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


Automating DNA origami opens door to many new uses
Researchers can build complex, nanometer-scale structures of almost any shape and form, using strands of DNA. But these particles must be designed by hand, in a complex and laborious process.

Simple attraction: Researchers control protein release from nanoparticles without encapsulation
A U of T Engineering team has designed a simpler way to keep therapeutic proteins where they are needed for long periods of time. The discovery is a potential game-changer for the treatment of chronic illnesses or injuries that often require multiple injections or daily pills.

Restoring chemotherapy sensitivity by boosting microRNA levels
By increasing the level of a specific microRNA (miRNA) molecule, researchers have for the first time restored chemotherapy sensitivity in vitro to a line of human pancreatic cancer cells that had developed resistance to a common treatment drug.

The next generation of carbon monoxide nanosensors
The detection of carbon monoxide (CO) in the air is a vital issue, as CO is a poisonous gas and an environmental pollutant. CO typically derives from the incomplete combustion of carbon-based fuels, such as cooking gas and gasoline; it has no odour, taste, or colour and hence it is difficult to detect.

Single-step hydrogen peroxide production could be cleaner, more efficient
Bottles of dilute hydrogen peroxide sit on shelves in medicine cabinets across the world, yet synthesizing the chemical at the large scale requires a surprisingly complicated process that is economically unfeasible for all but a few industrial facilities.

Nanoscale Trojan horses treat inflammation
Nanosized Trojan horses created from a patient's own immune cells have successfully treated inflammation by overcoming the body's complex defense mechanisms, perhaps leading to broader applications for treating diseases characterized by inflammation, such as cancer and cardiovascular diseases.

Two-stage nanoparticle delivery of piperlongumine and TRAIL anti-cancer therapy
A team of researchers from Cornell University in Ithaca, New York demonstrated a drug delivery mechanism that utilizes two independent vehicles, allowing for delivery of chemically and physically dis-tinct agents.

ORNL demonstrates large-scale technique to produce quantum dots
A method to produce significant amounts of semiconducting nanoparticles for light-emitting displays, sensors, solar panels and biomedical applications has gained momentum with a demonstration by researchers at the Department of Energy's Oak Ridge National Laboratory.

Action of nanoparticles on platelet activation and plasmatic coagulation
Hemostasis is a highly regulated process with key function for human life. The process is based on a rather complex interplay between endothelial cells, plasmatic coagulation and platelets.

Rice experts unveil submicroscopic tunable, optical amplifier
Rice University photonics researchers have unveiled a new nanoparticle amplifier that can generate infrared light and boost the output of one light by capturing and converting energy from a second light.
More Nanoparticles Current Events and Nanoparticles News Articles

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.


Nanoparticles - Nanocomposites ? 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,...

Engineered Nanoparticles: Structure, Properties and Mechanisms of Toxicity

Engineered Nanoparticles: Structure, Properties and Mechanisms of Toxicity
by Ashok K Singh (Author)


Engineered Nanoparticles: Structure, Properties and Mechanisms of Toxicity is an indispensable introduction to engineered nanomaterials (ENM) and their potential adverse effects on human health and the environment. Although research in the area of pharmacology and toxicology of ENM is rapidly advancing, a possible correlation between their physicochemical properties and biomedical properties or toxicity is not yet fully understood. This understanding is essential to develop strategies for the safe applications and handling of ENM. The book comprehensively defines the current understanding of ENM toxicity, first describing these materials and their physicochemical properties, and then discussing the toxicological theory and methodology before finally demonstrating the potential impact of...

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...

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.

Handbook of Nanoparticles

Handbook of Nanoparticles
by Mahmood Aliofkhazraei (Editor)


This Handbook covers all aspects of Nanoparticles, from their preparation to their practical application. The chapters present different ways to synthesize nanometer particles, as well as their functionalization and other surface treatments to allow them to a practical use. Several industrial applications of such nanometer particles are also covered in this Handbook. It is a complete reference for those working with Nanotechnology at the lab level, from students to professionals.

Gold Clusters, Colloids and Nanoparticles  I (Structure and Bonding)

Gold Clusters, Colloids and Nanoparticles I (Structure and Bonding)
by D. Michael P. Mingos (Editor)


The series Structure and Bonding publishes critical reviews on topics of research concerned with chemical structure and bonding. The scope of the series spans the entire Periodic Table and addresses structure and bonding issues associated with all of the elements. It also focuses attention on new and developing areas of modern structural and theoretical chemistry such as nanostructures, molecular electronics, designed molecular solids, surfaces, metal clusters and supramolecular structures. Physical and spectroscopic techniques used to determine, examine and model structures fall within the purview of Structure and Bonding to the extent that the focus is on the scientific results obtained and not on specialist information concerning the techniques themselves. Issues associated with the...

Chitosan Based Carbon Nanodots and Nanoparticles for Bio-applications

Chitosan Based Carbon Nanodots and Nanoparticles for Bio-applications
by Abhay Sachdev (Author), P. Gopinath (Author)


Carbon dots (C-dots) with multicolour fluorescence feature are presently gaining much importance in the area of bioanalytics and bioimaging due to their biocompatible and strong fluorescent nature. Herein, we report a one-step method for synthesizing multicolour, surface passivated carbon dots using chitosan as a ‘greener’ source through microwave pyrolysis approach. The present study also deals with the synthesis of chitosan-pDNA (GFP) nanocomplexes for gene delivery applications. Development of such biofriendly imaging agents and nanocarriers has huge diagnostic and therapeutic potential.

Nanoparticle Emissions From Combustion Engines (Springer Tracts on Transportation and Traffic)

Nanoparticle Emissions From Combustion Engines (Springer Tracts on Transportation and Traffic)
by Jerzy Merkisz (Author), Jacek Pielecha (Author)


This book focuses on particulate matter emissions produced by vehicles with combustion engines. It describes the physicochemical properties of the particulate matter, the mechanisms of its formation and its environmental impacts (including those on human beings). It discusses methods for measuring particulate mass and number, including the state-of-the-art in Portable Emission Measurement System (PEMS) equipment for measuring the exhaust emissions of both light and heavy-duty vehicles and buses under actual operating conditions. The book presents the authors’ latest investigations into the relations between particulate emission (mass and number) and engine operating parameters, as well as their new findings obtained through road tests performed on various types of vehicles, including...

Nanoparticle Technology Handbook

Nanoparticle Technology Handbook
by Masuo Hosokawa (Editor), Kiyoshi Nogi (Editor), Makio Naito (Editor), Toyokazu Yokoyama (Editor)


Nanoparticle technology, which handles the preparation, processing, application and characterisation of nanoparticles, is a new and revolutionary technology. It becomes the core of nanotechnology as an extension of the conventional Fine Particle / Powder Technology. Nanoparticle technology plays an important role in the implementation of nanotechnology in many engineering and industrial fields including electronic devices, advanced ceramics, new batteries, engineered catalysts, functional paint and ink, Drug Delivery System, biotechnology, etc.; and makes use of the unique properties of the nanoparticles which are completely different from those of the bulk materials.
This new handbook is the first to explain complete aspects of nanoparticles with many application examples showing...

© 2016 BrightSurf.com