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Napredni procesi i tehnologije omogućavaju realizaciju suvremenih, ekoloških i biorazgradivih novih materijala posebnih funkcionalnih svojstava. Prilagodbom procesa postupka dobivanja biorazgradivog polimera željenog oblika moguće je dobiti materijal koji se dodatno može funkcionalizirati posebnim prevlakama s ciljem dobivanja antimikrobnih materijala. U ovom će radu stoga biti opisan postupak dobivanja medicinskog katetera od biorazgradivog polilaktida postupkom taložnog očvršćivanja (3D tiska) koji je pogodan za antimikrobnu funkcionalizaciju. Model katetera iz PLA polimera 3D tiskan je u optimalnim uvjetima nakon pripreme modela pomoću g-coda koji omogućava kvalitetan ispis te osigurava adekvatnu čvrstoću elemenata katetera. Pri izradi prototipa niže razine korišten je 3D printer Creality CR-10 max s prilagodljivom temperaturom podloge i mlaznice, dok se sam proces izvedbe prototipa proveo metodom taložnog očvršćivanja.

For the purpose of this investigation, a sensitive, and rapid inductively coupled plasma mass spectrometry (ICP-MS) spectroscopy was applied in determination of antimicrobialy active elements of the core/shell microcapsules. Microcapsules of different sizes (120 and 450 μm) and chemical composition were prepared with zinc and sodium alginate in the shell (and with or withouth chitosan), as well as filled with the antimicrobial silver in the core. After preparation, and prior the analysis, the samples were digested in an microwave oven using 55.55% v/v HNO3 and 44.45% v/v H2O2. Digested samples were transferred to ICP-MS and analysed with aim to monitor the levels of zinc and silver, both being powerful antimicrobial agents. The results show that there is a significant difference in levels of antimicrobial metals between samples prepared with and without chitosan. Whilst Zn levels appeared marginally higher (up to 20 %) in the group of samples prepared without chitosan, compared with the group with it, the Ag content showed larger overall variability (more than 72%). Particularly, smaller microcapsules (120 μm), had the following elemental composition of antimicrobial metals: 98.32 μg/g of Ag and 106.75 μg of Zn. In contrast, three times larger microcapsules (450 μm) contained two times higher amounts of silver (190.98 μg/g) and only 20 % higher amounts of zinc (121.35 μg/g). Nevertheless, after performing the leaching experiments, obtained results proved that the amounts of antimicrobial elements were high enough for efficient antimicrobial activity of newly prepared microcapsules. Therefore such samples can be efficiently applied as antimicrobial coatings on many different items.

Polymer coatings on different materials with antimicrobial / antiviral properties are of global interest due to the COVID-19 pandemic. Surfaces can be functionalized by application of sol gel procedure during which the antimicrobial agents in a form of nanoparticles or microcapsulae filled with nanoparticles are attached to the rough or plain surfaces. The efforts towards finding optimal solution can be easily done by using statistical tools and computer modeling, and applied on the findining of the optimal sol gel process parameters and the best formulation of antimicrobial coatings. After successful optimization, new coatings are applied as wound dressings, bandages and catheters as well as other medical materials. The goal of this presentation is therefore to emphasize the antimicrobial properties of silver nanoparticles in mixtures with other antimicrobial and antiviral active components. Moreover, the steps of modeling and optimization using response surface methodology applied in optimization will be presented and the results will be compared to our previous finding. Finally, the future perspectives will be presented related to a recent finding on the emerging new antimicrobial technologies in the fight against microorganisms and viruses.

Common injuries of the musculoskeletal system that require surgical repair have a failure rate of up to 40%, so there is a need for the development of new materials that can be inserted in the place of the injury. In addition, infections caused by antibiotic-resistant bacteria during the hospital care cause more deaths than AIDS, tuberculosis and viral hepatitis together [1]. Therefore, there is a need for development of new antimicrobial implants containing coatings [2] active against Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA), microorganism strains resistant to antibiotics. The antimicrobial coatings with mixtures of nanoparticles are applied on the surface of materials by sol-gel process and characterized by different spectroscopic, microscopic and chromatographic methods [3]. The combination of the electro-spinning of the yarns and their surface modification can result in antimicrobial materials interesting for medical implants. Therefore, here we propose the functionalization of the continuous yarns from electrospun fibers (Figure 1) with antimicrobial coating containing antimicrobial nanoparticles by dip coating methodology. Since recent biological investigation showed that the biphasic scaffold components are noncytotoxic, and that tendon and bone cells can be grown on the cuff and block, [4] we expect that proposed combination of treatments will result in antimicrobial materials useful in hospital care.

Antiviral and antibacterial materials Materials Science and Engineering Materials Science for a Better Future

In this paper, the influence of moist heat sterilization and ethylene oxide sterilization on the physical-mechanical properties of compresses was investigated. The investigation was performed on commercially available samples of compresses. The resistance of cellulose to various chemical agents primarily determines the behaviour of cotton fibres under the action of various chemicals, where for use in the field of medicine (medical textiles) during sterilization there must be no change in physical- mechanical and chemical properties. In order to determine the effect of two types of sterilization on cotton fibre compresses, according to EN 14079:2008, standardized methods of textile strength in the experimental part of the paper was used. Determination of degree of polymerization with morphological characteristics determined by scanning electron microscope (SEM) were carried out as well. The results showed that ethylene oxide sterilization slightly increases the degree of polymerization (DP). This fact does not affect the safety of using the compresses, because a higher value of DP compress indicates better mechanical properties, what is necessary for their usage.

This book utilizes current scientific advances to better understand the principles of degradation of historical textile materials (including ancient mummies, dresses, jewellery and musical instruments) and their characterisation. Moreover, it highlights the importance of multidisciplinary procedures as a part of complex task when only a relatively low amount of materials are available for analysis. In such cases, only sensitive, selective and reliable analytical procedures, such as microscopy, spectroscopy and chromatography, can be applied in the characterization of precious materials. As this book explores current scientific advances to better understand the principles of materials characterisation, it is of broad general interest to the general public, but also to the chemical, anthropological and conservation-restoration communities. Moreover, it also offers particular support to a global audience interested in the preservation of historical materials.

Antibacterial Metal Fibers and Metal Nanoparticles

The antimicrobial textiles market is likely to grow significantly in the upcoming years. According to the recent estimations, the global antimicrobial textiles market will grow from USD 10.7 billion in 2021 to USD 14.7 billion by 2026. Moreover, as healthcare associated diseases are increasing in a number of hospitals, it is very important to protect medical devices as well as clothing used in the hospital. For that purpose material engineering enables that the antimicrobial products are integrated into devices and fabrics of healthcare. By this, the result is material that is resistant to the growth and spread of microbes and therefore can be odor-free. In the medical industry, the demand for antimicrobial textiles is high for hospital gowns, patient clothes, curtain, bed cover, surgical supplies, wipes, and others. Therefore the antimicrobial textiles have attracted a great interest in recent years due to their potential for reducing the transmission of infections in medical and health care environments. Antimicrobial textile materials reduce the adhesion of viruses and provide biocidal and antiviral activity or combinatory effects are today even more important due to the recent COVID-19 pandemic. This work presents our recent results in optimization and production of the hydrophobic antibacterial materials. [1]. The antimicrobial effects were tested on several different model microorganisms (Escherichia coli, Candida albicans, Staphylococus aureus, Klebsiella pseudomonia, MRSA and others). Obtained data on the toxicity to particular microoganisms was discussed, and the chemical characterization was performed by spectroscopic, chromatographic and microscopic techniques [2, 3]. By this, the hydrophobic materials were developed [4] and afterwards the antimicrobial effects were optimized [5]. The future perspectives of the emerging antimicrobial materials presents their significant role in the fight against microorganisms and viruses, needed for better future perspectives. ACKNOWLEDGEMENTS: This work was financially fully supported by the Croatian Science Foundation, project IP-2019-04-1381 under title „Antibacterial coating for biodegradable medicine materials ABBAMEDICA“.

New antimicrobial materials – hope for the future

Global Conference on Semiconductors, Optoelectronics and Nanostructures

Aktivna sredstva poput nanočestica srebra i srebrov ion poznati su po svojim antimikrobnim svojstvima. Različiti proizvodi koji sadrže navedena sredstva koriste se dugi niz godina u liječenju tegoba kao što su kronične rane. S ciljem izrade medicinskog proizvoda, upotrebom sol-gel postupka su na površinu tekstilnog supstrata nanesene i vezane mikrokapsule koje su u jezgri sadržavale srebrov nitrat, ili nanočestice srebra vezane natrijevim alginatom, plašt sačinjen od cinkovog sulfata, koji je u nekim uzorcima sadržavao i hitozan. Upotrebom ove recepture mikrokapsula omogućeno je kontrolirano otpuštanje antimikrobnog srebra. U ovome radu predstavljeni su rezultati otpuštanja Ag+ iona u vodenom mediju dobiveni metodom UV/VIS spektrometrije. Zahvaljujući svojoj strukturi, tj. kemijskom sastavu, mikrokapsule su postigle kontrolirano otpuštanje, pri čemu su mikrokapsule koje su sadržavale hitozan otpuštale manje koncentracije Ag+ iona u odnosu na mikrokapsule bez hitozana.

Encapsulated Nanoparticles Protective Medical Textiles

World Health Organization has recognized the problem of antimicrobial resistance as one of the most important issues in world health protection. Due to the increasing resistance of harmful bacteria and other microorganisms to conventional drugs, it is necessary to develop new solutions for medical textile materials. The antimicrobial properties of silver ions are intensively investigated in a form of silver ions and silver nanoparticles, so their application on medical textile materials is very important. Therefore, this study aimed to functionalize textile surfaces with antimicrobial microcapsules filled with antimicrobial substances. The characterization tests were performed by ultraviolet and visible spectrometry on samples containing silver in microcapsules in both nanoparticle and ionic forms. Testing of the samples was performed on ready-made microcapsules obtained from sodium alginate, which contained silver in their core. In contrast, the outer shell was made of zinc sulfate 7-hydrate. The encapsulation method using the Buchi Encapsulator B-390 encapsulator was used to obtain these microcapsules. For characterization purposes, the test was performed on a two-beam Lambda 20 instrument, manufactured by Perkin Elmer from the United States. The test was performed in the ultraviolet and visible range, in the range of 190 to 900 nm. The test was performed in an aqueous medium in which the microcapsules released silver. The obtained test results will enable the determination of the concentration of silver released over time from microcapsules in an aqueous medium, and based on the obtained results, the antimicrobial properties of silver ions will be estimated based on the released quantities that are efficient for removal of certain strains of microorganisms on textile medical materials.

World Health Organization has emphasized that the problem of antimicrobial resistance is one of the most important issues in protection of the global population health. Moreover, the WHO has encouraged researchers and scientist to strive in detecting more powerful and more innovative solutions in producing antimicrobial materials. Therefore this presentation will bring the state-of-the-art initiatives that enable efficient functionalization of antimicrobial polymer surfaces. The most powerful activity against microorganisms that are resistant to antibiotics are nanoparticles of metals and metalo oxides. Therefore, this study will introduce to the scientific community the methodologies and procedures that we use for functionalization of 3D printed polymers, as well as textile surfaces. Such coatings can contain pure nanoparticles, or their combination with other active species. Moreover, in specific cases the antimicrobial substances can be filled materials that will enable their slow release into the environment. Lastly, the presentation will show the most important characterization methodologies needed for successful monitoring of the antimicrobial reagents. To conclude, the presentation will summarize the state-of-the-at technologies used in functionalization of antimicrobial polymers, to be shared in the scientific community for the benefit of all.

According to the World Health Organization, it is common knowledge that bacterial resistance to antibiotics is one of the major threats to global health. Infections caused by resistant bacteria affect the entire health system where infection with a resistant strain can happen to anyone. Things get more difficult if the wounds heal slowly and require specific medical care. Medical dressings are used to treat such wounds, where the textile plays an important role as a carrier of drugs. The emphasis is on finding new ways of treatment, the application of drugs to textiles, where nature is an inexhaustible source of ideas, especially bee products. Royal jelly and propolis are one of the bee products that have many medicinal properties. Propolis consists of resin, wax and essential oils, vitamins and minerals, but the emphasis is on flavonoids. Flavonoids are found in plant resin and become pharmacologically active by the enzymatic modification that bees make when making propolis. They, in combination with other components of propolis, carry most of the positive effects that propolis has. Propolis has the properties of antibiotics, anaesthetics, antioxidants and antiseptics, so it works great against most viruses, but also fungi and parasites. This paper was focused on the research of the possibilities provided by the application of inorganic-organic substances with royal jelly and propolis, but also the application of natural substances themselves for the modification of polyamide nonwoven textiles. The basic construction characteristics of polyamide nonwoven textiles have been determined. 3-glycidyloxypropyltrimethoxysilane (GLYMO) as the precursor and paraffin for the second treatment were selected. Propolis and royal jelly in stoichiometric proportions to each of the treatments were added. The morphological characteristics of the samples were determined by scanning electron microscope (SEM) and the analysis of samples in the infrared region was performed with the addition for surface analysis (FTIR ATR). For modified samples by sol-gel process or with the use of only natural means, it is assuming that they could find application in the field of medical textiles (compresses, bandages, plasters, etc.). Given this purpose, the aim of this paper was to find a formulation with as much natural composition as possible, due to ecological requirements, but also the previously mentioned high resistance of bacteria.

Characterization of historical and modern samples is very important in materials engineering. In historical samples, valuable cultural heritage needs preservation and the obtained results dictate decisions on cleaning, conservation and restoration steps. In contrast, modern newly functionalized polymers with nanoparticles on their surface will have future application depending on the results of precise information on the sample's chemical composition. In both cases the samples are very precious or expensive, rare and usually available for the analysis in very small amounts. In such cases particularly sensitive methodologies like ICP-OES and ICP-MS can provide the vital information on the sample composition. Moreover, their coupling to SEM-EDX, FTIR and other methodologies are unavoidable routine in analytical laboratories [1, 2]. Methods applied should be non-destructive and sensitive enough to detect trace elements in small sample amounts. The goal of this research was to present procedures for fast and simple determination of specific elements of interest in historical and modern materials by ICP-OES, SEM-EDX and ICP-MS. For quality insurance reasons, a comparative method applied for chemical analysis was AAS. Although ICP-OES, ICP-MS and AAS were destructive methods which demanded dissolving of samples prior the analysis, their combination was very useful in analysis of historical and modern samples. SEM-EDS was a simple and non-destructive method which provided information on chemical composition of sample surfaces, morphology and topology, while ICP-OES, ICP-MS and AAS enabled the full insight into their average chemical composition [3].

Polymer Science and Engineering of Antimicrobial Surfaces

Design of antibacterial coating using Design of Experiments

Skin is a great barrier protecting human body which possesses excellent regenerative properties. Today there is almost no person who has not had a mechanical injury of the skin or mucosa during his life. Sometimes wounds do not heal in a timely fashion, and they require a special approach to healing. Such wounds are called chronic wounds and are treated with systemic and local treatment procedures. There is a large number of products on the market that are combined in treatment, which is expected given the different metabolism of patients (Actisorb Silver 220, Arglaes etc.). In some patients, biofilm is forming ; this process takes place very quickly, within a day or two and intensifies inflammation, inhibiting extracellular matrix deposition and tissue repair [1]. This condition places the patients in significant danger and recurrent surgical procedures (wound debridement or even tissue amputation). Existing wound care products have significantly improved the patient care but cannot address the multifactorial nature of impaired wound healing. The ideal wound dressings are supposed to cover the wound, preserve the body water content, be oxygen permeable to allow oxygen access to growing tissue, and prevent the growth of environmental pathogens without interfering with the wound healing [2]. By making dressings for chronic wounds in several layers with the newer methods of textile technology (3D fabrics, fabrics/knits/nonwoven of electrospun fibers) from biodegradable polymers (PGA, PLA, PDS) with active substances, it is possible to contribute to more successful healing of chronic wounds. Active substances (Ag+, metal/metal oxide nanoparticles, propolis, etc.) are released by different mechanisms of action (pH, chemical bonds, temperature) certainly contribute to the process of local treatment of chronic wounds. The utilized materials are biodegradable and immunocompatible, and do not support cell ingrowth and cellular adhesion so to avoid complications if removal is necessary.

LA-ICP-MS was proposed as an effective method for characterization of antimicrobial polymers that contain nanoparticles