During the project we developed several different methods of entrapment of bacterial cell into the LBL layers. This achievement is one amongst several which are in progress for preparing manuscripts, patenting or submitted in journals. The LBL method enable changing surface electrostatic properties of the cell, which can be used as an attachment on different appositively charged surfaces. The group from KULeuven from Belgium and GEUS from Denmark isolated Aminobacter MSH1 bacterial strain that can degrade BAM in drinking water. They applied this strain to the rapid sand filter, but the activity of the filter could be maintained only 1-2 weeks. They asked us if we can help them using our approaches of immobilisation. At that time we had developed a method for surface modification of bacterial cells as well as modification of surfaces using polyelectrolytes. In cooperation with above mentioned institutions we tested activities of immobilized bacteria using different immobilisation strategies. The use of LBL methods was one of them and enabled us to determine that the surface on which the cells are immobilized can have toxic effects if we used polyelectrolytes. At the end our method prolonged activities of MSH1 strain from a week to several months. This approach was then upscaled and tested in environmental conditions for cleaning BAM contaminated drinking water.
COBISS.SI-ID: 30114087
The conventional treatment of periodontal disease does not solve the high incidence of re-colonization of the periodontal pockets by pathogens. Here, we introduce an innovative concept of incorporating autochthonous bacteria as potential probiotics into nanofibers for local treatment. We selected and isolated the strain 25.2.M from the oral microbiota of healthy volunteers. It was identified as Bacillus sp. based on 16S rRNA sequence analyses. The strain is non-pathogenic, produces the antimicrobial substances and can grow over the periodontal pathogen Aggregatibacter actinomycetemcomitans in vitro, making it a promising probiotic candidate. The strain 25.2.M was successfully incorporated into the nanofibers in the form of spores (107 CFU/mg), the viability of which were exceptional (max. change of 1 log unit) both during the electrospinning and after 12 months of storage. The release of the bacteria was delayed from chitosan/poly(ethylene oxide) compared to poly(ethylene oxide) nanofibers and the antimicrobial activity against A. actinomycetemcomitans was confirmed. The developed nano-delivery system for administration into periodontal pockets thus offers a promising approach for the inhibition of periodontal pathogens and the restoration of the healthy oral microbiota.
COBISS.SI-ID: 4619633
In the project we tested effect of deposition of polyelectrolytes on Staphylococcus bacteria including S. epidermidis and S. aureus. The survivability of these bacteria was high and the stage of the most effective LBL deposition was during the stationary phase of cells. In cooperation with University of Maribor we incorporated LBL covered S. epidermidis in the solution for electrospinning. Here we developed a novel electrospun biocompatible nanofibrous material loaded with commensal bacteria S. epidermidis which can be used in preventive treatment of the diabetic. Two biocompatible polymers (carboxymethylcellulose and polyethylene oxide) were combined with a bacterium isolate from the skin located between the toes of a healthy adult (identified using a matrix-assisted laser desorption/ionization mass spectrometry-based method as a strain of Staphylococcus epidermidis). Higher bacteria loads in the material were assured through their encapsulation in polyethylenimine. The nanofibrous material was characterized using scanning electron microscopy, zeta-potential measurements and through evaluation of cell growth and viability. Nanometer formation was confirmed using scanning electron microscopy, while the zeta-potential measurements revealed successful bacteria encapsulation. Viable and sufficiently growing cells were confirmed prior and after their incorporation. The prepared materials were proven suitable to deliver viable commensal bacteria in a comparable share to the Staphylococcaceae in the foot microbiome making this approach promising for preventive diabetic foot treatment.
COBISS.SI-ID: 21588502
In our project one of the goals was to develop layered multicellular structure. Here we used soft suport in comparison to the hard described in the achievement bellow. For the purposes of detection of attached microbes and growth on the surfaces we developed discontinuous method for measurement of amount of attached and released bacteria from the surfaces. When we developed this method, we evaluated with the use of pathogenic strains of S. aureus on the material prepared by the group from Tomsk Polytechnic University. Herein TiO2 nanotubes (NTs) were fabricated via electrochemical anodization and coated with silver and calcium phosphate (CaP) nanoparticles (NPs) by electrophoretic deposition. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) revealed that Ag and CaP NPs were successfully deposited onto the TiO2 NTs. Using X-ray diffraction, only anatase and Ti were observed after deposition of Ag and CaP NPs. However, X-ray photoelectron spectroscopy (XPS) analysis revealed that the binding energy (BE) of the Ag and CaP NP core levels corresponded to metallic Ag, hydroxyapatite and amorphous calcium phosphate, based on the knowledge that CaP NPs synthesized by precipitation have the nanocrystalline structure of hydroxyapatite. The application of Ag NPs allows for decreasing the water contact angle and thus increasing the surface free energy. It was concluded that the CaP NP surfaces are superhydrophilic. A significant antimicrobial effect was observed on the TiO2 NT surface after the application of Ag NPs and/or CaP NPs compared with that of the pure TiO2 NTs. Thus, fabrication of TiO2 NTs, Ag NPs and CaP NPs with PEI is promising for diverse biomedical applications, such as in constructing a biocompatible coating on the surface of Ti that includes an antimicrobial effect.
COBISS.SI-ID: 31977255
In our project one of the goals was to develop layered multicellular structure. However, the analystics for determining growth on surfaces of material where cells are deposited have not been developed yet. For thsi purposes we developed discontinuous method for measurement of amount of attached and released bacteria from the surfaces. When we developed this method, we evaluated with the use of pathogenic strains of S. aureus on the material prepared by the group from Tomsk Polytechnic University. The prepared surface using electron beam melting (EBM) method, which is allowing the production of porous implants with highly defined external dimensions and internal architectures. The increasing surface area of the implant may also increase the abilities of pathogenic microorganisms to adhere to the surfaces and form a biofilm, which may result in serious complications. The aim of this study was to explore the modifications of Ti6Al4V alloy scaffolds to reduce the abilities of bacteria to attach to the EBM-manufactured implant surface. The layers composed of silver (Ag), calcium phosphate (CaP) nanoparticles (NPs) and combinations of both were formed on the EBM-fabricated metallic scaffolds by electrophoretic deposition in order to provide them with antimicrobial properties. The assay of bacterial colonization on the surface was performed with the exposure of scaffold surfaces to Staphylococcus aureus cells for up to 17?h. Principal component analysis (PCA) was used to assess the relationships between different surface features of the studied samples and bacterial adhesion. The results indicate that by modifying the implant surface with appropriate nanostructures that change the hydrophobicity and the surface roughness at the nano scale, physical cues are provided that disrupt bacterial adhesion. Our results clearly show that AgNPs at a concentration of approximately 0.02?mg/?m2 that were deposited together with CaPNPs covered by positively charge polyethylenimine (PEI) on the surface of EBM-sintered Ti6Al4V scaffolds hindered bacterial growth, as the total number of attached cells (NAC) of S. aureus remained at the same level during the 17 h of exposure, which indicates bacteriostatic activity.
COBISS.SI-ID: 32170279