1. Biocompatible polyelectrolyte multilayers with copper oxide and zinc oxide nanoparticles for inhibiting bacterial growthNives Matijaković Mlinarić, Stefanie Altenried, Atiđa Selmani, Juraj Nikolić, Aleksander Učakar, Anamarija Zore, Anže Abram, Sandro Lehner, Andrijana Sever Škapin, Monika Kušter, Eva Roblegg, Davor Kovačević, Qun Ren, Klemen Bohinc, 2024, izvirni znanstveni članek Povzetek: The prevalence of bacterial infections presents a significant challenge in the medical field, demanding effective strategies to impede bacterial adhesion and growth on various surfaces. The conducted study investigates the efficacy of polyelectrolyte multilayers─comprising poly(allylamine hydrochloride) (PAH) and alginate (ALG)─embedded with zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) to inhibit bacterial adhesion on stainless-steel surfaces. Surface characterization involved zeta potential, contact angle, and roughness assessments. The effect of NP composition, size, and morphology in conjunction with polycation or polyanion terminating multilayers was evaluated against planktonic and surface-adhered Escherichia coli (E. coli) cells. Surfaces with the positively charged PAH-terminating multilayer displayed higher water contact angles (≈ 63°) than the negatively charged ALG-terminating multilayers (≈ 45°). Multilayers containing ZnO NPs showed a significant inhibition of planktonic E. coli growth, >99%. Moreover, complete growth inhibition of surface-adhered E. coli was achieved for multilayers containing both ZnO and CuO. Due to their larger specific surface area, rod-like ZnO NPs displayed higher antibacterial activity. The samples with ALG as the terminating layer showed more substantial antibacterial properties than samples with PAH as the terminating layer. Biocompatibility tests on immortalized human keratinocyte cells revealed good compatibility with multilayers incorporating NPs. In summary, this study underscores the potential of ZnO and CuO NPs within PAH/ALG multilayers for antibacterial applications without compromising their cytocompatibility.
Ključne besede: polyelectrolyte multilayers, alginate, poly(allylamine hydrochloride), CuO, ZnO, nanoparticles, Escherichia coli
Objavljeno v DiRROS: 06.06.2024; Ogledov: 56; Prenosov: 49
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2. Effect of sucrose concentration on streptococcus mutans adhesion to dental material surfacesAnamarija Zore, Franc Rojko, Nives Matijaković Mlinarić, Jona Veber, Aleksander Učakar, Roman Štukelj, Andreja Pondelak, Andrijana Sever Škapin, Klemen Bohinc, 2024, izvirni znanstveni članek Povzetek: Enamel demineralization, known as dental caries, is instigated by the bacterium Streptococcus mutans, which generates acid during carbohydrate metabolism. Among carbohydrates, sucrose is the most cariogenic and capable of biofilm formation. This study aimed to explore and comprehend Streptococcus mutans’ adherence to two prevalent dental material surfaces, i.e., a cobalt–chromium(Co-Cr) alloy and a resin-based composite, under the influence of various sucrose concentrations. To understand bacterial adhesion, the surfaces were characterized using profilometry, tensiometry, and surface charge measurements. Bacterial adhesion was evaluated using scanning electron microscopy and crystal violet dye methods. Results revealed that the composite surface exhibited greater rough-ness compared with the Co-Cr alloy surface. Both surfaces displayed hydrophilic properties and a negative surface charge. Bacterial adhesion experiments indicated lower bacterial adherence to the Co-Cr alloy than to the composite surface before the addition of sucrose. However, the introduction of sucrose resulted in biofilm development on both surfaces, showcasing a similar increase in bacterial adhesion, with the highest levels being observed at a 5% sucrose concentration in the bacterial suspension. In conclusion, the findings suggest sucrose-rich foods could facilitate bacterial adaptation despite less favorable surface characteristics, thereby promoting biofilm formation.
Ključne besede: bacterial adhesion, streptococcus mutans, dental material surfaces, sucrose concentration
Objavljeno v DiRROS: 31.01.2024; Ogledov: 269; Prenosov: 106
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3. Antibacterial effect of polymethyl methacrylate resin base containing TiO2 nanoparticlesAnamarija Zore, Anže Abram, Aleksander Učakar, Ivo Godina, Franc Rojko, Roman Štukelj, Andrijana Sever Škapin, Rajko Vidrih, Olivera Dolić, Valentina Veselinović, Klemen Bohinc, 2022, izvirni znanstveni članek Povzetek: Restorations in dentistry must reproduce the aspect of the patient’s natural teeth and require non-toxicity, biocompatibility, and good mechanical properties in order to last longer. Restorations are permanently in contact with microbes that can adhere to and form biofilms. The purpose of this study was to determine the adhesion extent of Streptococcus mutans to polymethyl methacrylate (PMMA) resin base containing TiO2 nanoparticles. To understand the adhesion of Streptococcus mutans on the modified resin-based surfaces, the following surface properties were measured: the roughness, contact angle, zeta potential and CIE color parameters. Evaluation of tensile stress performance in TiO2 modified PMMA showed that the maximum tensile stress of the modified PMMA resin decreases with an increasing amount of TiO2 nanoparticles. The increasing amount of TiO2 decreases the roughness and causes contact angles in the border between hydrophilic and hydrophobic surfaces. All the studied surfaces are negatively charged and added TiO2 tends to increase the zeta potential. The addition of TiO2 nanoparticles increases the lightness and decreases the intensity of the red and yellow color. The increasing addition of TiO2 nanoparticles into PMMA increases the morphological change of bacterial cells.
Ključne besede: bacterial adhesion, Streptococcus mutans, polymethyl methacrylate resin, TiO2, surface properties
Objavljeno v DiRROS: 20.12.2023; Ogledov: 235; Prenosov: 119
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4. Antifungal effect of polymethyl methacrylate resin base with embedded Au nanoparticlesIvan Marić, Anamarija Zore, Franc Rojko, Andrijana Sever Škapin, Roman Štukelj, Aleksander Učakar, Rajko Vidrih, Valentina Veselinović, Marijan Gotić, Klemen Bohinc, 2023, izvirni znanstveni članek Povzetek: Full and partial restorations in dentistry must replicate the characteristics of the patient’s natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ∆E between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are rougher and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans.
Ključne besede: fungal adhesión, C. albicans, polymethyl methacrylate resin, Au, surface properties, composites
Objavljeno v DiRROS: 24.07.2023; Ogledov: 445; Prenosov: 162
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5. Biophysical properties of foamed and solid polymers used in orthotics and prostheticsKlemen Bohinc, Anže Abram, Anamarija Zore, Roman Štukelj, Ana Lenarčič, Rajko Vidrih, Andrijana Sever Škapin, 2021, izvirni znanstveni članek Povzetek: Orthotic and prosthetic materials should have good mechanical and antibacterial properties. Therefore, in our study, we consider four common foamed closed-cells and two solid polymeric materials regarding their mechanical behaviour and tendency for bacterial adhesion. For all materials, the surface roughness, hydrophobicity, zeta potential, tensile properties, hardness and CIE color parameters were measured. We found that foamed polymeric materials have higher roughness, higher hydrophobicity, lower Young's modulus, lower maximum tensile strength and lower hardness than solid materials. Bacterial adhesion test measurements based on observation by scanning electron microscopy show much a lower adhesion extent of S. aureus on solid materials than on foamed materials. The measured biophysical properties could be the key data for users to select the optimal materials.
Ključne besede: surface characterization, bacterial adhesion, foamed materials, prosthetic and orthotic material, surfaces
Objavljeno v DiRROS: 22.05.2023; Ogledov: 338; Prenosov: 222
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