Cracking and self-healing of the peptide glass. Credit: Nature (2024). DOI: 10.1038/s41586-024-07408-x
A team of materials scientists from Tel Aviv University and Ben-Gurion University of the Negev, both in Israel, working with a colleague from California Institute of Technology, in the U.S., has found that mixing a certain peptide with water results in the creation of a self-assembling and self-healing glass.
While investigating the properties of other proteins, the group stumbled upon the discovery, which has been published in Nature Communications. Silvia Marchesan, with the University of Trieste, in Italy, has published a News and Views piece in the same journal issue, outlining the newly found glass and possible uses for it.
In this new effort, the research team was investigating the possibility of using short peptides as stand-ins for conventional components of complex macro-molecules. As part of that effort, they worked with a dipeptide molecule that consisted of two phenylalanine residues when they discovered that mixing it with nothing but water led to the creation of a self-assembling type of supramolecular amorphous glass as the water evaporated at room temperature.
What was most surprising about the discovery was that peptide self-assembly in the past has typically led to the creation of materials with a crystalline structure, something that would not be transparent and thus not even close to glass.
Upon discovering the new type of glass, the researchers began investigating its properties. They found that in addition to automatically building itself, the glass was both self-healing and adhesive, despite being highly rigid.
It was also deemed to be extremely strong. The researchers found that it was as transparent as traditional glass, and further investigation showed that the glass could be used to make glass panes and coatings to create hydrophilic surfaces. They also found it could be used to make things that require precision, such as optical lenses that could be used for a wide range of magnification purposes.
The research team suggests that additional testing could lead to a wide variety of uses for the glass, noting that the new type of glass does not require a lot of energy to produce as is typical with most glasses now in commercial use.
Spicy foods taste spicy because they contain a family of compounds called capsaicinoids. Capsaicin is the major culprit. It’s found in chilies, jalapeños, cayenne pepper, and is even the active ingredient in pepper spray.
Capsaicin doesn’t actually physically heat up your mouth. The burning sensation comes from receptors in the mouth reacting to capsaicin and sending a signal to the brain that something is very hot.
That’s why the “hot” chlli sensation feels so real—we even respond by sweating. To alleviate the heat, you need to remove the capsaicin from your mouth.
So why doesn’t drinking water help make that spicy feeling go away? And what would work better instead?
Water-loving and water-hating molecules
To help us choose what might wash the capsaicin away most effectively, it’s helpful to know that capsaicin is a hydrophobic molecule. That means it hates being in contact with water and will not easily mix with it.
Look what happens when you try to mix hydrophobic sand with water.
On the other hand, hydrophilic molecules love water and are very happy to mix with it.
You’ve likely seen this before. You can easily dissolve hydrophilic sugar in water, but it’s hard to wash away hydrophobic oils from your pan using tap water alone.
If you try to wash hydrophobic capsaicin away with water, it won’t be very effective, because hydrophilic and hydrophobic substances don’t mix.
Going for iced water will be even less effective, as hydrophobic capsaicin is even less soluble in water at lower temperatures. You may get a temporary sense of relief while the cold liquid is in your mouth, but as soon as you swallow it, you’ll be back where you started.
Instead, a good choice would be to consume something that is also hydrophobic. This is because of an old-but-true adage in chemistry that “like dissolves like.”
The idea is that generally, hydrophobic substances will not dissolve in something hydrophilic—like water—but will dissolve in something that is also hydrophobic, as the video shows.
My mouth is on fire. What should I drink instead of water?
A swig of oil would likely be effective, but is perhaps not so palatable.
Milk makes for an ideal choice for two reasons.
The first is that milk contains hydrophobic fats, which the capsaicin will more easily dissolve in, allowing it to be washed away.
The second is that dairy products contain a protein called casein. Casein is an emulsifier, a substance that helps oils and water mix, as in this video:
Casein plays a large role in keeping the fat mixed throughout your glass of milk, and it also has a strong affinity for capsaicin. It will readily wrap up and encapsulate capsaicin molecules and assist in carrying them away from the receptor. This relieves the burning sensation.
Okay, but I hate drinking milk. What else can I try?
What about raita? This dish, commonly served with Indian curries, is made primarily from yogurt. So aside from being its own culinary experience, raita is rich in fats, and therefore contains plenty of hydrophobic material. It also contains casein, which will again help lock up and remove the capsaicin.
Ice cream would also work, as it contains both casein and large amounts of hydrophobic substances.
This is commonly suggested as a suitable approach to stop the burning. At first glance, this may seem a good idea because capsaicin is highly soluble in alcohol.
However, most beers only contain between 4 and 6% alcohol. The bulk of the liquid in beer is water, which is hydrophilic and cannot wash away capsaicin. The small amount of alcohol in your beer would make it slightly more effective, but not to any great degree.
Your curry and beer may taste great together, but that’s likely the only benefit.
In truth, an alcoholic beverage is not going to help much unless you go for something with a much, much higher alcohol content, which comes with its own problems.
The inhibitor 7,8-dihydroxyflavone (purple) bound to pyridoxal phosphatase (green) Credit: Marian Brenner / JMU
A low vitamin B6 level has negative effects on brain performance. A research team from Würzburg University Medicine has now found a way to delay the degradation of the vitamin.
Vitamin B6 is important for brain metabolism. Accordingly, in various mental illnesses, a low vitamin B6 level is associated with impaired memory and learning abilities, with a depressive mood, and even with genuine depression. In older people, too little vitamin B6 is linked to memory loss and dementia.
Although some of these observations were made decades ago, the exact role of vitamin B6 in mental illness is still largely unclear. What is clear, however, is that an increased intake of vitamin B6 alone, for example in the form of dietary supplements, is insufficient to prevent or treat disorders of brain function.
A research team from Würzburg University Medicine has now discovered another way to increase vitamin B6 levels in cells more effectively: namely by specifically inhibiting its intracellular degradation. Antje Gohla, Professor of Biochemical Pharmacology at the Department of Pharmacology and Toxicology at Julius-Maximilians-Universität Würzburg (JMU), is responsible for this.
Other participants come from the Rudolf Virchow Center for Integrative and Translational Bioimaging at JMU, the Leibniz-Forschungsinstitut für Molekulare Pharmakologie-FMP Berlin and the Institute for Clinical Neurobiology at Würzburg University Hospital. The team has now published the results of their investigations in the journal eLife.
Enzyme blockade improves learning ability
“We were already able to show in earlier studies that genetically switching off the vitamin B6-degrading enzyme pyridoxal phosphatase in mice improves the animals’ spatial learning and memory capacity,” explains Gohla. In order to investigate whether such effects can also be achieved by pharmacological agents, the scientists have now looked for substances that bind and inhibit pyridoxal phosphatase.
“In our experiments, we identified a natural substance that can inhibit pyridoxal phosphatase and thus slow down the degradation of vitamin B6,” explains the pharmacologist. The working group was actually able to increase vitamin B6 levels in nerve cells that are involved in learning and memory processes. The name of this natural substance: 7,8-Dihydroxyflavone.
New approach for drug therapy
7,8-Dihydroxyflavone has already been described in numerous other scientific papers as a molecule that can improve learning and memory processes in disease models for mental disorders. The new knowledge of its effect as an inhibitor of pyridoxal phosphatase now opens up new explanations for the effectiveness of this substance. This could improve the mechanistic understanding of mental disorders and represent a new drug approach for the treatment of brain disorders, the scientists write in their study.
The team also considers it a great success that 7,8-Dihydroxyflavone has been identified as an inhibitor of pyridoxal phosphatase for the first time—after all, this class of enzymes is considered to be particularly challenging for drug development.
A long way to a drug
When will people benefit from this discovery? “It’s too early to say,” explains Marian Brenner, a first author of the study. However, there is much to suggest that it could be beneficial to use vitamin B6 in combination with inhibitors of pyridoxal phosphatase for various mental disorders and neurodegenerative diseases.
In a next step, Gohla and her team now want to develop improved substances that inhibit this enzyme precisely and highly effectively. Such inhibitors could then be used to specifically test whether increasing cellular vitamin B6 levels is helpful in mental or neurodegenerative diseases.
The study, led by the research groups of Varpu Marjomäki at JYU and Antti Haapala at UEF, investigated the antiviral potential of different wood species against enveloped coronaviruses and non-enveloped enteroviruses. The work has been published in ACS Applied Materials & Interfaces.
The COVID-19 pandemic and recurrent viral outbreaks have underscored the urgent need for innovative strategies to reduce virus transmission.
While wood has been a fundamental material in human environments for centuries, its antiviral properties have not been extensively explored—until now. This research is the first to systematically evaluate the inherent antiviral efficacy of the sawn wood material from various tree species, including both coniferous and deciduous trees, under different environmental conditions.
Key findings
Pine and Spruce: These coniferous species demonstrated excellent antiviral activity against enveloped coronaviruses, significantly reducing viral infectivity within just 10 to 15 minutes. However, their efficacy against non-enveloped enteroviruses was less pronounced.
Oak: This hardwood species was notably effective against non-enveloped enteroviruses, showcasing its potential for broader antiviral applications.
Chemical Composition: Analysis at UEF revealed that the antiviral properties are primarily governed by the chemical composition of the wood, including the presence of resin acids, terpenes, and phenolic compounds. These chemicals vary significantly between species and are influenced by environmental factors such as temperature and humidity.
Porosity and Absorption: While the porosity of wood and the absorption characteristics of viruses play a role, the study highlights that the chemical makeup of the wood is the key determinant in its antiviral functionality.
The research also found that thermal treatments and the addition of plastics to wood, such as in wood-plastic composites, can compromise the antiviral properties of the material. This insight opens new avenues for utilizing untreated or minimally processed wood surfaces in public health applications.
Future directions
The research teams from UEF and JYU will continue their investigation into the most effective antiviral components of wood and their mechanisms of action as part of the ongoing European Doctorate Program DESTINY. This future research aims to identify specific bioactive compounds that can be harnessed to develop sustainable and effective antiviral materials and coatings.
“This study marks a significant step forward in understanding how natural materials can be leveraged to enhance public health,” said Varpu Marjomäki, lead virologist at JYU.
“Our findings suggest that wood, a sustainable and widely available material, could play a crucial role in reducing viral transmission in various settings,” added Antti Haapala, lead material engineer at UEF.
“The synergistic roles between the different chemicals present are a continuing theme of investigation,” states Professor Haapala from Department of Chemistry.
This work introduces a technique for using hydrogen and electricity to create pharmaceuticals. Hydrogen can be made using renewable energy sources such as solar power, making the process more sustainable. Credit: UW–Madison
The world needs greener ways to make chemicals. In a new study, University of Wisconsin–Madison researchers demonstrate one potential path toward this goal by adapting hydrogen fuel cell technologies. These technologies are already used to power some electric vehicles, laptops and cell phones.
“The chemical industry is a massive energy consumer, and there is a big push to decarbonize the industry,” says Shannon Stahl, a professor in the UW–Madison Department of Chemistry who guided much of the research. “Renewable electricity can provide energy to produce chemicals with a much lower carbon footprint than burning fossil fuels.”
The conventional process uses large quantities of zinc metal as the source of electrons, but handling zinc is complicated and generates large amounts of environmentally unfriendly waste. Working with scientists at the pharmaceutical maker Merck & Co. Inc., UW–Madison chemists and engineers sought to develop a more sustainable method to manufacture ingredients needed to make many types of drugs.
In their search for an alternative process, the researchers took inspiration from hydrogen fuel cells, which use hydrogen gas as the source of electrons to generate electricity.
“The process we are working with needs a green source of electrons,” says Stahl. “We realized that fuel cell technology could be modified to make chemicals rather than electricity,”
Hydrogen gas is an ideal choice in many ways, according to Stahl. It can be generated from renewable electricity, and it creates very little waste. Developing a hydrogen-based way to make pharmaceuticals aligns with renewed interest in a “hydrogen economy.”
“This work is connected to a broader effort to create a hydrogen infrastructure that goes beyond fuel cells and energy production,” says Mathew Johnson, a postdoctoral researcher in the chemistry department who led the study. “This work shows that hydrogen can be combined with electricity to make new drugs.”
The researchers developed a system that uses a type of organic compound called a quinone to pull electrons away from hydrogen. An important feature of this process is that it works well in the absence of water. Fuel cells typically need water to operate effectively, but water can interfere with steps used to make the drug ingredients.
The system then uses electricity to supercharge the electrons, giving the electrons more energy than hydrogen could normally provide.
The team, which included postdoctoral researcher Jack Twilton, chemistry professor Daniel Weix and chemical and biological engineering professor Thatcher Root, described their new system in a paper published Aug. 21 in the journal Nature. They show how it can be used to make dozens of important organic molecules, including a large batch of a pharmaceutical ingredient.
The team is now working to improve the process so it can be used for industrial-scale production. And Stahl and his collaborators see even bigger opportunities for this technology.
“This is a broadly applicable technology for chemical production,” says Johnson. “Many chemical processes need electrons. This is not limited to pharmaceuticals. It should be a very versatile technology.”
More information: Jack Twilton et al, Quinone-mediated hydrogen anode for non-aqueous reductive electrosynthesis, Nature (2023). DOI: 10.1038/s41586-023-06534-2
Calculated results using the persistent homology method (persistence diagram) for amorphous carbon structures and the resulting energy predictions. Credit: 2023 Minamitani et al., Persistent homology-based descriptor for machine-learning potential of amorphous structures. The Journal of Chemical Physics
How is a donut similar to a coffee cup? This question often serves as an illustrative example to explain the concept of topology. Topology is a field of mathematics that examines the properties of objects that remain consistent even when they are stretched or deformed—provided they are not torn or stitched together. For instance, both a donut and a coffee cup have a single hole. This means, theoretically, if either were pliable enough, it could be reshaped into the other.
This branch of mathematics provides a more flexible way to describe shapes in data, such as the connections between individuals in a social network or the atomic coordinates of materials. This understanding has led to the development of a novel technique: topological data analysis.
In a study, titled “Persistent homology-based descriptor for machine-learning potential of amorphous structures,” in The Journal of Chemical Physics, researchers from SANKEN (The Institute of Scientific and Industrial Research) at Osaka University and two other universities have used topological data analysis and machine learning to formulate a new method to predict the properties of amorphous materials.
A standout technique in the realm of topological data analysis is persistent homology. This method offers insights into topological features, specifically the “holes” and “cavities” within data. When applied to material structures, it allows us to identify and quantify their crucial structural characteristics.
Now, these researchers have employed a method that combines persistent homology and machine learning to predict the properties of amorphous materials. Amorphous materials, which include substances like glass, consist of disordered particles that lack repeating patterns.
A crucial aspect of using machine-learning models to predict the physical properties of amorphous substances lies in finding an appropriate method to convert atomic coordinates into a list of vectors. Merely utilizing coordinates as a list of vectors is inadequate because the energies of amorphous systems remain unchanged with rotation, translation, and permutation of the same type of atoms.
Consequently, the representation of atomic configurations should embody these symmetry constraints. Topological methods are inherently well-suited for such challenges. “Using conventional methods to extract information about the connections between numerous atoms characterizing amorphous structures was challenging. However, the task has become more straightforward with the application of persistent homology,” explains Emi Minamitani, the lead author of the study.
The researchers discovered that by integrating persistent homology with basic machine-learning models, they could accurately predict the energies of disordered structures composed of carbon atoms at varying densities. This strategy demands significantly less computational time compared to quantum mechanics-based simulations of these amorphous materials.
The techniques showcased in this study hold potential for facilitating more efficient and rapid calculations of material properties in other disordered systems, such as amorphous glasses or metal alloys.
More information: Emi Minamitani et al, Persistent homology-based descriptor for machine-learning potential of amorphous structures, The Journal of Chemical Physics (2023). DOI: 10.1063/5.0159349
by Wenke Dargel, Martin-Luther-Universität Halle-Wittenberg
A starch implant photographed in microscopic image Credit: Uni Halle / Esfahani Golbarg
A special type of starch could soon be used as an excipient in medicine to improve the treatment of patients. A research team from Martin Luther University Halle-Wittenberg (MLU) has discovered that it makes a suitable drug release system and has advantages over already established excipients. The team reports on its research in the Journal of Controlled Release.
Many active pharmaceutical ingredients are difficult to administer at present as they are poorly absorbed by the body and break down too quickly.
These problems can be overcome by drug delivery systems, which release active substances in the body in a controlled manner over a prolonged period of time. An example of one such application are drug-delivery implants. Once injected, the body degrades them over a longer period of time and the desired substance is released. This technology is already being used to treat diseases like cancer and bacterial infections.
Most currently used drug delivery systems are based on polylactide-co-glycolide (PLGA) and polylactide (PLA). However, these materials have several disadvantages.
“When PLGA and PLA degrade in the body, they create an acidic environment which results in an irregular release of the substances. Optimal treatment would, of course, involve a controlled release. The acidic environment can cause local inflammation and also inactivate drugs prior to their release,” explains Professor Karsten Mäder from the Institute of Pharmacy at MLU. His team has been working for many years on improving existing drug systems and developing new alternatives.
In the current study, the researchers investigated starch as a possible excipient. “Starch could provide an alternative for PLGA and PLA because it is already widely used as an excipient in medicinal products and medical devices,” Mäder adds.
The researchers used a special pharmaceutical-grade starch in their experiments. Rod-shaped implants were created using a special extrusion process. Earlier studies by the team had already confirmed that starch is a suitable carrier substance for the controlled release of drugs. For the current study, the researchers tested the rods in mice. They were able to show that the new system works particularly well for poorly water-soluble drugs, as it releases them continuously over several weeks. There were also no side effects and the starch implant degraded completely.
“Our study shows that special starches could be used in drug delivery systems,” concludes Mäder. However, before this invention could be applied to humans, large-scale clinical studies on its efficacy and safety would need to be conducted.
More information: Golbarg Esfahani et al, A starch-based implant as a controlled drug release system: Non-invasive in vivo characterization using multispectral fluorescence imaging, Journal of Controlled Release (2023). DOI: 10.1016/j.jconrel.2023.05.006
Atomic force microscopy (AFM) height contour map of a Berkovich indenter. Credit: Zhang Xianlong
Nanoindentation testing is a high-precision instrumented indentation test technique that has the advantages of non-destructive testing and simplicity. However, researchers found that when testing the same sample with different Berkovich indenters, inconsistency still arises even if the indenters are regularly calibrated. This inconsistency poses challenges in accurately testing material hardness and comparing data from different laboratories.
In a study published in the Journal of Materials Research and Technology, researchers from the Materials Research Center of the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) reported that using different Berkovich indenters for nanoindentation testing, excluding fused silica, yields inconsistent results, and they analyzed the reasons behind this inconsistency.
The researchers identified two main factors contributing to the inconsistent experimental results, i.e., defects in the indenter tip and the indentation size effect.
To quantify their impact on experimental results, they developed a finite element model of the indenter using the indenter area function and proposed a method to correct the indentation size effect on the load-displacement curve.
The results indicated that while defects in the indenter tip have a small direct impact on the experimental results, they do affect the results indirectly by influencing the indentation size effect.
The indentation size effect correction method and indenter modeling approach introduced in this study are expected to be utilized in inverse finite element analysis to determine the constitutive relationship of the tested material.
More information: Xianlong Zhang et al, Inconsistent nanoindentation test hardness using different Berkovich indenters, Journal of Materials Research and Technology (2023). DOI: 10.1016/j.jmrt.2023.07.063
Artificial intelligence is growing into a pivotal tool in chemical research, offering novel methods to tackle complex challenges that traditional approaches struggle with. One subtype of artificial intelligence that has seen increasing use in chemistry is machine learning, which uses algorithms and statistical models to make decisions based on data and perform tasks that it has not been explicitly programmed for.
However, to make reliable predictions, machine learning also demands large amounts of data, which isn’t always available in chemical research. Small chemical datasets simply do not provide enough information for these algorithms to train on, which limits their effectiveness.
Scientists, in the team of Berend Smit at EPFL, have found a solution in large language models such as GPT-3. Those models are pre-trained on massive amounts of texts, and are known for their broad capabilities in understanding and generating human-like text. GPT-3 forms the basis of the more popular artificial intelligence ChatGPT.
The study, published in Nature Machine Intelligence, unveils a novel approach that significantly simplifies chemical analysis using artificial intelligence. Contrary to initial skepticism, the method doesn’t directly ask GPT-3 chemical questions.
“GPT-3 has not seen most of the chemical literature, so if we ask ChatGPT a chemical question, the answers are typically limited to what one can find on Wikipedia,” says Kevin Jablonka, the study’s lead researcher.
“Instead, we fine-tune GPT-3 with a small data set converted into questions and answers, creating a new model capable of providing accurate chemical insights.”
This process involves feeding GPT-3 a curated list of Q&As. “For example, for high-entropy alloys, it is important to know whether an alloy occurs in a single phase or has multiple phases,” says Smit. “The curated list of Q&As are of the type: Q= ‘Is the (name of the high entropy alloy) single phase?’ A= ‘Yes/No.'”
He continues, “In the literature, we have found many alloys of which the answer is known, and we used this data to fine-tune GPT-3. What we get back is a refined AI model that is trained to only answer this question with a yes or no.”
In tests, the model, trained with relatively few Q&As, correctly answered over 95% of very diverse chemical problems, often surpassing the accuracy of state-of-the-art machine-learning models. “The point is that this is as easy as doing a literature search, which works for many chemical problems,” says Smit.
One of the most striking aspects of this study is its simplicity and speed. Traditional machine learning models require months to develop and demand extensive knowledge. In contrast, the approach developed by Jablonka takes five minutes and requires zero knowledge.
The implications of the study are profound. It introduces a method as easy as conducting a literature search, applicable to various chemical problems. The ability to formulate questions like “Is the yield of a [chemical] made with this (recipe) high?” and receive accurate answers can revolutionize how chemical research is planned and carried out.
In the paper, the authors say, “Next to a literature search, querying a foundational model (e.g., GPT-3,4) might become a routine way to bootstrap a project by leveraging the collective knowledge encoded in these foundational models.” Or, as Smit succinctly puts it, “This is going to change the way we do chemistry.”
Representation of the irreversible damage to the microorganism caused by coating the surface on the right with the new material developed by the UAB and ICN2 researchers. Credit: Chemical Engineering Journal (2024). DOI: 10.1016/j.cej.2024.148674
Researchers from the UAB and the ICN2 have developed an innovative material to fight against the spread of pathogens, infections and antimicrobial resistance. Inspired by the substances secreted by mussels to adhere to rocks, it can be used as a coating to protect health care fabrics and provides an effective alternative to commonly used materials such as paper, cotton, surgical masks and commercial plasters.
The research is published in the Chemical Engineering Journal.
The overuse of antibiotics has led to the development of antimicrobial resistance (AMR), a growing threat to public health worldwide. AMR occurs when bacteria change over time and no longer respond to drugs, antibiotics and other related antimicrobial medicines, making infections harder to treat and increasing the risk of pathogen spread, severe illness and death.
In fact, the World Health Organization (WHO) and United Nations (UN) have reported that AMR poses a major threat to human health around the world, probably overtaking cancer as the world’s leading cause of death by 2050.
In this scenario, the development of novel and more efficient antibacterial materials has become essential to reduce pathogen spread, thus preventing infections. Of relevance is the control of bacterial populations in health environments such as hospitals and other health care units to avoid the so-called nosocomial infections, mainly due to bacterial colonization on biomedical surfaces.
Today, this type of infection is the sixth leading cause of death in industrialized countries, and much higher in the developing world, specially affecting immunocompromised and intensive care patients (e.g., burns) and those with chronic pathologies such as diabetes.
Among the different materials that may spread bacterial populations, fabrics represent an integral part of patient care: From the clothes of doctors, surgeons and nurses to medical curtains, bed sheets, pillow coverings, masks, gloves, and bandages, which are directly in contact with sutures and wounds. For all these reasons, antibacterial coatings for medical fabrics have become a very active field of research.
Researchers from the UAB Department of Biochemistry and Molecular Biology, the UAB Institute for Neuroscience (INc-UAB), and the Catalan Institute for Nanoscience and Nanotechnology (ICN2) have developed a family of biocompatible and bioinspired coatings produced by the co-polymerization between catechol derivatives and amino-terminal ligands.
Based on this, they have demonstrated that the use of these mussel-inspired coatings as efficient antimicrobial materials, based on their ability to evolve chemically over time in the presence of air and humid atmospheres, favoring the continuous formation of Reactive Oxygen Species (ROS). In fact, in addition to the formation of ROS, the synthetic methodology results in an excess of superficial free amino groups that induce the disruption of pathogen membranes.
“One of the main components found in the coatings (catechol and polyphenol derivatives) is found in the strands secreted by mussels, which are responsible for their adhesion to rocks under extreme conditions, under saline water,” explain UAB professor Victor Yuste and ICN2 researcher Salvio Suárez. “The fact that the coatings we have developed are inspired by this organism allows them to adhere to practically any type of surface and, in addition, are highly resistant to different environmental conditions such as humidity or the presence of fluids.
“In addition, natural compounds help to obtain more biodegradable, biocompatible materials with lower antimicrobial resistance compared to other bactericidal systems that end up generating resistance and, therefore, rapidly lose effectiveness.”
All of the commonly used sanitary equipment such as paper, cotton, surgical masks, and commercial plasters exhibited intrinsic multi-pathway antibacterial activity with rapid responses against a broad spectrum of microbial species. This included microorganisms that have developed resistance to extreme environmental conditions (such as B. subtilis), as well as pathogens considered the primary source responsible for many current infections, particularly those acquired in health care facilities.
These pathogens encompass multi-resistant microorganisms from both Gram-negative (E. coli and P. aeruginosa) and Gram-positive (S. aureus, methicillin-resistant S. aureus—MRSA and E. faecalis). These materials have also exhibited efficacy against fungi such as C. albicans and C. auris.
Moreover, its efficient application was demonstrated in wet atmospheres, as those found in health care environments, where respiratory droplets and/or other biofluids are present, thus reducing the risks of indirect contact transmission. Such antimicrobial activity was attributed to a direct contact killing process, where the pathogen is initially attached to the coating by catechol molecules and other polyphenol derivatives.
Then, a multi-pathway antibacterial effect is activated, mainly focused on a sustained generation of biosafety levels of ROS and electrostatic interactions with protic amino groups exposed to the surface. These antibacterial mechanisms induced a fast (180 minutes for bacteria and 24 hours for fungi) and efficient (more than 99%) response against pathogens, causing irreversible damage to the microorganisms.
These innovative coatings follow a simple one-step and scalable synthesis under mild conditions, using affordable materials and green chemistry-based methodologies. Moreover, the polyphenolic nature of their compositions and the absence of additional external antimicrobial agents enhance the simplicity of the bio-inspired coatings and avoid the induction of AMR and its cytotoxic effects on host cells and the environment.
Worth mentioning is that different parameters such as color, thickness and adhesion were fine-tuned, thus offering an adaptable solution for the different demands of the final material application. In general, the designed bio-inspired coatings have demonstrated a huge potential for further translation into clinics, as they represent a feasible alternative to existing antimicrobial materials.
