Using a simple, scalable method, a material that can be used as a sensor is developed

February 14, 2017

Erlantz Lizundia, a researcher in the UPV/EHU's department of Physical Chemistry and expert in cellulose, started the research during a period of time he spent in Canada. The research group he was in specialised in the helix-shaped organisation of a product extracted from cellulose, cellulose nanocrystals (CNCs). Under specific conditions, the crystals can assume a helical structure, or what is the same, they can form chiral nematic structures when the crystals are organised into ordered layers, and membranes with unique properties can thus be obtained: "The membrane displays a different colour depending on the distance existing between the layers of cellulose nanocrystals that form the helical, or chiral nematic structure. An interaction takes place between the structure and the light and, as a result, the wavelength of the light changes and materials in bright colours are obtained," explained Lizundia. This capacity to change colour displayed by the structure "could prove very useful in enabling these membranes to be used as sensors; for example, when they are put into a humid environment, the structure will swell and the distance between the layers will increase and the colour will change," he added. This effect is known as structural coloration and is very common in nature. The colour of a whole host of animals (snakes, chameleons) and plants is the direct consequence of their supramolecular structure, and contrary to what one may think, is not linked to the presence of pigments. Suitable as metal sensors and for bioimaging purposes

Inserting carbon dots into the chiral nematic structure of the cellulose nanocrystals makes this material particularly suited as a detector for the presence of iron so, as Lizundia explains, "it is very useful for detecting environmental pollution or the presence of metals in the body. I, specifically, studied the material's response to zinc and iron, as they are both present in large quantities in environmental and biological matters. I was able to see that the interaction of the metal ions with the carbon nanoparticles influences the degree of fluorescence emitted by the nanoparticles. The fluorescence diminishes in the presence of iron, whereas it increases in the presence of zinc".

Another possible application of this material could be in bioimaging. In the research conducted, Lizundia only managed to get as far as testing that it does in fact offer this possibility. "I will shortly be embarking on research to go further into this subject and use these nanoparticles to create bioimages". Bioimaging consists of creating images using non-invasive methods in biological processes, such as cell processes, as well as measuring the interaction between molecules in real time in the location where these interactions are taking place.
Additional information

The UPV/EHU researcher Erlantz Lizundia conducted his research work in collaboration with the University of British Columbia (UBC) in Canada, and with the FPInnovations organisation, also Canadian. At that time, Lizundia was a researcher in the department of Physical Chemistry on the UPV/EHU's Leioa campus. Right now, however, he is assistant lecturer in the Department of Graphic Expression and Engineering Projects in the Faculty of Engineering in Bilbao.

Bibliographic reference

E. Lizundia, T.D. Nguyen, J. L. Vilas, W. Y. Hamad, M. J. MacLachlan.. Chiroptical luminescent nanostructured cellulose films. Materials Chemistry Frontiers. 2016. DOI: 10.1039/C6QM00225K.

Wanting to go a step beyond what he had learned in Canada, Lizundia considered incorporating other functional nanoparticles into this chiral nematic structure, particles whose properties change in the presence of external stimuli. He chose some carbon nanodots, firstly because they are fluorescent, in other words, they emit colour when excited by ultraviolet light, and secondly, because he was able to obtain them by using sugar as the raw material. "I obtained these nanoparticles by subjecting glucose to hydrothermal treatment using water and heat only and by means of a fast, cheap process," the researcher pointed out.

The final material displayed the characteristics Lizundia had been seeking. Firstly, "it is an environmentally friendly material as it is non-toxic and its raw materials are of a renewable nature, and the synthesis process is fast, simple and scalable. Secondly, the fact that the material is fluorescent gives it interesting properties enabling it to be used as a sensor," specified Lizundia.

University of the Basque Country

Related Nanoparticles Articles from Brightsurf:

An ionic forcefield for nanoparticles
Nanoparticles are promising drug delivery tools but they struggle to get past the immune system's first line of defense: proteins in the blood serum that tag potential invaders.

Phytoplankton disturbed by nanoparticles
Products derived from nanotechnology are efficient and highly sought-after, yet their effects on the environment are still poorly understood.

How to get more cancer-fighting nanoparticles to where they are needed
University of Toronto Engineering researchers have discovered a dose threshold that greatly increases the delivery of cancer-fighting drugs into a tumour.

Nanoparticles: Acidic alert
Researchers of Ludwig-Maximilians-Universitaet (LMU) in Munich have synthesized nanoparticles that can be induced by a change in pH to release a deadly dose of ionized iron within cells.

3D reconstructions of individual nanoparticles
Want to find out how to design and build materials atom by atom?

Directing nanoparticles straight to tumors
Modern anticancer therapies aim to attack tumor cells while sparing healthy tissue.

Sweet nanoparticles trick kidney
Researchers engineer tiny particles with sugar molecules to prevent side effect in cancer therapy.

A megalibrary of nanoparticles
Using straightforward chemistry and a mix-and-match, modular strategy, researchers have developed a simple approach that could produce over 65,000 different types of complex nanoparticles.

Dialing up the heat on nanoparticles
Rapid progress in the field of metallic nanotechnology is sparking a science revolution that is likely to impact all areas of society, according to professor of physics Ventsislav Valev and his team at the University of Bath in the UK.

Illuminating the world of nanoparticles
Scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) have developed a light-based device that can act as a biosensor, detecting biological substances in materials; for example, harmful pathogens in food samples.

Read More: Nanoparticles News and Nanoparticles Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to