#Nanopore Method Improves Accuracy of DNA Sequencing EPFL scientists have developed a method that improves the accuracy of DNA sequencing up to a thousand times.
which uses nanopores to read individual nucleotides, paves the way for better-and cheaper-DNA sequencing.
One of the most critical biological and medical tools available today, it lies at the core of genome analysis. Reading the exact make-up of genes,
scientists can detect mutations, or even identify different organisms. A powerful DNA sequencing method uses tiny
However,"nanopore sequencing"is prone to high inaccuracy because DNA usually passes through very fast. EPFL scientists have discovered now a viscous liquid that slows down the process up to a thousand times,
The breakthrough is published in Nature Nanotechnology. Reading too fast DNA is a long molecule made up of four repeating different building-blocks.
"and are strung together in various combinations that contain the cell's genetic information, such as genes. Essentially
In nanopore sequencing, DNA passes through a tiny pore in a membrane, much like a thread goes through a needle.
Slowing things down The lab of Aleksandra Radenovic at EPFL's Institute of Bioengineering has now overcome the problem of speed by using a thick,
viscous liquid that slows the passage of DNA two to three orders of magnitude. As a result, sequencing accuracy improves down to single nucleotides.
The team then created a nanopore on membrane, almost 3 nm wide. The next step was to dissolve DNA in a thick liquid that contained charged ions and
Finally, the team tested their system by passing known nucleotides, dissolved in the liquid, through the nanopore multiple times.
Although still at a testing stage, the team is aiming to continue their work by testing entire DNA strands."
which is promising for sequencing with solid-state nanopores, "says Jiandong Feng. The scientists also predict that using high-end electronics
and control of the viscosity gradient of the liquid could further optimize the system. By combining ionic liquids with nanopores on molybdenum disulfide thin films, they hope to create a cheaper DNA sequencing platform with a better output.
The work offers an innovative way that can improve one of the best DNA sequencing methods available."
"In years to come, sequencing technology will definitely shift from research to clinics, "says Aleksandra Radenovic."
"For that, we need rapid and affordable DNA sequencing -and nanopore technology can deliver
#Researchers Develop Stretchable, Transparent Conductor with Gold Nanomesh Researchers have discovered a new stretchable, transparent conductor that can be folded
or stretched and released, resulting in a large curvature or a significant strain, at least 10,000 times without showing signs of fatigue.
This is a crucial step in creating a new generation of foldable electronics-think a flat-screen television that can be rolled up for easy portability-and implantable medical devices.
The work, published Monday in the Proceedings of the National Academy of Sciences, pairs gold nanomesh with a stretchable substrate made with polydimethylsiloxane
or PDMS. The substrate is stretched before the gold nanomesh is placed on it-a process known as"prestretching
"-and the material showed no sign of fatigue when cyclically stretched to a strain of more than 50 percent.
The gold nanomesh also proved conducive to cell growth, indicating it is a good material for implantable medical devices.
Fatigue is a common problem for researchers trying to develop a flexible, transparent conductor, making many materials that have good electrical conductivity,
flexibility and transparency-all three are needed for foldable electronics-wear out too quickly to be practical,
said Zhifeng Ren, a physicist at the University of Houston and principal investigator at the Texas Center for Superconductivity,
who was the lead author for the paper. The new material, produced by grain boundary lithography,
In materials science,"fatigue"is used to describe the structural damage to a material caused by repeated movement or pressure, known as"strain cycling."
That means the materials aren't durable enough for consumer electronics or biomedical devices.""Metallic materials often exhibit high cycle fatigue,
and fatigue has been a deadly disease for metals, "the researchers wrote.""We weaken the constraint of the substrate by making the interface between the Au (gold) nanomesh and PDMS slippery,
and expect the Au nanomesh to achieve superstretchability and high fatigue resistance, "they wrote in the paper."
"Free of fatigue here means that both the structure and the resistance do not change or have little change after many strain cycles."
"the Au nanomesh does not exhibit strain fatigue when it is stretched to 50 percent for 10,000 cycles."
The researchers used mouse embryonic fibroblast cells to determine biocompatibility; that, along with the fact that the stretchability of gold nanomesh on a slippery substrate resembles the bioenvironment of tissue
or organ surfaces, suggest the nanomesh"might be implanted in the body as a pacemaker electrode,
a connection to nerve endings or the central nervous system, a beating heart, and so on, "they wrote. Ren's lab reported the mechanics of making a new transparent and stretchable electric material,
using gold nanomesh, in a paper published in Nature Communications in January 2014. This work expands on that,
producing the material in a different way to allow it to remain fatigue-free through thousands of cycles s
#UCLA Scientists Use Powerful Microscope to Image 3d Positions of Individual Atoms Atoms are the building blocks of all matter On earth,
a UCLA professor of physics and astronomy and a member of UCLA California Nanosystems Institute, is published Sept. 21 in the online edition of the journal Nature Materials.
For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography,
which involves measuring how light waves scatter off of a crystal. However, X-ray crystallography only yields information about the average positions of many billions of atoms in the crystal
and not about individual atomsprecise coordinates. t like taking an average of people On earth, Miao said. ost people have a head, two eyes, a nose and two ears.
Because X-ray crystallography doesn reveal the structure of a material on a per-atom basis,
when the materials are components of machines like jet engines. oint defects are very important to modern science and technology,
However, scanning transmission electron microscopes only produce two-dimensional images. So creating a 3-D picture requires scientists to scan the sample once,
and re-scan it repeating the process until the desired spatial resolution is achieved before combining the data from each scan using a computer algorithm.
Using a scanning transmission electron microscope at the Lawrence Berkeley National Laboratory Molecular Foundry, Miao and his colleagues analyzed a small piece of tungsten,
said Peter Ercius, a staff scientist at Lawrence Berkeley National Laboratory and an author of the paper.
thanks to the electron beam energy being kept below the radiation damage threshold of tungsten. Miao and his team showed that the atoms in the tip of the tungsten sample were arranged in nine layers, the sixth
which will help inform our understanding of the properties of these important materials at the most fundamental scale. think this work will create a paradigm shift in how materials are characterized in the 21st century,
and are discussed in many physics and materials science textbooks. Our results are the first experimental determination of a point defect inside a material in three dimensions.
Wolfgang Theis of the University of Birmingham; Hadi Ramezani-Dakhel and Hendrik Heinz of the University of Akron;
and Laurence Marks of Northwestern University. This work was supported primarily by the U s. Department of energy Office of Basic energy Sciences (grant DE-FG02-13er46943 and contract DE-AC025CH11231
#Chemists Use DNA Molecules to Design Rapid and Inexpensive Medical Diagnostic Tests Chemists at the University of Montreal used DNA molecules to developed rapid, inexpensive medical
diagnostic tests that take only a few minutes to perform. Their findings, which will officially be published tomorrow in the Journal of the American Chemical Society,
may aid efforts to build point-of-care devices for quick medical diagnosis of various diseases ranging from cancer, allergies, autoimmune diseases, sexually transmitted diseases (STDS),
and many others. The new technology may also drastically impact global health, due to its low cost and easiness of use
when atoms are brought too close together-to detect a wide array of protein markers that are linked to various diseases.
The design was created by the research group of Alexis Vallée-Bélisle, a professor in the Department of chemistry at University of Montreal."
and the results sent back to the doctor's office. If we can move testing to the point of care,
which would enhance the effectiveness of medical interventions. The key breakthrough underlying this new technology came by chance."
(or traffic) at the surface of a sensor, which drastically reduced the signal of our tests,
"said Sahar Mashid, postdoctoral scholar at the University of Montreal and first author of the study."
and limits the ability of this DNA to hybridize to its complementary strand located on the surface of a gold electrode.
Francesco Ricci, a professor at University of Rome Tor Vergata who also participated in this study,
explains that this novel signaling mechanism produces sufficient change in current to be measured using inexpensive electronics similar to those in the home glucose test meter used by diabetics to check their blood sugar.
allowing us to build inexpensive devices that could detect dozens of disease markers in less than five minutes in the doctor's office
including pathogen detection in food or water and therapeutic drug monitoring at home, a feature which could drastically improve the efficient of various class of drugs and treatments a
#New Nanosheet-Based Photonic crystal Changes Color in Response to Moisture LMU chemists have developed a photonic crystal from ultrathin nanosheets
which are extremely sensitive to moisture. hese photonic nanostructures change color in response to variations in local humidity.
This makes them ideal candidates for the development of novel user interfaces for touchless devices, says Professor Bettina Lotsch of the Department of chemistry at LMU and the Max Planck Institute for Solid State Research in Stuttgart.
The new sensing platform is described in the journal dvanced Materials he humidity around a fingertip is slightly higher than the overall level of moisture in the ambient air
explains Katalin Szendrei, a member of Prof. Lotsch research group. his difference can be detected by our photonic sensor,
and causes it to change color without any contact with the nearby fingertip. It is this extreme sensitivity to local moisture that makes the nanostructure so interesting for use in ouchlessscreens. ontactless control is a particularly attractive option for next-generation positioning interfaces such as ticket machines or cash dispensers,
which are used by hundreds of customers each day. In this case, touchless navigation has obvious advantages with respect to hygiene,
Unparalleled sensitivity and response time Photonic crystals are arranged periodically nanostructures which have the ability to reflect, guide and confine light.
They are also found in the biological world, where examples include mother-of-pearl and the iridescent wing-scales of certain butterflies,
Lotsch and her team have developed now photonic crystals based on nanosheets of phosphatoantimonic acid. The new nanomaterial is extremely moisture sensitive and at the same time chemically stable,
transparent and easy to fabricate into nanosheets. In comparison with other vapor sensors based on nanosheets, the new photonic architecture displays markedly increased response times, higher sensitivity and long-term stability. his unique combination of properties enables it to track
and color-code finger movements in real time, says Pirmin Ganter, who also works in Bettina Lotsch group.
In addition, the new system is stable on exposure to air, and therefore functions not just under controlled conditions in the laboratory but also in the constantly varying environment of the real world.
Lotsch and her collaborators have applied already for patent protection for the novel device and, together with the Fraunhofer EMFT in Munich,
they are already working on a prototype screen which, in addition to providing for color-coding, will also be equipped with an electronic readout capability n
#Using Defects in Liquid crystals to Create New Materials A team of engineers at the University of Wisconsin-Madison has demonstrated a versatile fabrication method to use defects in liquid crystals as small tubing,
which can be used to channel molecules into specific positions to create new nanostructures and materials.
"says Nicholas Abbott, a UW-Madison professor of chemical and biological engineering.""It's quite a versatile approach."
"Abbott and his team at the Materials Research Science and Engineering Center (MRSEC) at University of Wisconsin, Madison, have so far been successful in assembling phospholipids within imperfections in liquid crystals.
Phospholipids are molecules that are capable of arrange themselves into layers on the walls of living cells.
and other semiconducting structures that are important in electronics. The selective abilities of a membrane can also be imitated through this approach,
"We've done a lot of work in the past at the interfaces of liquid crystals, but we're now looking inside the liquid crystal,
resulting in amphiphilic building blocks in the form of a permanent nanostructure. The research is an example of how liquid crystal research is taking us from the nano to macro world,
"The research team consisted of Xiaoguang Wang, Daniel S. Miller and Emre Bukusoglu graduate students from UW-Madison,
and Juan J. de Pablo former engineering professor at UW-Madison, currently at the University of Chicago.
#Self-Assembled DNA NANOSTRUCTURES Could Be used as Smart Drug-Delivery Vehicles Researchers from Aalto University have published an article in the recent Trends in Biotechnology journal.
The article discusses how DNA molecules can be assembled into tailored and complex nanostructures, and further, how these structures can find uses in therapeutics and bionanotechnological applications.
In the review article, the researchers outline the superior properties of DNA NANOSTRUCTURES, and how these features enable the development of efficient biological DNA-nanomachines.
Moreover, these DNA NANOSTRUCTURES provide new applications in molecular medicine, such as novel approaches in tackling cancer.
Tailored DNA structures could find targeted cells and release their molecular payload (drugs or antibodies) selectively into these cells."
"Nowadays, software and techniques to design and simulate DNA NANOSTRUCTURES are extremely powerful and user friendly, and thus, researchers can easily construct their own DNA-objects for various uses.
The big boom in the field of structural DNA NANOTECHNOLOGY happened in 2006, when Paul Rothemund introduced a technique dubbed'DNA origami'.
'This method is the starting point for practically all other straightforward design approaches available today, "describes Veikko Linko, an Academy of Finland postdoctoral researcher from Biohybrid Materials Group.
Versatile DNA NANOSTRUCTURES The most important feature of a DNA-based nanostructure is its modularity. DNA structures can be fabricated with nanometer-precision,
and most importantly, other molecules such as RNA, proteins, peptides and drugs can be anchored to them with the same resolution.
Such a high accuracy can be exploited in creating nanosized optical devices as well as molecular platforms and barcodes for various imaging techniques and analytics.
Furthermore the researchers from Aalto University and University of Jyväskylä have shown recently how DNA origamis can be used in efficient fabrication of custom-shaped metal nanoparticles that could be used in various fields of material sciences.
For molecular medicine, tiny DNA-based devices could be utilized not only in detecting single molecules but also in modulating cell signaling.
In the near future, highly sophisticated DNA-robots could be used even in creating artificial immune systems.
A system based on tailored DNA-devices could help to avoid unnecessary drug treatments, since programmed DNA-nanorobots could detect various agents from the blood stream,
and immediately start the battle against disease. Groundbreaking approach to create nanomaterials The research group lead by Professor Mauri Kostiainen works extensively with DNA NANOSTRUCTURES,
and the group has published just recently two research articles regarding DNA-based applications in biotechnology and molecular medicine.
The researchers have coated DNA NANOSTRUCTURES with virus capsid proteins in order to significantly improve their transport to human cells;
this could find uses for example in enhanced drug delivery. In addition, the group has designed a modular DNA-based enzymatic nanoreactor that can be exploited in diagnostics at the molecular scale level v
#Novel Microfluidic Hybrid Device Reliably Detects Ebola virus A team led by researchers at UC Santa cruz has developed chip-based technology for reliable detection of Ebola virus and other viral pathogens.
The system uses direct optical detection of viral molecules and can be integrated into a simple, portable instrument for use in field situations where rapid,
accurate detection of Ebola infections is needed to control outbreaks. Laboratory tests using preparations of Ebola virus
and other hemorrhagic fever viruses showed that the system has the sensitivity and specificity needed to provide a viable clinical assay.
The current gold standard for Ebola virus detection relies on a method called polymerase chain reaction (PCR) to amplify the virus's genetic material for detection.
Because PCR works on DNA molecules and Ebola is an RNA VIRUS, the reverse transcriptase enzyme is used to make DNA copies of the VIRAL RNA prior to PCR amplification and detection."
"said senior author Holger Schmidt, the Kapany Professor of Optoelectronics at UC Santa cruz.""We're detecting the nucleic acids directly,
Adding a"preconcentration"step during sample processing on the microfluidic chip extended the limit of detection well beyond that achieved by other chip-based approaches,
Schmidt's lab at UC Santa cruz worked with researchers at Brigham Young University and UC Berkeley to develop the system.
Virologists at Texas Biomedical Research Institute in San antonio prepared the viral samples for testing. The system combines two small chips, a microfluidic chip for sample preparation and an optofluidic chip for optical detection.
For over a decade, Schmidt and his collaborators have been developing optofluidic chip technology for optical analysis of single molecules as they pass through a tiny fluid-filled channel on the chip.
The microfluidic chip for sample processing can be integrated as a second layer next to or on top of the optofluidic chip.
Schmidt's lab designed and built the microfluidic chip in collaboration with coauthor Richard Mathies at UC Berkeley who pioneered this technology.
It is made of a silicon-based polymer, polydimethylsiloxane (PDMS), and has microvalves and fluidic channels to transport the sample between nodes for various sample preparation steps.
nontarget biomolecules are washed off, and the bound targets are released then by heating, labeled with fluorescent markers,
and transferred to the optofluidic chip for optical detection. Schmidt noted that the team has not yet been able to test the system starting with raw blood samples.
"We are also working to use the same system for detecting less dangerous pathogens and do the complete analysis here at UC Santa cruz
#Researchers Visualize Nano-Sized Gateways That Control Activity of Mitochondrial Battery Mitochondria are referred often to as the powerhouses of our cells,
because they generate chemical energy similar to that obtained from a battery. Whether it's a brain,
nano-sized gateways control the activity of the mitochondrial battery, by carefully allowing certain proteins
what has been an essential mystery in biology and is published on 25 september in the prestigious journal, Science.
According to the lead researcher, Professor Trevor Lithgow, from the newly launched Biomedicine Discovery Institute (BDI) at Monash University in Melbourne, Australia,
opening the way to direct applications for medical research"he said. Professor Lithgow and his team used a novel technology that enables the systematic expansion of the genetic codes of living organisms to include unnatural amino acids beyond the common twenty.
The technology had been used in a handful of labs outside of Australia. Professor Lithgow and lead researcher Dr. Takuya Shiota from the BDI focused on the TOM protein complex
a large, complicated set of molecules embedded in the mitochondrial membrane in ways that have confounded long researchers.
According to Professor Lithgow TOM 40 has resisted all attempts, using x-ray crystallography and other standard techniques in structural biology to unlock its transport secrets.
The Lithgow lab, working with colleagues from Nagoya, Kyoto and Tokyo, ramped up scale of the technology making literally hundreds of re-coded TOM 40 complexes, each one with a novel additional 21st amino acid.
What they ended up with was a Rubik's Cube of three dimensional data, which in the end had a unique solution that explained the structure of the TOM 40 protein complex
and precisely how it operates as the gateway for entry into mitochondria. Having shown the technology works-Professor Lithgow believes other labs working on diverse processes in human cell biology will mimic these experiments to determine how their chosen nanomachines operate.
This includes processes from DNA damage and repair to regulation events in metabolic disorders and cancer."
"This new technology has revealed what has been a major unknown in biology, and other cellular mysteries are now ripe for the picking"he said.
The research is the culmination of more than 15 years work by Professor Lithgow, from the newly launched Biomedicine Discovery Institute (BDI) at Monash University.
He started working on the process of how proteins and other molecules enter into mitochondria as a postdoctoral researcher for the Human Frontiers Science Program in Basel,
and after returning to Australia continued to seek TOM 40's secret.""With this discovery I'll focus for a couple more years to transfer this technology across to other labs in Australia,
but I will then bow out: we will have answered by then all the questions that have driven me since my time in Switzerland,
According to Professor John Carroll, Director of the BDI, the research is a great example of the interdisciplinary approach that will be the hallmark of the Institute."
"We bring scientists from across all the biomedical disciplines together with mathematicians, chemists and others to make important discoveries that provide critical new information about how our bodies function.
The international effort needed to unlock this problem is a great example of the global nature of modern biomedical research.
It is essential to work with the best and most talented scientists irrespective of where they are based in the world,
The new method has a wide range of potential therapeutic applications. Selective intermolecular recognition is at the heart of all biological processes.
Thus proteins that bind specifically to complementary chemical structures are also indispensable for many biochemical and biotechnological applications.
Targeted modification of such proteins therefore plays a significant role in medical diagnostics and therapies.
Now researchers led by Professor Heinrich Leonhardt at LMU's Biocenter and Professor Christian Hackenberger of the Leibniz Institute for Molecular Pharmacology in Berlin have developed a new strategy that permits specific chemical modification of virtually any protein more rapidly
and more efficiently than was hitherto possible. Their results appear in the new edition of the journal Angewandte Chemie.
Many of the methods routinely used in the biosciences are based on the specific modification of proteins, in particular antibodies,
For example, chemotherapeutic agents used in the treatment of cancer are linked often chemically to antibodies that recognize antigens found only on the surface of the target tumor.
and stable derivatives of antibodies that we have used using with great success in our laboratory for many years,
Adaptor for attachment of reactive agents Since the engineered nanobodies are recognized now as targets by TTL,
"We can then exploit these'unnatural'tyrosine derivatives as chemical adaptors. In a subsequent step, with the aid of various well established chemical methods,
we can then add virtually any molecule with the required properties to the appropriate adaptors,
One obvious and highly promising application is in the production of so-called antibody-drug conjugates (ADCS) for use in tumor therapy.
As mentioned above, ADCS enable cytotoxic agents to be transported directly to the tumor tissue thus minimizing deleterious side-effects."
"But the relative lack of efficient ways to attach chemotherapeutic drugs to antibodies currently represents a major technological bottleneck,
#Researchers Build Optical Rectennas Using Carbon nanotubes and Tiny Rectifiers Optical rectennas, antenna-rectifier diodes that convert light into DC current, have been built using multiwall carbon nanotubes with integrated nanoscale rectifiers.
The produced optical rectennas hold promise as photodetectors that do not require cooling and energy harvesters that could be used for conversion of waste heat to electricity.
Their development could also lead to advancements in the efficiency of solar energy capture. The carbon nanotubes in the devices function as antennas for capturing light.
When the light waves strike the nanotube antennas, an oscillating charge is created that travels through the rectifier devices.
A small direct current (DC) is created when due to the rectifiers switching on and off at record speeds on the petahertz scale.
A considerable amount of current is produced when an array is composed of billions of such rectennas.
We could ultimately make solar cells that are twice as efficient at a cost that is ten times lower,
Georgia Tech Using nanometer scale components, researchers have demonstrated the first optical rectenna, a device that combines the functions of an antenna and a rectifier diode to convert light directly into DC current.
Rectennas, developed in the 1960s and 1970s, have functioned at very short wavelengths of 10 m. Since then,
The antennas had to be sufficiently small enough for coupling optical wavelengths and the rectifier diode had to have the ability to operate rapidly to capture electromagnetic wave oscillations.
However, the low cost and potential high efficiency of a rectenna capable of capturing visible light caused researchers to continue their study.
and make a device work, thanks to advances in fabrication technology. -Prof Baratunde Cola, Georgia Tech The team employed nanoscale fabrication techniques alongside metallic multiwall carbon nanotubes to build devices that utilized light's wave nature rather than its particle nature.
The researchers observed that the device functioned within a temperature range of 5°C to 77°C
the researchers grew forests of vertically aligned carbon nanotubes on a conductive substrate. Atomic layer chemical vapour deposition was used to in sulate the nanotubes with a coating of aluminum oxide.
Optically transparent thin calcium layers were deposited then using physical vapor deposition over the nanotube forest.
A potential difference of 2ev was achieved which is sufficient for ejecting electrons out of the carbon nanotube antennas upon the absorption of visible light Light in the form of oscillating waves interacts with nanotubes after going through the calcium-aluminum electrode.
The nanotube tips have metal-insulator-metal junctions that work as rectifiers. These rectifiers switch on and off at time intervals in the femtosecond range.
This means the electrons flow in one direction towards the top electrode. The 10nm diode functions at such a high frequency due to the ultra-low capacitance,
which is in a few attofarads. rectenna is basically an antenna coupled to a diode, but when you move into the optical spectrum,
that usually means a nanoscale antenna coupled to a metal-insulator-metal diode. The closer you can get the antenna to the diode
the more efficient it is. So the ideal structure uses the antenna as one of the metals in the diode
which is the structure we made-Prof Baratunde Cola, Georgia Tech The rectennas were grown on rigid substrates
however the team aims to grow rectennas on foil or other suitable materials for developing flexible photodetectors and solar cells.
Cola intends to improve the efficiency of the rectennas in a number of ways such as changing materials,
allowing multiple conduction channels in the carbon nanotubes, and reducing the structural resistance. e think we can reduce the resistance by several orders of magnitude just by improving the fabrication of our device structures,
ased on what others have done and what the theory is showing us, I believe that these devices could get to greater than 40 percent efficiency.
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