Tag Archives: University of Queensland (UQ)

Clay film keeps your apples fresh

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Which apple would you like to eat?

Caption: Extent of decay in apples treated with clay film and cling wrap. Credit: Miharu Eguchi National Institute for Materials Science eguchi.miharu@nims.go.jp

This research into food packaging comes from Japan’s National Institute for Materials in a March 8, 2022 press release (also on EurekAlert but published on April 12, 2022),

An international research team consisting of NIMS, The University of Queensland and National Taiwan University has succeeded in creating a clay film with its gas permeability optimized for long-term storage of fresh produce by adjusting the sizes of the clay nanosheet particles comprising it. The team then uniformly coated the surfaces of various fruits with the film. This treatment kept the fruits’ respiration rates low without completely depriving them of oxygen, preventing them from decaying.

Efforts have been made to develop gas barrier films using clay nanosheets. Although some researchers attempted to improve the film properties of clay nanosheets by adding organic polymers to them, films can also be formed using only clay nanosheets without additives. Only a few studies had previously evaluated the physical properties of clay films composed solely of clay nanosheets.

This international joint research team focused on the gas permeability of clay films and found that a film composed of clay nanosheets with particle sizes in the range of several dozen nanometers (1 nm = one millionth of 1 mm) had relatively high permeability to gas molecules as they can pass through gaps between particles. This gas permeability is equivalent to that of plastic bags with minute pores used to store fresh produce. These bags are able to adequately reduce oxygen supply to fresh fruit, preventing it from ripening too rapidly. The gas permeability similarities between the clay film and the plastic bags inspired the research team to assess the ability of the clay film to preserve the quality of fresh produce for long periods of time.

In this research, the team applied a suspension of clay nanosheets to the surfaces of various fruits (e.g., apples, bananas and oranges) to form uniform films on their surfaces. The team also prepared untreated fruits and fruits covered in cling wrap for comparison. The gas emissions and appearance of these treated and untreated fruits were monitored for several months. As shown in the figure [above], the untreated apples (the first photo from the left) had decayed by the end of the experimental period and the apples covered only in cling wrap (the fourth photo from the left) had also decayed and grown mold. By contrast, the apples coated with the clay film (the two middle photos) did not decay or grew mold, presumably because the film reduced the external oxygen supply needed for ripening and mold growth. In addition, the clay film was confirmed to be in tight contact with the surfaces of the apples it coated, suggesting that it may be able to effectively block the diffusion of ethylene into the air, a phytohormone which plays an important role in inducing fruit ripening.

In addition to its potential ability to restrict the external oxygen supply and ethylene diffusion, the clay film may be able to prevent odor compounds produced by fresh produce from diffusing into the air, possibly making them less attractive to pests. In future research, the team plans to improve the ease of application and strength of the clay film to make it more suitable for preserving the quality of fresh produce during its transportation to the market.

This project was carried out by an international joint research team consisting of Miharu Eguchi (Senior Researcher, Mesoscale Materials Chemistry Group, International Center for Materials Nanoarchitectonics, NIMS) and researchers from The University of Queensland and National Taiwan University. This work was supported in part by  JST-ERATO Yamauchi Materials Space-Tectonics Project.

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

Highly adhesive and disposable inorganic barrier films: made from 2D silicate nanosheets and water by Miharu Eguchi, Muxina Konarova, Nagy L. Torad, Te-An Chang, Dun-Yen Kang, Joe Shapter and Yusuke Yamauchi. J. Mater. Chem. A, 2022,10, 1956-1964 DOI: https://doi.org/10.1039/D1TA08837H First published 02 Dec 2021 Print version published January 28, 2022

This paper is behind a paywall.

Nanotechnology-enabled pain relief for tooth sensitivity

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A November 23, 2021 news item on phys.org announces research from Australia that may lead to pain relief for anyone with sensitive teeth,

In an Australian first, researchers from the University of Queensland have used nanotechnology to develop effective ways to manage tooth sensitivity.

Dr. Chun Xu from UQ’s [University of Queensland] School of Dentistry said the approach might provide more effective long-term pain relief for people with sensitive teeth, compared to current options.

A November 23, 2021 University of Queensland press release, which originated the news item, describes the condition leading to tooth sensitivity and how the proposed solution works (Note: Links have been removed),

“Dentin tubules are located in the dentin, one of the layers below the enamel surface of your teeth,” Dr Xu said.

“When tooth enamel has been worn down, and the dentin are exposed, eating or drinking something cold or hot can cause a sudden sharp flash of pain.

“The nanomaterials used in this preclinical study can rapidly block the exposed dentin tubules and prevent the unpleasant pain.

“Our approach acts faster and lasts longer than current treatment options.

“The materials could be developed into a paste, so people who have sensitive teeth could simply apply this paste to the tooth and massage for one to three minutes.

“The next step is clinical trials.”

Tooth sensitivity affects up to 74 per cent of the population, at times severely impacting quality of life and requiring expensive treatment.

“If clinical trials are successful people will benefit from this new method that can be used at home, without the need to go to a dentist in the near future,” Dr Xu said.

“We hope this study encourages more research using nanotechnology to address dental problems.”

The team also included researchers from UQ’s Australian Institute for Bioengineering and Nanotechnology (AIBN.

…

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

Calcium-Doped Silica Nanoparticles Mixed with Phosphate-Doped Silica Nanoparticles for Rapid and Stable Occlusion of Dentin Tubules by Yuxue Cao, Chun Xu, Patricia P. Wright, Jingyu Liu, Yueqi Kong, Yue Wang, Xiaodan Huang, Hao Song, Jianye Fu, Fang Gao, Yang Liu, Laurence J. Walsh, and Chang Lei. ACS Appl. Nano Mater. 2021, 4, 9, 8761–8769 DOI: https://doi.org/10.1021/acsanm.1c01365 Publication Date:August 25, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.

Australian scientists say that sunscreens with zinc oxide nanoparticles aren’t toxic to you

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The Australians have had quite the struggle over whether or not to use nanotechnology-enabled sunscreens (see my Feb. 9, 2012 posting about an Australian nanosunscreen debacle and I believe the reverberations continue even ’til today). This latest research will hopefully help calm the waters. From a Dec. 4, 2018 news item on ScienceDaily,

Zinc oxide (ZnO) has long been recognized as an effective sunscreen agent. However, there have been calls for sunscreens containing ZnO nanoparticles to be banned because of potential toxicity and the need for caution in the absence of safety data in humans. An important new study provides the first direct evidence that intact ZnO nanoparticles neither penetrate the human skin barrier nor cause cellular toxicity after repeated application to human volunteers under in-use conditions. This confirms that the known benefits of using ZnO nanoparticles in sunscreens clearly outweigh the perceived risks, reports the Journal of Investigative Dermatology.

A December 4, 2018 Elsevier (Publishing) press release (also on EurekAlert), which originated the news item, provides international context for the safety discussion while providing more details about this latest research,

The safety of nanoparticles used in sunscreens has been a highly controversial international issue in recent years, as previous animal exposure studies found much higher skin absorption of zinc from application of ZnO sunscreens to the skin than in human studies. Some public advocacy groups have voiced concern that penetration of the upper layer of the skin by sunscreens containing ZnO nanoparticles could gain access to the living cells in the viable epidermis with toxic consequences, including DNA damage. A potential danger, therefore, is that this concern may also result in an undesirable downturn in sunscreen use. A 2017 National Sun Protection Survey by the Cancer Council Australia found only 55 percent of Australians believed it was safe to use sunscreen every day, down from 61 per cent in 2014.

Investigators in Australia studied the safety of repeated application of agglomerated ZnO nanoparticles applied to five human volunteers (aged 20 to 30 years) over five days. This mimics normal product use by consumers. They applied ZnO nanoparticles suspended in a commercial sunscreen base to the skin of volunteers hourly for six hours and daily for five days. Using multiphoton tomography with fluorescence lifetime imaging microscopy, they showed that the nanoparticles remained within the superficial layers of the stratum corneum and in the skin furrows. The fate of ZnO nanoparticles was also characterized in excised human skin in vitro. They did not penetrate the viable epidermis and no cellular toxicity was seen, even after repeated hourly or daily applications typically used for sunscreens.

“The terrible consequences of skin cancer and photoaging are much greater than any toxicity risk posed by approved sunscreens,” stated lead investigator Michael S. Roberts, PhD, of the Therapeutics Research Centre, The University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, and School of Pharmacy and Medical Sciences, University of South Australia, Sansom Institute, Adelaide, QLD, Australia.

“This study has shown that sunscreens containing nano ZnO can be repeatedly applied to the skin with minimal risk of any toxicity. We hope that these findings will help improve consumer confidence in these products, and in turn lead to better sun protection and reduction in ultraviolet-induced skin aging and cancer cases,” he concluded.

“This study reinforces the important public health message that the known benefits of using ZnO nano sunscreens clearly outweigh the perceived risks of using nano sunscreens that are not supported by the scientific evidence,” commented Paul F.A. Wright, PhD, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia, in an accompanying editorial. “Of great significance is the investigators’ finding that the slight increase in zinc ion concentrations in viable epidermis was not associated with cellular toxicity under conditions of realistic ZnO nano sunscreen use.

A November 21, 2018 University of South Australia press release (also on EurekAlert) provides some additional insight into the Australian situation,, Note: Links have been removed,

It’s safe to slap on the sunscreen this summer – in repeated doses – despite what you have read about the potential toxicity of sunscreens.

A new study led by the University of Queensland (UQ) and University of South Australia (UniSA) provides the first direct evidence that zinc oxide nanoparticles used in sunscreen neither penetrate the skin nor cause cellular toxicity after repeated applications.

The research, published this week in the Journal of Investigative Dermatology, refutes widespread claims among some public advocacy groups – and a growing belief among consumers – about the safety of nanoparticulate-based sunscreens.

UQ and UniSA lead investigator, Professor Michael Roberts, says the myth about sunscreen toxicity took hold after previous animal studies found much higher skin absorption of zinc-containing sunscreens than in human studies.

“There were concerns that these zinc oxide nanoparticles could be absorbed into the epidermis, with toxic consequences, including DNA damage,” Professor Roberts says.

The toxicity link was picked up by consumers, sparking fears that Australians could reduce their sunscreen use, echoed by a Cancer Council 2017 National Sun Protection Survey showing a drop in the number of people who believed it was safe to use sunscreens every day.

Professor Roberts and his co-researchers in Brisbane, Adelaide, Perth and Germany studied the safety of repeated applications of zinc oxide nanoparticles applied to five volunteers aged 20-30 years.

Volunteers applied the ZnO nanoparticles every hour for six hours on five consecutive days.

“Using superior imaging methods, we established that the nanoparticles remained within the superficial layers of the skin and did not cause any cellular damage,” Professor Roberts says.

“We hope that these findings help improve consumer confidence in these products and in turn lead to better sun protection. The terrible consequences of skin cancer and skin damage caused by prolonged sun exposure are much greater than any toxicity posed by approved sunscreens.”

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

Support for the Safe Use of Zinc Oxide Nanoparticle Sunscreens: Lack of Skin Penetration or Cellular Toxicity after Repeated Application in Volunteers by Yousuf H. Mohammed, Amy Holmes, Isha N. Haridass, Washington Y. Sanchez, Hauke Studier, Jeffrey E. Grice, Heather A.E. Benson, Michael S. Roberts. Jurnal of Investigative Dermatology. DOI: https://doi.org/10.1016/j.jid.2018.08.024 Article in Press Published online (Dec. 4, 2018?)

As of Dec. 11, 2018, this article is open access.

Nanopatch more effective with poliovirus

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No more needles or syringes that’s the Nanopatch promise and its one I’ve been writing about since 2009. It seems 2017 marks another step closer to seeing this idea become a product. From an Oct. 5, 2017 news item on ScienceDaily,

Efforts to rid the world of polio have taken another significant step, thanks to research led by University of Queensland [UQ] bioscience experts and funding from the World Health Organisation (WHO).

A fresh study of the Nanopatch — a microscopic vaccine delivery platform first developed by UQ researchers — has shown the device more effectively combats poliovirus than needles and syringes.

Here’s a prototype,

Caption: This is an image of the intended commercial product. Credit: Courtesy Vaxxas Pty Ltd

An Oct. 5, 2017 University of Queensland press release (also on EurekAlert), which originated the news item, provides more detail (Note: Links have been removed),

Head of UQ’s School of Chemistry and Molecular Biosciences Professor Paul Young said the breakthrough provided the next step in consigning polio to history.

“Polio was one of the most dreaded childhood diseases of the 20th century, resulting in limb disfigurement and irreversible paralysis in tens of millions of cases,” Professor Young said.

“This most recent study showed the Nanopatch enhanced responses to all three types of inactivated poliovirus vaccines (IPV) – a necessary advancement from using the current live oral vaccine.

“We are extremely grateful to the WHO for providing funding to Vaxxas Pty Ltd, the biotechnology company commercialising the Nanopatch.

“The support specifically assists pre-clinical studies and good manufacturing practices.”

Patch inventor Professor Mark Kendall said the study exhibited a key advantage of the Nanopatch.

“It targets the abundant immune cell populations in the skin’s outer layers, rather than muscle, resulting in a more efficient vaccine delivery system,” Professor Kendall said.

“The ease of administration, coupled with dose reduction observed in this study suggests that the Nanopatch could facilitate inexpensive vaccination of inactivated poliovirus vaccines.”

UQ Australian Institute for Biotechnology and Nanotechnology researcher Dr David Muller said effectively translating the dose could dramatically reduce the cost.

“A simple, easy-to-administer polio Nanopatch vaccine could increase the availability of the IPV vaccine and facilitate its administration in door-to-door and mass vaccination campaigns,” said Dr Muller.

“As recently as 1988, more than 350,000 cases occurred every year in more than 125 endemic countries.

“Concerted efforts to eradicate the disease have reduced incidence by more than 99 per cent.”

“Efforts are being intensified to eradicate the remaining strains of transmission once and for all.”

Data from the study encourages efforts by Vaxxas – established by UQ’s commercialisation company UniQuest – to bring the technology to use for human vaccinations.

“The research we are undertaking in conjunction with UQ and WHO can improve the reach of life-saving vaccines to children everywhere,” Vaxxas chief executive officer David Hoey said.

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

High-density microprojection array delivery to rat skin of low doses of trivalent inactivated poliovirus vaccine elicits potent neutralising antibody responses by David A. Muller, Germain J. P. Fernando, Nick S. Owens, Christiana Agyei-Yeboah, Jonathan C. J. Wei, Alexandra C. I. Depelsenaire, Angus Forster, Paul Fahey, William C. Weldon, M. Steven Oberste, Paul R. Young, & Mark A. F. Kendall. Scientific Reports 7, Article number: 12644 (2017) doi:10.1038/s41598-017-13011-0 Published online: 03 October 2017

This paper is open access.

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