Tag Archives: hydrogels

Seeing signs of osteoarthritis before joint replacements necessary

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A November 29, 2024 Canadian Light Source (CLS) news release (also received via email) by Brian Owens describes research that could benefit people who don’t know they have the beginning signs of osteoarthritis,

An imaging technique currently available only at synchrotrons like the Canadian Light Source at the University of Saskatchewan (USask) could one day enable doctors to detect osteoarthritis while patients can still be treated with medication – before they require joint replacement — thanks to research by USask scientist Brian Eames and colleagues.

In a pair of studies, Eames, a professor of Anatomy, Physiology, and Pharmacology in the USask College of Medicine, found that phase contrast imaging (PCI) detects very subtle changes in cartilage. He says the technique, which takes advantage of the high-energy light produced by the synchrotron, provides “fantastic” imaging of cartilage.

In the most recent study, Eames and colleagues (Daniel Chen, College of Engineering; Ali Honoramooz, Western College of Veterinary Medicine; Bill Dust, College of Medicine; and PhD student Hamed Alizadeh) used PCI to determine how well 3D-bioprinted cartilage could repair damaged joints. They compared the performance of cells impregnated in two different materials – one a squishy material called hydrogel and the other a hybrid construct combining hydrogel with a stiff plastic material. They hypothesized that the hybrid construct would shield the cells from forces in the recovering joint, so that the proper type of cartilage (hyaline) could form.

When they implanted these materials into animal joints, the researchers found that both helped new cartilage form, with the hydrogel doing slightly better by some measures. The hybrid, however, had one advantage: It formed less fibrocartilage, which was consistent with the team’s hypothesis. Fibrocartilage is a tougher form of cartilage that is created when joints are under stress. Having less fibrocartilage provides better joint function.

In an earlier study, Eames found that the superior resolution of PCI enabled more precise mapping of the articular cartilage surface than MRI – currently the “go to” imaging technique for osteoarthritis

Eames says that, while both sets of results are interesting, he’s more excited about the potential they hint at for bringing PCI into the clinical setting. PCI’s precision and ability to detect subtle changes “might be able to increase the ability to detect osteoarthritis earlier than regular clinical monitoring,” giving doctors more options for early treatment and researchers potential new targets for drug development.

While a football-field-sized synchrotron will never be a standard part of a hospital imaging suite, Eames says some companies are already working on ways to adapt the technology to make it portable for clinical use.

“The [CLS] is a nice test case for the technology that others can try to adapt for clinical use in humans,” he says.

Eames is seen discussing the work in this video,

Here are links to both papers mentioned in the news release, with the most recent work being first,

Comparison study on hyaline cartilage versus fibrocartilage formation in a pig model by using 3D-bioprinted hydrogel and hybrid constructs by Hamed Alizadeh Sardroud, Gustavo Dos Santos Rosa, William Dust, Tat-Chuan Cham, Gwen Roy, Sarah Bater, Alan Chicoine, Ali Honaramooz, Xiongbiao Chen and B Frank Eames. Biofabrication, 015014 Volume 17, Number 1 DOI 10.1088/1758-5090/ad88a6 Published 5 November 2024 • © 2024 The Author(s). Published by IOP Publishing Ltd

This paper is open access.

MRI overestimates articular cartilage thickness and volume compared to synchrotron radiation phase-contrast imaging by Suranjan Bairagi, Mohammad-Amin Abdollahifar, Oghenevwogaga J. Atake, William Dust, Sheldon Wiebe, George Belev, L. Dean Chapman, M. Adam Webb, Ning Zhu, David M. L. Cooper, B. Frank Eames. PLOS DOI: https://doi.org/10.1371/journal.pone.0291757 Published: October 3, 2023

This paper is open access.

‘Jelly’ batteries

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Caption: Researchers have developed soft, stretchable ‘jelly batteries’ that could be used for wearable devices or soft robotics, or even implanted in the brain to deliver drugs or treat conditions such as epilepsy. Credit: University of Cambridge

A July 18, 2024 news item on Nanowerk announces bioinspried stretchy batteries from the University of Cambridge,

Researchers have developed soft, stretchable ‘jelly batteries’ that could be used for wearable devices or soft robotics, or even implanted in the brain to deliver drugs or treat conditions such as epilepsy.

The researchers, from the University of Cambridge, took their inspiration from electric eels, which stun their prey with modified muscle cells called electrocytes.

Like electrocytes, the jelly-like materials developed by the Cambridge researchers have a layered structure, like sticky Lego, that makes them capable of delivering an electric current.

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A July 17, 2024 University of Cambridge press release (also on EurekAlert), which originated the news item, offers more details,

The self-healing jelly batteries can stretch to over ten times their original length without affecting their conductivity – the first time that such stretchability and conductivity has been combined in a single material. The results are reported in the journal Science Advances.

The jelly batteries are made from hydrogels: 3D networks of polymers that contain over 60% water. The polymers are held together by reversible on/off interactions that control the jelly’s mechanical properties.

The ability to precisely control mechanical properties and mimic the characteristics of human tissue makes hydrogels ideal candidates for soft robotics and bioelectronics; however, they need to be both conductive and stretchy for such applications.

“It’s difficult to design a material that is both highly stretchable and highly conductive, since those two properties are normally at odds with one another,” said first author Stephen O’Neill, from Cambridge’s Yusuf Hamied Department of Chemistry. “Typically, conductivity decreases when a material is stretched.”

“Normally, hydrogels are made of polymers that have a neutral charge, but if we charge them, they can become conductive,” said co-author Dr Jade McCune, also from the Department of Chemistry. “And by changing the salt component of each gel, we can make them sticky and squish them together in multiple layers, so we can build up a larger energy potential.”

Conventional electronics use rigid metallic materials with electrons as charge carriers, while the jelly batteries use ions to carry charge, like electric eels.

The hydrogels stick strongly to each other because of reversible bonds that can form between the different layers, using barrel-shaped molecules called cucurbiturils that are like molecular handcuffs. The strong adhesion between layers provided by the molecular handcuffs allows for the jelly batteries to be stretched, without the layers coming apart and crucially, without any loss of conductivity.

The properties of the jelly batteries make them promising for future use in biomedical implants, since they are soft and mould to human tissue. “We can customise the mechanical properties of the hydrogels so they match human tissue,” said Professor Oren Scherman, Director of the Melville Laboratory for Polymer Synthesis, who led the research in collaboration with Professor George Malliaras from the Department of Engineering. “Since they contain no rigid components such as metal, a hydrogel implant would be much less likely to be rejected by the body or cause the build-up of scar tissue.”

In addition to their softness, the hydrogels are also surprisingly tough. They can withstand being squashed without permanently losing their original shape, and can self-heal when damaged.

The researchers are planning future experiments to test the hydrogels in living organisms to assess their suitability for a range of medical applications.

The research was funded by the European Research Council and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI). Oren Scherman is a Fellow of Jesus College, Cambridge.

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

Highly stretchable dynamic hydrogels for soft multilayer electronics by Stephen J. K. O’Neill, Zehuan Huang, Xiaoyi Chen, Renata L. Sala, Jade A. McCune, George G. Malliaras, and Oren A. Scherman. Science Advances 17 Jul 2024 Vol 10, Issue 29 DOI: 10.1126/sciadv.adn5142

This paper appears to be open access.

Regenerate damaged skin, cartilage, and bone with help from silkworms?

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A July 24, 2024 news item on phys.org highlights research into regenerating bone and skin, Note: A link has been removed,

Researchers are exploring new nature-based solutions to stimulate skin and bone repair.

In the cities of Trento and Rovereto in northern Italy and Bangkok in Thailand, scientists are busy rearing silkworms in nurseries. They’re hoping that the caterpillars’ silk can regenerate human tissue. For such a delicate medical procedure, only thoroughbreds will do.

“By changing the silkworm, you can change the chemistry,” said Professor Antonella Motta, a researcher in bioengineering at the University of Trento in Italy. That could, in turn, affect clinical outcomes. “This means the quality control should be very strict.”

Silk has been used in surgical sutures for hundreds of years and is now emerging as a promising nature-based option for triggering human tissue to self-regenerate. Researchers are also studying crab, shrimp and mussel shells and squid skin and bone for methods of restoring skin, bone and cartilage. This is particularly relevant as populations age.

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A July 23, 2024 article by Gareth Willmer for Horizon Magazine, the EU (European Union) research & innovation magazine, which originated the news item, provides more details,

‘Tissue engineering is a new strategy to solve problems caused by pathologies or trauma to the organs, as an alternative to transplants or artificial device implantations,’ said Motta, noting that these interventions can often fail or expire. ‘The idea is to use the natural ability of our bodies to rebuild the tissue.’

The research forms part of the five-year EU-funded SHIFT [Shaping Innovative Designs for Sustainable Tissue Engineering Products] project that Motta coordinates, which includes universities in Europe, as well as partners in Asia and Australia. Running until 2026, the research team aim to scale up methods for regenerating skin, bone and cartilage using bio-based polymers and to get them ready for clinical trials. The goal is to make them capable of repairing larger wounds and tissue damage.

The research builds on work carried out under the earlier REMIX [Regenerative Medicine Innovation Crossing – Research and Innovation Staff Exchange in Regenerative Medicine] project, also funded by the EU, which made important advances in understanding the different ways in which these biomaterials could be used. 

Building a scaffold

Silk, for instance, can be used to form a “scaffold” in damaged tissue that then activates cells to form new tissue and blood vessels. The process could be used to treat conditions such as diabetic ulcers and lower back pain caused by spinal disc degeneration. The SHIFT team have been exploring minimally invasive procedures for treatment, such as hydrogels that can be applied directly to the skin, or injected into bone or cartilage.

The approaches using both silkworms and some of the marine organisms have great potential, said Motta. 

‘We have three or four systems with different materials that are really promising,’ she said. By the end of SHIFT, the goal is to have two or three prototypes that can be developed together with start-up and spin-off companies created in collaboration with the project. 

One of the principles of the SHIFT team has been been exploring how best to harness the concept of a circular economy. For example, they are looking into how waste products from the textile and food industries can be reused in these treatments.

Yet with complicated interactions at a microscale, and the need to prevent the body from rejecting foreign materials, such tissue engineering is a big challenge. 

‘The complexity is high because the nature of biology is not easy,’ said Motta. ‘We cannot change the language of the cells, but instead have to learn to speak the same language as them.’

But she firmly believes the nature-based rather than synthetic approach is the way to go and thinks treatments harnessing SHIFT’s methods could become available in the early 2030s. 

‘I believe in this approach,’ said Motta. ‘Bone designed by nature is the best bone we can have.’

Skin care

Another EU-funded project known as SkinTERM [Skin Tissue Engineering and Regenerative Medicine: From skin repair to regeneration], which runs for almost five years until mid-2025, is also looking at novel ways to get tissue to self-regenerate, focusing on skin. To treat burns and other surface wounds today, a thin layer of skin is sometimes grafted from another part of the body. This can cause the appearance of disfiguring scars and the patient’s mobility may be impacted when the tissue contracts as it heals. Current skin-grafting methods can also be painful.

The SkinTERM team are therefore investigating how inducing the healing process in the networks of cells surrounding a wound might enable skin to repair itself. 

‘We could do much better if we move towards regeneration,’ said Dr Willeke Daamen, who coordinates SkinTERM as a researcher in soft tissue regeneration at Radboud University in Nijmegen, the Netherlands. ‘The ultimate goal would be to get the same situation before and after being wounded.’

Researchers are studying a particular mammal – the spiny mouse – which has a remarkable ability to heal without scarring. It is able to self-repair damage to other tissues like the heart and spinal cord too. This is also true of early foetal skin.

The team are examining these systems to learn more about how they work and the processes occurring in the area around cells, known as the extracellular matrix. They hope to identify factors that might have a role in the regenerative process, and test how it might be induced in humans. 

Kick-start

‘We’ve been trying to learn from those systems on how to kick-start such processes,’ said Daamen. ‘We’ve made progress in what kinds of compounds seem at least in part to be responsible for a regenerative response.’

Many lines of research are being carried out among a new generation of multidisciplinary scientists being trained in this area, and a lot has already been achieved, said Daamen.

They have managed to create scaffolds using different components related to skin regeneration, such as the proteins collagen and elastin. They have also collected a vast amount of data on genes and proteins with potential roles in regeneration. Their role will be further tested by using them on scar-prone cells cultured on collagen scaffolds.

‘The mechanisms are complex,’ said Dr Bouke Boekema, a senior researcher at the Association of Dutch Burn Centres in Beverwijk, the Netherlands, and vice-coordinator of SkinTERM. 

‘If you find a mechanism, the idea is that maybe you can tune it so that you can stimulate it. But there’s not necessarily one magic bullet.’

By the end of the project next year, Boekema hopes the research could result in some medical biomaterial options to test for clinical use. ‘It would be nice if several prototypes were available for testing to see if they improve outcomes in patients.’

Research in this article was funded by the Marie Skłodowska-Curie Actions (MSCA). The views of the interviewees don’t necessarily reflect those of the European Commission. If you liked this article, please consider sharing it on social media.

Interesting. Over these last few months, I’ve been stumbling across more than my usual number of regenerative medicine stories.

Programmable living materials made with 3D printing methods and synthetic biology

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There’s more than one ‘living’ material story here on this blog; it’s the plant cells that make this latest story different from the others. From a May 1, 2024 news item on phys.org, Note: A link has been removed,

Scientists are harnessing cells to make new types of materials that can grow, repair themselves and even respond to their environment. These solid “engineered living materials” are made by embedding cells in an inanimate matrix that’s formed in a desired shape. Now, researchers report in ACS Central Science that they have 3D printed a bioink containing plant cells that were then genetically modified, producing programmable materials. Applications could someday include biomanufacturing and sustainable construction.

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Caption: After 24 days, the colors produced by plant cells in two different bioinks printed in this leaf-shaped engineered living material are clearly visible. Credit: Adapted from ACS Central Science 2024, DOI: 10.1021/acscentsci.4c00338

A May 1, 2024 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, explains what makes this living material different,

Recently, researchers have been developing engineered living materials, primarily relying on bacterial and fungal cells as the live component. But the unique features of plant cells have stirred enthusiasm for their use in engineered plant living materials (EPLMs). However, the plant cell-based materials created to date have had fairly simple structures and limited functionality. Ziyi Yu, Zhengao Di and colleagues wanted to change that by making intricately shaped EPLMs containing genetically engineered plant cells with customizable behaviors and capabilities.

The researchers mixed tobacco plant cells with gelatin and hydrogel microparticles that contained Agrobacterium tumefaciens, a bacterium commonly used to transfer DNA segments into plant genomes. This bioink mixture was then 3D printed on a flat plate or inside a container filled with another gel to form shapes such as grids, snowflakes, leaves and spirals. Next, the hydrogel in the printed materials was cured with blue light, hardening the structures. During the ensuing 48 hours, the bacteria in the EPLMs transferred DNA to the growing tobacco cells. The materials were then washed with antibiotics to kill the bacteria. In the following weeks, as the plant cells grew and replicated in the EPLMs, they began producing proteins dictated by the transferred DNA.

In this proof-of-concept study, the transferred DNA enabled the tobacco plant cells to produce green fluorescent proteins or betalains — red or yellow plant pigments that are valued as natural colorants and dietary supplements. By printing a leaf-shaped EPLM with two different bioinks — one that created red pigment along the veins and the other a yellow pigment in the rest of the leaf — the researchers showed that their technique could produce complex, spatially controlled and multifunctional structures. Such EPLMs, which combine the traits of living organisms with the stability and durability of non-living substances, could find use as cellular factories to churn out plant metabolites or pharmaceutical proteins, or even in sustainable construction applications, according to the researchers.

The authors acknowledge funding from National Key Research and Development Program of China, the National Natural Science Foundation of China, the Natural Science Foundation of Jiangsu Province, and the State Key Laboratory of Materials-Oriented Chemical Engineering.

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

Advancing Engineered Plant Living Materials through Tobacco BY-2 Cell Growth and Transfection within Tailored Granular Hydrogel Scaffolds by Yujie Wang, Zhengao Di, Minglang Qin, Shenming Qu, Wenbo Zhong, Lingfeng Yuan, Jing Zhang, Julian M. Hibberd, and Ziyi Yu. ACS Cent. Sci. 2024, 10, 5, 1094–1104 DOI: https://doi.org/10.1021/acscentsci.4c00338 Publication Date:May 1, 2024 Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.

This paper is open access.

I think the last three years in particular have seen an upsurge of living materials stories (on this blog, at least). This one is a favourite of mine,

If you’re curious to see more, I suggest using the search term ‘living materials’.

Nanocellulose film and Kiragami hydrogels

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A Kirigami pattern of the hydrogel (top) and the hydrogel swollen from dry state (bottom). (Image: NIMS) [downloaded from https://www.nanowerk.com/nanotechnology-news3/newsid=65005.php]

An April 11, 2024 news item on Nanowerk highlights research that combines kiragami with hydrogel production, Note 1: A link has been removed, Note 2: Kiragami is described in the excerpt after this one,

New options for making finely structured soft, flexible and expandable materials called hydrogels have been developed by researchers at Tokyo University of Agriculture and Technology (TUAT). Their work extends the emerging field of ‘kirigami hydrogels’, in which patterns are cut into a thin film allowing it to later swell into complex hydrogel structures.

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An April 12, 2024 Tokyo University of Agriculture and Technology (TUAT) press release, which originated the news item, on JCN Newswire, Note: Distribution of press releases can be spread out over days (sometimes identical press releases are sent out twice, months apart),

Hydrogels have a network of water-attracting (hydrophilic) molecules, allowing their structure to swell substantially when exposed to water that becomes incorporated within the molecular network. Researchers Daisuke Nakagawa and Itsuo Hanasaki worked with an initially dry film composed of nanofibers of cellulose, the natural material that forms much of the structure of plant cell walls.

They used laser processing to cut structures into the film before water was added allowing the film to swell. The particular design of the Kirigami pattern works in such a way that the width increases when stretched in the longitudinal direction, which is called the auxetic property. This auxetic property emerges provided that the thickness grows sufficiently when the original thin film is wet.

“As Kirigami literally means the cut design of papers [emphasis mine], it was originally intended for thin sheet structures. On the other hand, our two-dimensional auxetic mechanism manifests when the thickness of the sheet is sufficient, and this three dimensionality of the hydrogel structure emerges by swelling when it is used. It is convenient to store it in the dry state before use, rather than keeping the same water content level of the hydrogel.” says Hanasaki. “Furthermore, the auxeticity is maintained during the cyclic loading that causes the adaptive deformation of the hydrogel to reach another structural state. It will be important for the design of intelligent materials.”

Potential applications for the adaptive hydrogels include soft components of robotic technologies, allowing them to respond flexibly when interacting with objects they are manipulating, for example. They might also be incorporated into soft switches and sensor components. Hydrogels are also being explored for medical applications, including tissue engineering, wound dressings, drug delivery systems and materials that can adapt flexibly to movement and growth. The advance in kirigami hydrogels achieved by the TUAT team significantly extends the options for future hydrogel applications.

“Keeping the designed characteristics while showing adaptivity to the environmental condition is advantageous for the development of multifunctionality,” Hanasaki concludes

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

Adaptive plasticity of auxetic Kirigami hydrogel fabricated from anisotropic swelling of cellulose nanofiber film by Daisuke Nakagawa & Itsuo Hanasaki. Science and Technology of Advanced Materials Volume 25, 2024 – Issue 1 Article: 2331959 DOI: https://doi.org/10.1080/14686996.2024.2331959 Published online: 02 Apr 2024

This is an open access paper.

Mending a broken heart with hydrogels and cellulose nanocrystals (CNC)

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Courtesy: University of Waterloo

This February 12, 2024 news item on ScienceDaily highlights work from the University of Waterloo,

You can mend a broken heart this valentine’s day now that researchers invented a new hydrogel that can be used to heal damaged heart tissue and improve cancer treatments.

University of Waterloo chemical engineering researcher Dr. Elisabeth Prince teamed up with researchers from the University of Toronto and Duke University to design the synthetic material made using cellulose nanocrystals [CNC], which are derived from wood pulp.

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A February 12, 2024 University of Waterloo news release (also on EurekAlert), which originated the news item, fills in some details,

The material is engineered to replicate the fibrous nanostructures and properties of human tissues, thereby recreating its unique biomechanical properties.

“Cancer is a diverse disease and two patients with the same type of cancer will often respond to the same treatment in very different ways,” Prince said. “Tumour organoids are essentially a miniaturized version of an individual patient’s tumour that can be used for drug testing, which could allow researchers to develop personalized therapies for a specific patient.”

As director of the Prince Polymer Materials Lab, Prince designs synthetic biomimetic hydrogels for biomedical applications. The hydrogels have a nanofibrous architecture with large pores for nutrient and waste transport, which affect mechanical properties and cell interaction. 

Prince, a professor in Waterloo’s Department of Chemical Engineering, utilized these human-tissue mimetic hydrogels to promote the growth of small-scale tumour replicas derived from donated tumour tissue. 

She aims to test the effectiveness of cancer treatments on the mini-tumour organoids before administering the treatment to patients, potentially allowing for personalized cancer therapies. This research was conducted alongside Professor David Cescon at the Princess Margaret Cancer Center.

Prince’s research group at Waterloo is developing similar biomimetic hydrogels to be injectable for drug delivery and regenerative medical applications as Waterloo researchers continue to lead health innovation in Canada.

Her research aims to use injected filamentous hydrogel material to regrow heart tissue damaged after a heart attack. She used nanofibers as a scaffolding for the regrowth and healing of damaged heart tissue. 

“We are building on the work that I started during my PhD to design human-tissue mimetic hydrogels that can be injected into the human body to deliver therapeutics and repair the damage caused to the heart when a patient suffers a heart attack,” Prince said.

Prince’s research is unique as most gels currently used in tissue engineering or 3D cell culture don’t possess this nanofibrous architecture. Prince’s group uses nanoparticles and polymers as building blocks for materials and develops chemistry for nanostructures that accurately mimic human tissues.

The next step in Prince’s research is to use conductive nanoparticles to make electrically conductive nanofibrous gels that can be used to heal heart and skeletal muscle tissue.

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

Nanocolloidal hydrogel mimics the structure and nonlinear mechanical properties of biological fibrous networks by Elisabeth Prince, Sofia Morozova, Zhengkun Chen, and Eugenia Kumacheva. Proceedings of the National Academy of Sciences (PNAS) December 13, 2023 120 (51) e2220755120 DOI: https://doi.org/10.1073/pnas.2220755120

This paper is behind a paywall.

Using insect corpses to create biodegradable plastics

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Caption: Black soldier flies are a good source of chemicals to make bioplastics. Credit: Cassidy Tibbetts

The American Chemical Society (ACS) held its Fall 2023 meeting (Aug. 13 -17, 2023) and amongst roughly 12,000 presentations there was this one on insects and degradable plastics as described in an August 14, 2023 ACS news release (also on EurekAlert),

Imagine using insects as a source of chemicals to make plastics that can biodegrade later — with the help of that very same type of bug. That concept is closer to reality than you might expect. Today, researchers will describe their progress to date, including isolation and purification of insect-derived chemicals and their conversion into functional bioplastics.

The researchers will present their results at the fall meeting of the American Chemical Society (ACS). ACS Fall 2023 is a hybrid meeting being held virtually and in-person Aug. 13–17, and features about 12,000 presentations on a wide range of science topics.

“For 20 years, my group has been developing methods to transform natural products — such as glucose obtained from sugar cane or trees — into degradable, digestible polymers that don’t persist in the environment,” says Karen Wooley, Ph.D., the project’s principal investigator. “But those natural products are harvested from resources that are also used for food, fuel, construction and transportation.”

So Wooley began searching for alternative sources that wouldn’t have these competing applications. Her colleague Jeffery Tomberlin, Ph.D., suggested she could use waste products left over from farming black soldier flies, an expanding industry that he has been helping to develop.

The larvae of these flies contain many proteins and other nutritious compounds, so the immature insects are increasingly being raised for animal feed and to consume wastes. However, the adults have a short life span after their breeding days are over and are then discarded. At Tomberlin’s suggestion, those adult carcasses became the new starting material for Wooley’s team. “We’re taking something that’s quite literally garbage and making something useful out of it,” says Cassidy Tibbetts, a graduate student working on the project in Wooley’s lab at Texas A&M University.

When Tibbetts examined the dead flies, she determined that chitin is a major component. This nontoxic, biodegradable, sugar-based polymer strengthens the shell, or exoskeleton, of insects and crustaceans. Manufacturers already extract chitin from shrimp and crab shells for various applications, and Tibbetts has been applying similar techniques using ethanol rinses, acidic demineralization, basic deproteinization and bleach decolorization to extract and purify it from the insect carcasses. She says her fly-sourced chitin powder is probably purer, since it lacks the yellowish color and clumpy texture of the traditional product. She also notes that obtaining chitin from flies could avoid possible concerns over some seafood allergies. Some other researchers isolate chitin or proteins from fly larvae, but Wooley says her team is the first that she knows of to use chitin from discarded adult flies, which — unlike the larvae — aren’t used for feed.

While Tibbetts continues to refine her extraction techniques, Hongming Guo, another graduate student in Wooley’s lab, has been converting the purified fly chitin into a similar polymer known as chitosan. [emphasis mine] He does this by stripping off chitin’s acetyl groups. That exposes chemically reactive amino groups that can be functionalized and then crosslinked. These steps transform chitosan into useful bioplastics such as superabsorbent hydrogels, which are 3D polymer networks that absorb water.

Guo has produced a hydrogel that can absorb 47 times its weight in water in just one minute. This product could potentially be used in cropland soil to capture floodwater and then slowly release moisture during subsequent droughts, Wooley says. “Here in Texas, we’re constantly either in a flood or drought situation,” she explains, “so I’ve been trying to think of how we can make a superabsorbent hydrogel that could address this.” And because the hydrogel is biodegradable, she says it should gradually release its molecular components as nutrients for crops.

This summer, the team is starting a project to break down chitin into its monomeric glucosamines. These small sugar molecules will then be used to make bioplastics, such as polycarbonates or polyurethanes, which are traditionally made from petrochemicals. Black soldier flies also contain many other useful compounds that the group plans to use as starting materials, including proteins, DNA, fatty acids, lipids and vitamins.

The products made from these chemical building blocks are intended to degrade or digest when they’re discarded, so they won’t contribute to the current plastic pollution problem. Wooley’s vision for that process would align it with the sustainable, circular economy concept: “Ultimately, we’d like the insects to eat the waste plastic as their food source, and then we would harvest them again and collect their components to make new plastics,” she says. “So the insects would not only be the source, but they would also then consume the discarded plastics.”

The researchers acknowledge support and funding from the Welch Foundation and a private donation.

As you can see from the news release, there were two related presentations,

Title
Harvesting of building blocks from insect feedstocks for transformation into carbohydrate-derived superabsorbent hydrogels

Abstract
A primary interest in the Wooley laboratory is the production of functional polymers from renewable sources that are capable of reverting to those natural products once their purpose has been served. As scaled-up production of biomass-based biodegradable polymers continues to grow, we’ve recognized a need to avoid competition with resources that are important to food, fuel, construction and other societal demands. Therefore, we’re turning to unique supply chains, including harvesting of naturally-derived building blocks from black soldier flies (BSF), a rapidly growing feed crop industry. This presentation will highlight efforts to isolate carbohydrate feedstocks from BSF and transform them into superabsorbent hydrogel materials, which are designed to address global challenges with flooding and drought associated with climate change.

Title
Harvesting of naturally-derived building blocks from adult black soldier flies

Abstract
The urgent threat to our environment created by plastic pollution has continued to grow and develop as we face the well-established problems arising from traditional plastic production using petrochemicals and their accumulation. Polymeric materials constructed from natural building blocks are promising candidates to displace environmentally-persistent petrochemical counterparts, due to their similar thermal and mechanical properties and greater breadth of compositions, structures and properties, sustainability and degradability, thereby redefining the current plastic economy. A key goal in the exploration of building blocks from natural polymers is to avoid competition with resources critical to food, fuel, construction and other societal demands. This requires turning to unique supply chains, such as black soldier flies (BSF).

BSF provides an immense array of potential utility to society, ranging from being a protein source for animal feed to composting waste. However, the larvae are almost exclusively of use for these processes and the adults serve the sole purpose of reproducing. Once the adults die, they are currently considered as waste and disposed of. Intrigued with the opportunity to create a value chain using the adult BSF, studies focusing on optimization and scalability for the digestion of adult black soldier flies to produce high quality chitin and utilize it as a feedstock for the production of super-absorbent hydrogel networks will be discussed.

If you’d like to know more about this work, there’s an ACS Fall 2023 Media Briefings webpage, which includes the briefing for “Transforming flies into degradable plastics.” It runs approximately 10 mins. 29 secs.

Ionic skin for ‘smart’ skin

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An April 28, 2022 University of British Columbia (UBC) news release (also on EurekAlert) announces a step forward in the attempt to create ‘smart’ skin, Note: Links have been removed,

In the quest to build smart skin that mimics the sensing capabilities of natural skin, ionic skins have shown significant advantages. They’re made of flexible, biocompatible hydrogels that use ions to carry an electrical charge. In contrast to smart skins made of plastics and metals, the hydrogels have the softness of natural skin. This offers a more natural feel to the prosthetic arm or robot hand they are mounted on, and makes them comfortable to wear.

These hydrogels can generate voltages when touched, but scientists did not clearly understand how — until a team of researchers at UBC devised a unique experiment, published today in Science.

“How hydrogel sensors work is they produce voltages and currents in reaction to stimuli, such as pressure or touch – what we are calling a piezoionic effect. But we didn’t know exactly how these voltages are produced,” said the study’s lead author Yuta Dobashi, who started the work as part of his master’s in biomedical engineering at UBC.

Working under the supervision of UBC researcher Dr. John Madden, Dobashi devised hydrogel sensors containing salts with positive and negative ions of different sizes. He and collaborators in UBC’s physics and chemistry departments applied magnetic fields to track precisely how the ions moved when pressure was applied to the sensor.

“When pressure is applied to the gel, that pressure spreads out the ions in the liquid at different speeds, creating an electrical signal. Positive ions, which tend to be smaller, move faster than larger, negative ions. This results in an uneven ion distribution which creates an electric field, which is what makes a piezoionic sensor work.”

The researchers say this new knowledge confirms that hydrogels work in a similar way to how humans detect pressure, which is also through moving ions in response to pressure, inspiring potential new applications for ionic skins.

“The obvious application is creating sensors that interact directly with cells and the nervous system, since the voltages, currents and response times are like those across cell membranes,” says Dr. Madden, an electrical and computer engineering professor in UBC’s faculty of applied science. “When we connect our sensor to a nerve, it produces a signal in the nerve. The nerve, in turn, activates muscle contraction.”

“You can imagine a prosthetic arm covered in an ionic skin. The skin senses an object through touch or pressure, conveys that information through the nerves to the brain, and the brain then activates the motors required to lift or hold the object. With further development of the sensor skin and interfaces with nerves, this bionic interface is conceivable.”

Another application is a soft hydrogel sensor worn on the skin that can monitor a patient’s vital signs while being totally unobtrusive and generating its own power.

Dobashi, who’s currently completing his PhD work at the University of Toronto, is keen to continue working on ionic technologies after he graduates.

“We can imagine a future where jelly-like ‘iontronics’ are used for body implants. Artificial joints can be implanted, without fear of rejection inside the human body. Ionic devices can be used as part of artificial knee cartilage, adding a smart sensing element.  A piezoionic gel implant might release drugs based on how much pressure it senses, for example.”

Dr. Madden added that the market for smart skins is estimated at $4.5 billion in 2019 and it continues to grow. “Smart skins can be integrated into clothing or placed directly on the skin, and ionic skins are one of the technologies that can further that growth.”

The research includes contributions from UBC chemistry PhD graduate Yael Petel and Carl Michal, UBC professor of physics, who used the interaction between strong magnetic fields and the nuclear spins of ions to track ion movements within the hydrogels. Cédric Plesse, Giao Nguyen and Frédéric Vidal at CY Cergy Paris University in France helped develop a new theory on how the charge and voltage are generated in the hydrogels.

Interview language(s): English (Dobashi, Madden), French (Plesse, Madden), Japanese (Dobashi)

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

Piezoionic mechanoreceptors: Force-induced current generation in hydrogels by
Yuta Dobashi, Dickson Yao, Yael Petel, Tan Ngoc Nguyen, Mirza Saquib Sarwar, Yacine Thabet, Cliff L. W. Ng, Ettore Scabeni Glitz, Giao Tran Minh Nguyen, Cédric Plesse, Frédéric Vidal, Carl A. Michal and John D. W. Madden. Science • 28 Apr 2022 • Vol 376, Issue 6592 • pp. 502-507 • DOI: 10.1126/science.aaw1974

This paper is behind a paywall.

Removing vandals’ graffiti from street art with nanotechnology-enabled method and Happy Italian Research in the World Day and more …

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Happy Italian Research in the World Day! Each year since 2018 this has been celebrated on the day that Leonardo da Vinci was born over 500 years ago on April 15. It’s also the start of World Creativity and Innovation Week (WCIW), April 15 – 21, 2021 with over 80 countries (Italy, The Gambia, Mauritius, Belarus, Iceland, US, Syria, Vietnam, Indonesia, Denmark, etc.) celebrating. By the way, April 21, 2021 is the United Nations’ World Creativity and Innovation Day. Now, onto some of the latest research, coming from Italy, on art conservation.

There’s graffiti and there’s graffiti as Michele Baglioni points out in an April 13, 2021 American Chemical Society (ACS) press conference (Rescuing street art from vandals’ graffiti) held during the ACS Spring 2021 Meeting being held online April 5-30, 2021.

An April 13, 2021 news item on ScienceDaily announced the research,

From Los Angeles and the Lower East Side of New York City to Paris and Penang, street art by famous and not-so-famous artists adorns highways, roads and alleys. In addition to creating social statements, works of beauty and tourist attractions, street art sometimes attracts vandals who add their unwanted graffiti, which is hard to remove without destroying the underlying painting. Now, researchers report novel, environmentally friendly techniques that quickly and safely remove over-paintings on street art.

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A new eco-friendly method can remove the graffiti that this person is about to spray on the street art behind them. Credit: FOTOKITA/Shutterstock.com

An April 13, 2021 ACS news release (also on EurekAlert), which originated the news item, provides details about this latest work and how it fits into the field of art conservation,

“For decades, we have focused on cleaning or restoring classical artworks that used paints designed to last centuries,” says Piero Baglioni, Ph.D., the project’s principal investigator. “In contrast, modern art and street art, as well as the coatings and graffiti applied on top, use materials that were never intended to stand the test of time.”

Research fellow Michele Baglioni, Ph.D., (no relation to Piero Baglioni) and coworkers built on their colleagues’ work and designed a nanostructured fluid, based on nontoxic solvents and surfactants, loaded in highly retentive hydrogels that very slowly release cleaning agents to just the top layer — a few microns in depth. The undesired top layer is removed in seconds to minutes, with no damage or alteration to the original painting.

Street art and overlying graffiti usually contain one or more of three classes of paint binders — acrylic, vinyl or alkyd polymers. Because these paints are similar in composition, removing the top layer frequently damages the underlying layer. Until now, the only way to remove unwanted graffiti was by using chemical cleaners or mechanical action such as scraping or sand blasting. These traditional methods are hard to control and often damaged the original art.

“We have to know exactly what is going on at the surface of the paintings if we want to design cleaners,” explains Michele Baglioni, who is at the University of Florence (Italy). “In some respects, the chemistry is simple — we are using known surfactants, solvents and polymers. The challenge is combining them in the right way to get all the properties we need.”

Michele Baglioni and coworkers used Fourier transform infrared spectroscopy to characterize the binders, fillers and pigments in the three classes of paints. After screening for suitable low-toxicity, “green” solvents and biodegradable surfactants, he used small angle X-ray scattering analyses to study the behavior of four alkyl carbonate solvents and a biodegradable nonionic surfactant in water.

The final step was formulating the nanostructured cleaning combination. The system that worked well also included 2-butanol and a readily biodegradable alkyl glycoside hydrotrope as co-solvents/co-surfactants. Hydrotropes are water-soluble, surface-active compounds used at low levels that allow more concentrated formulations of surfactants to be developed. The system was then loaded into highly retentive hydrogels and tested for its ability to remove overpaintings on laboratory mockups using selected paints in all possible combinations.

After dozens of tests, which helped determine how long the gel should be applied and removed without damaging the underlying painting, he tested the gels on a real piece of street art in Florence, successfully removing graffiti without affecting the original work.

“This is the first systematic study on the selective and controlled removal of modern paints from paints with similar chemical composition,” Michele Baglioni says. The hydrogels can also be used for the removal of top coatings on modern art that were originally intended to preserve the paintings but have turned out to be damaging. The hydrogels will become available commercially from CSGI Solutions for Conservation of Cultural Heritage, a company founded by Piero Baglioni and others. CSGI, the Center for Colloid and Surface Science, is a university consortium mainly funded through programs of the European Union.

And, there was this after the end of the news release,

The researchers acknowledge support and funding from the European Union NANORESTART (Nanomaterials for the Restoration of Works of Art) Program [or NanoRestArt] and CSGI.

The NanoRestArt project has been mentioned here a number of times,

The project ended in November 2018 but the NanoRestArt website can still be accessed.

Congratulations to Molly Shoichet (her hydrogels are used in regenerative medicine and more) for winning the $1 million Gerhard Herzberg Canada Gold Medal

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I imagine that most anyone who’s been in contact with Ms. Shoichet is experiencing a thrill on hearing this morning’s (November 10, 2020) news about winning Canada’s highest honour for science and engineering research. (Confession: she, very kindly, once gave me a brief interview for a posting on this blog, more about that later).

Why Molly Shoichet won the Gerhard Herzberg Canada Gold Medal

Emily Chung’s Nov. 10, 2020 news item on the Canadian Broadcasting Corporation (CBC) website announces the exciting news (Note: Links have been removed),

A Toronto chemical engineering professor has won the $1 million Gerhard Herzberg Canada Gold Medal, the country’s top science prize, for her work designing gels that mimic human tissues.

The Natural Sciences and Engineering Research Council of Canada (NSERC) announced Tuesday [Nov. 10, 2020] that Molly Shoichet, professor of chemical engineering and applied chemistry and Canada Research Chair in Tissue Engineering at the University of Toronto is this year’s recipient of the award, which recognizes “sustained excellence” and “overall influence” of research conducted in Canada in the natural sciences or engineering.

Shoichet’s hydrogels are used for drug development and  delivery and regenerative medicine to heal injuries and treat diseases.

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NSERC said Shoichet’s work has led to the development of several “game-changing” applications of such materials. They “delivered a crucial breakthrough” by allowing cells to be grown in three dimensions as they do in the body, rather than the two dimensions they typically do in a petri dish.

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Hydrogels are polymer materials — materials such as plastics, made of repeating units — that become swollen with water.

“If you’ve ever eaten Jell-o, that’s a hydrogel,” Shoichet said. Slime and the absorbent material inside disposable diapers are also hydrogels.

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Shoichet was born in Toronto, and studied science and engineering at the Massachusetts Institute of Technology and the University of Massachusetts Amherst. After graduating, she worked in the biotech industry alongside “brilliant biologists,” she said. She noticed that the biologists’ research was limited by what types of materials were available.

As an engineer, she realized she could help by custom designing materials for biologists. She could make materials specifically suit their needs, to answer their specific questions by designing hydrogels to mimic particular tissues.

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Her collaborations with biologists have also generated three spinoff companies, including AmacaThera, which was recently approved to run human trials of a long-acting anesthetic delivered with an injectable hydrogel to deal with post-surgical pain.

Shoichet noted that drugs given to deal with that kind of pain lead to a quarter of opioid addictions, which have been a deadly problem in Canada and around the world.

“What we’re really excited about is not only meeting that critical need of providing people with greater pain relief for a sustained period of time, but also possibly putting a dent in the operation,” she said. 

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Liz Do’s Nov. 10, 2020 University of Toronto news release provides more details (Note: Links have been removed),

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The  Herzberg Gold Medal is awarded by the Natural Sciences and Engineering Research Council (NSERC) in recognition of research contributions characterized by both excellence and influence.

“I was completely overwhelmed when I was told the good news,” says Shoichet. “There are so many exceptional people who’ve won this award and I admire them. To think of my peers putting me in that same category is really incredible.”

A pioneer in regenerative medicine, tissue engineering and drug delivery, Shoichet and her team are internationally known for their discovery and innovative use of 3D hydrogels.

“One of the challenges facing drug screening is that many of the drugs discovered work well in the lab, but not in people, and a possible explanation for this discrepancy is that these drugs are discovered in environments that do not reflect that of the body,” explains Shoichet.

Shoichet’s team has invented a series of biomaterials that provide a soft, three-dimensional environment in which to grow cells. These hydrogels — water-swollen materials — better mimic human tissue than hard two-dimensional plastic dishes that are typically used. “Now we can do more predictive drug screening,” says Shoichet.

Her lab is using these biomaterials to discover drugs for breast and brain cancer and a rare lung disease. Shoichet’s lab has been equally innovative in regenerative medicine strategies to promote repair of the brain after stroke and overcome blindness.

“Everything that we do is motivated by answering a question in biology, using our engineering and chemistry tools to answer those questions,” says Shoichet.

“The hope is that our contributions will ultimately make a positive impact in the cancer community and in treating diseases for which we can only slow the progression rather than stop and reverse, such as with blindness.”

Shoichet is also an advocate for and advisor on the fields of science and engineering. She has advised both federal and provincial governments through her service on Canada’s Science, Technology and Innovation Council and the Ontario Research Innovation Council. From 2014 to 2018, she was the Senior Advisor to the President on Science & Engineering Engagement at the University of Toronto. She is the co-founder of Research2Reality [emphasis mine], which uses social media to promote innovative research across the country. She also served as Ontario’s first Chief Scientist [emphasis mine], with a mandate to advance science and innovation in the province.

Shoichet is the only person to be elected a fellow of all three of Canada’s National Academies and is a foreign member of the U.S. National Academy of Engineering, and fellow of the Royal Society (UK) — the oldest and most prestigious academic society.

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Doug Ford (premier of Ontario) and Molly Shoichet

She did serve as Ontario’s first Chief Scientist—for about six months (Nov. 2017 – July 2018). Molly Shoichet was fired when a new provincial government was elected in the summer of 2018. Here’s more about the incident from a July 4, 2018 article by Ryan Maloney for huffingtonpost.ca (Note: Links have been removed),

New Ontario Premier Doug Ford has fired the province’s first chief scientist.

Dr. Molly Shoichet, a renowned biomedical engineer who teaches at the University of Toronto, was appointed in November [2017] to advise the government and ensure science and research were at the forefront of decision-making.

Shoichet told HuffPost Canada in an email that the she does not believe the decision was about her, and “I don’t even know whether it was about this role.” She said she is disappointed but honoured to have served Ontarians, even for a short time.

Ford’s spokesman, Simon Jefferies told The Canadian Press Wednesday that the government is starting the process of “finding a suitable and qualified replacement.” [emphasis mine]

The move comes just days after Ford’s Progressive Conservatives officially took power in Canada’s largest province with a majority government.

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Almost a year later, there was no replacement in sight according to a June 24, 2019 opinion piece by Kimberly Girling (then the Research and Policy Director of the Evidence for Democracy not-for-profit) for the star.com,

Premier Doug Ford, I’m concerned for your government.

I know you feel it too. Last week, one year into your mandate and faced with sharply declining polls after your first provincial budget, you conducted a major cabinet shuffle. This shuffle is clearly an attempt to “put the right people in the right place at the right time” and improve the outcomes of your cabinet. But I’m still concerned.

Since your election, your caucus has made many bold decisions. Unfortunately, it seems many are Ontarians unhappy with most of these decisions, and I’m not sure the current shuffle is enough to fix this.

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[] I think you’re missing someone.

What about a Chief Scientist?

It isn’t a radical idea. Actually, you used to have one. Ontario’s first Chief Scientist, Dr. Molly Shoichet, was appointed to advise the government on science policy and champion science and innovation for Ontario. However, when your government was elected, you fired Dr. Shoichet within the first week.

It’s been a year, and so far we haven’t seen any attempts to fill this vacant position. [emphasis mine]

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I wonder if Doug Ford and his crew regret the decision to fire Shoichet especially now that the province is suffering from a new peak in rising COVID-19 case numbers. These days government could do with a little bit of good news.

The only way we might ever know is if Doug Ford writes a memoir (in about 20 or 30 years from now).

Molly Shoichet, Research2Reality, and FrogHeart

A May 11, 2015 posting announced the launch of Research2Reality and it’s in this posting that I have a few comments from Molly Shoichet about co-founding a national science communication project. Given how busy she was at the time, I was amazed she took a few minutes to speak to me and took more time to make it possible for me to interview Raymond Laflamme (then director of the Institute for Quantum Computing at the University of Waterloo [Ontario]) and a prominent physicist.

Here are the comments Molly Shoichet offered (from the May 11, 2015 posting),

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“I’m very excited about this and really hope that other people will be too,” says Shoichet. The audience for the Research2Reality endeavour is for people who like to know more and have questions when they see news items about science discoveries that can’t be answered by investigating mainstream media programmes or trying to read complex research papers.

This is a big undertaking. ” Mike [Mike MacMillan, co-founder] and I thought about this for about two years.” Building on the support they received from the University of Toronto, “We reached out to the vice-presidents of research at the top fifteen universities in the country.” In the end, six universities accepted the invitation to invest in this project,

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Five years later, it’s still going.

Finally: Congratulations Molly Shoichet!