Nav: Home

A golden age for particle analysis

November 28, 2018

Process engineers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have developed a method which allows the size and shape of nanoparticles in dispersions to be determined considerably quicker than ever before. Based on gold nanorods, they demonstrated how length and diameter distributions can be measured accurately in just one step instead of the complicated series of electron microscopic images which have been needed up until now. Nanoparticles from precious metals are used, for example, as catalysts and contrast agents for diagnosing cancer.

Even in the Middle Ages, gold particles were used to create vibrant red and blue colours, for example to illustrate biblical scenes in stained glass windows. This effect is caused by the interaction between the electromagnetic fields of the incoming light with the electrons in the metal which are made to vibrate collectively. Nowadays, nanoparticles of gold or silver are of interest for applications in biotechnology and as catalysts whilst their optical properties are also still being used, for example for medical imaging purposes, where they act as a contrast agent for diagnosing tumours. The particles are synthesised specially for the various purposes, as their properties depend on their size, shape, surface, inner structure and composition.

Monitoring this synthesis process is very complex: whilst it is relatively straightforward to determine the size of the nanoparticles using optical measuring techniques, a great many electron microscopic images have to be analysed in a detailed and time-consuming process before the shape of the particle can be determined. This hinders the development of new manufacturing and processing methods, as time-consuming measurements are needed to keep track of any changes to the size or properties of the particles.

Determining size and shape in just one step

Together with working groups from the field of mathematics led by Dr. Lukas Pflug and Prof. Dr. Michael Stingl, Professorship of Mathematical Optimisation, and physical chemistry, led by Prof. Dr. Carola Kryschi, Chair of Physical Chemistry, process engineers at FAU led by Simon Wawra and Prof. Dr. Wolfgang Peukert, Chair of Particle Technology, have developed a new method for measuring the length and diameter distribution of plasmonic gold nanorods in one single experiment. In a first step, the particles are dispersed in water in an ultrasonic bath and made to sink using centrifugation. At the same time they are targeted with flashes of light and their spectral properties recorded using a detector. 'By combining multi-wavelength absorption optics and analytical ultracentrifugation, we were able to measure the optical and sedimentary properties of the nanorods simultaneously,' explains Prof. Dr. Wolfgang Peukert. The researchers based their analysis method on the fact that both sedimentation speed and strength of light absorption depend on the diameter and length of nanorods. 'The distribution of length, diameter, aspect ratio, surface and volume can be derived directly as a result,' explains Wolfgang Peukert.

Method can also be used for particles of other shapes

The method developed at FAU is not only restricted to nanoparticles made of precious metals. It can be used on a number of plasmonically active materials and can also be extended to other geometric shapes. During synthesis, sphere-shaped particles are created at the same time as nanorods, and their distribution and percentage by mass in the sample can also be measured accurately. Peukert: 'Our new method allows a comprehensive and quantitative analysis of these highly interesting particle systems. We believe that our work will contribute to being able to characterise plasmonic nanoparticles rapidly and reliably during synthesis and in a number of applications.'
-end-


University of Erlangen-Nuremberg

Related Nanoparticles Articles:

Chemists perform surgery on nanoparticles
A team of chemists led by Carnegie Mellon's Rongchao Jin has for the first time conducted site-specific surgery on a nanoparticle.
Nanoparticles remain unpredictable
The way that nanoparticles behave in the environment is extremely complex.
Gold standards for nanoparticles
KAUST researchers reveal how small organic 'citrate' ions can stabilize gold nanoparticles, assisting research on the structures' potential.
Lipid nanoparticles for gene therapy
Twenty-five years have passed since the publication of the first work on solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) as a system for delivering drugs.
Nanoparticles hitchhiking their way along strands of hair
In shampoo ads, hair always looks like a shiny, smooth surface.
Better contrast agents based on nanoparticles
Scientists at the University of Basel have developed nanoparticles which can serve as efficient contrast agents for magnetic resonance imaging.
Gentle cancer treatment using nanoparticles works
Cancer treatments based on laser irridation of tiny nanoparticles that are injected directly into the cancer tumor are working and can destroy the cancer from within.
Radiation-guided nanoparticles zero in on metastatic cancer
Zap a tumor with radiation to trigger expression of a molecule, then attack that molecule with a drug-loaded nanoparticle.
Nanoparticles can grow in cubic shape
Use of nanoparticles in many applications, e.g. for catalysis, relies on the surface area of the particles.
Nanoparticles deliver anticancer cluster bombs
Scientists have devised a triple-stage 'cluster bomb' system for delivering the chemotherapy drug cisplatin, via tiny nanoparticles designed to break up when they reach a tumor.

Related Nanoparticles Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Changing The World
What does it take to change the world for the better? This hour, TED speakers explore ideas on activism—what motivates it, why it matters, and how each of us can make a difference. Guests include civil rights activist Ruby Sales, labor leader and civil rights activist Dolores Huerta, author Jeremy Heimans, "craftivist" Sarah Corbett, and designer and futurist Angela Oguntala.
Now Playing: Science for the People

#521 The Curious Life of Krill
Krill may be one of the most abundant forms of life on our planet... but it turns out we don't know that much about them. For a create that underpins a massive ocean ecosystem and lives in our oceans in massive numbers, they're surprisingly difficult to study. We sit down and shine some light on these underappreciated crustaceans with Stephen Nicol, Adjunct Professor at the University of Tasmania, Scientific Advisor to the Association of Responsible Krill Harvesting Companies, and author of the book "The Curious Life of Krill: A Conservation Story from the Bottom of the World".