University of São Paulo: Material made with CO2 is able to prevent fungal and bacterial infections

A biomaterial capable of protecting medical and dental implants from contamination by microorganisms such as bacteria and fungi, avoiding any infections that may complicate the patient’s health status. And all this still helping the environment, through the use of carbon dioxide (CO2), which can be removed from the atmosphere and used as raw material in its production. The technology, developed by researchers at the São Carlos Institute of Chemistry (IQSC) at USP, generated an article that was published in the Journal of Sol-Gel Science and Technology , an international scientific journal.

Elton de Souza Lima, the author of the research carried out during his doctorate at IQSC, explains that:

“The biomaterial can be used as a film to cover the surface of an implant or even be used as a membrane for the healing of chronic wounds. The advantage of this material in relation to those already routinely used is the sustainability associated with its process of obtaining [through the use of CO2] and also its high antimicrobial activity, being effective even against some microorganisms resistant to antibiotics. It is worth mentioning that one of the main causes of implant failures is infections caused by fungi and bacteria, and solving this problem has been the subject of great efforts by science. ”

The material has a different name, called polyhydroxyurethane (PHU) or Isocyanate Free Polyurethane (NIPU). Currently, PHUs have “a thousand and one utilities”, which can be applied in civil construction, the shoe industry, vehicles, furniture, fabrics, biomedical devices, clothing, wall coverings or used as adhesives, foams, etc. The prototype developed during USP research, specifically, in addition to using CO2 as a raw material, has in its composition silicate, which is a type of mineral, phosphoric acid and silicone, the latter component, one of the differentials of technology.

“We were the first researchers to prepare hydroxyurethanes with silicone segments and to show their applicability in coatings. The benefit of using silicone is that it allows the material to be more flexible and resistant to moisture, water and aggressive media, as in solutions with sulfuric acid and caustic soda ”, explains Ubirajara Pereira Rodrigues Filho, professor at IQSC and one of authors of the work.

The use of silicone makes the material more flexible and resistant. – Photo: Henrique Fontes
The professor says that the new technology can also be used as an anti-corrosion coating on steel plates and titanium alloys, which are normally used in implants, thus avoiding material wear. It does not stop there. Another possible application of the technology created at USP is its use as a glue to adhere layers of glass to windows, for example. The expectation is that the product will be on the market within two years.

Safety and efficacy against pathogens
To evaluate the effectiveness of the biomaterial against microorganisms and the safety of its application, the researchers counted on partner universities, which were responsible for carrying out several tests, among them, which demonstrated that the product is not toxic when applied to fibroblasts, which are the main cells involved in healing and responsible for maintaining the integrity of the skin. In another test, called “wettability”, the objective was to investigate a possible deformation of the material in a liquid medium, which did not happen with USP’s polyhydroxyurethane, on the contrary, it proved to be hydrophobic, that is, it manages to “protect itself ”Of the water, contributing so that any metal that is coated by it does not suffer corrosion in aqueous environments. Last but not least, tests were carried out to analyze the antimicrobial activity of the material. At Anhanguera University, under the coordination of Professor Márcio L. Santos, the technology was tested with three bacteria:Escherichia coli , Staphylococcus aureus and Enterococcus faecium (resistant to the antibiotic vancomycin), organisms capable of causing everything from minor intoxications to pneumonia and meningitis. The results confirmed the efficiency of the IQSC material for the elimination of 95% to 100% of pathogens.

At the Federal University of São Carlos (UFSCar), the material was tested against several types of fungi, two of which are very dangerous for humans due to the risk of causing infections and leading to death of hospitalized patients or those with compromised immunity. They are: Candida albicans and Aspergillus fumigatus . The mortality rate of these pathogens can reach 60% in immunocompromised people.

According to UFSCar professor Iran Malavazi, the results were encouraging and show a promising path: “In the tests we carried out, polyurethanes demonstrated, against different types of fungi, both biocidal [managed to kill the fungi] and biostatic activities [stopped the multiplication / growth of microorganisms] . In addition, as we are not talking about a medicine that will be ingested by the patient and that can trigger the resistance of the fungi after some time of application, we will have a great gain within the hospital environment. It is also worth mentioning the capacity of this biomaterial to be produced on a large scale, in addition to its mechanism of action being able to attack not only a specific target, but several ”, says the professor.


Material produced at the Chemistry Institute of São Carlos can be applied as a film to prevent corrosion of metals – Photo: Henrique Fontes
According to the expert, diseases caused by fungi are neglected, although they affect many people around the world. “If we add up all the infections and deaths caused by fungi, we would have a much higher lethality than, for example, that of malaria. People know little about fungi, they don’t have much information about the problems they cause. Some, even, can trigger pandemics and many have developed mechanisms of defense and resistance against the drugs currently available on the market. Unlike the fight against bacteria, in which we have a greater therapeutic arsenal, for fungi we have few options, only three therapeutic classes, which are already very old ”, he adds.

Sustainable production
Thinking of safer and more sustainable ways of producing the material was also a concern of scientists. In addition to using a product that contributes to the environment, patients who come into contact with this technology will be less at risk of suffering from allergies and infections in an eventual medical procedure: “The first advantage of using carbon dioxide in a chemical production route of a material is the offer of a way to mitigate this gas, which has the characteristics of retaining heat on the earth’s surface and, consequently, contributing to the warming of the planet. In terms of the production process, using the route with carbon dioxide, it was possible to replace isocyanate, a raw material used in traditional polyurethane production processes and which is highly toxic to humans and the environment ”, explains Kelen M.

The scientist, who currently works as a professor at the Federal Technological University of Paraná (UTFPR), adds that, to produce the material, it would even be possible to capture carbon dioxide directly from industries, which often release CO2 directly into the atmosphere during its manufacturing processes. In the future, another possibility would be to use Direct Air Capture (DAC ) technology to sequester CO2 directly from the atmosphere, a technology that has gained prominence due to the effects of global warming and the prize offered by the Tesla CEO , Elon Musk, of US $ 100 million for those who develop the best solution for this purpose.

The researchers reiterate that the new technology developed at IQSC is very promising, since the first results point to a material with a sustainable procurement process and with the potential to help in the great challenge that is to avoid microbial infections that often lead to medical and dental implants. some failure.

In the next steps of the study, the researchers intend to test the action of the material against other microorganisms, to delve into the mechanisms of action of the technology and, finally, to evaluate its biocompatibility for an eventual application in implants. In this sense, partnerships with the Faculty of Dentistry of Piracicaba, University of Campinas (Unicamp), through Professor Flávio B. Aguiar; with the Fraunhofer Institute for Advanced Materials, in the person of the researcher Klaus Rischka; and with Frankfurt Orofacial Regenerative Medicine, from the University of Frankfurt, through the collaboration of Professor Shahram Ghanaati.

The research was funded by the National Council for Scientific and Technological Development (CNPq), by the Coordination for the Improvement of Higher Education Personnel (Capes) and by the São Paulo State Research Support Foundation (Fapesp), through the Research Program on Global Climate Change.

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