Tag Archives: Sharklet

Antiviral, antibacterial surface for reducing spread of infectious diseases

In the past several years, scientists have created antibacterial surfaces by fabricating materials with specific types of nanostructures. According to a May 27, 2020 news item on Nanowerk, scientists have now been able to add antiviral properties (Note: A link has been removed),

The novel coronavirus pandemic has caused an increased demand for antimicrobial treatments that can keep surfaces clean, particularly in health care settings. Although some surfaces have been developed that can combat bacteria, what’s been lacking is a surface that can also kill off viruses.

Now, researchers have found a way to impart durable antiviral and antibacterial properties to an aluminum alloy used in hospitals, according to a report in ACS Biomaterials Science & Engineering (“Antiviral and Antibacterial Nanostructured Surfaces with Excellent Mechanical Properties for Hospital Applications”).

A May 27, 2020 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, describes the problem and the proposed solution,

Among other mechanisms, viruses and bacteria can spread when a person touches a site where germs have settled, such as a doorframe, handrail or medical device. A healthy person can often fight off these bugs, but hospital patients can be more vulnerable to infection. The number of hospital-acquired infections has been on the decline in the U.S., but they still cause tens of thousands of deaths every year, according to the U.S. Department of Health and Human Services. Chemical disinfectants or coatings containing hydrophobic compounds, silver ions or copper can reduce infectious contaminants on surfaces, but these treatments don’t last. However, nature has developed its own solutions for battling microorganisms, including microscopic structural features that render some insect wings lethal to bacteria. Scientists have replicated this effect by forming surfaces covered with minute pillars and other shapes that distort and kill bacterial cells. But Prasad Yarlagadda and colleagues wanted to inactivate viruses as well as bacteria, so they set out to generate a novel nanoscale topography on long-lasting, industrially relevant materials.

The team experimented with disks of aluminum 6063, which is used in doorframes, window panels, and hospital and medical equipment. Etching the disks with sodium hydroxide for up to 3 hours changed the initially smooth, hydrophobic surface into a ridged, hydrophilic surface. Bacteria or viruses were then applied to the etched disks. Most of the Pseudomonas aeruginosa and Staphylococcus aureus bacteria were inactivated after 3 hours on the surface, while viability of common respiratory viruses dropped within 2 hours; both results were better than with plastic or smooth aluminum surfaces. The disks retained their effectiveness even after tests designed to mimic hospital wear and tear. The researchers note this is the first report to show combined antibacterial and antiviral properties of a durable, nanostructured surface that has the potential to stop the spread of infections arising from physical surfaces in hospitals. This strategy could be extended to surfaces in other public areas, such as cruise ships, planes and airports, they say. The team is now studying the effects of their nano-textured aluminum surfaces on the novel coronavirus.

This approach reminds me of Sharklet, a company fabricating a material designed to mimic a shark’s skin which is naturally antibacterial due to the nanostructures on its skin (see my September 18, 2014 posting).

More about Sharklet later. First, here’s a link to and a citation for the paper about this latest work,

Antiviral and Antibacterial Nanostructured Surfaces with Excellent Mechanical Properties for Hospital Applications by Jafar Hasan, Yanan Xu, Tejasri Yarlagadda, Michael Schuetz, Kirsten Spann, and Prasad KDV Yarlagadda. ACS Biomater. Sci. Eng. 2020, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsbiomaterials.0c00348 Publication Date:May 7, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Business and science: a Sharklet update

You can find the Sharklet website here. I wasn’t able to find any news about recent business deals other than the company’s acquisition by Peaceful Union in May 2017. From a May 17, 2017 Sharklet news release on Business Wire (and on the company website here),

Sharklet Technologies, Inc., a biotechnology company lauded for the creation and commercialization of Sharklet®, the world’s first micro-texture that inhibits bacterial growth on surfaces, has announced that it has completed a financing event led by Peaceful Union, an equity medical device firm in Hangzhou, China. Terms of the transaction were not disclosed.

The acquisition of the company will enable Sharklet Technologies to accelerate the development of Sharklet for medical devices where chemical-free bacterial inhibition is desired as well as high-touch surfaces prone to bacterial contamination. The company also will accelerate development of a newly enhanced wound dressing technology to encourage healing.

Joe Bagan and Mark Spiecker led the transaction structure. “This is an important day for the company and investors,” said Joe Bagan, former board chair, and Mark Spiecker, former CEO. “Our investors will realize a significant transaction while enabling the company to accelerate growth.”

In concert with the investment, Sharklet Technologies founding member, chief technology officer, and Sharklet inventor Dr. Anthony Brennan, will become chairman of the board assuming duties from chairman Joe Bagan and CEO Mark Spiecker.

Interestingly, Bagan and Spiecker are Chief Executive Officer (CEO) and President, respectively at STAQ Pharma. I wonder if there are plans to sell this company too.

Getting back to Sharklet, I found two items of recent origin about business but I cannot speak to the accuracy or trustworthiness of either item. That said, you will find they provide some detail about Sharklet’s new business directions and new business ties.

While Sharklet’s current business associations have a sketchy quality, it seems that’s not unusual in business, especially where new technologies are concerned. For example, the introduction of electricity into homes and businesses was a tumultuous affair as the 2008 book, ‘Power Struggles; Scientific Authority and the Creation of Practical Electricity Before Edison’ by Michael Brian Schiffer makes clear, from the MIT [Massachusetts Institute of Technology] Press ‘Power Struggles’ webpage,

In 1882, Thomas Edison and his Edison Electric Light Company unveiled the first large-scale electrical system in the world to light a stretch of offices in a city. … After laying out a unified theoretical framework for understanding technological change, Schiffer presents a series of fascinating case studies of pre-Edison electrical technologies, including Volta’s electrochemical battery, the blacksmith’s electric motor, the first mechanical generators, Morse’s telegraph, the Atlantic cable, and the lighting of the Capitol dome. Schiffer discusses claims of “practicality” and “impracticality” (sometimes hotly contested) made for these technologies, and examines the central role of the scientific authority—in particular, the activities of Joseph Henry, mid-nineteenth-century America’s foremost scientist—in determining the fate of particular technologies. These emerging electrical technologies formed the foundation of the modern industrial world. Schiffer shows how and why they became commercial products in the context of an evolving corporate capitalism in which conflicting judgments of practicality sometimes turned into power struggles. [emphases mine]

Even given that the book’s focus is pre-Edison electricity, how do you mention Edison himself without even casually mentioning Nikola Tesla and George Westinghouse in the book’s overview? Getting back to my point, emerging technologies do not emerge easily.

Sharklet’s sharkskin-like material

It’s one of my favourite technologies but there hasn’t been much talk about Sharklet for the last few years. My Feb. 10, 2011 posting about it had this,

They used sharkskin as an example for making a ‘smarter’ material. Scientists have observed that nanoscale structures on a shark’s skin have antibacterial properties. This is especially important when we have a growing problem with bacteria that are antibiotic resistant. David Pogue’s (the program host) interviewed scientists at Sharklet and highlighted their work producing a plastic with nanostructures similar to those found on sharkskin for use in hospitals, restaurants, etc.  I found this on the Sharklet website (from a rotating graphic on the home page),

The World Health Organization calls antibiotic resistance a leading threat to human health.

Sharkjet provides a non-toxic approach to bacterial control and doesn’t create resistance.

The reason that the material does not create resistance is that it doesn’t kill the bacteria (antibiotics kill most bacteria but cannot kill all of them with the consequence that only the resistant survive and reproduce). Excerpted from Sharklet’s technology page,

While the Sharklet pattern holds great promise to improve the way humans co-exist with microorganisms, the pattern was developed far outside of a laboratory. In fact, Sharklet was discovered via a seemingly unrelated problem: how to keep algae from coating the hulls of submarines and ships. In 2002, Dr. Anthony Brennan, a materials science and engineering professor at the University of Florida, was visiting the U.S. naval base at Pearl Harbor in Oahu as part of Navy-sponsored research. The U.S. Office of Naval Research solicited Dr. Brennan to find new antifouling strategies to reduce use of toxic antifouling paints and trim costs associated with dry dock and drag.

The most recent news from Sharklet comes in a Sept. 16, 2014 news release on EurekAlert which refines the definition for Sharklet and provides research about the latest research on this material,

Transmission of bacterial infections, including MRSA and MSSA could be curbed by coating hospital surfaces with microscopic bumps that mimic the scaly surface of shark skin, according to research published in the open access journal Antimicrobial Resistance and Infection Control.

The study modelled how well different materials prevented the spread of human disease bacteria through touching, sneezes or spillages. The micropattern, named Sharklet™, is an arrangement of ridges formulated to resemble shark skin. The study showed that Sharklet harboured 94% less MRSA bacteria than a smooth surface, and fared better than copper, a leading antimicrobial material. The bacteria were less able to attach to Sharklet’s imperceptibly textured surface, suggesting it could reduce the spread of superbugs in hospital settings.

The surfaces in hospitals and healthcare settings are often rife with bacteria and patients are vulnerable to bacterial infection. Scientists are investigating the ability of different materials to prevent the spread of bacteria. Copper alloys are a popular option, as they are toxic to bacterial cells, interfering with their cellular processes and killing them. The Sharklet micropattern works differently – the size and composition of its microscopic features prevent bacteria from attaching to it. It mimics the unique qualities of shark skin, which, unlike other underwater surfaces, inhibits bacteria, because it is covered with a natural micropattern of tooth-like structures, called denticles.

Dr Ethan Mann, a research scientist at Sharklet Technologies, the manufacturer of the micropattern, says: “The Sharklet texture is designed to be manufactured directly into the surfaces of plastic products that surround patients in hospital, including environmental surfaces as well as medical devices. Sharklet does not introduce new materials or coatings – it simply alters the shape and texture of existing materials to create surface properties that are unfavorable for bacterial contamination.”

The researchers from Sharklet Technologies compared how well two types of infection-causing bacteria, methicillin-resistant or susceptible Staphylococcus aureus (MRSA and MSSA), fared at contaminating three surfaces – the Sharklet micropattern, a copper alloy, and a smooth control surface. They created experimental procedures to mimic common ways bacteria infect surfaces. Sneezing was mimicked by using a paint sprayer to spread the bacterial solution on 10 samples of each surface. To mimic infected patients touching the surfaces, velveteen cloth was put in contact with bacteria for 10s, and then placed on another set of each test surface for 10s. A third set of each surface was immersed in bacterial solution for an hour, then rinsed and dried, to mimic spills.

Surfaces were sampled for remaining contaminations either immediately following exposure to MSSA and MRSA or 90 minutes after being exposed. The Sharklet micropattern reduced transmission of MSSA by 97% compared to the smooth control, while copper was no better than the control. The micropattern also harboured 94% less MRSA bacteria than the control surface, while the copper had 80% less.

Dr Mann says: “Shark skin itself is not an antimicrobial surface, rather it seems highly adapted to resist attachment of living organisms such as algae and barnacles. Shark skin has a specific roughness and certain properties that deter marine organisms from attaching to the skin surface. We have learned much from nature in building this material texture for the future.”

Here’s an illustration the researchers have provided,

Caption: This is an image of the Sharklet micropattern, which mimics the denticles of shark skin. Credit: Mann et al.

Caption: This is an image of the Sharklet micropattern, which mimics the denticles of shark skin.
Credit: Mann et al.

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

Surface micropattern limits bacterial contamination by Ethan E Mann, Dipankar Manna, Michael R Mettetal, Rhea M May, Elisa M Dannemiller, Kenneth K Chung, Anthony B Brennan, and Shravanthi T Reddy. Antimicrobial Resistance and Infection Control 2014, 3:28  doi:10.1186/2047-2994-3-28

This is an open access paper.

No more boat scraping with new coating from Duke University

There’s a lot of interest in finding ways to discourage bacteria from growing on various surfaces, for example, Sharklet, which is based on nanostructures on sharkskin, is a product being developed for hospitals (my Feb. 10, 2011 posting) and there are polymers that ‘uninvite’ bacteria at the University of Nottingham (my Aug. 13, 2012 posting).

A Jan. 31, 2013 news item on Nanowerk highlights the latest work being done at Duke University,

Duke University engineers have developed a material that can be applied like paint to the hull of a ship and will literally be able to dislodge bacteria, keeping it from accumulating on the ship’s surface. This buildup on ships increases drag and reduces the energy efficiency of the vessel, as well as blocking or clogging undersea sensors.

The team’s research was published online,

Bioinspired Surfaces with Dynamic Topography for Active Control of Biofouling by Phanindhar Shivapooja, Qiming Wang, Beatriz Orihuela, Daniel Rittschof, Gabriel P. López1, Xuanhe Zhao. Advanced Materials, Article first published online: 6 JAN 2013, DOI: 10.1002/adma.201203374

Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The article is behind a paywall but the abstract is freely available,

Dynamic change of surface area and topology of elastomers is used as a general, environmentally friendly approach for effectively detaching micro- and macro-fouling organisms adhered on the elastomer surfaces. Deformation of elastomer surfaces under electrical or pneumatic actuation can debond various biofilms and barnacles. The bio-inspired dynamic surfaces can be fabricated over large areas through simple and practical processes. This new mechanism is complementary with existing materials and methods for biofouling control.

Duke University’s Jan. 31, 2013 news release by Richard Merritt, which originated the news item, provides more detail from the researchers,

“We have developed a material that ‘wrinkles,’ or changes it surface in response to a stimulus, such as stretching or pressure or electricity,” said Duke engineer Xuanhe Zhao, assistant professor in Duke’s Pratt School of Engineering. “This deformation can effectively detach biofilms and other organisms that have accumulated on the surface.”

Zhao has already demonstrated the ability of electric current to deform, or change, the surface of polymers.

The researchers tested their approach in the laboratory with simulated seawater, as well as on barnacles. These experiments were conducted in collaboration with Daniel Rittsch of the Duke University Marine Lab in Beaufort, N.C.

Keeping bacteria from attaching to ship hulls or other submerged objects can prevent a larger cascade of events that can reduce performance or efficiency. Once they have taken up residence on a surface, bacteria often attract larger organisms, such as seaweed and larva of other marine organisms, such as worms, bivalves, barnacles or mussels.

There are other ways to introduce efficiencies in marine transp0rtation as per my June 27, 2012 posting about Zyvex Marine and its new composites which will make for lighter vessels.

Don’t kill bacteria, uninvite them

The relentless campaign against bacteria has had some unintended consequences, we’ve made bacteria more resistant and more virulent. Researchers at the University of Nottingham (UK) have taken a different approach from attempting to eradicate or kill; they’ve discovered a class of polymers that ‘uninvites’ bacteria from their surfaces. From the Aug. 13, 2012 news item on ScienceDaily,

Using state-of-the-art technology, scientists at The University of Nottingham have discovered a new class of polymers that are resistant to bacterial attachment. These new materials could lead to a significant reduction in hospital infections and medical device failures.

Medical device associated infections can lead to systemic infections or device failure, costing the NHS £1bn a year. Affecting many commonly used devices including urinary and venous catheters — bacteria form communities known as biofilms. This ‘strength in numbers approach’ protects them against the bodies’ natural defences and antibiotics.

Experts in the Schools of Pharmacy and Molecular Medical Sciences, have shown that when the new materials are applied to the surface of medical devices they repel bacteria and prevent them forming biofilms.

There’s a video of the scientists discussing their work on this new class of polymers,

In order to find this new class of polymers, the scientists had to solve another problem first. From the Aug. 12, 2012 University of Nottingham press release,

Researchers believed there were new materials that could resist bacteria better but they had to find them. This meant screening thousands of different chemistries and testing their reaction to bacteria — a challenge which was beyond conventional materials development or any of our current understanding of the interaction of micro-organisms with surfaces.

The discovery has been made with the help of experts from the Massachusetts Institute of Technology (MIT) — who initially developed the process by which thousands of unique polymers can now be screened simultaneously.

Professor Alexander said: “This is a major scientific breakthrough — we have discovered a new group of structurally related materials that dramatically reduce the attachment of pathogenic bacteria (Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli). We could not have found these materials using the current understanding of bacteria-surface interactions. The technology developed with the help of MIT means that hundreds of materials could be screened simultaneously to reveal new structure-property relationships. In total thousands of materials were investigated using this high throughput materials discovery approach leading to the identification of novel materials resisting bacterial attachment. This could not have been achieved using conventional techniques.”

Once they found this new class of polymers, researchers tested for effectiveness (from the Aug. 12, 2012 university press release),

These new materials prevent infection by stopping biofilm formation at the earliest possible stage — when the bacteria first attempt to attach themselves to the device. In the laboratory experts were able to reduce the numbers of bacteria by up to 96.7per cent — compared with a commercially available silver containing catheter — and were effective at resisting bacterial attachment in a mouse implant infection model. By preventing bacterial attachment the body’s own immune system can kill the bacteria before they have time to generate biofilms.

You can read more about this work in the paper the researchers have published (as well as, the news item on ScienceDaily or the University of Nottingham press release for more accessible explanations). You will need to get past a paywall (from the news item on ScienceDaily),

Andrew L Hook, Chien-Yi Chang, Jing Yang, Jeni Luckett, Alan Cockayne, Steve Atkinson, Ying Mei, Roger Bayston, Derek J Irvine, Robert Langer, Daniel G Anderson, Paul Williams, Martyn C Davies, Morgan R Alexander. Combinatorial discovery of polymers resistant to bacterial attachment. Nature Biotechnology, 2012; DOI: 10.1038/nbt.2316

This research reminded me of Sharklet, a product being developed in the US for use in hospitals. Designed to mimic sharkskin, the product discourages bacteria from settling on its surface. It was featured in my Feb. 10, 2011 posting.

Thoughts on part 4 of (PBS) Nova’s Making Stuff series

Last night (Feb.9.11) PBS aired the final part of the Making Stuff  series as part of its Nova tv programming. It was titled Making Stuff Smarter and did not feature a single bot of any kind or any nanoscale computers or labs on chips thereby frustrating (not in a bad way) some of my expectations but I should have become accustomed to that by now.

There was a focus on something called biomimicry, a term I did not hear used while I was watching (confession: I didn’t watch every single minute of the show), where researchers try to make materials that mimic a process or ability observed in nature. They used sharkskin as an example for making a ‘smarter’ material. Scientists have observed that nanoscale structures on a shark’s skin have antibacterial properties. This is especially important when we have a growing problem with bacteria that are antibiotic resistant. David Pogue’s (the program host) interviewed scientists at Sharklet and highlighted their work producing a plastic with nanostructures similar to those found on sharkskin for use in hospitals, restaurants, etc.  I found this on the Sharklet website (from a rotating graphic on the home page),

The World Health Organization calls antibiotic resistance a leading threat to human health.

Sharkjet provides a non-toxic approach to bacterial control and doesn’t create resistance.

The reason that the material does not create resistance is that it doesn’t kill the bacteria (antibiotics kill most bacteria but cannot kill all of them with the consequence that only the resistant survive and reproduce). Excerpted from Sharklet’s technology page,

While the Sharklet pattern holds great promise to improve the way humans co-exist with microorganisms, the pattern was developed far outside of a laboratory. In fact, Sharklet was discovered via a seemingly unrelated problem: how to keep algae from coating the hulls of submarines and ships. In 2002, Dr. Anthony Brennan, a materials science and engineering professor at the University of Florida, was visiting the U.S. naval base at Pearl Harbor in Oahu as part of Navy-sponsored research. The U.S. Office of Naval Research solicited Dr. Brennan to find new antifouling strategies to reduce use of toxic antifouling paints and trim costs associated with dry dock and drag.

Dr. Brennan was convinced that using an engineered topography could be a key to new antifouling technologies. Clarity struck as he and several colleagues watched an algae-coated nuclear submarine return to port. Dr. Brennan remarked that the submarine looked like a whale lumbering into the harbor. In turn, he asked which slow moving marine animals don’t foul. The only one? The shark.

Dr. Brennan was inspired to take an actual impression of shark skin, or more specifically, its dermal denticles. Examining the impression with scanning electron microscopy, Dr. Brennan confirmed his theory. Shark skin denticles are arranged in a distinct diamond pattern with tiny riblets. Dr. Brennan measured the ribs’ width-to-height ratios which corresponded to his mathematical model for roughness – one that would discourage microorganisms from settling. The first test of Sharklet yielded impressive results. Sharklet reduced green algae settlement by 85 percent compared to smooth surfaces.

There’s more to the story so I encourage you to take a look at the page. What I find compelling about biomimicry is that we are learning from nature and mimicking it rather than try to control or destroy what we view as dangerous to us or, in some cases, not valuable. Interestingly, this program featured the military quite prominently in other segments while, as far as I’m aware, failing to mention biomimcry  which suggests (I’m putting on my semiotic hat) that our ideas about controlling nature and using warlike metaphors to describe scientific and medical efforts are still dominant socially and being reproduced.

I enjoyed (with qualifications regarding some of the subtext) the program series (all three of the shows I managed to watch) but, as I’ve noted previously, I’m not the target market so some of it was a bit too fluffy for me.

I found this fourth installment the most interesting and I was delighted to see that they featured climbing robots (based on geckos and mentioned in my Aug. 2, 2010 posting) and invisibility (mentioned most recently in my Jan. 26, 2011 posting although that features a different approach than the one mentioned in the program) along with a few items that were new to me.

Coincidentally the National Film Board of Canada is featuring a film short titled, Magic Molecule in its Feb. 9, 2011 newsletter. Produced in 1964, it introduces us to the fabulous world of plastics. In some ways, it’s very similar to the Making Stuff series. The tone is upbeat and very much pro plastics and its wonders.