Tag Archives: antibiotics

Nanobiotics and artificial intelligence (AI)

Antibiotics at the nanoscale = nanobiotics. For a more complete explanation, there’s this (Note: the video runs a little longer than most of the others embedded on this blog),

Before pushing further into this research, a note about antibiotic resistance. In a sense, we’ve created the problem we (those scientists in particular) are trying to solve.

Antibiotics and cleaning products kill 99.9% of the bacteria, leaving 0.1% that are immune. As so many living things on earth do, bacteria reproduce. Now, a new antibiotic is needed and discovered; it too kills 99.9% of the bacteria. The 0.1% left are immune to two antibiotics. And,so it goes.

As the scientists have made clear, we’re running out of options using standard methods and they’re hoping this ‘nanoparticle approach’ as described in a June 5, 2023 news item on Nanowerk will work, Note: A link has been removed,

Identifying whether and how a nanoparticle and protein will bind with one another is an important step toward being able to design antibiotics and antivirals on demand, and a computer model developed at the University of Michigan can do it.

The new tool could help find ways to stop antibiotic-resistant infections and new viruses—and aid in the design of nanoparticles for different purposes.

“Just in 2019, the number of people who died of antimicrobial resistance was 4.95 million. Even before COVID, which worsened the problem, studies showed that by 2050, the number of deaths by antibiotic resistance will be 10 million,” said Angela Violi, an Arthur F. Thurnau Professor of mechanical engineering, and corresponding author of the study that made the cover of Nature Computational Science (“Domain-agnostic predictions of nanoscale interactions in proteins and nanoparticles”).

In my ideal scenario, 20 or 30 years from now, I would like—given any superbug—to be able to quickly produce the best nanoparticles that can treat it.”

A June 5, 2023 University of Michigan news release (also on EurekAlert), which originated the news item, provides more technical details, Note: A link has been removed,

Much of the work within cells is done by proteins. Interaction sites on their surfaces can stitch molecules together, break them apart and perform other modifications—opening doorways into cells, breaking sugars down to release energy, building structures to support groups of cells and more. If we could design medicines that target crucial proteins in bacteria and viruses without harming our own cells, that would enable humans to fight new and changing diseases quickly.

The new [computer] model, named NeCLAS [NeCLAS (Nanoparticle-Computed Ligand Affinity Scoring)], uses machine learning—the AI technique that powers the virtual assistant on your smartphone and ChatGPT. But instead of learning to process language, it absorbs structural models of proteins and their known interaction sites. From this information, it learns to extrapolate how proteins and nanoparticles might interact, predict binding sites and the likelihood of binding between them—as well as predicting interactions between two proteins or two nanoparticles.

“Other models exist, but ours is the best for predicting interactions between proteins and nanoparticles,” said Paolo Elvati, U-M associate research scientist in mechanical engineering.

AlphaFold, for example, is a widely used tool for predicting the 3D structure of a protein based on its building blocks, called amino acids. While this capacity is crucial, this is only the beginning: Discovering how these proteins assemble into larger structures and designing practical nanoscale systems are the next steps.

“That’s where NeCLAS comes in,” said Jacob Saldinger, U-M doctoral student in chemical engineering and first author of the study. “It goes beyond AlphaFold by showing how nanostructures will interact with one another, and it’s not limited to proteins. This enables researchers to understand the potential applications of nanoparticles and optimize their designs.”

The team tested three case studies for which they had additional data: 

  • Molecular tweezers, in which a molecule binds to a particular site on another molecule. This approach can stop harmful biological processes, such as the aggregation of protein plaques in diseases of the brain like Alzheimer’s.
  • How graphene quantum dots break up the biofilm produced by staph bacteria. These nanoparticles are flakes of carbon, no more than a few atomic layers thick and 0.0001 millimeters to a side. Breaking up biofilms is likely a crucial tool in fighting antibiotic-resistant infections—including the superbug methicillin-resistant Staphylococcus aureus (MRSA), commonly acquired at hospitals.
  • Whether graphene quantum dots would disperse in water, demonstrating the model’s ability to predict nanoparticle-nanoparticle binding even though it had been trained exclusively on protein-protein data.

While many protein-protein models set amino acids as the smallest unit that the model must consider, this doesn’t work for nanoparticles. Instead, the team set the size of that smallest feature to be roughly the size of the amino acid but then let the computer model decide where the boundaries between these minimum features were. The result is representations of proteins and nanoparticles that look a bit like collections of interconnected beads, providing more flexibility in exploring small scale interactions.

“Besides being more general, NeCLAS also uses way less training data than AlphaFold. We only have 21 nanoparticles to look at, so we have to use protein data in a clever way,” said Matt Raymond, U-M doctoral student in electrical and computer engineering and study co-author.  

Next, the team intends to explore other biofilms and microorganisms, including viruses.

The Nature Computational Science study was funded by the University of Michigan Blue Sky Initiative, the Army Research Office and the National Science Foundation. 

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

Domain-agnostic predictions of nanoscale interactions in proteins and nanoparticles by Jacob Charles Saldinger, Matt Raymond, Paolo Elvati & Angela Violi. Nature Computational Science volume 3, pages 393–402 (2023) DOI: https://doi.org/10.1038/s43588-023-00438-x Published: 01 May 2023 Issue Date: May 2023

This paper is behind a paywall.

McGill University team gets better understanding of nonribosomal peptide synthetases (NRPSs) also described as nanomachines

This research from McGill University (Montréal, Canada) focuses on enzymes and their possible utility as nanomachines for producing drugs. (For the uninitiated, nano means billionth, which, in turn, means these enzymes are measured at the nanoscale.)

An April 30, 2020 McGill University news release (also on EurekAlert) describes the work,

Many of the drugs and medicines that we rely on today are natural products taken from microbes like bacteria and fungi. Within these microbes, the drugs are made by tiny natural machines – mega-enzymes known as nonribosomal peptide synthetases (NRPSs). A research team led by McGill University has gained a better understanding of the structures of NRPSs and the processes by which they work. This improved understanding of NRPSs could potentially allow bacteria and fungi to be leveraged for the production of desired new compounds and lead to the creation of new potent antibiotics, immunosuppressants and other modern drugs.

“NRPSs are really fantastic enzymes that take small molecules like amino acids or other similar sized building blocks and assemble them into natural, biologically active, potent compounds, many of which are drugs,” said Martin Schmeing, Associate Professor in the Department of Biochemistry at McGill University, and corresponding author on the article that was recently published in Nature Chemical Biology. “An NRPS works like a factory assembly line that consists of a series of robotic workstations. Each station has multi-step workflows and moving parts that allow it to add one building block substrate to the growing drug, elongating and modifying it, and then passing it off to the next little workstation, all on the same huge enzyme.”

Ultra-intensive light beam allows scientists to see proteins

n their paper featured on the cover of the May 2020 issue of Nature Chemical Biology, the team reports visualizing an NRPS mechanical system by using the CMCF beamline at the Canadian Light Source (CLS). The CLS is a Canadian national lab [these types of labs are sometimes called synchrotrons] that produces the ultra-intense beams of X-rays required to image proteins, as even mega-enzymes are too small to see with any light microscope.

“Scientists have long been excited about the potential of bioengineering NRPSs by identifying the order of building blocks and reorganizing the workstations in the enzyme to create new drugs, but the effort has rarely been successful,” said Schmeing. “This is the first time anyone has seen how these enzymes transform keto acids into a building block that can be put into a peptide drug. This helps us understand how the NRPSs can use so very many building blocks to make the many different compounds and therapeutics.”

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

Structural basis of keto acid utilization in nonribosomal depsipeptide synthesis by Diego A. Alonzo, Clarisse Chiche-Lapierre, Michael J. Tarry, Jimin Wang & T. Martin Schmeing. Nature Chemical Biology volume 16, pages493–496(2020) Published: 17 February 2020

This paper is behind a paywall.

October 2019 science and art/science events in Vancouver and other parts of Canada

This is a scattering of events, which I’m sure will be augmented as we properly start the month of October 2019.

October 2, 2019 in Waterloo, Canada (Perimeter Institute)

If you want to be close enough to press the sacred flesh (Sir Martin Rees), you’re out of luck. However, there are still options ranging from watching a live webcast from the comfort of your home to watching the lecture via closed circuit television with other devoted fans at a licensed bistro located on site at the Perimeter Institute (PI) to catching the lecture at a later date via YouTube.

That said, here’s why you might be interested,

Here’s more from a September 11, 2019 Perimeter Institute (PI) announcement received via email,

Surviving the Century
MOVING TOWARD A POST-HUMAN FUTURE
Martin Rees, UK Astronomer Royal
Wednesday, Oct. 2 at 7:00 PM ET

Advances in technology and space exploration could, if applied wisely, allow a bright future for the 10 billion people living on earth by the end of the century.

But there are dystopian risks we ignore at our peril: our collective “footprint” on our home planet, as well as the creation and use of technologies so powerful that even small groups could cause a global catastrophe.

Martin Rees, the UK Astronomer Royal, will explore this unprecedented moment in human history during his lecture on October 2, 2019. A former president of the Royal Society and master of Trinity College, Cambridge, Rees is a cosmologist whose work also explores the interfaces between science, ethics, and politics. Read More.

Mark your calendar! Tickets will be available on Monday, Sept. 16 at 9 AM ET

Didn’t get tickets for the lecture? We’ve got more ways to watch.
Join us at Perimeter on lecture night to watch live in the Black Hole Bistro.
Catch the live stream on Inside the Perimeter or watch it on Youtube the next day
Become a member of our donor thank you program! Learn more.

It took me a while to locate an address for PI venue since I expect that information to be part of the announcement. (insert cranky emoticon here) Here’s the address: Perimeter Institute, Mike Lazaridis Theatre of Ideas, 31 Caroline St. N., Waterloo, ON

Before moving onto the next event, I’m including a paragraph from the event description that was not included in the announcement (from the PI Outreach Surviving the Century webpage),

In his October 2 [2019] talk – which kicks off the 2019/20 season of the Perimeter Institute Public Lecture Series – Rees will discuss the outlook for humans (or their robotic envoys) venturing to other planets. Humans, Rees argues, will be ill-adapted to new habitats beyond Earth, and will use genetic and cyborg technology to transform into a “post-human” species.

I first covered Sir Martin Rees and his concerns about technology (robots and cyborgs run amok) in this November 26, 2012 posting about existential risk. He and his colleagues at Cambridge University, UK, proposed a Centre for the Study of Existential Risk, which opened in 2015.

Straddling Sept. and Oct. at the movies in Vancouver

The Vancouver International Film Festival (VIFF) opened today, September 26, 2019. During its run to October 11, 2019 there’ll be a number of documentaries that touch on science. Here are three of the documentaries most closely adhere to the topics I’m most likely to address on this blog. There is a fourth documentary included here as it touches on ecology in a more hopeful fashion than is the current trend.

Human Nature

From the VIFF 2019 film description and ticket page,

One of the most significant scientific breakthroughs in history, the discovery of CRISPR has made it possible to manipulate human DNA, paving the path to a future of great possibilities.

The implications of this could mean the eradication of disease or, more controversially, the possibility of genetically pre-programmed children.

Breaking away from scientific jargon, Human Nature pieces together a complex account of bio-research for the layperson as compelling as a work of science-fiction. But whether the gene-editing powers of CRISPR (described as “a word processor for DNA”) are used for good or evil, they’re reshaping the world as we know it. As we push past the boundaries of what it means to be human, Adam Bolt’s stunning work of science journalism reaches out to scientists, engineers, and people whose lives could benefit from CRISPR technology, and offers a wide-ranging look at the pros and cons of designing our futures.

Tickets
Friday, September 27, 2019 at 11:45 AM
Vancity Theatre

Saturday, September 28, 2019 at 11:15 AM
International Village 10

Thursday, October 10, 2019 at 6:45 PM
SFU Goldcorp

According to VIFF, the tickets for the Sept. 27, 2019 show are going fast.

Resistance Fighters

From the VIFF 2019 film description and ticket page,

Since mass-production in the 1940s, antibiotics have been nothing less than miraculous, saving countless lives and revolutionizing modern medicine. It’s virtually impossible to imagine hospitals or healthcare without them. But after years of abuse and mismanagement by the medical and agricultural communities, superbugs resistant to antibiotics are reaching apocalyptic proportions. The ongoing rise in multi-resistant bacteria – unvanquishable microbes, currently responsible for 700,000 deaths per year and projected to kill 10 million yearly by 2050 if nothing changes – and the people who fight them are the subjects of Michael Wech’s stunning “science-thriller.”

Peeling back the carefully constructed veneer of the medical corporate establishment’s greed and complacency to reveal the world on the cusp of a potential crisis, Resistance Fighters sounds a clarion call of urgency. It’s an all-out war, one which most of us never knew we were fighting, to avoid “Pharmageddon.” Doctors, researchers, patients, and diplomats testify about shortsighted medical and economic practices, while Wech offers refreshingly original perspectives on environment, ecology, and (animal) life in general. As alarming as it is informative, this is a wake-up call the world needs to hear.

Sunday, October 6, 2019 at 5:45 PM
International Village 8

Thursday, October 10, 2019 at 2:15 PM
SFU Goldcorp

According to VIFF, the tickets for the Oct. 6, 2019 show are going fast.

Trust Machine: The Story of Blockchain

Strictly speaking this is more of a technology story than science story but I have written about blockchain and cryptocurrencies before so I’m including this. From the VIFF 2019 film description and ticket page,

For anyone who has questions about cryptocurrencies like Bitcoin (and who doesn’t?), Alex Winter’s thorough documentary is an excellent introduction to the blockchain phenomenon. Trust Machine offers a wide range of expert testimony and a variety of perspectives that explicate the promises and the risks inherent in this new manifestation of high-tech wizardry. And it’s not just money that blockchains threaten to disrupt: innovators as diverse as UNICEF and Imogen Heap make spirited arguments that the industries of energy, music, humanitarianism, and more are headed for revolutionary change.

A propulsive and subversive overview of this little-understood phenomenon, Trust Machine crafts a powerful and accessible case that a technologically decentralized economy is more than just a fad. As the aforementioned experts – tech wizards, underground activists, and even some establishment figures – argue persuasively for an embrace of the possibilities offered by blockchains, others criticize its bubble-like markets and inefficiencies. Either way, Winter’s film suggests a whole new epoch may be just around the corner, whether the powers that be like it or not.

Tuesday, October 1, 2019 at 11:00 AM
Vancity Theatre

Thursday, October 3, 2019 at 9:00 PM
Vancity Theatre

Monday, October 7, 2019 at 1:15 PM
International Village 8

According to VIFF, tickets for all three shows are going fast

The Great Green Wall

For a little bit of hope, From the VIFF 2019 film description and ticket page,

“We must dare to invent the future.” In 2007, the African Union officially began a massively ambitious environmental project planned since the 1970s. Stretching through 11 countries and 8,000 km across the desertified Sahel region, on the southern edges of the Sahara, The Great Green Wall – once completed, a mosaic of restored, fertile land – would be the largest living structure on Earth.

Malian musician-activist Inna Modja embarks on an expedition through Senegal, Mali, Nigeria, Niger, and Ethiopia, gathering an ensemble of musicians and artists to celebrate the pan-African dream of realizing The Great Green Wall. Her journey is accompanied by a dazzling array of musical diversity, celebrating local cultures and traditions as they come together into a community to stand against the challenges of desertification, drought, migration, and violent conflict.

An unforgettable, beautiful exploration of a modern marvel of ecological restoration, and so much more than a passive source of information, The Great Green Wall is a powerful call to take action and help reshape the world.

Sunday, September 29, 2019 at 11:15 AM
International Village 10

Wednesday, October 2, 2019 at 6:00 PM
International Village 8
Standby – advance tickets are sold out but a limited number are likely to be released at the door

Wednesday, October 9, 2019 at 11:00 AM
International Village 9

As you can see, one show is already offering standby tickets only and the other two are selling quickly.

For venue locations, information about what ‘standby’ means and much more go here and click on the Festival tab. As for more information the individual films, you’ll links to trailers, running times, and more on the pages for which I’ve supplied links.

Brain Talks on October 16, 2019 in Vancouver

From time to time I get notices about a series titled Brain Talks from the Dept. of Psychiatry at the University of British Columbia. A September 11, 2019 announcement (received via email) focuses attention on the ‘guts of the matter’,

YOU ARE INVITED TO ATTEND:

BRAINTALKS: THE BRAIN AND THE GUT

WEDNESDAY, OCTOBER 16TH, 2019 FROM 6:00 PM – 8:00 PM

Join us on Wednesday October 16th [2019] for a series of talks exploring the
relationship between the brain, microbes, mental health, diet and the
gut. We are honored to host three phenomenal presenters for the evening:
Dr. Brett Finlay, Dr. Leslie Wicholas, and Thara Vayali, ND.

DR. BRETT FINLAY [2] is a Professor in the Michael Smith Laboratories at
the University of British Columbia. Dr. Finlay’s  research interests are
focused on host-microbe interactions at the molecular level,
specializing in Cellular Microbiology. He has published over 500 papers
and has been inducted into the Canadian  Medical Hall of Fame. He is the
co-author of the  books: Let Them Eat Dirt and The Whole Body
Microbiome.

DR. LESLIE WICHOLAS [3]  is a psychiatrist with an expertise in the
clinical understanding of the gut-brain axis. She has become
increasingly involved in the emerging field of Nutritional Psychiatry,
exploring connections between diet, nutrition, and mental health.
Currently, Dr. Wicholas is the director of the Food as Medicine program
at the Mood Disorder Association of BC.

THARA VAYALI, ND [4] holds a BSc in Nutritional Sciences and a MA in
Education and Communications. She has trained in naturopathic medicine
and advocates for awareness about women’s physiology and body literacy.
Ms. Vayali is a frequent speaker and columnist that prioritizes
engagement, understanding, and community as pivotal pillars for change.

Our event on Wednesday, October 16th [2019] will start with presentations from
each of the three speakers, and end with a panel discussion inspired by
audience questions. After the talks, at 7:30 pm, we host a social
gathering with a rich spread of catered healthy food and non-alcoholic
drinks. We look forward to seeing you there!

Paetzhold Theater

Vancouver General Hospital; Jim Pattison Pavilion, Vancouver, BC

Attend Event

That’s it for now.

Panning for silver nanoparticles in your clothes washer

A March 20, 2018 news item on phys.org describes a new approach to treating wastewater (Note: Links have been removed),

Humans have known since ancient times that silver kills or stops the growth of many microorganisms. Hippocrates, the father of medicine, is said to have used silver preparations for treating ulcers and healing wounds. Until the introduction of antibiotics in the 1940s, colloidal silver (tiny particles suspended in a liquid) was a mainstay for treating burns, infected wounds and ulcers. Silver is still used today in wound dressings, in creams and as a coating on medical devices.

Since the 1990s, manufacturers have added silver nanoparticles to numerous consumer products to enhance their antibacterial and anti-odor properties. Examples include clothes, towels, undergarments, socks, toothpaste and soft toys. Nanoparticles are ultra-small particles, ranging from 1 to 100 nanometers in diameter – too small to see even with a microscope. According to a widely cited database, about one-fourth of nanomaterial-based consumer products currently marketed in the United States contain nanosilver.

Multiple studies have reported that nanosilver leaches out of textiles when they are laundered. Research also reveals that nanosilver may be toxic to humans and aquatic and marine organisms. Although it is widely used, little is understood about its fate or long-term toxic effects in the environment.

We are developing ways to convert this potential ecological crisis into an opportunity by recovering pure silver nanoparticles, which have many industrial applications, from laundry wastewater. In a recently published study, we describe a technique for silver recovery and discuss the key technical challenges. Our approach tackles this problem at the source – in this case, individual washing machines. We believe that this strategy has great promise for getting newly identified contaminants out of wastewater.

A March 20, 2018 essay by Sukalyan Sengupta, Professor of Wastewater Treatment, and Tabish Nawaz. Doctoral Student, both at University of Massachusetts at Dartmouth on The Conversation website, which originated the news item, expands on the theme (Note: Links have been removed),

Use of nanosilver in consumer products has steadily risen in the past decade. The market share of silver-based textiles rose from 9 percent in 2004 to 25 percent in 2011.

Several investigators have measured the silver content of textiles and found values ranging from 0.009 to 21,600 milligrams of silver per kilogram of textile. Studies show that the amount of silver leached in the wash solution depends on many factors, including interactions between detergent and other chemicals and how silver is attached to the textiles.

In humans, exposure to silver can harm liver cells, skin and lungs. Prolonged exposure or exposure to a large dose can cause a condition called Argyria, in which the victim’s skin turns permanently bluish-gray.

Once silver goes down the drain and ends up at wastewater treatment plants, it can potentially harm bacterial treatment processes, making them less efficient, and foul treatment equipment. More than 90 percent of silver nanoparticles released in wastewater end up in nutrient-rich biosolids left over at the end of sewage treatment, which often are used on land as agricultural fertilizers.

Silver is toxic in aquatic environments, a concern that’s becoming more serious with the increased use of silver nanoparticles and awareness that oceans, rivers, and lakes are dangerously stressed.

Sengupta and Nawaz go on to describe their proposed solution (Note: Links have been removed),

Our research shows that the most efficient way to remove silver from wastewater is by treating it in the washing machine. At this point silver concentrations are relatively high, and silver is initially released from treated clothing in a chemical form that is feasible to recover.

A bit of chemistry is helpful here. Our recovery method employs a widely used chemistry process called ion exchange. Ions are atoms or molecules that have an electrical charge. In ion exchange, a solid and a liquid are brought together and exchange ions with each other.

For example, household soaps do not lather well in “hard” water, which contains high levels of ions such as magnesium and calcium. Many home water filters use ion exchange to “soften” the water, replacing those materials with other ions that do not affect its properties in the same way.

For this process to work, the ions that switch places must both be either positively or negatively charged. Nanosilver is initially released from textiles as silver ion, which is a cation – an ion with a positive charge (hence the plus sign in its chemical symbol, Ag+).

Even at the source, removing silver from washwater is challenging. Silver concentrations in the wash solution are relatively low compared to other cations, such as calcium, that could interfere with the removal process. Detergent chemistry complicates the picture further because some detergent components can potentially interact with silver.

To recover silver without picking up other chemicals, the recovery process must use materials that have a chemical affinity for silver. In a previous study, we described a potential solution: Using ion-exchange materials embedded with sulfur-based chemicals, which bind preferentially with silver.

In our new study, we passed washwater through an ion-exchange resin column and analyzed how each major detergent ingredient interacted with silver in the water and affected the resin’s ability to remove silver from the water. By manipulating process conditions such as pH, temperature and concentration of nonsilver cations, we were able to identify conditions that maximized silver recovery.

We found that pH and the levels of calcium ions (Ca2+) were critical factors. Higher levels of hydrogen or calcium ions bind up detergent ingredients and prevent them from interacting with silver ions, so the ion-exchange resin can remove the silver from the solution. We also found that some detergent ingredients – particularly bleaching and water-softening agents – made the ion-exchange resin work less efficiently. Depending on these conditions, we recovered between 20 percent and 99 percent of the silver in the washwater.

The researchers go on to propose a new approach to treating wastewater (Note: A link has been removed),

Today wastewater is collected from multiple sources, such as homes and businesses, and piped over long distances to centralized wastewater treatment plants. But increasing evidence shows that these facilities are ill-equipped to keep newly identified contaminants out of the environment, since they use one common treatment scheme for many different waste streams.

We believe the future is in decentralized systems that can treat different types of wastewater with specific technologies designed specifically for the materials they contain. If wastewater from laundromats contains different contaminants than wastewater from restaurants, why treat them the same way?

Interesting, non? In any event, here’s a link to and a citation for what I believe is the researchers’ latest paper on this subject,

Silver Recovery from Laundry Washwater: The Role of Detergent Chemistry by Tabish Nawaz and Sukalyan Sengupta. ACS Sustainable Chem. Eng., 2018, 6 (1), pp 600–608 DOI: 10.1021/acssuschemeng.7b02933 Publication Date (Web): November 21, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall. For anyone who can’t get access, Karla Lant provides a bit more technical detail about the work in her February 2, 2018 article for fondriest.com.

Nanocoating to reduce dental implant failures

Scientists at Plymouth University (UK) have developed a nanocoating that could reduce the number of dental implant failures. From a March 24, 2017 news item on Nanowerk (Note: A link has been removed),

According to the American Academy of Implant Dentistry (AAID), 15 million Americans have crown or bridge replacements and three million have dental implants — with this latter number rising by 500,000 a year. The AAID estimates that the value of the American and European market for dental implants will rise to $4.2 billion by 2022.

Dental implants are a successful form of treatment for patients, yet according to a study published in 2005, five to 10 per cent of all dental implants fail.

The reasons for this failure are several-fold – mechanical problems, poor connection to the bones in which they are implanted, infection or rejection. When failure occurs the dental implant must be removed.

The main reason for dental implant failure is peri-implantitis. This is the destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. This occurs when pathogenic microbes in the mouth and oral cavity develop into biofilms, which protects them and encourages growth. Peri-implantitis is caused when the biofilms develop on dental implants.

A research team comprising scientists from the School of Biological Sciences, Peninsula Schools of Medicine and Dentistry and the School of Engineering at the University of Plymouth, have joined forces to develop and evaluate the effectiveness of a new nanocoating for dental implants to reduce the risk of peri-implantitis.

The results of their work are published in the journal Nanotoxicology (“Antibacterial activity and biofilm inhibition by surface modified titanium alloy medical implants following application of silver, titanium dioxide and hydroxyapatite nanocoatings”).

A March 27, 2017 Plymouth University press release, which originated the news item, gives more details about the research,

In the study, the research team created a new approach using a combination of silver, titanium oxide and hydroxyapatite nanocoatings.

The application of the combination to the surface of titanium alloy implants successfully inhibited bacterial growth and reduced the formation of bacterial biofilm on the surface of the implants by 97.5 per cent.

Not only did the combination result in the effective eradication of infection, it created a surface with anti-biofilm properties which supported successful integration into surrounding bone and accelerated bone healing.

Professor Christopher Tredwin, Head of Plymouth University Peninsula School of Dentistry, commented:

“In this cross-Faculty study we have identified the means to protect dental implants against the most common cause of their failure. The potential of our work for increased patient comfort and satisfaction, and reduced costs, is great and we look forward to translating our findings into clinical practice.”

The University of Plymouth was the first university in the UK to secure Research Council Funding in Nanoscience and this project is the latest in a long line of projects investigating nanotechnology and human health.

Nanoscience activity at the University of Plymouth is led by Professor Richard Handy, who has represented the UK on matters relating to the Environmental Safety and Human Health of Nanomaterials at the Organisation for Economic Cooperation and Development (OECD). He commented:

“As yet there are no nano-specific guidelines in dental or medical implant legislation and we are, with colleagues elsewhere, guiding the way in this area. The EU recognises that medical devices and implants must: perform as expected for its intended use, and be better than similar items in the market; be safe for the intended use or safer than an existing item, and; be biocompatible or have negligible toxicity.”

He added:

“Our work has been about proving these criteria which we have done in vitro. The next step would be to demonstrate the effectiveness of our discovery, perhaps with animal models and then human volunteers.”

Dr Alexandros Besinis, Lecturer in Mechanical Engineering at the School of Engineering, University of Plymouth, led the research team. He commented:

“Current strategies to render the surface of dental implants antibacterial with the aim to prevent infection and peri-implantitis development, include application of antimicrobial coatings loaded with antibiotics or chlorhexidine. However, such approaches are usually effective only in the short-term, and the use of chlorhexidine has also been reported to be toxic to human cells. The significance of our new study is that we have successfully applied a dual-layered silver-hydroxyapatite nanocoating to titanium alloy medical implants which helps to overcome these risks.”

Dr Besinis has been an Honorary Teaching Fellow at the Peninsula School of Dentistry since 2011 and has recently joined the School of Engineering. His research interests focus on advanced engineering materials and the use of nanotechnology to build novel biomaterials and medical implants with improved mechanical, physical and antibacterial properties.

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

Antibacterial activity and biofilm inhibition by surface modified titanium alloy medical implants following application of silver, titanium dioxide and hydroxyapatite nanocoatings by A. Besinis, S. D. Hadi, H. R. Le, C. Tredwin & R. D. Handy.  Nanotoxicology Volume 11, 2017 – Issue 3  Pages 327-338  http://dx.doi.org/10.1080/17435390.2017.1299890 Published online: 17 Mar 2017

This paper appears to be open access.

Maple syrup as an antibiotic helper?

This maple syrup research is from McGill University in Montréal, Québec (from an April 16, 2015 McGill University news release; also on EurekAlert),

A concentrated extract of maple syrup makes disease-causing bacteria more susceptible to antibiotics, according to laboratory experiments by researchers at McGill University.

The findings, which will be published in the journal Applied and Environmental Microbiology, suggest that combining maple syrup extract with common antibiotics could increase the microbes’ susceptibility, leading to lower antibiotic usage. Overuse of antibiotics fuels the emergence of drug-resistant bacteria, which has become a major public-health concern worldwide.

Prof. Nathalie Tufenkji’s research team in McGill’s Department of Chemical Engineering prepared a concentrated extract of maple syrup that consists mainly of phenolic compounds. Maple syrup, made by concentrating the sap from North American maple trees, is a rich source of phenolic compounds.

The researchers tested the extract’s effect in the laboratory on infection-causing strains of certain bacteria, including E. coli and Proteus mirabilis (a common cause of urinary tract infection). By itself, the extract was mildly effective in combating bacteria. But the maple syrup extract was particularly effective when applied in combination with antibiotics. The extract also acted synergistically with antibiotics in destroying resistant communities of bacteria known as biofilms, which are common in difficult-to-treat infections, such as catheter-associated urinary tract infections.

“We would have to do in vivo tests, and eventually clinical trials, before we can say what the effect would be in humans,” Tufenkji says. “But the findings suggest a potentially simple and effective approach for reducing antibiotic usage. I could see maple syrup extract being incorporated eventually, for example, into the capsules of antibiotics.”

The scientists also found that the extract affects the gene expression of the bacteria, by repressing a number of genes linked with antibiotic resistance and virulence.

All maple syrup samples used in the study were purchased at local markets in Montreal, then frozen until the beginning of each experiment, which involved a series of steps to produce the phenolic-rich extract.

Tufenkji, who holds the Canada Research Chair in Biocolloids and Surfaces, has also studied the potential for cranberry derivatives to fight infection-causing bacteria. The new study is co-authored by postdoctoral fellows Vimal Maisuria and Zeinab Hosseinidoust.

Here’s a link to and a citation for the paper which at this time (April 24, 2014) is not yet published,,

Polyphenolic Extract from Maple Syrup Potentiates Antibiotic Susceptibility and Reduces Biofilm Formation of Pathogenic Bacteria by Vimal B. Maisuria, Zeinab Hosseinidoust, and Nathalie Tufenkji. doi: 10.1128/AEM.00239-15 AEM [Applied and Environmental Microbiology].00239-15

My guess is that this paper will be behind a paywall. Fear not! There is a very informative 3 mins. or so video,

I particularly appreciated the maple leaf-shaped glass container (still full) which is shown prominently when the researcher mentions purchasing the syrup from local markets.

Nanosilver resistance

Researchers at Australia’s University of New South Wales (UNSW) have published a study where they claim that bacteria have develop resistance to nanosilver, a product used widely for its antibacterial properties. From the May 8, 2013 news item on ScienceDaily,

Researchers from UNSW have cautioned that more work is needed to understand how micro-organisms respond to the disinfecting properties of silver nano-particles, increasingly used in consumer goods, and for medical and environmental applications.

Although nanosilver has effective antimicrobial properties against certain pathogens, overexposure to silver nano-particles can cause other potentially harmful organisms to rapidly adapt and flourish, a UNSW study reveals.

The May 8, 2013 UNSW news release, which originated the news item, notes,

“We found an important natural ability of a widely occurring bacteria to adapt quite rapidly to the antimicrobial action of nanosilver. This is the first unambiguous evidence of this induced adaptation,” says co-author Dr Cindy Gunawan, from the UNSW School of Chemical Engineering.

Using an experimental culture, UNSW researchers observed that nanosilver was effective in suppressing a targeted bacteria (Escherichia coli), but that its presence initiated the unexpected emergence, adaptation and abnormally fast growth of another bacteria species (Bacillus).

The news release mentions some of the implications,

The efficacy of nanosilver to suppress certain disease-causing pathogens has been well-documented, and as a result, it has become widely used in medicine to coat bandages and wound dressings. It also has environmental uses in water and air purification systems, and is used in cosmetics and detergents, and as a surface coating for things like toys and tupperware.

But the researchers say this exploitation of nanosilver’s antimicrobial properties have “gained momentum due in part to a lack of evidence for the potential development of resistant microorganisms”.

“Antimicrobial action of nanosilver is not universal and the widespread use of these products should take into consideration the potential for longer-term adverse outcomes,” says Gunawan.

The researchers say these adverse impacts could be more pronounced given the near-ubiquitous nature of the Bacillus bacteria, which originate from airborne spores, and because the resistance trait can potentially be transferred to the genes of other micro-organisms.

“For the medical use of nanosilver, this implies the potential for reduced efficacy and the development of resistant populations in clinical settings,” says co-author Dr Christopher Marquis, a senior lecturer from the UNSW School of Biotechnology and Biomolecular Sciences. [emphasis mine]

I have touched on the issue of resistance and bacteria previously in the context of finding new ways to deal with them in my Don’t kill bacteria, uninvite them posting of Aug. 13, 2012 about developing new materials that resist bacteria and and there’s my mention of Sharklet, a material based on the nanoscale properties of sharkskin and which has potential for use in hospital settings, in my Feb. 10, 2011 posting.

For those who’d like to read about this work from the University of New South Wales, the ScienceDaily news item provides a link to and a citation for the paper which has been published in Small. This paper is behind a paywall and the publisher (Wiley Online Library), puzzingly and in comparison to other publishers, has made the paper hard to find.