TAG: "Nanotechnology"

Research on cell biology mystery may reveal root causes of Alzheimer’s


A well-known cellular structure orchestrates how vault nanoparticles naturally form in cells.

In the 1980s, professor Leonard Rome and his then-postdoctoral fellow Nancy Kedersha made a breakthrough in cell biology when they discovered vaults, naturally occurring nanoparticles — of a size measured in nanometers (1 nanometer = 1 billionth of a meter) — that are composed mostly of proteins and number in the thousands inside every cell of the body.

In the decades since, Rome’s team has discovered how to form vaults in the laboratory using the proteins they consist of. While naturally occurring vaults contain other elements, Rome’s team built empty ones, which eventually enabled them to pursue the idea of inserting drug molecules into vaults. Those could then be put in serum, injected into patients, and directed to specific cells where they release the drugs. Thus, vaults are being developed as a highly accurate drug-delivery system that is being commercialized.

But one question that Rome and his team couldn’t answer was how the natural vaults originally formed inside cells. Now Rome and his collaborators at UCLA’s California NanoSystems Institute appear to have solved that mystery.

In a study published online today (Oct. 30) in the journal ACS Nano, Rome’s team, led by first author and postdoctoral scholar Jan Mrazek, report data that suggests that polyribosomes — small molecular machines that read genetic information and form proteins inside cells — work like 3-D printers to both create and link together proteins and correctly form them into vaults. (Watch a brief animated explanation of how it works.)

“This idea needs some further research and confirmation, but it is a very elegant model and we are convinced that it explains how vaults are formed,” said Rome, who is associate director of the California NanoSystems Institute. “If the model is correct, it reveals something new about cell biology — that this polyribosome that has been known for 50 years has a heretofore unknown function. Namely, it orchestrates the assembly of macromolecular complexes such as vaults, and other structures in a cell that are made of multiple proteins.”

Mrazek said that this possible function of polyribosomes may also provide new understanding of protein aggregation, which is a clumping of deformed proteins that happens in such diseases as Alzheimer’s, Parkinson’s and Lou Gehrig’s.

“If a protein is not made correctly, it’s possible that these deformities can alter the guided assembly of macromolecules by the polyribosomes,” Mrazek said. “Once you understand that there is a machine in the cell that directs the formation of these macromolecular complexes, you can see where things might go wrong with that machine. By studying nanotechnology we have revealed something unknown about basic cell biology that might have wider implications.”

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Biosensor technology could allow rapid detection of Ebola virus


Rapid detection of viruses among potential applications of research at UC Santa Cruz.

Ali Yanik, UC Santa Cruz

In 2010, Ahmet Ali Yanik published his first paper on the rapid detection of Ebola virus using new biosensor technology he and colleagues at Boston University had invented. But he found there was little interest at the time in developing the technology further.

“People told me that there wasn’t any profit in it because this disease only affects people in the developing world,” Yanik said.

Now, however, Ebola hemorrhagic fever has captured the attention of first world countries in a big way. The current outbreak in West Africa began spreading out of control just as Yanik was setting up his lab as a new faculty member at UC Santa Cruz, where he is an assistant professor of electrical engineering. Yanik plans to resume his work on virus detection in addition to ongoing projects involving biosensors for other biomedical applications. The current Ebola crisis may subside before his technology can be perfected, since there are still many challenges to overcome, but the need will remain for simple and inexpensive virus detection techniques, he said.

“The truth is that Lassa virus, which is related to Ebola and also causes hemorrhagic fever, infects nearly half a million people every year in Africa and kills more people than Ebola, but it doesn’t make the news. So there has been an ongoing crisis with hemorrhagic fever viruses, and now it’s finally getting some serious attention,” Yanik said.

His goal is to create a low-cost biosensor that can be used to detect specific viruses without the need for skilled operators or expensive equipment. “We need a platform for virus detection that is like the pregnancy tests you can use at home,” Yanik said. “The initial symptoms of hemorrhagic fever are similar to the flu, and you just cannot treat every person with flu symptoms as a potential Ebola-infected patient. It needs to be simple and cheap.”

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Engineers develop prototype of low-cost, disposable lung infection detector


NSF grant supports UC Irvine’s efforts to improve manufacturing process for nanodevices.

Imagine a low-cost, disposable breath analysis device that a person with cystic fibrosis could use at home along with a smartphone to immediately detect a lung infection, much like the device police use to gauge a driver’s blood alcohol level.

Timely knowledge of a lung infection would let people with CF or other inflammatory respiratory conditions seek immediate treatment and thereby prevent life-shortening permanent damage to their already vulnerable airways.

Thanks to a nearly $1.3 million grant from the National Science Foundation, UC Irvine engineers can continue developing this type of nanotechnology device – and potentially many others – using a more wide-scale manufacturing process.

Materials scientist Regina Ragan and electrical engineer Filippo Capolino have created a nano-optical sensor that can detect trace levels of infection in a small sample of breath. They made the sensor in the laboratory but would like to see it become commercially available. In addition to diagnosing medical conditions, the device could be modified to monitor environmental conditions – for instance, identifying harmful airborne agents produced through automotive or chemical industry practices.

Nanotechnologies such as this sensor depend on extremely small, nanometer-scale building blocks. A nanometer is about 100,000 times smaller than the width of a human hair. Fabricating on this tiny scale poses huge challenges, since most of the current methods that achieve a high level of precision are too costly and slow to be viable for manufacturing.

“With support from the NSF and input from industry, our goal is to help nanoscale manufacturing processes leave the laboratory – where they’ve been confined – and become usable in widespread commercial applications,” said Ragan, associate professor of chemical engineering & materials science and principal investigator on the project.

This grant highlights the strength of our faculty in both nanosciences and advanced manufacturing,” said Gregory Washington, dean of The Henry Samueli School of Engineering. “The Samueli School is poised to move forward as a force in this area.”

Co-principal investigators are Capolino, associate professor of electrical engineering & computer science; Ozdal Boyraz, associate professor of electrical engineering & computer science; and Marc Madou, Chancellor’s Professor of mechanical & aerospace engineering.

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Scientists engineer antibiotics to catch up in race against drug resistance


Souped-up antibiotics attack cells responsible for making bacteria resistant to new drugs.

We face an urgent global health problem because scientists are not developing new antibiotics as fast as bacteria are developing antibiotic resistance.

But new research from UCLA has made important progress toward solving this problem. An interdisciplinary team of scientists from UCLA’s California NanoSystems Institute has developed a method to re-engineer antibiotics that sharply enhances their activity against certain key bacterial cells, called persisters, that are responsible for making bacteria resistant to new drugs.

Persister cells slow down their metabolism and shut down their mechanisms for taking in molecules, preventing normal antibiotics from getting into them, which is necessary for the drug to kill the bug. After the persister cells survive the initial antibiotic treatment, they pass on their genes as the bacteria reproduce.

Led by Gerard Wong, professor in the UCLA Department of Chemistry and Biochemistry and the Department of Bioengineering, and Andrea Kasko, associate professor of bioengineering, the team has developed a method analogous to taking an ordinary car and adding high-performance parts to make a fast and furious street racer.

“We’re in an unsustainable race with bacteria. They become resistant to our antimicrobials too fast,” Wong said. “It takes upwards of $100 million to develop one antibiotic drug, and bacteria develop resistance to it within two years. It’s a race that we can’t win. This reality brought us to the idea of taking an existing antibiotic and renovating it, giving it a new, complementary antimicrobial ability while preserving its original ability to make a better drug overall.”

The study was published Aug. 18 online in the journal ACS Nano.

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Seeding innovations in brain research


UC Berkeley, UCSF, Berkeley Lab join forces on BRAINseed collaboration.

Michel Maharbiz of electrical engineering and computer science describes a project to probe more deeply into the cerebral cortex. (Photo by Roy Kaltschmidt, Berkeley Lab)

Two state-of-the-art research areas – nanotech and optogenetics – were the dominant theme last Thursday, Sept. 18, as six researchers from UC Berkeley, UC San Francisco and Lawrence Berkeley National Laboratory sketched out their teams’ bold plans to jump-start new brain research.

The rapid-fire talks kicked off a one-of-a-kind collaboration among the three institutions in which each put up $1.5 million over three years to seed innovative but risky research. Called BRAINseed, the partnership could yield discoveries that accelerate President Barack Obama’s national BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative and California’s own Cal-BRAIN Initiative.

“It’s clear to everybody that any attempt to understand how the brain works, or ultimately what we might mean by cognition, is so daunting and so large that no one institution could hope to be a stand-alone leader in such an effort,” said Graham Fleming, UC Berkeley vice chancellor for research. “The synergies between UCSF, Lawrence Berkeley National Lab and UC Berkeley are very strong, and we complement one another in very effective ways.”

“This tri-partnership is unprecedented in the history of our institutions,” noted Horst Simon, deputy director of Berkeley Lab. “We are putting money down to fund a real collaboration that makes people sit down together and address some of the most challenging questions today.”

“BRAINseed underscores the tremendous power embodied in the institutions in the Bay Area, and the potential for amazing things to happen if we can overcome the geographical separations,” said Keith Yamamoto, UCSF vice chancellor for research.

When Obama announced the federal BRAIN Initiative in April 2013, he allocated $110 million for fiscal year 2014. This funding is already supporting several projects at UC Berkeley. Obama has proposed even more funding in future years “to revolutionize our understanding of the human mind and uncover new ways to treat, prevent, and cure brain disorders like Alzheimer’s, schizophrenia, autism, epilepsy and traumatic brain injury.”

Similarly, Cal-BRAIN — short for California Blueprint for Research to Advance Innovations in Neuroscience — aims to “accelerate the development of brain mapping techniques, including the development of new technologies.” The initial appropriation in this year’s state budget was $2 million.

Both Cal-BRAIN and the national initiative are expected to spur new startups in the area of neurotechnology based on the tools and inventions created in research labs. The innovations developed through these initiatives could have broad applications in disease monitoring beyond the brain and even outside the health care field.

“What we want to do is build a climate of collaboration so that we are stronger competitors in the national brain program and Cal-BRAIN,” Fleming said. “We see BRAINseed as a model for future collaborations (among the three institutions).”

Probing deeper into the brain

The six winning projects of 17 proposals originally submitted focus on new methods of mapping the brain and studying neurons deeper in the brain than ever before.

Fiberless deep brain imaging: Using novel nanocrystals developed by Bruce Cohen at Lawrence Berkeley National Laboratory, and biosensing and bioactuating molecules synthesized by Chris Chang and Ehud Isacoff at UC Berkeley, researchers hope to probe cell-to-cell communication deeper in the brain than ever before. The technique takes advantage of the fact that near infrared (NIR) light with its shorter wavelengths penetrates deeper into the brain than does visible light. The nanocrystals from Cohen’s lab absorb the NIR light and convert it into visible light. The visible light can then trigger optogenetic photoswitches that turn neuron receptors on and off, as well as activate biosensors that record the release of neurotransmitters at the synapse. Coupled with techniques developed by Charly Craik and Robert Edwards at UCSF for targeting probes to specific cells, the researchers on this project hope to be able to study cell signaling in the many layers of the cortex.

Integrated nanosystems: Our senses of touch and hearing, as well as our ability to feel pain and detect the position of our body in space, are all made possible by a special class of proteins known as mechanoreceptors. Scientists studying this system in cell culture have traditionally used micropipettes to apply pressure to mechanoreceptors, while microelectrodes record the resulting neural activity. But small as they are, these devices are much too bulky to precisely stimulate single receptors or make accurate neural recordings. A team led by UCSF’s Young-wook Jun is devising a system to overcome these limitations. In the new setup, magnetic nanoparticles controlled by micromagnetic “tweezers” will have the capacity to stimulate individual mechanoreceptors, and high-resolution optical signals emitted by “quantum dots,” developed in the lab of Paul Alivisatos of UC Berkeley and Berkeley Lab, will offer a truer picture of neural activity in sensory neurons. They will collaborate with UCSF’s Yuh Nung Jan.

In vivo optogenetic mechanisms: We think of the action of neurotransmitters as rapid and localized, but the effects of acetylcholine (ACh) in the brain are actually quite diffuse and unfold slowly. The hormone-like characteristics of ACh make it difficult to understand through conventional neurophysiology experiments. As a result, ACh transmission, which plays a role in Alzheimer’s and Parkinson’s diseases and in addiction, is poorly understood despite decades of study. UC Berkeley’s Richard Kramer has devised a system that enables researchers to use light to switch ACh receptors on and off in animals. Using this system, Kramer and UCSF’s Michael P. Stryker will be able to study how ACh modulates behavior in a wholly new way.

Acousto-optic virtual waveguides: Optogenetics approaches to probe the brain’s grey matter, or cortex, work only as deep as the light can penetrate, typically only a fraction of a millimeter below the surface. UC Berkeley engineers have developed a novel way to channel light deeper – more than a millimeter deep – to probe cell-to-cell signaling. Engineer Michel Maharbiz proposes to use ultrasound to create ‘waveguides’ that can steer light below the surface of the cortex, stimulating photoswitches that enable the study of neurotransmitters. With light-sensitive probes developed at Berkeley Lab and cell-imaging techniques from UCSF, the technology would open new avenues for non-invasive in-vivo imaging and stimulation of local brain areas. Maharbiz’s collaborators are Jim Schuck of Berkeley Lab, Reza Alam of UC Berkeley and Vikaas Singh Sohal of UCSF.

Optical integrators of neuronal activity: One of the greatest challenges in understanding the brain is connecting what happens over large volumes and hundreds of thousands of neurons to the signals transmitted at the individual synapse, the connection between nerve cells where communication takes place. Because calcium is key to neuronal signaling, a team led by Evan Miller, UC Berkeley assistant professor of molecular and cell biology and of chemistry, plans to use probes developed in his lab that ‘remember’ calcium concentration. Along with co-collaborators Pam den Besten and Terumi Kohwi-Shigematsu at UCSF and Berkeley Lab, respectively, Miller plans to investigate neuronal activity in models of disease. They can then correlate this with what happens over a larger volume of the brain. The technique combines “click chemistry” pioneered at UC Berkeley with probes generated in the Department of Chemistry to integrate images over different scales. This technique is a vital first step in developing tools that remember neuronal activity and enable 3D reconstruction of activity across entire brain regions with cellular resolution.

Development of instrumentation and computational methods: Though great progress has been made in mapping the function of the human brain, researchers have been stymied by limitations in both recording devices and the ability to analyze and understand brain signals. UCSF’s Edward F. Chang, M.D., is leading a team that aims to achieve up to a thousandfold increase in the density and electronic sophistication of recording arrays. The vast amount of data collected by these arrays will be stored and analyzed by some of the world’s most powerful computers at the National Energy Research Scientific Computing Center (NERSC), enabling a new level of understanding of the brain in both health and disease. Chang’s collaborators are Peter Denes and Kristofer Bouchard of Berkeley Lab and Fritz Sommer of UC Berkeley.

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Targeted leukemia treatment shows promise


UC Davis develops unique treatment approach.

Noriko Satake, UC Davis

Noriko Satake, UC Davis pediatric oncologist and researcher, has demonstrated in laboratory studies that a new, targeted treatment for leukemia is effective.

Satake’s research was published Sept. 9 in the British Journal of Haematology.

“We identified a novel molecular target that is important for the growth of precursor B-cell acute lymphoblastic leukemia (ALL), the most common cancer in children,” Satake said. “We developed a unique treatment approach using a drug that blocks the target molecule and kills leukemia cells, a nanoparticle vehicle that carries the drug, and an antibody driver that delivers the nanocomplexes (drug-loaded nanoparticles) to leukemia cells.

“We showed great efficacy of these new drug nanocomplexes on a cell line and on primary leukemia samples,” she added. “We also demonstrated that they had minimal toxicities on normal blood cells.”

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Nanoparticles could provide applications to diagnose, treat cancer


Versatile particles offer wide variety of uses.

Kit Lam and colleagues from UC Davis and other institutions have created dynamic nanoparticles (NPs) that could provide an arsenal of applications to diagnose and treat cancer. Built on an easy-to-make polymer, these particles can be used as contrast agents to light up tumors for MRI and PET scans or deliver chemo and other therapies to destroy tumors. In addition, the particles are biocompatible and have shown no toxicity. The study was published online today (Aug. 26) in Nature Communications.

“These are amazingly useful particles,” noted co-first author Yuanpei Li, a research faculty member in the Lam laboratory. “As a contrast agent, they make tumors easier to see on MRI and other scans. We can also use them as vehicles to deliver chemotherapy directly to tumors; apply light to make the nanoparticles release singlet oxygen (photodynamic therapy) or use a laser to heat them (photothermal therapy) – all proven ways to destroy tumors.”

Jessica Tucker, program director of Drug and Gene Delivery and Devices at the National Institute of Biomedical Imaging and Bioengineering, which is part of the National Institutes of Health, said the approach outlined in the study has the ability to combine both imaging and therapeutic applications in a single platform, which has been difficult to achieve, especially in an organic, and therefore biocompatible, vehicle.

“This is especially valuable in cancer treatment, where targeted treatment to tumor cells and the reduction of lethal effects in normal cells is so critical,” she added.

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Nanoparticles show promise for cancer treatment, possible HIV cure

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Nanoparticles show promise for cancer treatment, possible HIV cure


UCLA-led team engineers vault nanoparticles to create novel drug delivery system.

A multidisciplinary team of scientists from UCLA and Stanford University has used a naturally occurring nanoparticle called a vault to create a novel drug delivery system that could lead to advances in the treatment of cancer and HIV.

The research team was led by Dr. Leonard Rome, associate director of UCLA’s California NanoSystems Institute, and Dr. Jerome Zack, co-director of the UCLA AIDS Institute, both of whom are also members of UCLA’s Jonsson Comprehensive Cancer Center. Co-first authors on the study were Daniel Buehler, a UCLA postdoctoral researcher and Matthew Marsden, adjunct assistant professor in the department of medicine and a member of the AIDS Institute.

Their findings could lead to cancer treatments that are more effective with smaller doses and to therapies that could potentially eradicate the HIV virus.

The paper is the cover story of the Aug. 26 print edition of the journal ACSNano, and it was recently published online.

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New Nano3 microscope to allow high-resolution look inside cells


Instrument could pave way for new treatments and drug discovery.

FEI Scios dual-beam microscope

UC San Diego’s Nanofabrication Cleanroom Facility (Nano3) is the first institution to obtain a novel FEI Scios dual-beam microscope, with an adaptation for use at cryogenic temperatures. The new microscope will enable research among a highly diverse user base, ranging from materials science to structural and molecular biology.

As Nano3 Technical Director Bernd Fruhberger explains: “There is a tremendous interest in utilizing this instrument among faculty from multiple departments. The departments of nanoengineering, materials and aerospace engineering, electrical and computer engineering, chemistry, physics and biology at UC San Diego all have projects in need of this tool, and have been actively involved in making the procurement of the tool a reality.

“The instrument provides state-of-the-art capabilities for cross-sectioning, preparation of sections for transmission electron microscopy and more,” he adds, “but what truly differentiates it is the novel cryo-capability, which will make it possible for cell biologists to see the structures of biological cells in higher resolution to better understand how cells function at a molecular level. This could possibly pave the way for new treatments and drug discovery.”

Elizabeth Villa, a new assistant professor in the Department of Chemistry & Biochemistry at UC San Diego, along with her colleagues at Germany’s Max Planck Institute of Biochemistry, adapted a focused-ion-beam microscope for biological applications during her postdoctoral studies. The design was adopted by the Dutch company FEI into a first-of-a-kind prototype that Villa will further develop in UC San Diego in collaboration with the company.

Villa notes that UC San Diego has an established academic tradition in the area of molecular imaging –most notably reflected in the work of biochemist Roger Tsien. Tsien won the 2008 Nobel Prize in Chemistry for the discovery and development of the green fluorescent protein, which revolutionized the fields of cell biology and neurobiology by allowing scientists to peer inside living cells and watch their behavior in real time.

“What I’m doing is similar,” explains Villa, “only I’m using electron microscopy, which gives us higher-resolution images. The idea behind our method is to bring together people who do structural biology with people who do cell biology by using a new tool that will allow us to see the structures of the cells, at high resolution, and better understand what molecules are doing.”

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Livermore Lab to develop next-generation neural devices with $5.6M grant


Technology will help doctors better understand, treat PTSD, traumatic brain injury.

Lawrence Livermore National Laboratory engineer Kedar Shah works on a neural device at the Lab's Center for Micro- and Nanotechnology.

Lawrence Livermore National Laboratory recently received $5.6 million from the Department of Defense’s Defense Advanced Research Projects Agency (DARPA) to develop an implantable neural interface with the ability to record and stimulate neurons within the brain for treating neuropsychiatric disorders.

The technology will help doctors to better understand and treat post-traumatic stress disorder (PTSD), traumatic brain injury (TBI), chronic pain and other conditions.

Several years ago, researchers at Lawrence Livermore in conjunction with Second Sight Medical Products developed the world’s first neural interface (an artificial retina) that was successfully implanted into blind patients to help partially restore their vision. The new neural device is based on similar technology used to create the artificial retina.

“DARPA is an organization that advances technology by leaps and bounds,” said LLNL’s project leader Satinderpall Pannu, director of the Lab’s Center for Micro- and Nanotechnology and Center for Bioengineering, a facility dedicated to fabricating biocompatible neural interfaces. “This DARPA program will allow us to develop a revolutionary device to help patients suffering from neuropsychiatric disorders and other neural conditions.”

The project is part of DARPA’s SUBNETS (Systems-Based Neurotechnology for Emerging Therapies) program. The agency is launching new programs to support President Obama’s BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative, a new research effort aimed to revolutionize our understanding of the human mind and uncover ways to treat, prevent and cure brain disorders.

LLNL and Medtronic are collaborating with UC San Francisco, UC Berkeley, Cornell University, New York University, PositScience Inc. and Cortera Neurotechnologies on the DARPA SUBNETS project. Some collaborators will be developing the electronic components of the device, while others will be validating and characterizing it.

As part of its collaboration with LLNL, Medtronic will consult on the development of new technologies and provide its investigational Activa PC+S deep brain stimulation (DBS) system, which is the first to enable the sensing and recording of brain signals while simultaneously providing targeted DBS. This system has recently been made available to leading researchers for early-stage research and could lead to a better understanding of how various devastating neurological conditions develop and progress. The knowledge gained as part of this collaboration could lead to the next generation of advanced systems for treating neural disease.

The LLNL Neural Technology group will develop an implantable neural device with hundreds of electrodes by leveraging their thin-film neural interface technology, a more than tenfold increase over current Deep Brain Stimulation (DBS) devices. The electrodes will be integrated with electronics using advanced LLNL integration and 3D packaging technologies. The goal is to seal the electronic components in miniaturized, self-contained, wireless neural hardware. The microelectrodes that are the heart of this device are embedded in a biocompatible, flexible polymer.

Surgically implanted into the brain, the neural device is designed to help researchers understand the underlying dynamics of neuropsychiatric disorders and re-train neural networks to unlearn these disorders and restore proper function. This will enable the device to be eventually removed from the patient instead of being dependent on it.

Using the Center for Micro- and Nanotechnology’s unique capabilities, Pannu and his team of engineers have achieved 25 patents and many publications during the last decade. The team’s goal with the DARPA SUBNETS program is to build a prototype neural device in four years for clinical trials at UCSF.

“We are very excited about this project,” Pannu said. “This is a great opportunity to develop therapies that have the potential to advance health care for our service members, veterans and the general public.”

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Targeting tumors using silver nanoparticles


New platform increases efficacy of drug delivery, allows excess particles to be washed away.

Prostate cancer cells were targeted by two separate silver nanoparticles (red and green), while the cell nucleus was labeled in blueusing Hoescht dye.

Scientists at UC Santa Barbara have designed a nanoparticle that has a couple of unique — and important — properties. Spherical in shape and silver in composition, it is encased in a shell coated with a peptide that enables it to target tumor cells. What’s more, the shell is etchable so those nanoparticles that don’t hit their target can be broken down and eliminated. The research findings appear today in the journal Nature Materials.

The core of the nanoparticle employs a phenomenon called plasmonics. In plasmonics, nanostructured metals such as gold and silver resonate in light and concentrate the electromagnetic field near the surface. In this way, fluorescent dyes are enhanced, appearing about tenfold brighter than their natural state when no metal is present. When the core is etched, the enhancement goes away and the particle becomes dim.

UCSB’s Ruoslahti Research Laboratory also developed a simple etching technique using biocompatible chemicals to rapidly disassemble and remove the silver nanoparticles outside living cells. This method leaves only the intact nanoparticles for imaging or quantification, thus revealing which cells have been targeted and how much each cell internalized.

“The disassembly is an interesting concept for creating drugs that respond to a certain stimulus,” said Gary Braun, a postdoctoral associate in the Ruoslahti Lab in the Department of Molecular, Cellular and Developmental Biology (MCDB) and at Sanford-Burnham Medical Research Institute. “It also minimizes the off-target toxicity by breaking down the excess nanoparticles so they can then be cleared through the kidneys.”

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Using light-heated water to deliver drugs


UC San Diego researchers use near-infrared light to warm water-infused particles.

In this schematic representation, a hydrated polymeric nanoparticle is exposed to near-infrared light. The NIR heats pockets of water inside the nanoparticle, causing the polymer soften and allowing encapsulated molecules to diffuse into the surrounding environment.

Researchers from the UC San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences, in collaboration with materials scientists, engineers and neurobiologists, have discovered a new mechanism for using light to activate drug-delivering nanoparticles and other targeted therapeutic substances inside the body.

This discovery represents a major innovation, said Adah Almutairi, Ph.D., associate professor and director of the joint UC San Diego-KACST Center of Excellence in Nanomedicine. Up to now, she said, only a handful of strategies using light-triggered release from nanoparticles have been reported.

The mechanism, described in today’s (April 1) online issue of ACS Nano, employs near-infrared (NIR) light from a low-power laser to heat pockets of water trapped within non-photo-responsive polymeric nanoparticles infused with drugs. The water pockets absorb the light energy as heat, which softens the encapsulating polymer and allows the drug to be released into the surrounding tissue. The process can be repeated multiple times, with precise control of the amount and dispersal of the drug.

“A key advantage of this mechanism is that it should be compatible with almost any polymer, even those that are commercially available,” said Mathieu Viger, a postdoctoral fellow in Almutairi’s laboratory and co-lead author of the study. “We’ve observed trapping of water within particles composed of all the biodegradable polymers we’ve so far tested.”

The method, noted Viger, could thus be easily adopted by many biological laboratories.

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