Silver nanoparticles: material of the future…or remedy for the present?
Robust growth of nanotechnology and nanomaterials is possible through the development of precision manufacturing techniques and testing methods, but above all, it is driven by huge market interest. Manufacturers are constantly looking for new, innovative solutions that will enable them to offer better products to their customers while gaining a competitive advantage at the same time. The attractiveness of nanotechnology is also influenced by its wide application; nanotechnology enables development of new, functional and thus interesting technologies, and so it adds new image and features to even the most traditional and known products.
Nanotechnology is an interdisciplinary field that combines the strength of many sciences including physics, chemistry, materials engineering and medicine. The essence of nanotechnology is to create and apply structures, materials and devices with nanometric dimensions in a controlled manner. Nanomaterials are chemicals or materials with particle sizes of 1-100 nm in at least one dimension. Such a small size and thus a strongly developed specific surface determines the properties different from microscopic or macroscopic counterparts of the same substances. Such properties include, first and foremost, improved mechanical and optical properties, increased chemical activity and reduced burden on the environment. Many readers have probably already heard about nanotechnology, for example, in terms of the Polish method of producing graphene or the latest achievements of technological giants in the production of ultra-efficient processors. The achievements of nanotechnology are already being applied in everyday life, e.g. through the use of the described processors in computers, smartphones, cars, sensors, TV sets, payment cards and even store tags (RFID identification).
As mentioned above, technologies using nanometric electronic components are nothing new to us today. Therefore, what about applications in other industries such as medicine, construction or automotive? Many publications point out that nanotechnology can be an answer to the challenges of the future and it may also provide tools to solve problems in many areas of life. Perhaps it is time to leverage the strength of this science in the fight against bacteria, fungi and viruses?
Bacteria and viruses have the ability to continually evolve through the exchange of genetic material by acquiring new characteristics that help them reproduce and survive in the environment. This is how they also become resistant to antibiotics which makes the implemented treatment ineffective and associated with serious complications and risk of death. Those phenomena result in the emergence of superbugs, or bacteria that are highly resistant to antibiotics, examples of which include methicillin-resistant Staphylococcus aureus and the New Delhi bacterium, which has been discovered relatively recently. To continue our considerations in the medical sector, it is necessary to refer to the current epidemic situation in the world. The pandemic of SARS-CoV-2 coronavirus that causes the disease known as COVID-19 has made us pay special attention to the aspects of personal hygiene and microbiological cleanliness of surfaces and objects we come in contact with every day.
A huge problem in the medical sector are nosocomial infections, most commonly caused by insufficient staff hygiene, contaminated clothing, non-sterile medical equipment, improperly conducted cleaning processes, which in turn leads to contamination of the patient’s environment. It is estimated that each year there are thousands of cases of nosocomial infections, which continue to be an unresolved problem in modern healthcare, endangering the health and life of patients and generating additional costs. Research show that nearly 30% of patients are diagnosed with at least one nosocomial infection during hospital treatment. Infections cause complications that result in a patient’s loss of health and, in extreme cases, might even cause loss of life. Nosocomial infections cannot be completely eliminated from hospital practice, however, all measures should be taken to limit their negative impact on patients’ health.
Nevertheless, the continuous develop-ment and implementation of materials with self-disinfecting surfaces should not be limited only to details used in hospitals, but should be applied wherever there is a risk of microbiological contamination, i.e. in public toilets, stores, schools and also in your own home. One way to reduce the risk of infection is to create clean room based on materials with self-disinfecting and self-cleaning properties with the addition of silver nanoparticles.
The materials most widely used in our daily lives are polymers. In 2019, the global production of plastics reached 368 million tons, with 58 million tons of plastics produced in Europe alone. This shows how widely these materials are used. In terms of application, plastics can be divided into engineering plastics, porous plastics, coating plastics, adhesive plastics, fibrous plastics and special plastics such as biomedical polymers.
The application of silver nanoparticles in polymer products (Polydef technology) guarantees continuous surface protection against microbial growth. It is an unquestionable advantage of this technology that the developed components containing silver nanoparticles show antibacterial effectiveness for all types of thermoplastic polymers. The active substance is strongly bound and homogeneously distributed in the material, which ensures an antimicrobial action regardless of material abrasion. The activity of silver does not change over time, which guarantees a lasting effect, unlike conventional biocidal preparations such as organic biocides. It is worth noting that silver demonstrates a biocidal activity in very low concentrations, so despite the high price of the concentrated additive, low dosage does not result in a significant increase in the price of the manufactured component. Application of nanotechnology in finishing does not require specialised equipment because it is performed with the existing standard equipment used in the production of polymer components. It is also important to remember about elements manufactured with the use of incremental technologies, e.g. 3D printing, which are strongly developing recently. Additives containing silver nanoparticles (Polydef 3D) can also be used in the production of filaments for 3D printing in FDM technology, which is based on a wide group of polymers such as PLA, PETG, ABS, ASA, PA.
The Polydef line of additives is not limited to thermoplastic polymers. Silver nanoparticles can also be used in thermosetting plastics such as epoxy resins, phenoplastics, polyurethanes and polyester resins. Biocidal epoxy resins can be used, for example, in various types of flooring used in hospitals, warehouses or halls. They can also be used in powder coatings, varnishes or in adhesives for metals, glass, ceramics or plastics. Polyurethanes with bactericidal, fungicidal and virucidal properties, on the other hand, can be used in anti-bedsore viscoelastic hospital mattresses, allergy pillows, athletic shoe insoles, pumice stones or polyurethane adhesives.
The solutions used in building materials, such as primers, paints and even ceramic tiles, are also interesting. The use of silver nanoparticles in primers or paints prevents fungal blooms in highly humid spaces. An extremely promising solution is the use of silver nanoparticles for the protection of ceramic cladding panels (tiles) (AGuscio technology), which are commonly used in shopping malls, public restrooms and hospitals. Permanent loading of ceramic tiles with silver nanoparticles ensures more than 90% reduction of bacteria and almost total reduction of viruses. This was confirmed in a series of tests and analyses using, among other things, the method for “Measurement of antiviral activity on plastics and other non-porous surfaces”, as described in ISO 21702:2019. An unquestionable advantage of the technology is the fact that the developed component based on silver nanoparticles shows antibacterial effectiveness on all types of ceramic tiles. At the same time, its chemical bonding with the surface guarantees durability of the solution and prevents the silver from being washed out during cleaning.
The described technologies offered by Smart Nanotechnologies provide a solution to the problems of infections and contribute to the maintenance of the sanitary regime during the ongoing epidemics. Therefore, the potential of those solutions should be viewed not only from the perspective of the national or European market, but above all, on a global scale. Materials with self-disinfecting properties should be the new standard, and nanotechnologies, in addition to being a potentially limitless prospect for economic development, offer hope for a safer tomorrow by providing an alternative in the fight against microorganisms.