Posts belonging to Category DNA

Inkjet Printers Grow Nerve Stem Cells

Inkjet printers and lasers are parts of a new way to produce cells important to research on nerve regeneration. Researchers at Iowa State University have developed a nanotechnology that uses inkjet printers to print multi-layer graphene circuits….It turns out mesenchymal stem cells adhere and grow well on the treated circuit’s raised, rough, and 3D nanostructures. Add small doses of electricity—100 millivolts for 10 minutes per day over 15 days—and the stem cells become Schwann-like cells, [which secrete substances that promote the health of nerve cells].

nerve cells

This technology could lead to a better way to differentiate stem cells,” says Metin Uz, a postdoctoral research associate in chemical and biological engineering. The researchers report the results could lead to changes in how nerve injuries are treated inside the body. “These results help pave the way for in vivo peripheral nerve regeneration where the flexible graphene electrodes could conform to the injury site and provide intimate electrical stimulation for nerve cell regrowth,” the researchers write in a summary of their findings.


How To Capture Quickly Cancer Markers

A nanoscale product of human cells that was once considered junk is now known to play an important role in intercellular communication and in many disease processes, including cancer metastasis. Researchers at Penn State have developed nanoprobes to rapidly isolate these rare markers, called extracellular vesicles (EVs), for potential development of precision cancer diagnoses and personalized anticancer treatments.

Lipid nanoprobes

Most cells generate and secrete extracellular vesicles,” says Siyang Zheng, associate professor of biomedical engineering and electrical engineering. “But they are difficult for us to study. They are sub-micrometer particles, so we really need an electron microscope to see them. There are many technical challenges in the isolation of nanoscale EVs that we are trying to overcome for point-of-care cancer diagnostics.”

At one time, researchers believed that EVs were little more than garbage bags that were tossed out by cells. More recently, they have come to understand that these tiny fat-enclosed sacks — lipids — contain double-stranded DNA, RNA and proteins that are responsible for communicating between cells and can carry markers for their origin cells, including tumor cells. In the case of cancer, at least one function for EVs is to prepare distant tissue for metastasis.

The team’s initial challenge was to develop a method to isolate and purify EVs in blood samples that contain multiple other components. The use of liquid biopsy, or blood testing, for cancer diagnosis is a recent development that offers benefits over traditional biopsy, which requires removing a tumor or sticking a needle into a tumor to extract cancer cells. For lung cancer or brain cancers, such invasive techniques are difficult, expensive and can be painful.

Noninvasive techniques such as liquid biopsy are preferable for not only detection and discovery, but also for monitoring treatment,” explains Chandra Belani, professor of medicine and deputy director of the Cancer Institute,Penn State College of Medicine, and clinical collaborator on the study.

We invented a system of two micro/nano materials,” adds Zheng. “One is a labeling probe with two lipid tails that spontaneously insert into the lipid surface of the extracellular vesicle. At the other end of the probe we have a biotin molecule that will be recognized by an avidin molecule we have attached to a magnetic bead.”


Artificial Embryo From Stem Cells

Scientists at the University of Cambridge have managed to create a structure resembling a mouse embryo in culture, using two types of stem cells – the body’s ‘master cells’ – and a 3D scaffold on which they can grow. Understanding the very early stages of embryo development is of interest because this knowledge may help explain why a significant number of human pregnancies fail at this time.

Once a mammalian egg has been fertilised by a sperm, it divides multiple times to generate a small, free-floating ball of stem cells. The particular stem cells that will eventually make the future body, the embryonic stem cells (ESCs) cluster together inside the embryo towards one end: this stage of development is known as the blastocyst. The other two types of stem cell in the blastocyst are the extra-embryonic trophoblast stem cells (TSCs), which will form the placenta, and primitive endoderm stem cells that will form the so-called yolk sac, ensuring that the foetus’s organs develop properly and providing essential nutrients.

Using a combination of genetically-modified mouse ESCs and TSCs, together with a 3D scaffold known as an extracellular matrix, Cambridge researchers were able to grow a structure capable of assembling itself and whose development and architecture very closely resembled the natural embryo.  There is a  remarkable degree of communication between the two types of stem cell: in a sense, the cells are telling each other where in the embryo to place themselves.

artificial embryo

We knew that interactions between the different types of stem cell are important for development, but the striking thing that our new work illustrates is that this is a real partnership – these cells truly guide each other,”  says Professor Zernicka-Goetz. “Without this partnership, the correct development of shape and form and the timely activity of key biological mechanisms doesn’t take place properly.”

Comparing their artificial ‘embryo’ to a normally-developing embryo, the team was able to show that its development followed the same pattern of development. The stem cells organise themselves, with ESCs at one end and TSCs at the other.

The study has been published in the journal Science.


How To Eradicate Undetectable HIV Cells

French researchers have identified a marker that makes it possible to differentiate “dormantHIVinfected cells from healthy cells. This discovery will make it possible to isolate and analyze reservoir cells which, by silently hosting the virus, are responsible for its persistence even among patients receiving antiviral treatment, whose viral load is undetectable. It offers new therapeutic strategies for targeting infected cells. This research is part of the ANRS strategic program “Réservoirs du VIH”.

HIV detection

Since 1996, there has been consensus among the scientific community that a cure for HIV will involve targetingreservoir cells” that host the virus in the organisms of patients undergoing triple therapy. HIV can remain hidden in these reservoirs, in latent form, for several decades, eluding the immune system’s response and antiviral treatments, without any viral protein being expressed. But if treatment ceases, the virus massively proliferates and the disease progresses again. Patients must therefore receive treatment for life. To envisage eliminating this dormant virus, a first stage consists in distinguishing the HIV-infected reservoir cells from their healthy counterpart cells, which resemble them to a very large degree. This is what has been achieved by a team of researchers, who have identified a marker of reservoir cells: a protein present only on the surface of infected cells.

Hypothesizing that HIV might leave a mark on the surface of its host cell, researchers from the Institut de génétique humaine (CNRS/Montpellier University) first worked in vitro on an infection model developed in their laboratory. After comparing infected cells and healthy cells, they noticed one particular protein, coded by a gene among the hundred of those expressed in a specific way by infected cells. Present only on the surface of the infected cells, the CD32a protein thus met, in vitro, the criteria of a reservoir cell marker. This was then confirmed by experiments on clinical samples. By studying blood samples from 12 patients living with HIV and receiving treatment, the researchers isolated the cells expressing the marker and observed that almost all were HIV carriers. In vitro, the activation of these cells induced a production of viruses capable of reinfecting healthy cells whereas their elimination entailed a significant delay in viral production.

The findings are the result of a collaboration between the CNRS, Montpellier University, Inserm, the Institut Pasteur, the Henri-Mondor AP-HP hospital in Créteil, the Gui de Chauliac hospital (CHU de Montpellier) and the VRI (Vaccine Research Institute), and is published in the journal Nature on March 15, 2017. A patent owned by the CNRS has been filed for the diagnostic and therapeutic use of the identified marker.


Shape-shifting Molecular Robots

A research group at Tohoku University and Japan Advanced Institute of Science and Technology has developed a molecular robot consisting of biomolecules, such as DNA and protein. The molecular robot was developed by integrating molecular machines into an artificial cell membrane. It can start and stop its shape-changing function in response to a specific DNA signal.

This is the first time that a molecular robotic system has been able to recognize signals and control its shape-changing function. What this means is that molecular robots could, in the near future, function in a way similar to living organisms.

Using sophisticated biomolecules such as DNA and proteins, living organisms perform important functions. For example, white blood cells can chase bacteria by sensing chemical signals and migrating toward the target. In the field of chemistry and synthetic biology, elemental technologies for making various molecular machines, such as sensors, processors and actuators, are created using biomolecules. A molecular robot is an artificial molecular system that is built by integrating molecular machines. The researchers believe that realization of such a system could lead to a significant breakthrough – a bio-inspired robot designed on a molecular basis.

molecular robot

The molecular robot developed by the research group is extremely small – about one millionth of a meter – similar in size to human cells. It consists of a molecular actuator, composed of protein, and a molecular clutch, composed of DNA. The shape of the robot’s body (artificial cell membrane) can be changed by the actuator, while the transmission of the force generated by the actuator can be controlled by the molecular clutch. The research group demonstrated through experiments that the molecular robot could start and stop the shape-changing behavior in response to a specific DNA signal.

The findings were published in Science Robotics.


Car Pollution: Nanoparticles Travel Directly From The Nose To The Brain

The closer a person lives to a source of pollution, like a traffic dense highway, the more likely they are to develop Alzheimer’s or dementia, according to a study by the University of Southern California (USC) that has linked a close connection to pollution and the diseases. In a mobile lab, located just off of one of Los Angeles’ busiest freeways, USC scientists used a state-of-the-art pollution particle collector capable of gathering nano-sized particulate matter.

car pollution


We have shown that, as you would expect, the closer you get to the sources of these particles in our case the freeways, the higher the concentrations. So there is an exponential decay with distance. That means basically that, the concentration of where we are right now and if we were, let’s just say 20 or 10 or 50 yards from the freeway, those levels would be probably 10 times higher than where we are right now,” says Costas Sioutas, USC Professor of Environmental Engineering.

That means proximity to high concentrations of fossil fuel pollution, like a congested freeway, could be hazardous. Particulate matter roughly 30 times thinner than the width of a human hair, called PM2.5, is inhaled and can travel directly through the nose into the brain. Once there, the particles cause inflammatory responses and can result in the buildup of a type of plaque, which is thought to further the progression of Alzheimer’s. “Our study brought in this new evidence and I would say probably so far the most convincing evidence that the particle may increase the risk of dementia. This is really a public health problem. And I think the policy makers need to be aware of that, the public health risk associated with high level of PM2.5,” explains Jiu-Chiuan Chen, Associate Professor of Preventive Medicine.

USC researchers analyzed the data of more than 3,500 women who had the APOE4 gene, the major known risk-factor gene for Alzheimer’s disease. It showed that, over the course of a decade, the women who lived in a location with high levels of the PM2.5 pollution were 92 percent more likely to develop dementia.


Killing Cancer Cells From Inside

Researchers have witnessed – for the first time – cancer cells being targeted and destroyed from the inside, by an organo-metal compound discovered by the University of Warwick (UK). Professor Peter J. Sadler, and his group in the Department of Chemistry, have demonstrated that Organo-Osmium FY26 – which was first discovered at Warwick – kills cancer cells by locating and attacking their weakest part.

osmium compound fy26 in cancer cell
This is the first time that an Osmium-based compound – which is fifty times more active than the current cancer drug cisplatin – has been seen to target the disease. Using the European Synchrotron Radiation Facility (ESRF), researchers analysed the effects of Organo-Osmium FY26 in ovarian cancer cells – detecting emissions of X-ray fluorescent light to track the activity of the compound inside the cells

Looking at sections of cancer cells under nano-focus, it was possible to see an unprecedented level of minute detail. Organelles like mitochondria, which are the ‘powerhouses’ of cells and generate their energy, were detectable. In cancer cells, there are errors and mutations in the DNA of mitochondria, making them very weak and susceptible to attack.

FY26 was found to have positioned itself in the mitochondriaattacking and destroying the vital functions of cancer cells from within, at their weakest point. Researchers were also able to see natural metals which are produced by the body – such as zinc and calcium – moving around the cells. Calcium in particular is known to affect the function of cells, and it is thought that this naturally-produced metal helps FY26 to achieve an optimal position for attacking cancer.


How To Track Stem Cells In The Body

Rice University researchers have synthesized a new and greatly improved generation of contrast agents for tagging and real-time tracking of stem cells in the body. The agent combines ultrashort carbon nanotubes and bismuth clusters that show up on X-rays taken with computed tomography (CT) scanners. The stable compound performs more than eight times better than the first-generation material introduced in 2013, according to the researchers.

An improved compound of bismuth and carbon nanotubes called Bi4C@US-tubes, developed at Rice University could enhance the ability to track stem cells as they move through the body and target diseases

The primary application will be to track them in stem-cell therapies to see if the cells are attracted to the site of disease — for example, cancer — and in what concentration,” said Rice chemist Lon Wilson of the compound the researchers call Bi4C@US-tubes.

Magnetic resonance imaging is currently used for that purpose and it works quite well, but X-ray technology in the clinic is much more available,” he said. “It’s faster and cheaper, and it could facilitate preclinical studies to track stem cells in vivo.”

Bismuth is used in cosmetics, pigments and pharmaceuticals, notably as the active ingredient in pink bismuth (aka Pepto-Bismol), an antacid. For this application, bismuth nanoclusters developed by the lab of Rice chemist Kenton Whitmire, a co-author of the paper, are combined with carbon nanotubes chemically treated to shorten them to between 20 and 80 nanometers and add defects to their side walls. The nanoclusters, which make up about 20 percent of the compound, appear to strongly attach to the nanotubes via these defects.

When introduced into stem cells, the treated nanotubes become easy to spot, Wilson said. “It’s very interesting to see a cell culture that is opaque to X-rays. They’re not as dark as bone (which X-rays cannot penetrate), but they’re really dark when they’re loaded with these agents.”

The process developed by Wilson’s team and colleagues at CHI St. Luke’s Health-Baylor St. Luke’s Medical Center and Baylor College of Medicine is detailed this month in the American Chemical Society journal ACS Applied Materials and Interfaces.


‘Protective’ DNA strands are shorter in adults who had more infections as infants

New research indicates that people who had more infections as babies harbor a key marker of cellular aging as young adults: the protective stretches of DNA which “cap” the ends of their chromosomes are shorter than in adults who were healthier as infants.

TELOMERESThe 46 chromosomes of the human genome, with telomeres highlighted in white

These are important and surprising findings because — generally speaking — shorter chromosome ‘caps’ are associated with a higher burden of disease later in life,” said lead author Dan Eisenberg, an assistant professor of anthropology at the University of Washington.

The ‘caps’ Eisenberg and his co-authors measured are called telomeres. These are long stretches of DNA at the ends of our chromosomes, which protect our genes from damage or improper regulation. One Nobel Prize-winning scientist who studies telomeres has compared them to aglets — the plastic or metal sheath covering ends of shoelaces. When aglets wear down, the shoelace is exposed to fraying and degradation from environmental forces.

Like aglets, telomeres don’t last forever. In most of our cells, telomeres get shorter each time that cell divides. And when they get too short, the cell either quits dividing or dies.

That makes telomere length particularly important for the cells of our immune system, especially the white blood cells circulating in our bloodstream. When activated against a pathogen, white blood cells undergo rapid rounds of cell division to raise a defensive force against the infectious invader. But if telomeres in white blood cells are already too short, the body may struggle to mount an effective immune response.

Many studies — in laboratory animals and humans — have associated shorter telomeres with poor health outcomes, especially in adults,” said Eisenberg. But few studies have addressed whether or not events early in a person’s life might affect telomere length. To get at this question, Eisenberg turned to the Cebu Longitudinal Health and Nutrition Survey, which has tracked the health of over 3,000 infants born in 1983-1984 in Cebu City in the Philippines. Researchers collected detailed data every two months from mothers on the health and feeding habits of their babies up through age two. Mothers reported how often their babies had diarrhea — a sign of infection — as well as how often they breastfed their babies. As these babies grew up, scientists collected additional health data during follow-up surveys over the next 20 years. In 2005, 1,776 of these offspring donated a blood sample. By then, they were 21- or 22-year-old young adults.

Eisenberg measured telomere length in cells from those blood samples. He then combined the data on adult telomere length with information about their health and feeding habits as babies. He found that babies with higher reported cases of diarrhea at 6 to 12 months also had the shortest telomeres as adults.

The findings have been published in the American Journal of Human Biology.


Stem Cells Boost Bones Repair

A recent study, affiliated with UNIST (South Korea) has developed a new method of repairing injured bone using stem cells from human bone marrow and a carbon material with photocatalytic properties, which could lead to powerful treatments for skeletal system injuries, such as fractures or periodontal disease. In the study, the research team reported that the use of human bone marrow-derived mesenchymal stem cells (hBMSCs) has been tried successfully in fracture treatment due to their potential to regenerate bone in patients who have lost large areas of bone from either disease or trauma. Recently, many attempts have been made to enhance the function of stem cells using carbon nanotubes, graphenes, and nano-oxides.

Professor Kim and Professor Suh (UNIST) examined the C₃N₄sheets. They discovered that this material absorbs red light and then emits fluorescence, which can be used to speed up bone regeneration. Professor Suh conducted a biomedical application of this material. After two days of testing, the material showed no cytotoxicity, making it useful as biomaterials.

bone-repairUpper left) Chemical bonding and physical structure of C₃N₄4 sheets. (Lower left) In a liquid state, red light is transmitted at a maximum of 450nm and emitted at a wavelength of 635 nm. (Right) After 4 weeks of loading C₃N₄4 sheets into the skull-damaged mice, the skull was regenerated by more than 90%.

This research has opened up the possibility of developing a new medicine that effectively treats skeletal injuries, such as fractures and osteoporosis,” said Professor Young-Kyo Seo. “It will be a very useful tool for making artificial joints and teeth with the use of 3D printing. This is an important milestone in the analysis of biomechanical functions needed for the development of biomaterials, including adjuvants for hard tissues such as damaged bones and teeth.”

This research has been jointly conducted by Professor Youngkyo Seo of Life Sciences and Dr. Jitendra N. Tiwari of Chemistry in collaboration with Professor Kwang S. Kim of Natural Science, Professor Pann-Ghill Suh of Life Sciences, and seven other researchers from UNIST.  The results of the study has been published in the January issue of ACS Nano journal.


Damaged teeth can be regrown naturally

A way to naturally regrow damaged teeth has been discovered by scientists in a breakthrough that could significantly reduce the need for fillings. Researchers at King’s College London (KCL) found that a drug designed to treat Alzheimer’s disease was able to stimulate the tooth to create new dentine capable of filling in large cavitiesTeeth can already cope with small areas of damage using the same process, but when the holes become too large a dentist must insert artificial cements or the tooth will be lost.


The simplicity of our approach makes it ideal as a clinical dental product for the natural treatment of large cavities, by providing both pulp protection and restoring dentine,” said Professor Paul Sharpe, lead author of a paper in the journal Scientific Reports.  “In addition, using a drug that has already been tested in clinical trials for Alzheimer’s disease provides a real opportunity to get this dental treatment quickly into clinics.”

If a tooth is damaged or infected, the soft inner pulp can become exposed, risking further infection. When this happens, a band of dentine, the hard material that makes up most of the tooth, will attempt to bridge the gap and seal off the pulp. But the researchers found that the natural repair mechanism could be boosted if the drug  Tideglusib was used. Previously it has been trialled as a treatment for various neurological disorders, including Alzheimer’s. It works by stimulating stem cells, which can turn into any type of tissue in the body, already present in the pulp to create new dentine.

The drug and a substance called glycogen synthase kinase were applied to the tooth on a biodegradable sponge made from collagen. As the sponge degraded, it was replaced by dentineleading to complete, natural repair”, according to a statement about the research issued by KCL.


DNA DataStorage, New Frontier For Nanotechnology

Nanotechnology holds a lot of promise to almost every aspect of our lives from consumer electronics to ending life-threatening illnesses. However, the greatest challenge nanotechnology is facing is the limitation of how much smaller they can shrink the physical size of semiconductors. However, a group of scientists are taking that challenge and if they are successful, we may be well on our way to a future much wilder than science fiction – molecular electronics.


Molecular electronics works at the most minute scale using single molecules including its sub properties and characteristics. The concept of molecular electronics was first originated in 1997 by Mark Reed and his colleagues.

This is what a team of Russian and Israeli scientists are trying to explore as the demand for smaller electronic devices proliferate. Their study proposes to “metallizeDNA using nanoparticles of silver.

First of all, the DNA can hold a great amount of information despite its small size. What’s more intriguing is that the ability of DNA is not limited to storing only genetic information. The study has revealed that the DNA has more uncanny and unique features.

The first feature they discovered was that the DNA has superconducting abilities when placed between two superconductors. The second feature was that they can effect charge transport, which happen when you introduce metal atoms along the strand. Moreover, the scientists also discovered that the conductivity of the DNA molecules depend on the type of substrate they are placed on.

Although the scientists were able to ‘metallize‘ atoms, the distribution was not even along the entire length of the strands, which means not all of it becomes ‘metal.’ However, they found out that these DNA molecules can interact with silver nanoparticles resulting in an even metal DNA strand.

If further experimentation and testing become successful, such nanowire would be 1.1 nanometers high and 400 nanometers long.

The study is published in Advanced Materials.