upper levels of rooms.

Bourouiba notes that the presence of the high-speed gas cloud is independent of the type of organism or pathogen that the cloud may contain. The droplets within it depend on pathogenesis coupled with a patient’s physiology — a combination which her laboratory has focused on deciphering in the context of influenza. She is now expanding her studies and modeling to translate the work to Covid-19, and says now is a critical time to invest in research.

“This virus is going to stay with us for a while — and certainly data suggest that it is not going to suddenly disappear when the weather changes,” she says. “There’s a fine and important balance between safety, precautions and action that is important to strike to enable and dramatically accelerate research to be done now so we can be better prepared and informed for actions in the weeks and months to come when the worst of the pandemic will unfold.”

She is also working with others to evaluate ways to limit a cloud’s dispersal and slow Covid-19 transmission to health care workers and others in shared spaces. “A surgical mask is not protective against inhalation of a pathogen from the cloud,” she says. “For an infected patient wearing it, it can contain some of the forward ejecta from coughs or sneezes, but these are very violent ejections and masks are completely open on all sides, and fluid flows through the path of least resistance.”

Based on the data, she recommends that health care workers consider wearing a respirator, whenever possible. And, for the general public, Bourouiba emphasizes that the risk of contracting COVID-19 remains relatively low locally, and that risk should be thought of in the context of the community.

Wash those hands

Another good way to protect yourself against all of those tiny infectious droplets is to wash your hands. (Again, and again, and again.)

Ruben Juanes, an MIT professor of civil and environmental engineering, and of earth, atmospheric and planetary sciences, published a study in December showing the importance of improving rates of handwashing at key airports in order to curtail the spread of an epidemic. Now, he says, following the Covid-19 outbreak, governments around the world have imposed unprecedented restrictions on mobility, including the closure of airports and suspension of flight routes.

At the same time, the World Health Organization, U.S. Centers for Disease Control, and many other health agencies all recommend hand-hygiene as the number one precaution measure against disease spread. “Following our recent paper on the impact of hand-hygiene on global disease spreading,” Juanes says, “we are now investigating the combined effect of restrictions on human mobility and enhanced engagement with hand-hygiene on the global spread of COVID-19 through the world air-transportation network.”

Juanes says he and Christos Nicolaides PhD ’14, a professor at the University of Cyprus who was the lead author of the previous study, are working “with fine-grained, worldwide air-traffic data that accounts for all flights for the period between Jan. 15, 2020 until today (accounting for closures/cancellations) and the corresponding period of 2019 (base level) to elucidate the role of travel restrictions on the global spread of Covid-19 through detailed epidemiological modeling.”

“Furthermore,” he adds, “we simulate different hand-hygiene strategies at airports on top of travel restrictions with the goal of proposing an optimal strategy that combines travel restrictions and enhanced hand hygiene, to mitigate the advance of Covid-19 both in the short term (weeks) and the long term (the next flu season).”

Juanes says they will make the results immediately available via medarXiv, while the work follows peer-review in a journal. This would also allow the information to reach other academic and government institutions in a more timely way, he says.

Researchers at Oregon State University reach Milestone in use of Nanoparticles to kill Cancer with Heat

Abstract:
Researchers at Oregon State University have developed an improved technique for using magnetic nanoclusters to kill hard-to-reach tumors.

 

Magnetic nanoparticles – tiny pieces of matter as small as one-billionth of a meter – have shown anti-cancer promise for tumors easily accessible by syringe, allowing the particles to be injected directly into the cancerous growth.

Once injected into the tumor, the nanoparticles are exposed to an alternating magnetic field, or AMF. This field causes the nanoparticles to reach temperatures in excess of 100 degrees Fahrenheit, which causes the cancer cells to die.

But for some cancer types such as prostate cancer, or the ovarian cancer used in the Oregon State study, direct injection is difficult. In those types of cases, a “systemic” delivery method – intravenous injection, or injection into the abdominal cavity – would be easier and more effective.

The challenge for researchers has been finding the right kind of nanoparticles – ones that, when administered systemically in clinically appropriate doses, accumulate in the tumor well enough to allow the AMF to heat cancer cells to death.

Olena Taratula and Oleh Taratula of the OSU College of Pharmacy tackled the problem by developing nanoclusters, multiatom collections of nanoparticles, with enhanced heating efficiency. The nanoclusters are hexagon-shaped iron oxide nanoparticles doped with cobalt and manganese and loaded into biodegradable nanocarriers.

Findings were published in ACS Nano.

“There had been many attempts to develop nanoparticles that could be administered systemically in safe doses and still allow for hot enough temperatures inside the tumor,” said Olena Taratula, associate professor of pharmaceutical sciences. “Our new nanoplatform is a milestone for treating difficult-to-access tumors with magnetic hyperthermia. This is a proof of concept, and the nanoclusters could potentially be optimized for even greater heating efficiency.”

The nanoclusters’ ability to reach therapeutically relevant temperatures in tumors following a single, low-dose IV injection opens the door to exploiting the full potential of magnetic hyperthermia in treating cancer, either by itself or with other therapies, she added.

“It’s already been shown that magnetic hyperthermia at moderate temperatures increases the susceptibility of cancer cells to chemotherapy, radiation and immunotherapy,” Taratula said.

The mouse model in this research involved animals receiving IV nanocluster injections after ovarian tumors had been grafted underneath their skin.

“To advance this technology, future studies need to use orthotopic animal models – models where deep-seated tumors are studied in the location they would actually occur in the body,” she said. “In addition, to minimize the heating of healthy tissue, current AMF systems need to be optimized, or new ones developed.”

The National Institutes of Health, the OSU College of Pharmacy and Najran University of Saudi Arabia supported this research.

Also collaborating were OSU electrical engineering professor Pallavi Dhagat, postdoctoral scholars Xiaoning Li and Canan Schumann of the College of Pharmacy, pharmacy graduate students Hassan Albarqi, Fahad Sabei and Abraham Moses, engineering graduate student Mikkel Hansen, and pre-pharmacy undergrads Tetiana Korzun and Leon Wong.

Copyright © Oregon State University

Looking at Nanotechnology in Biotechnology

For some time, the difference between a biotechnology company and a pharmaceutical company was straightforward.

A biotechnology focused on developing drugs with a biological basis. Pharmaceutical companies focused on drugs with a chemical basis.

It was sort of an artificial distinction, and is even more so now because pharmaceutical companies haven’t excluded biologics from their portfolios.

At one time there were even distinctions in the definitions related to small molecules versus large molecules, but those are largely in the dustbin of biopharma vocabulary. It’s one reason why “biopharma” itself is a useful word to bridge the two, and really, biotech and pharma are largely interchangeable.

Nanotechnology Versus Biotechnology

But what about nanotechnology? Is that biotechnology?

The answer to that seems to be … yes and no.

Nanotechnology typically refers to technology that is less than 100 nanometers in size. Although not horribly useful for differentiating things on the microscopic—or smaller—scale, there are 25,400,000 nanometers in an inch. So … small. Really small.

Wouldn’t that refer to many drugs? Yes, probably.

But nanotechnology typicallyrefers to tech made of manmade and inorganic materials in that size range. Again, the key word is “typically.”

There is overlap.  Liji Thomas, writing for Azo Nano, says, “Nanobiotechnology deals with technology which incorporates nanomolecules into biological systems, or which miniaturizes biotechnology solutions to nanometer size to achieve greater reach and efficacy….

Bionanotechnology, on the other hand, deals with new nanostructures that are created for synthetic applications, the difference being that these are based upon biomolecules.”

Clear? Probably not. Here are some examples of biotechnology companies utilizing nanotechnology, along with whatever tools they need to develop their compounds.

PEEL Therapeutics. PEEL Therapeutics is a small biotech company, largely in stealth mode, founded by Joshua Schiffman, an associate professor of Pediatrics at the University of Utah and Avi Schroeder, an assistant professor of chemical engineering at the Technion-Israel Institute of Technology. 

Schiffman was doing work on a tumor suppressor gene, p53, which shows up at very high numbers in elephants. Elephants have significantly lower rates of cancer than humans, who normally have two normal copies of p53. Humans with a disease called Li-Fraumeni Syndrome, have only one, and they have a 100 percent change of getting cancer, or very close to it.

What PEEL is attempting to do is build a synthetic version of p53 and insert them into a novel drug delivery system using nanotechnology. “Peel,” by the way, is the phonetic spelling of the Hebrew word for elephants. eP53 has been successfully encapsulated in nanoparticles, and at least in petri dishes, has demonstrated proof of concept. Elephants are not being experimented upon.

Exicure. Based in Skokie, Illinois, Exicure (formerly known as AuraSense) is a clinical stage biotechnology company that’s working on a new class of immunomodulatory and gene regulating drugs that uses proprietary three-dimensional, spherical nucleic acid architecture.

The SNA technology came out of the laboratory of Chad Mirkin at the Northwestern University International Institute for Nanotechnology.

The company has received financing from the likes of Microsoft’s Bill Gates, Aonfounder Pat Ryan, David Walt, co-founder of Illumina, and Boon Hwee Koh, director of Agilent Technologies. 

The technology platform is complex, but it is essentially various single and double-stranded nucleic acids stuck on the outside of a nanosphere.

They are able to easily penetrate cells, which then trigger immune responses.

SpyBiotech. Headquartered in Oxford, UK, SpyBiotech focuses on the so-called “super glue” that combines two parts of the bacteria that causes strep throat. It was spun out of Oxford University, and was based on research performed by its Department of Biochemistry and the Jenner Institute. When the bacteria that cause step throat are separated, they are attracted to each other and attempt to reattach.

The company is working to use this principle to develop vaccines that, instead of using virus-causing bacteria, will bind onto viral infections.

One of the bacteria that can cause strep throat, impetigo and other infections, Streptococcus pyogenes, is often shortened to Spy, hence the name of the company. When Spy is split into a peptide (SpyTag) and its protein partner (SpyCatcher), they are attracted to each other. The researchers isolated the “glue” that creates the attraction, and believe it can be used to bond vaccines together.

The company has backing from GV,formerly Google Ventures, the venture fund backed by Alphabet/Google.

One of the company’s founders is Mark Howarth, professor of Protein Nanotechnology at the University of Oxford. The fact that he’s working on protein nanotechnology undercuts a traditional definition of nanotechnology as not using biological materials. On his website, Howarth notes that SpyTag and SpyCatcher “is the strongest protein interaction yet measured and is being applied around the world for diverse areas of basic research and biotechnology. We are extending this new class of protein interaction, to create novel possibilities for synthetic biology.”

Ultimately, when researchers are developing drugs, they are using whatever tools are necessary to find effective treatments for diseases. Biotechnology may more accurately be thought of as a set of tools and a philosophical approach to solving biological problems, compared to pharmaceuticals, and nanotechnology is yet another tool.

In the wider world of drug discovery and development, there is also increasing use of artificial intelligence, data science and computational algorithms as well. And who knows what will be used tomorrow.

New Cancer Research – Converting Cancer Cells to Fat Cells to Stop Cancer’s Spread

A method for fooling breast cancer cells into fat cells has been discovered by researchers from the University of Basel.

The team were able to transform EMT-derived breast cancer cells into fat cells in a mouse model of the disease – preventing the formation of metastases. The proof-of-concept study was published in the journal Cancer Cell. 

Malignant cells can rapidly respond and adapt to changing microenvironmental conditions, by reactivating a cellular process called epithelial-mesenchymal transition (EMT), enabling them to alter their molecular properties and transdifferentiate into a different type of cell (cellular plasticity).

Senior author of the study Gerhard Christofori, professor of biochemistry at the University of Basel, commented in a recent press release: “The breast cancer cells that underwent an EMT not only differentiated into fat cells, but also completely stopped proliferating.”

“As far as we can tell from long-term culture experiments, the cancer cells-turned-fat cells remain fat cells and do not revert back to breast cancer cells,” he explained.

Epithelial-mesenchymal transition and cancer 

Cancer cells can exploit EMT – a process that is usually associated with the development of organs during embryogenesis – in order to migrate away from the primary tumor and form secondary metastases. Cellular plasticity is linked to cancer survival, invasion, tumor heterogeneity and resistance to both chemo and targeted therapies. In addition, EMT and the inverse process termed mesenchymal-epithelial transition (MET) both play a role in a cancer cell’s ability to metastasize.

Using mouse models of both murine and human breast cancer the team investigated whether they could therapeutically target cancer cells during the process of EMT – whilst the cells are in a highly plastic state. When the mice were administered Rosiglitazone in combination with MEK inhibitors it provoked the transformation of the cancer cells into post-mitotic and functional adipocytes (fat cells). In addition, primary tumor growth was suppressed and metastasis was prevented. 

Cancer cells marked in green and a fat cell marked in red on the surface of a tumor (left). After treatment (right), three former cancer cells have been converted into fat cells. The combined marking in green and red causes them to appear dark yellow. Credit: University of Basel, Department of Biomedicine

Christofori highlights the two major findings in the study: 

“Firstly, we demonstrate that breast cancer cells that undergo an EMT and thus become malignant, metastatic and therapy-resistant, exhibit a high degree of stemness, also referred to as plasticity. It is thus possible to convert these malignant cells into other cell types, as shown here by a conversion to adipocytes.”

“Secondly, the conversion of malignant breast cancer cells into adipocytes not only changes their differentiation status but also represses their invasive properties and thus metastasis formation and their proliferation. Note that adipocytes do not proliferate anymore, they are called ‘post-mitotic’, hence the therapeutic effect.”

Since both drugs used in the preclinical study were FDA-approved the team are hopeful that it may be possible to translate this therapeutic approach to the clinic. 

“Since in patients this approach could only be tested in combination with conventional chemotherapy, the next steps will be to assess in mouse models of breast cancer whether and how this trans-differentiation therapy approach synergizes with conventional chemotherapy. In addition, we will test whether the approach is also applicable to other cancer types. These studies will be continued in our laboratories in the near future.”

Journal Reference: Ronen et al. Gain Fat–Lose Metastasis: Converting Invasive Breast Cancer Cells into Adipocytes Inhibits Cancer Metastasis. Cancer Cell. (2019). Available at: https://www.cell.com/cancer-cell/fulltext/S1535-6108(18)30573-7 

Gerhard Christofori was speaking to Laura Elizabeth Lansdowne, Science Writer for Technology Networks

Artificial synapses made from Zinc-Oxide nanowires – ideal candidate for use in building bioinspired “neuromorphic” processors

Image captured by an electron microscope of a single nanowire memristor (highlighted in colour to distinguish it from other nanowires in the background image). Blue: silver electrode, orange: nanowire, yellow: platinum electrode. Blue bubbles are dispersed over the nanowire. They are made up of silver ions and form a bridge between the electrodes which increases the resistance. Credit: Forschungszentrum Jülich

Scientists from Jülich together with colleagues from Aachen and Turin have produced a memristive element made from nanowires that functions in much the same way as a biological nerve cell.

The component is able to save and process information, as well as receive numerous signals in parallel. The resistive switching cell made from oxide crystal nanowires is thus an ideal candidate for use in building bioinspired “neuromorphic” processors, able to take over the diverse functions of biological synapses and neurons.

Computers have learned a lot in recent years. Thanks to rapid progress in artificial intelligence they are now able to drive cars, translate texts, defeat world champions at chess, and much more besides.

In doing so, one of the greatest challenges lies in the attempt to artificially reproduce the signal processing in the human brain.

In neural networks, data are stored and processed to a high degree in parallel. Traditional computers, on the other hand, rapidly work through tasks in succession and clearly distinguish between the storing and processing of information.

As a rule, neural networks can only be simulated in a very cumbersome and inefficient way using conventional hardware.

Systems with neuromorphic chips that imitate the way the human brain works offer significant advantages. These types of computers work in a decentralised way, having at their disposal a multitude of processors, which, like neurons in the brain, are connected to each other by networks. If a processor breaks down, another can take over its function.

What is more, just like in the brain, where practice leads to improved signal transfer, a bioinspired processor should have the capacity to learn.

“With today’s semiconductor technology, these functions are to some extent already achievable. These systems are, however, suitable for particular applications and require a lot of space and energy,” says Dr. Ilia Valov from Forschungszentrum Jülich. “Our nanowire devices made from zinc oxide crystals can inherently process and even store information, and are extremely small and energy efficient.”

For years, memristive cells have been ascribed the best chances of taking over the function of neurons and synapses in bioinspired computers. They alter their electrical resistance depending on the intensity and direction of the electric current flowing through them.

In contrast to conventional transistors, their last resistance value remains intact even when the electric current is switched off. Memristors are thus fundamentally capable of learning.

In order to create these properties, scientists at Forschungszentrum Jülich and RWTH Aachen University used a single zinc oxide nanowire, produced by their colleagues from the polytechnic university in Turin. Measuring approximately one 10,000th of a millimeter in size, this type of nanowire is over 1,000 times thinner than a human hair. The resulting memristive component not only takes up a tiny amount of space, but is also able to switch much faster than flash memory.

Nanowires offer promising novel physical properties compared to other solids and are used among other things in the development of new types of solar cells, sensors, batteries and computer chips. Their manufacture is comparatively simple. Nanowires result from the evaporation deposition of specified materials onto a suitable substrate, where they practically grow of their own accord.

In order to create a functioning cell, both ends of the nanowire must be attached to suitable metals, in this case platinum and silver. The metals function as electrodes, and in addition, release ions triggered by an appropriate electric current. The metal ions are able to spread over the surface of the wire and build a bridge to alter its conductivity.

Components made from single nanowiresare, however, still too isolated to be of practical use in chips. Consequently, the next step being planned by the Jülich and Turin researchers is to produce and study a memristive element, composed of a larger, relatively easy to generate group of several hundred nanowires offering more exciting functionalities.

More information: Gianluca Milano et al, Self-limited single nanowire systems combining all-in-one memristive and neuromorphic functionalities, Nature Communications (2018).  DOI: 10.1038/s41467-018-07330-7

Provided by Forschungszentrum Juelich

Explore further: Scientists create a prototype neural network based on memristors

Researchers Develop a universal DNA Nano-signature for early cancer detection – University of Queensland

Killer T cells surround cancer cell. Credit: NIH

Researchers from the University of Queensland’s Australian Institute for Bioengineering and Nanotechnology (AIBN) have discovered a unique nano-scaled DNA signature that appears to be common to all cancers.

Based on this discovery, the team has developed a novel technology that enables cancer to be quickly and easily detected from any tissue type, e.g. blood or biopsy.

The study, which was supported by a grant from the National Breast Cancer Foundation and is published in the journal Nature Communications, reveals new insight about how epigenetic reprogramming in cancer regulates the physical and chemical properties of DNA and could lead to an entirely new approach to point-of-care diagnostics.

“Because cancer is an extremely complicated and variable disease, it has been difficult to find a simple signature common to all cancers, yet distinct from healthy cells,” explains AIBN researcher Dr. Abu Sina.

To address this, Dr. Sina and Dr. Laura Carrascosa, who are working with Professor Matt Trau at AIBN, focussed on something called circulating free DNA.

Like healthy cells, cancer cells are always in the process of dying and renewing. When they die, they essentially explode and release their cargo, including DNA, which then circulates.

“There’s been a big hunt to find whether there is some distinct DNA signature that is just in the cancer and not in the rest of the body,” says Dr. Carrascosa.

So they examined epigenetic patterns on the genomes of cancer cells and healthy cells. In other words, they looked for patterns of molecules, called methyl groups, which decorate the DNA. These methyl groups are important to cell function because they serve as signals that control which genes are turned on and off at any given time.

In healthy cells, these methyl groups are spread out across the genome. However, the AIBN team discovered that the genome of a cancer cell is essentially barren except for intense clusters of methyl groups at very specific locations.

This unique signature—which they dubbed the cancer “methylscape”, for methylation landscape—appeared in every type of breast cancer they examined and appeared in other forms of cancer, too, including prostate cancer, colorectal cancer and lymphoma.

“Virtually every piece of cancerous DNA we examined had this highly predictable pattern,” says Professor Trau.

He says that if you think of a cell as a hard-drive, then the new findings suggest that cancer needs certain genetic programmes or apps in order to run.

“It seems to be a general feature for all cancer,” he says. “It’s a startling discovery.”

They also discovered that, when placed in solution, those intense clusters of methyl groups cause cancer DNA fragments to fold up into three-dimensional nanostructures that really like to stick to gold.

Taking advantage of this, the researchers designed an assay which uses gold nanoparticles that instantly change colour depending on whether or not these 3-D nanostructures of cancer DNA are present.

“This happens in one drop of fluid,” says Trau. “You can detect it by eye, it’s as simple as that.”

The technology has also been adapted for electrochemical systems, which allows inexpensive and portable detection that could eventually be performed using a mobile phone.

So far they’ve tested the new technology on 200 samples across different types of human cancers, and healthy cells. In some cases, the accuracy of cancer detection runs as high as 90%.

“It works for tissue derived genomic DNA and blood derived circulating free DNA,” says Sina. “This new discovery could be a game-changer in the field of point of care cancer diagnostics.” It’s not perfect yet, but it’s a promising start and will only get better with time, says the team.

“We certainly don’t know yet whether it’s the Holy Grail or not for all cancer diagnostics,” says Trau, “but it looks really interesting as an incredibly simple universal marker of cancer, and as a very accessible and inexpensive technology that does not require complicated lab based equipment like DNA sequencing.”

More information: Abu Ali Ibn Sina et al, Epigenetically reprogrammed methylation landscape drives the DNA self-assembly and serves as a universal cancer biomarker, Nature Communications(2018).  DOI: 10.1038/s41467-018-07214-w

Provided by University of Queensland

Explore further: New cancer monitoring technology worth its weight in gold

How nanotechnology research could cure cancer – genetic diseases

Genetic diseases may soon be a thing of the past thanks to nanotechnology, which employs tiny particles to manipulate cells and change our DNA.

Here is how cancer treatment often runs today: a patient develops an aggressive tumor. A surgeon operates to remove the tumor, but a few cancer cells remain, hiding in the body. Chemotherapy is administered, weakening both patient and cancer cells. But the cancer does not die; it comes back and eventually kills the patient.

Now imagine another scenario. After surgery, strands of DNA anchored in tiny gold particles are injected into the affected area. The DNA strands bind to the tumor cells, killing them directly, without the help of chemo. The healthy cells around the tumor cells, which don’t express the tumor gene, are untouched.

Just like that, all the tumor cell stragglers are rendered harmless, corrected on the genetic level. The patient is cured, and without having to endure months of chemotherapy and its brutal side effects: hair loss, nausea and extreme weakness.

The future of medicine won’t focus on treating the symptoms of a disease, according to reseachers: it will focus on curing it at the genetic level.

Nanotechnology, the science of working with particles that are one billionth of a meter, is enabling scientists to change gene expression on the cellular level, potentially curing a host of diseases.

“Nanotechnology medical developments over the coming years will have a wide variety of uses and could potentially save a great number of lives,” says Eleonore Pauwels, senior associate and scholar at the Wilson Center, an interdisciplinary policy research center.

The science of using nanoparticles got its start with a lecture by theoretical physicist Richard Feynman in 1959, but because of the technical challenges, it is only in the past 10 years or so that the technology has really taken off for practical medical applications.

Figuring out how to consistently create the right nanoparticle, get it into the right tissue, ensure it is not degraded and does what it was programmed to do, took some time.

The science of nanotechnology depends on the fact that when things get super small, they function differently. Protein, for example, is a naturally occurring nanoparticle. A single protein molecule is a very different entity than a human being, which is made up of many protein molecules.

Gold, which is used often in medicine, is red when broken down into tiny particles. That microscopic bright red color has been used for centuries to give red stained glass its color.

“Because of their small size, engineered nanomaterials have unique properties that do not exist at the larger scale: increased surface area, charge, reactivity and other physicochemical properties, all of which may affect how nanomaterials interact with biological entities, like cells,” says Sara Brenner, assistant professor of nanobioscience at SUNY Polytechnic Institute.

Scientists are learning to take advantage of those properties to create new treatments. One of the most powerful examples uses DNA, says Chad Mirkin, a professor at Northwestern University and director of the International Institute for Nanotechnology.

DNA is rod shaped and normally would not be able to enter cells, which have developed protection against entry from foreign DNA segments.

But by using nanotechnology, many little snippets of DNA can be attached to a tiny, round synthetic core. The receptors on cells that would block rod shaped DNA do not recognize the tiny spheres of DNA and allow it to enter.

Using that property, a whole new class of treatments for genetic diseases is being developed.

By being able to insert DNA into existing cells, scientists can “attack disease at its genetic root and turn off receptors that regulate how a cell functions, stopping a disease pathway in its tracks,” explains Mirkin.

Right now, most of the research into developing therapies using spheres of DNA is focused on disease of the liver, says Mirkin, as anything a person takes in is going to be processed in the liver. Another area of research into nanotech treatments is the skin, as the treatment can be applied topically, making it easy to target one area.

“Potential applications are virtually endless,” explains Brenner. “But some areas of investigation right now for gene therapy are cancer, diabetes, AIDS, cystic fibrosis and heart disease.”

As research into using nanoparticles advances, scientists hope to be able to not just turn off specific signals in cells, but also eventually insert genes to correct for defects and cure more complex diseases.

Called gene therapy, it would involve inserting larger fragments of DNA into cells that have faulty DNA. For example, cystic fibrosis is caused by a defective gene called CFTR. If scientists can figure out a way to get a non-defective copy of the gene into the cells and correct it, they could cure the disease.

“Approximately 4,000 diseases have been found to have a genetic component and are therefore potential targets for gene therapy,” according to Brenner.

While nanotechnology has the potential to revolutionize medicine and how we view treatment of diseases, there are still kinks to work out.

Some of the challenges with nanotechnology include how to get nanoparticles into the right cells and tissues, and how to get them into the cells safely without the nanoparticles degrading.

Nanotechnology is still in its infancy, however. It’s only recently that we were able to produce microscopes that allowed us to see and manipulate nanoparticles. 

Research requires bringing together a number of disciplines like chemistry, biomedical engineering, biology and physics. But pharmaceutical companies have already begun work on creating treatments using nanotech, and many are in various stages of development now. “It’s not a pipe dream,” says Mirkin. Being able to cure genetic diseases of all kinds is on the horizon.

University of Cambridge: Researchers to target hard-to-treat cancers

A £10 million interdisciplinary collaboration is to target the most challenging of cancers using nanomedicine.

“We are going to pierce through the body’s natural barriers and deliver anti-cancer drugs to the heart of the tumour.” – George Malliaras

While the survival rate for most cancers has doubled over the past 40 years, some cancers such as those of the pancreas, brain, lung and oesophagus still have low survival rates.

Such cancers are now the target of an Interdisciplinary Research Collaboration (IRC) led by the University of Cambridge and involving researchers from Imperial College London, University College London and the Universities of Glasgow and Birmingham.

“Some cancers are difficult to remove by surgery and highly invasive, and they are also hard to treat because drugs often cannot reach them at high enough concentration,” explains George Malliaras, Prince Philip Professor of Technology in Cambridge’s Department of Engineering, who leads the IRC. “Pancreatic tumour cells, for instance, are protected by dense stromal tissue, and tumours of the central nervous system by the blood-brain barrier.”

The aim of the project, which is funded for six years by the Engineering and Physical Sciences Research Council, is to develop an array of new delivery technologies that can deliver almost any drug to any tumour in a large enough concentration to kill the cancerous cells.

Chemists, engineers, material scientists and pharmacologists will focus on developing particles, injectable gels and implantable devices to deliver the drugs. Cancer scientists and clinicians from the Cancer Research UK Cambridge Centre and partner sites will devise and carry out clinical trials. Experts in innovative manufacturing technologies will ensure the devices are able to be manufactured and robust enough to withstand surgical manipulation.

One technology the team will examine is the ability of advanced materials to self-assemble and entrap drugs inside metal-organic frameworks. These structures can carry enormous amounts of drugs, and be tuned both to target the tumour and to release the drug at an optimal rate.

“We are going to pierce through the body’s natural barriers,” says Malliaras, “and deliver anti-cancer drugs to the heart of the tumour.”

Dr Su Metcalfe, a member of George Malliaras’s team and who is already using NanoBioMed to treat Multuple Sclerosis, added “the power of nanotechnology to synergise with potent anti-cancer drugs will be profound and the award will speed delivery to patients.”

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