Science Current Events | Science News | Brightsurf.com
 

Light touch keeps a grip on delicate nanoparticles

May 04, 2012
Using a refined technique for trapping and manipulating nanoparticles, researchers at the National Institute of Standards and Technology (NIST) have extended the trapped particles' useful life more than tenfold.* This new approach, which one researcher likens to "attracting moths," promises to give experimenters the trapping time they need to build nanoscale structures and may open the way to working with nanoparticles inside biological cells without damaging the cells with intense laser light.

Scientists routinely trap and move nanoparticles in a solution with "optical tweezers"-a laser focused to a very small point. The tiny dot of laser light creates a strong electric field, or potential well, that attracts particles to the center of the beam. Although the particles are attracted into the field, the molecules of the fluid they are suspended in tend to push them out of the well. This effect only gets worse as particle size decreases because the laser's influence over a particle's movement gets weaker as the particle gets smaller. One can always turn up the power of the laser to generate a stronger electric field, but doing that can fry the nanoparticles too quickly to do anything meaningful with them-if it can hold them at all.

NIST researchers' new approach uses a control and feedback system that nudges the nanoparticle only when needed, lowering the average intensity of the beam and increasing the lifetime of the nanoparticle while reducing its tendency to wander. According to Thomas LeBrun, they do this by turning off the laser when the nanoparticle reaches the center and by constantly tracking the particle and moving the tweezers as the particle moves.

"You can think of it like attracting moths in the dark with a flashlight," says LeBrun. "A moth is naturally attracted to the flashlight beam and will follow it even as the moth flutters around apparently at random. We follow the fluttering particle with our flashlight beam as the particle is pushed around by the neighboring molecules in the fluid. We make the light brighter when it gets too far off course, and we turn the light off when it is where we want it to be. This lets us maximize the time that the nanoparticle is under our control while minimizing the time that the beam is on, increasing the particle's lifetime in the trap."

Using this method at constant average beam power, 100-nanometer gold particles remained trapped 26 times longer than had been seen in previous experiments. Silica particles 350 nanometers in diameter lasted 22 times longer, but with the average beam power reduced by 33 percent. LeBrun says that their approach should be able to be combined with other techniques to trap and hold even smaller nanoparticles for extended periods without damaging them.

"We're more than an order of magnitude ahead of where we were before," says LeBrun. "We now hope to begin building complex nanoscale devices and testing nanoparticles as sensors and drugs in living cells."

###

* A. Balijepalli, J. Gorman, S. Gupta and T. LeBrun. Significantly Improved Trapping Lifetime of Nanoparticles in an Optical Trap using Feedback Control. Nano Letters. April 10, 2012. Available online http://3249238492kljf-pubs.acs.org/doi/abs/10.1021/nl300301x

National Institute of Standards and Technology (NIST)


Related Nanoparticles Current Events and Nanoparticles News Articles


Elastic gel to heal wounds
A team of bioengineers at Brigham and Women's Hospital (BWH), led by Ali Khademhosseini, PhD, and Nasim Annabi, PhD, of the Biomedical Engineering Division, has developed a new protein-based gel that, when exposed to light, mimics many of the properties of elastic tissue, such as skin and blood vessels.

Nanospiked bacteria are the brightest hard X-ray emitters
In a step that overturns traditional assumptions and practice, researchers at the Tata Institute of Fundamental Research, Mumbai and Institute for Plasma Research, Gandhi Nagar have fashioned bacteria to emit intense, hard x-ray radiation.

Physical study may give boost to hydrogen cars
The dream of a cleaner, greener transportation future burns brightly in the promise of hydrogen-fueled, internal combustion engine automobiles.

Chitosan-coated, chemotherapy-packed nanoparticles may target cancer stem cells
Nanoparticles packed with a clinically used chemotherapy drug and coated with an oligosaccharide derived from the carapace of crustaceans might effectively target and kill cancer stem-like cells, according to a recent study led by researchers at The Ohio State University Comprehensive Cancer Center - Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC - James).

X-rays and electrons join forces to map catalytic reactions in real-time
A new technique pioneered at the U.S. Department of Energy's Brookhaven National Laboratory reveals atomic-scale changes during catalytic reactions in real time and under real operating conditions.

Laser spectroscopy: A novel microscope for nanosystems
Scientists from Ludwig-Maximilians-Universitaet (LMU) in Munich and the Max Planck Institute for Quantum Optics can image the optical properties of individual nanoparticles with a novel microscope.

When inflammation occurs, kidneys work to protect themselves, researchers find
In an apparent effort to help themselves, inflamed kidney cells produce one of the same inflammation-suppressing enzymes fetuses use to survive, researchers report.

Robust new process forms 3-D shapes from flat sheets of graphene
Researchers from the University of Illinois at Urbana-Champaign have developed a new approach for forming 3D shapes from flat, 2D sheets of graphene, paving the way for future integrated systems of graphene-MEMS hybrid devices and flexible electronics.

Nanoparticle 'wrapper' delivers chemical that stops fatty buildup in rodent arteries
In what may be a major leap forward in the quest for new treatments of the most common form of cardiovascular disease, scientists at Johns Hopkins report they have found a way to halt and reverse the progression of atherosclerosis in rodents by loading microscopic nanoparticles with a chemical that restores the animals' ability to properly handle cholesterol.

Scientists highlight the importance of nanoscale hybrid materials for non-invasive cancer diagnosis
Various diagnostic imaging techniques are currently used for clinical imaging/disease diagnosis. The accuracy of diagnosis is mainly based on the type of energy used (such as X-ray, sound waves, photons and positrons) to derive the visual information, as well as the degree of spatial resolution (mesoscopic or microscopic) and the level of information that can be obtained (physiological, anatomical or molecular).
More Nanoparticles Current Events and Nanoparticles News Articles

Nanoparticles - Nanocomposites Ãâ Nanomaterials: An Introduction for Beginners

Nanoparticles - Nanocomposites – Nanomaterials: An Introduction for Beginners
by Dieter Vollath (Author)


Meeting the demand for a readily understandable introduction to nanomaterials and nanotechnology, this textbook specifically addresses the needs of students - and engineers - who need to get the gist of nanoscale phenomena in materials without having to delve too deeply into the physical and chemical details. The book begins with an overview of the consequences of small particle size, such as the growing importance of surface effects, and covers successful, field-tested synthesis techniques of nanomaterials. The largest part of the book is devoted to the particular magnetic, optical, electrical and mechanical properties of materials at the nanoscale, leading on to emerging and already commercialized applications, such as nanofluids in magnetic resonance imaging, high-performance...

Nanoparticles: From Theory to Application

Nanoparticles: From Theory to Application
by Günter Schmid (Editor)


Very small particles are able to show astonishing properties. For example, gold atoms can be combined like strings of pearls, while nanoparticles can form one-, two- and three-dimensional layers. These assemblies can be used, for instance, as semiconductors, but other electronic as well as optical properties are possible. An introduction to the booming field of "nanoworld" or "nanoscience", from fundamental principles to their use in novel applications. With its clear structure and comprehensive coverage, backed by numerous examples from recent literature, this is a prime reference for chemists and materials scientists working with and developing nanoparticle systems. A bestselling title in its second edition. A must-have reference for chemists and materials scientists.

Bio-Nanoparticles: Biosynthesis and Sustainable Biotechnological Implications

Bio-Nanoparticles: Biosynthesis and Sustainable Biotechnological Implications
by Om V. Singh (Editor)


Nanoparticles are the building blocks for nanotechnology; they are better built, long lasting, cleaner, safer, and smarter products for use across industries, including communications, medicine, transportation, agriculture and other industries. Controlled size, shape, composition, crystallinity, and structure-dependent properties govern the unique properties of nanotechnology. Bio-Nanoparticles: Biosynthesis and Sustainable Biotechnological Implications explores both the basics of and advancements in nanoparticle biosynthesis. The text introduces the reader to a variety of microorganisms able to synthesize nanoparticles, provides an overview of the methodologies applied to biosynthesize nanoparticles for medical and commercial use, and gives an overview of regulations governing their...

Nanoparticle- and Microparticle-based Delivery Systems: Encapsulation, Protection and Release of Active Compounds

Nanoparticle- and Microparticle-based Delivery Systems: Encapsulation, Protection and Release of Active Compounds
by David Julian McClements (Author)


Recent developments in nanoparticle and microparticle delivery systems are revolutionizing delivery systems in the food industry. These developments have the potential to solve many of the technical challenges involved in creating encapsulation, protection, and delivery of active ingredients, such as colors, flavors, preservatives, vitamins, minerals, and nutraceuticals. Nanoparticle- and Microparticle-based Delivery Systems: Encapsulation, Protection and Release of Active Compounds explores various types of colloidal delivery systems available for encapsulating active ingredients, highlighting their relative advantages and limitations and their use. Written by an international authority known for his clear and rigorous technical writing style, this book discusses the numerous kinds of...

Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation: Powerful Tools for the Characterization of Polymers, Proteins and Nanoparticles

Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation: Powerful Tools for the Characterization of Polymers, Proteins and Nanoparticles
by Stepan Podzimek (Author)


A comprehensive, practical approach to three powerful methods of polymer analysis and characterization This book serves as a complete compendium of three important methods widely used for the characterization of synthetic and natural polymers light scattering, size exclusion chromatography (SEC), and asymmetric flow field flow fractionation (A4F). Featuring numerous up-to-date examples of experimental results obtained by light scattering, SEC, and A4F measurements, Light Scattering, Size Exclusion Chromatography and Asymmetric Flow Field Flow Fractionation takes an all-in-one approach to deliver a complete and thorough explanation of the principles, theories, and instrumentation needed to characterize polymers from the viewpoint of their molar mass distribution, size, branching, and...

Surface Modification of Nanoparticle and Natural Fiber Fillers (Polymer Nano-, Micro- and Macrocomposites)

Surface Modification of Nanoparticle and Natural Fiber Fillers (Polymer Nano-, Micro- and Macrocomposites)
by Vikas Mittal (Editor)


A review of the various methodologies for the surface treatment of different types of inorganic spherical and fibrous fillers, describing ball milling, cationic polymerization, vapor phase grafting, plasma treatment and UV irradiation in detail. In addition, the book connects the resulting composite properties to the modified filler surface properties, thus allowing for a purposeful, application-oriented composite design.

Exposure Assessment and Safety Considerations for Working with Engineered Nanoparticles

Exposure Assessment and Safety Considerations for Working with Engineered Nanoparticles
by Michael J. Ellenbecker (Author), Candace Su-Jung Tsai (Author)


While invaluable for their uses in medicine as a drug delivery system or as an imaging agent in cancer detection, nanoparticles do present possible medical and environmental dangers. Due to the thousands of commercial and medical applications for engineered nanoparticles currently available or under development, guidelines for evaluating and controlling exposure to engineered nanoparticles are essential. Designed for EHS professionals working with nanoparticles, this important reference outlines the acceptable levels of exposure to nanoparticles and describes methods for evaluating and controlling worker exposure to engineered nanoparticles. With case studies on various nanoparticle exposures, the book sheds light on the toxicity of such nanoparticles as carbon nanotubes, fullerenes,...

Gold Nanoparticles for Physics, Chemistry and Biology

Gold Nanoparticles for Physics, Chemistry and Biology
by Catherine Louis (Author), Olivier Pluchery (Author)


The fascination with gold is a story which spans millennia, however scientists have recently found a new interest for gold when it is divided into miniscule grains, such as gold nanoparticles. This scientific enthusiasm started in various fields of science in the middle of the 1980s and the present book offers a panorama of the major scientific achievements obtained with gold nanoparticles. Various topics are reviewed such as: gold nanoparticle preparation methods, their plasmon resonance and thermo-optical properties, their catalytic properties, their use in biology and medicine as well as their possible toxicity and, finally, their future technological applications. The book also contains an in-depth study of the use of gold nanoparticles throughout the ages, starting from times where...

Lipid Nanoparticles: Production, Characterization and Stability (SpringerBriefs in Pharmaceutical Science & Drug Development)

Lipid Nanoparticles: Production, Characterization and Stability (SpringerBriefs in Pharmaceutical Science & Drug Development)
by Rohan Shah (Author), Daniel Eldridge (Author), Enzo Palombo (Author), Ian Harding (Author)


​What are lipid nanoparticles?  How are they structured?  How are they formed? What techniques are best to characterize them?  How great is their potential as drug delivery systems?  These questions and more are answered in this comprehensive and highly readable work on lipid nanoparticles. This work sets out to provide the reader with a clear and understandable understanding of the current practices in formulation, characterization and drug delivery of lipid nanoparticles. A comprehensive description of the current understanding of synthesis, characterization, stability optimization and drug incorporation of solid lipid nanoparticles is provided. Nanoparticles have attracted great interest over the past few decades with almost exponential growth in their research and...

Nanoparticles in the Lung: Environmental Exposure and Drug Delivery

Nanoparticles in the Lung: Environmental Exposure and Drug Delivery
by Akira Tsuda (Editor), Peter Gehr (Editor)


Nanoparticles have a physical dimension comparable to the size of molecular structures on the cell surface. Therefore, nanoparticles, compared to larger (e.g., micrometer) particles, are considered to behave differently when they interact with cells. Nanoparticles in the Lung: Environmental Exposure and Drug Delivery provides a better understanding of how inhaled nanoparticles behave in the human lungs and body. Featuring contributions from renowned subject-matter experts, this authoritative text describes the sequence of events that nanoparticles encounter in the lungs when moving from the air into the bloodstream. This includes deposition, interactions with the alveolar surface and epithelium, translocation across the air–blood tissue barrier, and accumulation in the body. In...

© 2015 BrightSurf.com