University of Delaware: Programming DNA to deliver cancer drugs


DNA has an important job — it tells your cells which proteins to make. Now, a research team at the University of Delaware has developed technology to program strands of DNA into switches that turn proteins on and off. Credit: University of Delaware

DNA has an important job—it tells your cells which proteins to make. Now, a research team at the University of Delaware has developed technology to program strands of DNA into switches that turn proteins on and off.

UD’s Wilfred Chen Group describes their results in a paper published Monday, March 12 in the journal Nature Chemistry. This technology could lead to the development of new cancer therapies and other drugs.

Computing with DNA

This project taps into an emerging field known as DNA computing. Data we commonly send and receive in everyday life, such as text messages and photos, utilize binary code, which has two components—ones and zeroes. DNA is essentially a code with four components, the nucleotides guanine, adenine, cytosine, and thymine. In cells, the arrangement of these four nucleotides determines the output—the proteins made by the DNA. Here, scientists have repurposed the DNA code to design logic-gated DNA circuits.

“Once we had designed the system, we had to first go into the lab and attach these DNA strands to various proteins we wanted to be able to control,” said study author Rebecca P. Chen, a doctoral student in chemical and biomolecular engineering (no relation to Wilfred Chen).

The custom sequence designed DNA strands were ordered from a manufacturer while the proteins were made and purified in the lab. Next, the protein was attached to the DNA to make protein-DNA conjugates.

The group then tested the DNA circuits on E. coli bacteria and human cells. The target proteins organized, assembled, and disassembled in accordance with their design.

“Previous work has shown how powerful DNA nanotechnology might possibly be, and we know how powerful proteins are within cells,” said Rebecca P. Chen. “We managed to link those two together.”

Applications to drug delivery

The team also demonstrated that their DNA-logic devices could activate a non-toxic cancer prodrug, 5-fluorocytosine, into its toxic chemotherapeutic form, 5-fluorouracil. Cancer prodrugs are inactive until they are metabolized into their therapeutic form.

In this case, the scientists designed DNA circuits that controlled the activity of a protein that was responsible for conversion of the prodrug into its active form. The DNA circuit and protein activity was turned “on” by specific RNA/DNA sequence inputs, while in the absence of said inputs the system stayed “off.”

To do this, the scientists based their sequence inputs on microRNA, small RNA molecules that regulate cellular gene expression. MicroRNA in cancer cells contains anomalies that would not be found in healthy cells. For example, certain microRNA are present in cancer cells but absent in healthy cells. The group calculated how nucleotides should be arranged to activate the cancer prodrug in the presence of cancer microRNA, but stay inactive and non-toxic in a non-cancerous environment where the microRNA are missing.

When the cancer microRNAs were present and able to turn the DNA circuit on, cells were unable to grow. When the circuit was turned off, cells grew normally.

Wilfred Chen (left) and Rebecca P. Chen are developing new biomolecular tools to address key global health problems. Credit: University of Delaware/ Evan Krape

This technology could have wide applications not only to other diseases besides cancer, but also beyond the biomedical field. For example, the research team demonstrated that their technology could be applied to the production of biofuels, by utilizing their technology to guide an enzymatic cascade, a series of chemical reactions, to break down a plant fiber.

Using the newly developed technology, researchers could target any DNA sequence of their choosing and attach and control any protein they want. Someday, researchers could “plug and play” programmed DNA into a variety of cells to address a variety of diseases, said study author Wilfred Chen, Gore Professor of Chemical Engineering.

“This is based on a very simple concept, a logical combination, but we are the first to make it work,” he said. “It can address a wide scope of problems, and that makes it very intriguing.”

More information: Rebecca P. Chen et al, Dynamic protein assembly by programmable DNA strand displacement, Nature Chemistry (2018). DOI: 10.1038/s41557-018-0016-9

Provided by: University of Delaware

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Is It Possible? Will You Soon be Able to Replace Your Glasses And Contacts With Nanoparticle Eyedrops?


A revolutionary, cutting-edge technology, developed by researchers at Bar-Ilan University’s Institute of Nanotechnology and Advanced Materials (BINA), has the potential to provide a new alternative to eyeglasses, contact lenses, and laser correction for refractive errors.

The technology, known as Nano-Drops, was developed by Dr. David Smadja (Ophthalmologist from Shaare Zedek Medical Center), Prof. Zeev Zalevsky, from Bar-Ilan’s Kofkin Faculty of Engineering, and Prof. Jean-Paul Moshe Lellouche, Head of the Department of Chemistry at Bar-Ilan. A related patent on this new invention was recently filed by Birad – Research & Development Company Ltd., the commercializing company of Bar-Ilan University.

Nano-Drops achieve their optical effect and correction by locally modifying the corneal refractive index. The magnitude and nature of the optical correction is adjusted by an optical pattern that is stamped onto the superficial layer of the corneal epithelium with a laser source. The shape of the optical pattern can be adjusted for correction of myopia (nearsightedness), hyperopia (farsightedness) or presbyopia (loss of accommodation ability). The laser stamping onto the cornea takes a few milliseconds and enables the nanoparticles to enhance and ‘activate’ this optical pattern by locally changing the refractive index and ultimately modifying the trajectory of light passing through the cornea.

The laser stamping source does not relate to the commonly known ‘laser treatment for visual correction’ that ablates corneal tissue. It is rather a small laser device that can connect to a smartphone and stamp the optical pattern onto the corneal epithelium by placing numerous adjacent pulses in a very speedy and painless fashion.  Tiny corneal spots created by the laser allow synthetic and biocompatible nanoparticles to enter and locally modify the optical power of the eye at the desired correction.

In the future this technology may enable patients to have their vision corrected in the comfort of their own home. To accomplish this, they would open an application on their smartphone to measure their vision, connect the laser source device for stamping the optical pattern at the desired correction, and then apply the Nano-Drops to activate the pattern and provide the desired correction.

Upcoming in-vivo experiments in rabbits will allow the researchers to determine how long the effect of the Nano-Drops will last after the initial application. Meanwhile, this promising technology has been shown, through ex-vivo experiments, to efficiently correct nearly 3 diopters of both myopia and presbyopia in pig eyes.

Bar-Ilan University, founded in 1955, was one of the first comprehensive research universities to be established in Israel.  From 70 students to 17,000, its milestone achievements in the sciences and humanities have made an indelible imprint on the landscape of the nation.  The university has 8 faculties, four of which focus on STEM research. They include Medicine, Exact Sciences (Physics, Chemistry, Computer Science, Biophysics and Mathematics), Life Sciences and Engineering.

Bar-Ilan University

Scientists create hybrid nanomaterials in fight against cancer and bacteria


IMAGE: SAMPLES OF NANOHYBRIDS OBTAINED IN NUST MISIS “INORGANIC NANOMATERIALS ” LABORATORY view more 

CREDIT: ©NUST MISIS

NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY MISIS

Scientists from the National University of Science and Technology MISIS (NUST MISIS), the State Research Center for Applied Microbiology and Biotechnology and the Queensland University (Brisbane, Australia) have created BN/Ag hybrid nanomaterials and have proved their effectiveness as catalysts and antibacterial agents as well as for treating oncological diseases. The results are published in the Beilstein Journal of Nanotechnology.

The interest in the nanomaterials is related to the fact that when a particle is decreased to nanometers (1 nanometer = 10-9 meter) its electronic structure changes, and the material acquires new physical and chemical properties. For example, a magneto can lose its magnetism completely when decreased to ten nanometers.

Today, scientists are beginning to study combinations of various materials at the nanolevel instead of as separate nanoparticles (fullerenes and nanotubes). They have come up with a concept of hybrid nanomaterials, which combine the properties of individual components.

Hybridization makes it possible to combine properties that were incompatible before, for example, to create a material that can be a solid and a plastic at the same time. In addition, the scientists noted that combinations of nanomaterials often showed better or even new properties. Today the nanohybrid area is only beginning to develop.

MISIS scientists are studying the properties of BN hybrid nanomaterials. BN (boron nitride) was chosen as the base for new hybrid nanoparticles because it is chemically inert and biocompatible and has low relative density.

BN hybrid nanomaterials are used as prospective key components of the next generation advanced biomaterials, catalysts and sensors. These hybrids have advantageous combination of properties, such as biocompatibility, high tensile strength and thermal conductivity as well as superb chemical stability and electrical insulation. This explains their rich functionality for developing new biomedicines, reinforcement of ultralight metals and polymers and production of transparent superhydrophobic films and quantum devices.

“We have studied BN/Ag nanohybrid properties and have discovered a high potential for new applications. We were especially interested in an application for treating oncological diseases as well as their activity as catalysts and antibacterial agents,” said Andrei Matveyev, a research author, Senior Research Fellow at the MISIS Inorganic Materials Laboratory.

According to Matveyev, these nanohybrids can be used in cancer therapy as a base for drug delivery medicines. The nanohybrids with the drug become containers to be delivered inside cancer cells. Nanohybrids are chemically modified by attaching folic acid (vitamin ?9) to its surface through an Ag nanoparticle.

The modified nanohybrids with folic acid are mostly accumulated in cancer cells, because they have an increased number of folic acid receptors, so the concentration grows thousand times higher than in healthy cells. In addition, the acidity in a cancer cell is also higher than in the intercellular space, which leads to the drug’s release from its nanocontainer.

“This is why the drug is mostly released inside cancer cells, which decreases the general concentration of the drug in the organism, thus preventing toxicity,” Matveyev notes.

The authors believe that nanohybrids modified for drug delivery can be applied to uses in isotope and neuron capture cancer therapy.

The synthesized particles have also demonstrated high antibacterial activity against test bacteria: Escherichia coli live in dirty water, so water disinfection by nanohybrids may prove useful in emergencies or during war time.

Nanohybrids based on BN/Ag nanoparticles can also be used as an ultraviolet photoactive material.

BREAKTHROUGH DISCOVERY – NEW GRAPHENE BIOMATERIAL REGENERATES HEART AND NERVE TISSUE


One of the biggest challenges to the recovery of someone who has experienced a major physical trauma such as a heart attack is the growth of scar tissue.

As scar tissue builds up in the heart, it can limit the organ’s functions, which is obviously a problem for recovery.

However, researchers from the Science Foundation Ireland-funded Advanced Materials and BioEngineering Research (AMBER) Centre have revealed a new biomaterial that actually ‘grows’ healthy tissue – not only for the heart, but also for people with extensive nerve damage.

In a paper published to Advanced Materials, the team said its biomaterial regenerating tissue responds to electrical stimuli and also eliminates infection.

The new material developed by the multidisciplinary research team is composed of the protein collagen, abundant in the human body, and the atom-thick ‘wonder material’ graphene.

The resulting merger creates an electroconductive ‘biohybrid’, combining the beneficial properties of both materials and creating a material that is mechanically stronger, with increased electrical conductivity.

This biohybrid material has been shown to enhance cell growth and, when electrical stimulation is applied, directs cardiac cells to respond and align in the direction of the electrical impulse.

Could repair spinal cord

It is able to prevent infection in the affected area because the surface roughness of the material – thanks to graphene – results in bacterial walls being burst, simultaneously allowing the heart cells to multiply and grow.

For those with extensive nerve damage, current repairs are limited to a region only 2cm across, but this new biomaterial could be used across an entire affected area as it may be possible to transmit electrical signals across damaged tissue.

Speaking of the breakthrough, Prof Fergal O’Brien, deputy director and lead investigator on the project, said: “We are very excited by the potential of this material for cardiac applications, but the capacity of the material to deliver physiological electrical stimuli while limiting infection suggests it might have potential in a number of other indications, such as repairing damaged peripheral nerves or perhaps even spinal cord.

“The technology also has potential applications where external devices such as biosensors and devices might interface with the body.”

The study was led by AMBER researchers at the Royal College of Surgeons in Ireland in partnership with Trinity College Dublin and Eberhard Karls University in Germany.

Programmable and Highly Scalable Molecular Fabrication of Trillions of Carbon-Nanotubes (CNT’s) for: Carbon-zero fuels, health & performance optimized air, water and precision medicine


Mattershift designs and manufactures nanotube membranes carbon-zero fuels, health and performance optimized air and water, and precision medicine.

ThOe startup was founded in 2013 to realize the potential of molecular factories, with the ultimate goal of printing matter from the air.

Science Advances – Large-scale polymeric carbon nanotube membranes with sub–1.27-nm pores

Abstract

Mattershift reports the first characterization study of commercial prototype carbon nanotube (CNT) membranes consisting of sub–1.27-nm-diameter CNTs traversing a large-area nonporous polysulfone film. The membranes show rejection of NaCl and MgSO4 at higher ionic strengths than have previously been reported in CNT membranes, and specific size selectivity for analytes with diameters below 1.24 nm. The CNTs used in the membranes were arc discharge nanotubes with inner diameters of 0.67 to 1.27 nm. Water flow through the membranes was 1000 times higher than predicted by Hagen-Poiseuille flow, in agreement with previous CNT membrane studies. Ideal gas selectivity was found to deviate significantly from that predicted by both viscous and Knudsen flow, suggesting that surface diffusion effects may begin to dominate gas selectivity at this size scale.

The most basic building block of a Mattershift Molecular Factory is the Programmable Molecular Gateway. It consists of a carbon nanotube fixed within a flexible polymer sheet and aligned so that both of its ends are open.

The gateways are called “programmable” because a great variety of gates can be added to their openings, allowing them to manipulate molecules in specific ways.

One example is a NEMS gate, which is a gateway with a Nano Electro Mechanical System (NEMS) attached. It’s similar to a Micro Electro Mechanical System (MEMS), like the kind used to create accelerometers in smartphones, for example, but NEMS are much smaller. The one shown above is a gate that can be opened and closed by sending an electrical signal through the nanotube to which it’s attached.

Another example is a catalyst gate. This is a gateway with a catalyst attached to the opening of the nanotube. All molecules passing through the gateway must interact with the catalyst, which may be active or passive, removing or adding electrons, combining or splitting molecular parts.

Protein gates may be used to allow only specific molecules to pass through the gateways, like therapeutically useful antibodies, ions, or anything else protein channels may select for. Protein gates consisting of enzymes may also be used for highly specific catalysis of reactions, like those involved in molecular assembly.

A great many types of gates are possible, and many have already been demonstrated in laboratories around the world

Each sheet is embedded with a large number of gateways to transform and transport molecules. A typical density of gateways is 250 Trillion per square meter of sheet.

By creating a series of gateway sheets that perform different functions — purification, catalysis, separation, concentration, further reactions, and so on, complex chemical synthesis can be achieved in compact, inexpensive devices. These factories may be as small as a shoebox or as large as a warehouse.

The key innovation at Mattershift has been to create an inexpensive and scalable platform for this library of gates. With the ability to deploy Programmable Molecular Gateways at scale, we believe practical molecular factories are now possible.

New York-based Mattershift has managed to create large-scale carbon nanotube (CNT) membranes that are able to combine and separate individual molecules.

Research Focus: “BIG” Things Coming from Nanotechnology (very small things)


It may be a cliché, but in the world of nanotechnology, big things really do come in small packages.

The study and application of nanotechnology—science, engineering, and technology conducted at 1 to 100 nanometers—is rapidly growing across medicine, chemistry, physics, materials science, engineering and more.

According to the U.S. National Nanotechnology Initiative (NNI), nanotechnology as we now know it has only been around approximately 30 years. Despite the field’s relatively young lifespan, it has already made significant strides.

Today, researchers are developing everything from next-generation electronics to more effective drug delivery systems at the nanoscale. In February, R&D Magazine took a special focus on this up-and-coming area of research.

Electronics

We kicked off our nanotechnology coverage highlighting a new method to enhance the capabilities of the memristor—an emerging nanotechnology that offers a simpler and smaller alternative to the transistor. In our article, “Memristor Could Enable More Data Storage” we outlined a new memristor technology that can store up to 128 discernible memory states per switch, which is almost four times higher than what has been previously reported.

In another article, “Achieving Printed Power Electronics Means Going Beyond Silver Nanoparticles we outlined the limitations of 3D printed electronics using silver nanoparticle inks for systems that use high-current density known as “power electronics.” In the article, Greg Fritz, a material scientist in the Charles Stark Draper Laboratory, outlined the challenges with silver nanoparticle inks and his team’s research into alternative nano-layered materials for printing power electronics.

Expert contributor Ahmed A. Busnaina, the director of the Center for High-rate Nanomanufacturing (CHN) at Northeastern University, also shared an article outlining his research on nanoscale high-throughput printing technology. He explained a directed assembly-based printing processes developed by CHN in his article, “Scalable Printing Sensors and Electronics at the Nanoscale.”

In Researchers Use Tin Oxide Nanocrystals to Improve Battery Performance, we highlighted scientists at Washington State University’s School of Mechanical and Materials Engineering who utilized tin oxide nanocrystals to improve the performance of both sodium-ion and lithium-ion batteries.

Medicine

Nanotechnology is not limited to applications within traditional ‘technology.’ Nanoscale science also has a growing presence in the medical field, as nanomaterials are being formulated with conventional pharmaceutical agents to create more effective, safer, and more targeted drug delivery systems. We outlined the overall benefits of this approach in “Nanotechnology Can Improve Safety, Effectiveness in Drug Delivery.”The article highlights the work of the Center for Nanotechnology in Drug Delivery at the UNC Eshelman School of Pharmacy which is investigating nanotechnology to treat stroke, neurodegenerative and neurodevelopmental disorders, nerve agent and pesticide poisoning and other diseases and injuries.

One disease area at the forefront of nanomedicine is oncology. We spoke with Piotr Grodzinski, PhD, the Chief of Nanodelivery Systems and Devices Branch at the Cancer Imaging Program of the National Cancer Institute (NCI), to learn more about the role of nanotechnology in oncology for our article, Nanoparticle-Based Cancer Treatment: A Look at its Origins and What’s Next.” The first nanoparticle-based cancer treatment—a formulation of the chemotherapy agent doxorubicin delivered via the nanoparticle material liposome—was approved in 1995. Today, researchers are working on more complex innovations, such as nanoparticle combination therapies and nanoparticles for delivery of immunostimulatory or immunomodulatory molecules.

Material Science

Graphene—a 2D nanomaterial consisting of a single layer of carbon atoms arranged in a hexagonal lattice—has a host of applications. We highlighted one that could improve food safety in, New Lasing Method Enables Edible Graphene Food Trackers.” The article highlighted researchers from Rice University who had enhanced their laser-induced graphene technique to “write” graphene patterns onto food and other materials, enabling embed conductive identification tags and sensors onto products.

We also highlighted a way nanotechnology could be used to create a safer and cleaner environment in, Nano-Crystals Key to Continuously Self-Cleaning Surfaces.”  The article features New Clean NanoSeptic Self-Cleaning Surfaces—skins and mats that can be adhered to most any surface that utilize mineral nano-crystals to create an oxidation reaction stronger than bleach, without using poisons, heavy metals or chemicals. The nano-crystals, charged by visible light, act as a catalyst and the oxidation reaction breaks down organic material into base components including CO2, enabling the surface to continuously oxidize organic contaminants at the microscopic level.

Chemistry

Finally, we tackled the benefits of nanotechnology in the field of chemistry. In the article “Membrane Allows More Precise Chemical Separation Using Charged Nanochannels,” we highlighted a new type of filter has been designed to allow manufacturers to separate organic compounds not only by their size, but also by their electrostatic charge. The highly selective membrane filters could enable manufacturers to separate and purify chemicals in ways that are currently impossible, allowing them to potentially use less energy and cut carbon emissions.

Next Month’s Special Focus

Next month, R&D Magazine is focusing on technologies that are sustainable and clean, known as “green” technologies. Green technologies are created to mitigate or reverse the effects of human activity on the environment, providing a better future for all.

Check back in April for more on what’s happening within the green technology space in R&D.

Watch Our YouTube Video: Nano-Enabled Energy Storage: Super Capacitors and Batteries

UTA researcher to develop nanomaterials to treat antibiotic-resistant infections


IMAGE: THIS IS HE DONG, THE UTA ASSOCIATE PROFESSOR OF CHEMISTRY AND BIOCHEMISTRY AND JOINT ASSOCIATE PROFESSOR OF BIOENGINEERING WHO RECEIVED THE GRANT. view more 

A researcher at The University of Texas at Arlington has been awarded a prestigious National Science Foundation Faculty Early Career Development, or CAREER, grant to develop new synthetic antimicrobial nanomaterials to treat antibiotic-resistant infections in hospitals and military facilities.

Bacterial resistance to conventional antibiotics is a major threat to public health, and antibiotic-resistant infections are associated with close to $20 billion in direct medical costs each year, according to the Alliance for the Prudent Use of Antibiotics. Overuse of existing antibiotics has worsened the problem, resulting in an urgent need to develop new types of antimicrobial agents to combat the ever-increasing emergence of multidrug-resistant bacterial infections.

“We are developing synthetic antimicrobial materials that only target toxic bacteria and are biocompatible with healthy mammalian cells,” said He Dong, the UTA associate professor of chemistry and biochemistry and joint associate professor of bioengineering who received the grant. “These new molecules show great promise to treat infections not only on external surfaces or the skin like traditional antimicrobial peptides do, but also internally through oral or intravenous treatments, as they do not attack healthy human cells.”

The earlier discovery of new antimicrobials based on small proteins or peptides had shown tremendous promise, but their widespread use and translation into clinical application was hampered by their toxicity toward a range of healthy human cells.

“Dong and her colleagues have taken this idea one step further by developing synthetic peptides that self-assemble into nanostructured fibers that can punch holes in the bacterial membrane, killing the pathogen,” said Frederick MacDonnell, the chair of UTA’s Department of Chemistry and Biochemistry. “These synthetic self-assembling antimicrobial nanofibers, or SAANs, are the nucleus of a new therapeutic platform that could have a transformative impact on the multi-billion-dollar research industry around conventional antibiotics.”

This new grant builds on work done over the last three years by Dong around nanomaterials that can mimic nature and self-assemble into larger groups of molecules that have antimicrobial effects without hurting other healthy cells. The $456,985 grant is aimed at furthering the understanding of how SAANs are so effective against bacteria without harming healthy mammalian cells.

“The multidisciplinary nature of this research, involving chemistry, microbiology, engineering, nanoscience and pharmaceutical sciences will also provide opportunities to train students at all levels,” Dong added. “We plan to collaborate closely with Dr. Liping Tang in UTA’s bioengineering department to develop intelligent SAANs technologies that will permit highly effective and accurate disease-specific diagnoses and therapies in the future.”

Dong will soon be transferring to UTA’s new 229,000-square-foot Science & Engineering Innovation & Research or SEIR building, a world-class research and teaching facility focused on health science research that is scheduled to open in July 2018. This facility will advance research at UTA by utilizing the modern concept of research lab neighborhoods to drive cross-disciplinary collaboration like Dong’s research. Each of the 12 research lab neighborhoods will accommodate multiple teams in a wide range of fields, including biology, bioengineering, computational research, nursing and kinesiology.

Dong came to UTA from Clarkson University, where she was an assistant professor of chemistry and biomolecular science. She earned her bachelor and master degrees in chemistry from Tsinghua University in Beijing, China, and her doctorate in chemistry from Rice University in Houston. She did her first post-doctoral fellowship in the Department of Surgery at Emory University in Atlanta, and her second in materials science and engineering at the University of California, Berkeley.

“Dr. Dong’s research exemplifies UTA’s interdisciplinary approach to research, especially in the area of health and the human condition, one of four themes of the University’s strategic plan,” added MacDonnell. “This early CAREER grant recognizes the potential of her research focus to make a real impact on the field.”

Shaping Stem Cell Research with Nanotechnology – Hope for Treating Parkinson’s; Heart Disease and ???


Nanoscientists have developed a technique that allows them to transform stem cells into bone cells on command. But could the process be used to treat deadly conditions such as heart disease and Parkinson’s?

Anyone who knows a thing or two about biology knows that stem cells have tremendous potential in medicine: anything from repairing and replenishing heart cells after an attack to replacing nerve cells that are progressively lost in the brain of a person with Parkinson’s.

One of the big challenges of using stem cells as a therapy is coaxing them to grow into the specific type of tissue that is required. In the body this happens thanks to precise chemical and physical signals, not all of which are yet understood or characterised.

Using chemicals to direct the fate of stem cells has worked in laboratories, but the outcomes are not always safe or predictable.

Now, a team from Northwestern University in the US thinks it has a solution. They say that they can direct the developmental fate of stem cells using only physical cues, by adapting a well-known technique that traces three-dimensional microscopic shapes and reconstructs them on flat surfaces.

The process is called scanning probe lithography.

By placing the stem cells on the nanopatterned surface, and without adding any kind of chemicals, the scientists found that they could induce the stem cells to develop into bone cells.

Extend this technique, they say, and it might be possible to turn stem cells into any type of cell on command.

When the body needs a repair to be carried out, a special type of stem cell – called mesenchymal stem cells or MSCs – can enter the blood circulation system. These cells travel around the body and actually home in on where they are needed.

MSCs have the potential to develop into a whole range of different tissue types – in other words, they are pluripotent.

The developmental decision that they make depends, in part, on the molecular structures in the matrix surrounding the cells that make up the tissue.

The structure of the matrix affects the softness of the tissue – so the brain is a soft, mushy tissue, while stiffer tissues include muscle, and rigid tissues include bone.

The US team has mimicked this real-life situation. Using the molecular structures in the matrix that surround a cell as a pattern, and with an array of pyramid-like points that are a hundred-thousand times smaller than the tip of a pencil and incredibly sharp, molecule by molecule they have built up a kind of nano-landscape with sculptures ranging in size from the nano- to the microscale, on a small piece of glass. The technique is called polymer pen lithography.

The researchers grew MSCs on one type of nanoscopic sculpture, and were able to direct their developmental fate.

“Starting with millions of possibilities, we quickly zeroed in on the pattern of features that best directed the stem cells into osteocytes [bone cells],” says Chad A Mirkin, who led the work.

Mirkin is professor of chemistry in the Weinberg College of Arts and Sciences and is also the director of Northwestern’s International Institute for Nanotechnology.

The potential of this tool is to be able to take pluripotent stem cells from a patient, run them over a selected three-dimensional matrix in order to convert them rapidly into a particular cell type of choice, and then return them to the patient for repair and replenishment of damaged tissues.

“With further development, researchers might be able to use this approach to prepare cells of any lineage on command,” Mirkin says.

“The three-dimensional aspect is very interesting, and mimics aspects of the environment in a highly stylized way,” says Fiona Watt, professor and director of the Centre for Stem Cells and Regenerative Medicine at Kings College London.

“Several reports argue that the topology imposed on a stem cell – how a stem cell is contained in 3D – affects its behaviour. When you consider your bones and cartilage, this makes perfect sense,” Watt adds.

One important aspect of this work according to Marilyn Monk, emeritus professor of molecular embryology at University College London’s Institute of Child Health, is that it provides evidence that stem-cell fate can solely be informed by the local three-dimensional molecular structure.

“But that’s not to say that this is the only way to direct stem-cell fate,” Monk says. “We know that regulation of development involves multiple mechanisms that operate independently and inter-dependently to bring about a final specific cell function.”

Nonetheless he believes the technique is a real advance. “It would be neat to see if they can take a stem cell, already committed in one developmental direction, and back it up so that it might become another type of cell again, using only their patterning technique,” he says.

“That would be the Nobel prize.”

Fighting Cancer and Drug Resistance – A ‘Nanosystem’ Does Both


Cancer is often referred to as “smart,” and this term often refers to the ability of these cells to proliferate without purpose or restraint.

The ability of cancer cells to develop multidrug resistance (MDR), a major problem that patients can face, making treatment against this disease even more elusive.

In an effort to combat both cancer cell proliferation and MDR, a recent study conducted by researchers from the National Health Research Institutes of Taiwan and the National Science Council of Taiwan have developed a nanosystem capable of addressing both challenges in the field of cancer therapy.

Drug Resistance and Cancer

Patients with several forms of blood cancer and solid tumors in the breast, ovaries, lungs and lower gastrointestinal tract can become untreatable as a result of multidrug resistance (MDR).

In MDR, the cancer cells of these patients become resistant to commonly used therapeutic drugs as a result of an overexpression of ATP-binding cassette (ABC) transporters that effectively push out drug molecules following administration.

P-glycoprotein and what is termed as the multidrug resistance-associated protein (MRP) are two of the most studied pumps present in cancer cells that are capable of rejecting chemotherapeutic drugs.

By avoiding the toxic effects of these drugs, cancer cells are able to continue to proliferate and metastasize to other organs of the body.

Unfortunately, some of the most commonly used cancer therapeutic drugs such as colchicine, vinblastine, doxorubicin, etoposide, paclitaxel, certain vinca alkaloids and other small molecules have shown resistance in various cancer cells.

Current research efforts in the field of anticancer drug discovery have looked towards the administration of combinatorial technology to be administered with cancer to effectively prevent cancer cells from physically removing therapeutic drugs when administered together.

While blocking the action of pumps like MRP and P-glycoprotein has shown some efficacy, transcription factors, such as c-Jun, which plays a role in cell, proliferation and MDR, can still potentiate metastasis.

Therefore, there remains a need to develop cancer therapies that work against drug resistance and simultaneously prevent further metastasis.

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The Efficacy of Administering Doxorubicin Mesoporous Silica Nanoparticles (MSNs)

Mesoporous silica nanoparticles (MSNs) are well-documented drug delivery vehicles that allow for a high drug loading capacity with minimal side effects upon administration.

The tunable size properties, thermal stability, photostability and ease of functionalization to different applications make MSNs one of the most promising options for therapeutic delivery systems.

In the recent study published in Nano Futures, the group of scientists led by Leu-Wei Lo covalently conjugated MSNs with doxorubicin and tested the ability of these nanosystems to be taken up by cancer cells in vitro.

The PC-3 cell line of metastatic human prostate carcinoma cells were treated with 100 μg/ml of either Dox-MSNs that were conjugated with DNAzyme, (Dox-MSN-Dz), Dox-MSNs or control MSNs for 24 hours to study the ability of these cells to survive following treatment.

The researchers found the Dox-MSN-Dz reduced cell survival rates by over 80%, whereas the Dox-MSNs alone still reduced cell survival rates by 60%.

The results of this study confirm the therapeutic potential of the developed multifunctional nanosystem, which incorporates doxorubicin, a widely used chemotherapeutic drug, MSNs and DNAzyme.

Not only did this nanosystem improve the cytotoxicity of doxorubicin to a resistance cancer cell line, but it also successfully reduced migration of cancer cells by inhibiting c-Jun.

While further in vivo studies need to be conducted to fully evaluate the ability of Dox-MSN-Dz to prevent metastasis and invade highly resistance cancer cells, the results of this study are promising.

Future research initiatives that incorporate different chemotherapeutic drugs into a similar nanosystem design could also show similar bifunctional properties as presented here.

Image Credit:

fusebulb/Shutterstock.com

References:

1 “A co-delivery nanosystem of chemotherapeutics and DNAzyme overcomes cancer drug resistance and metastasis” S. Sun, C. Liu, et al. Nano Futures. (2017). DOI: 10.1088/2399-1984/aa996f.

MIT: Researchers Develop Nanoparticles that Deliver the CRISPR genome-editing system – Big Step Forward for Cancer Research


In a new study, MIT researchers have developed nanoparticles that can deliver the CRISPR genome-editing system and specifically modify genes in mice.

The team used nanoparticles to carry the CRISPR components, eliminating the need to use viruses for delivery.

Using the new delivery technique, the researchers were able to cut out certain genes in about 80 percent of liver cells, the best success rate ever achieved with CRISPR in adult animals.

“What’s really exciting here is that we’ve shown you can make a nanoparticle that can be used to permanently and specifically edit the DNA in the liver of an adult animal,” says Daniel Anderson, an associate professor in MIT’s Department of Chemical Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

One of the genes targeted in this study, known as Pcsk9, regulates cholesterol levels. Mutations in the human version of the gene are associated with a rare disorder called dominant familial hypercholesterolemia, and the FDA recently approved two antibody drugs that inhibit Pcsk9.

However these antibodies need to be taken regularly, and for the rest of the patient’s life, to provide therapy. The new nanoparticles permanently edit the gene following a single treatment, and the technique also offers promise for treating other liver disorders, according to the MIT team.

Anderson is the senior author of the study, which appears in the Nov. 13 issue of Nature Biotechnology. The paper’s lead author is Koch Institute research scientist Hao Yin.

Other authors include David H. Koch Institute Professor Robert Langer of MIT, professors Victor Koteliansky and Timofei Zatsepin of the Skolkovo Institute of Science and Technology, and Professor Wen Xue of the University of Massachusetts Medical School.

Targeting Disease

Many scientists are trying to develop safe and efficient ways to deliver the components needed for CRISPR, which consists of a DNA-cutting enzyme called Cas9 and a short RNA that guides the enzyme to a specific area of the genome, directing Cas9 where to make its cut.

In most cases, researchers rely on viruses to carry the gene for Cas9, as well as the RNA guide strand. In 2014, Anderson, Yin, and their colleagues developed a nonviral delivery system in the first-ever demonstration of curing a disease (the liver disorder tyrosinemia) with CRISPR in an adult animal. However, this type of delivery requires a high-pressure injection, a method that can also cause some damage to the liver.

Later, the researchers showed they could deliver the components without the high-pressure injection by packaging messenger RNA (mRNA) encoding Cas9 into a nanoparticle instead of a virus. Using this approach, in which the guide RNA was still delivered by a virus, the researchers were able to edit the target gene in about 6 percent of hepatocytes, which is enough to treat tyrosinemia.

While that delivery technique holds promise, in some situations it would be better to have a completely nonviral delivery system, Anderson says.

One consideration is that once a particular virus is used, the patient will develop antibodies to it, so it couldn’t be used again.

Also, some patients have pre-existing antibodies to the viruses being tested as CRISPR delivery vehicles.

In the new Nature Biotechnology paper, the researchers came up with a system that delivers both Cas9 and the RNA guide using nanoparticles, with no need for viruses.

To deliver the guide RNAs, they first had to chemically modify the RNA to protect it from enzymes in the body that would normally break it down before it could reach its destination.

The researchers analyzed the structure of the complex formed by Cas9 and the RNA guide, or sgRNA, to figure out which sections of the guide RNA strand could be chemically modified without interfering with the binding of the two molecules. Based on this analysis, they created and tested many possible combinations of modifications.

“We used the structure of the Cas9 and sgRNA complex as a guide and did tests to figure out we can modify as much as 70 percent of the guide RNA,” Yin says. “We could heavily modify it and not affect the binding of sgRNA and Cas9, and this enhanced modification really enhances activity.”

Reprogramming the Liver

The researchers packaged these modified RNA guides (which they call enhanced sgRNA) into lipid nanoparticles, which they had previously used to deliver other types of RNA to the liver, and injected them into mice along with nanoparticles containing mRNA that encodes Cas9.

They experimented with knocking out a few different genes expressed by hepatocytes, but focused most of their attention on the cholesterol-regulating Pcsk9 gene. The researchers were able to eliminate this gene in more than 80 percent of liver cells, and the Pcsk9 protein was undetectable in these mice. They also found a 35 percent drop in the total cholesterol levels of the treated mice.

The researchers are now working on identifying other liver diseases that might benefit from this approach, and advancing these approaches toward use in patients.

“I think having a fully synthetic nanoparticle that can specifically turn genes off could be a powerful tool not just for Pcsk9 but for other diseases as well,” Anderson says.

“The liver is a really important organ and also is a source of disease for many people. If you can reprogram the DNA of your liver while you’re still using it, we think there are many diseases that could be addressed.”

“We are very excited to see this new application of nanotechnology open new avenues for gene editing,” Langer adds.

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