Tag Archives: Paola Borri

A roly-poly (woodlouse) gold rush

This environmental monitoring story focused on the roly-poly was announced in an April 18, 2023 news item on Statnano,

The woodlouse goes by many names: roly-poly, pill bug, potato bug, tomato bug, butchy boy, cheesy bob, and chiggy pig, to name just a few. It is best known for contracting into a ball when agitated. This crustacean (yes, it’s a crustacean, not an insect) thrives in heavily metal-contaminated areas due to its specialized digestive organ, called a hepatopancreas, that stores and expels unwanted metals.

Metal nanoparticles are common in industrial and research plants. However, they can leach into the surrounding environment. Currently, little is known about the toxicity of metal nanoparticles for nearby organisms because detecting metal nanoparticles, particularly gold, requires microscopic, 3D imaging that cannot be done in the field

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Caption: (a) Cartoon of a woodlouse depicting the hepatopancreas (HP) and the hind gut (HG). (b) Transmission overview of a single HP tubule, showing the helical structure. (c) Section from a HP tubule with the nuclei fluorescently labeled in blue. Credit: Iestyn Pope, Nuno G.C. Ferreira, Peter Kille, Wolfgang Langbein, and Paola Borri

An April 11, 2023 American Institute of Physics (AIP) news release (also on EurekAlert), which originated the news item, describes a new approach to detecting gold nanoparticles in roly-polys,

In Applied Physics Letters, by AIP Publishing, researchers from Cardiff University in the U.K. introduce a novel imaging method to detect gold nanoparticles in woodlice. With information about the quantity, location, and impact of gold nanoparticles within the organism, scientists can better understand the potential harm other metals may have on nature.

“Gold nanoparticles are used extensively for biological research applications owing to their biocompatibility and photostability and are available in a large range of shapes and sizes,” said author Wolfgang Langbein. “By using gold nanoparticles, which would not normally be present in the woodlice diet, we can study the journey of nanoparticles inside complex biological systems.”

The researchers developed an imaging method known as four-wave mixing microscopy, which flashes light that the gold nanoparticles absorb. The light flashes again and the subsequent scattering reveals the nanoparticles’ locations. Using this state-of-the-art technique, they locate the individual gold nanoparticles in the 3D cellular environment.

“By precisely pinpointing the fate of individual gold nanoparticles in the hepatopancreas of woodlice, we can gain a better understanding of how these organisms sequester and respond to metals ingested from the environment,” said Langbein. “Tracking this metal within these organisms is the first step enabling further study to determine, for example, if gold is collected within specific cells, or if it can interfere with the metabolisms in high doses.”

The use of gold nanoparticles in medical devices is increasing and with it, their abundance in the environment. This imaging technique will provide clarity into the little-understood mechanisms in the woodlice hepatopancreas and will also provide helpful environmental monitoring.

In the future, background-free four-wave mixing microscopy could be used to detect other metal nanoparticles and may be applied to organisms like fish larvae and even human cell cultures.

Here’s a link to and a citation for the paper,

Background-free four-wave mixing microscopy of small gold nanoparticles inside a multi-cellular organ by Iestyn Pope, Nuno G.C. Ferreira, Peter Kille, Wolfgang Langbein, and Paola Borri. Appl. Phys. Lett. 122, 153701 (2023) DOI: https://doi.org/10.1063/5.0140651Published online April 11, 2023

This paper is open access.

Nanodiamond alternative to organic fluorophores to view inside living human cells

No sooner is a Nobel prize (2014) awarded for nanoscopy which makes use of fluorescence to observe processes in living cells than there is an announcement about a new technique that avoids fluorescence and its attendant shortcomings. From an Oct. 27, 2014 news item on Nanowerk (Note: A link has been removed),

Nanodiamonds are providing scientists with new possibilities for accurate measurements of processes inside living cells with potential to improve drug delivery and cancer therapeutics.

Published in Nature Nanotechnology (“Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds”), researchers from Cardiff University have unveiled a new method for viewing nanodiamonds inside human living cells for purposes of biomedical research.

An Oct. 27, 2014 Cardiff University (Wales) news release, which originated the news item, explains why the use of nanodiamonds is superior to the use of organic flurophores,

Nanodiamonds are very small particles (a thousand times smaller than human hair) and because of their low toxicity they can be used as a carrier to transport drugs inside cells. They also show huge promise as an alternative to the organic fluorophores usually used by scientists to visualise processes inside cells and tissues.

A major limitation of organic fluorophores is that they have the tendency to degrade and bleach over time under light illumination. This makes it difficult to use them for accurate measurements of cellular processes. Moreover, the bleaching and chemical degradation can often be toxic and significantly perturb or even kill cells.

There is a growing consensus among scientists that nanodiamonds are one of the best inorganic material alternatives for use in biomedical research, because of their compatibility with human cells, and due to their stable structural and chemical properties.

Previous attempts by other research teams to visualise nanodiamonds under powerful light microscopes have run into the obstacle that the diamond material per se is transparent to visible light. Locating the nanodiamonds under a microscope had relied on tiny defects in the crystal lattice, which fluoresce under light illumination.

Production of the defects proved both costly and difficult to realise in a controlled way. Furthermore, the fluorescence light emitted by these defects, and in turn the image gleaned from the microscopic exploration of these flawed nanodiamonds, is sometimes also unstable.

In their latest paper, researchers from Cardiff University’s Schools of Biosciences and Physics showed that non-fluorescing nanodiamonds (diamonds without defects) can be imaged optically and far more stably via the interaction between the illuminating light and the vibrating chemical bonds in the diamond lattice structure which results in scattered light at a different colour.

The paper describes how two laser beams beating at a specific frequency are used to drive chemical bonds to vibrate in sync. One of these beams is then used to probe this vibration and generate a light, called coherent anti-Stokes Raman scattering (CARS).

By focusing these laser beams onto the nanodiamond, a high-resolution CARS image is generated. Using an in-house built microscope, the research team was able to measure the intensity of the CARS light on a series of single nanodiamonds of different sizes.

The nanodiamond size was accurately measured by means of electron microscopy and other quantitative optical contrast methods developed within the researcher’s lab. In this way, they were able to quantify the relationship between the CARS light intensity and the nanoparticle size.

Consequently, the calibrated CARS signal enabled the team to analyse the size and number of nanodiamonds that had been delivered into living cells, with a level of accuracy hitherto not achieved by other methods.

Professor Paola Borri from the School of Biosciences, who led the study, said: “This new imaging modality opens the exciting prospect of following complex cellular trafficking pathways quantitatively with important applications in drug delivery. The next step for us will be to push the technique to detect nanodiamonds of even smaller sizes than what we have shown so far and to demonstrate a specific application in drug delivery.”

Here’s a link to and a citation for the paper,

Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds by Iestyn Pope, Lukas Payne, George Zoriniants, Evan Thomas, Oliver Williams, Peter Watson, Wolfgang Langbein, & Paola Borri. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.210 Published online 12 October 2014

The paper is behind a paywall but there is a free preview with ReadCube Access.

For anyone who’d like to read more about fluorescence and its use in nanoscopy there’s my Oct. 8, 2014 posting about the 2014 Nobel Prize in Chemistry and in my Oct. 27, 2014 posting about a specific use for determining how bipolar disorder may affect the brain.