Bisphosphonates offer protection against prosthetic joint infections caused by Staphylococcus aureus and Staphylococcus epidermidis biofilms

Enhancing Titanium Disk Performance through In-Pack Cold Atmospheric Plasma Treatment

While titanium dental implants have already been clinically established, ongoing research is continuously being conducted to advance the fields of osseointegration and bacterial resistance, seeking further improvements in these areas. In this study, we introduce an innovative method for treating titanium surfaces within tightly sealed packaging. Specifically, titanium discs, enclosed in surgical-grade packaging, underwent treatment using cold atmospheric plasma (CAP). The surfaces were thoroughly characterized in terms of wettability, crystalline structure, and chemical composition. Hemocompatibility analyses were conducted using blood diluted in sodium citrate (1:9) exposed to titanium discs for 30 min inside a CO2 incubator at 37 °C. Subsequently, various blood parameters were evaluated, including prothrombin time (PT), activated partial thromboplastin time (APTT), and platelet adhesion. Microbiological analyses were also performed using Pseudomonas aeruginosa (ATCC 27853) for 4 h at 37 °C. The treatment with CAP Jet resulted in a reduction in contact angle without causing any changes in the crystalline structure. No statistically significant differences were observed in the blood parameters. The plasma-treated samples exhibited lower PT and APTT values compared to those of the control group. The surfaces treated with CAP Jet showed increased platelet activation, platelet density, and thrombus formation when compared with the untreated samples. Moreover, the treated surfaces demonstrated lower bacterial colony formation compared with other surfaces.

3D-Printed Drug Delivery Systems: The Effects of Drug Incorporation Methods on Their Release and Antibacterial Efficiency

Additive manufacturing technologies have been widely used in the medical field. More specifically, fused filament fabrication (FFF) 3D-printing technology has been thoroughly investigated to produce drug delivery systems. Recently, few researchers have explored the possibility of directly 3D printing such systems without the need for producing a filament which is usually the feedstock material for the printer. This was possible via direct feeding of a mixture consisting of the carrier polymer and the required drug. However, as this direct feeding approach shows limited homogenizing abilities, it is vital to investigate the effect of the pre-mixing step on the quality of the 3D printed products. Our study investigates the two commonly used mixing approaches-solvent casting and powder mixing. For this purpose, polycaprolactone (PCL) was used as the main polymer under investigation and gentamicin sulfate (GS) was selected as a reference. The produced systems' efficacy was investigated for bacterial and biofilm prevention. Our data show that the solvent casting approach offers improved drug distribution within the polymeric matrix, as was observed from micro-computed topography and scanning electron microscopy visualization. Moreover, this approach shows a higher drug release rate and thus improved antibacterial efficacy. However, there were no differences among the tested approaches in terms of thermal and mechanical properties.

Electrochemical modification of the Ti-15Mo alloy surface in solutions containing ZnO and Zn3(PO4)2 particles

This paper reports on the plasma electrolytic oxidation (PEO) of titanium alloy Ti-15Mo in baths containing zinc to obtain biomaterials with bacteriostatic and antibacterial properties. The Ti-15Mo surface was oxidised in a 0.1 M Ca(H₂PO₂)₂ bath containing zinc compound particles: ZnO or Zn₃(PO₄)₂. During the PEO process, the applied voltage was 300 V, and the current density was 150 mA∙cm^-2. The surface morphology, roughness and wettability were determined. It has been noted that both roughness and wettability of Ti-15Mo alloy surface increased after PEO. EDX and XPS chemical composition analysis was carried out, and Raman spectroscopy was also performed indicating that Zn has been successfully incorporated into oxide layer. To investigate the antibacterial properties of the PEO oxide coatings, microbial tests were carried out. The bacterial adhesion test was performed using four different bacterial strains: reference Staphylococcus aureus (ATCC 25923), clinical Staphylococcus aureus (MRSA 1030), reference Staphylococcus epidermidis (ATCC 700296) and clinical Staphylococcus epidermidis (15560). Performed zinc-containing oxide coatings did not indicate the bacteria growth inducing effect. Additionally, the cytocompatibility of the formed oxide layers was characterised by MG-63 osteoblast-like live/dead tests. The surface bioactivity and cytocompatibility increased after the PEO process. The zinc was successfully incorporated into the titanium oxide layer. Based on the obtained results of the studies, it can be claimed that zinc-containing PEO layers can be an interesting course of bacteriostatic titanium biomaterials development.

Structural and Functional Dynamics of Staphylococcus aureus Biofilms and Biofilm Matrix Proteins on Different Clinical Materials

Medical device-associated staphylococcal infections are a common and challenging problem. However, detailed knowledge of staphylococcal biofilm dynamics on clinically relevant surfaces is still limited. In the present study, biofilm formation of the Staphylococcus aureus ATCC 25923 strain was studied on clinically relevant materials-borosilicate glass, plexiglass, hydroxyapatite, titanium and polystyrene-at 18, 42 and 66 h. Materials with the highest surface roughness and porosity (hydroxyapatite and plexiglass) did not promote biofilm formation as efficiently as some other selected materials. Matrix-associated poly-N-acetyl-β-(1-6)-glucosamine (PNAG) was considered important in young (18 h) biofilms, whereas proteins appeared to play a more important role at later stages of biofilm development. A total of 460 proteins were identified from biofilm matrices formed on the indicated materials and time points-from which, 66 proteins were proposed to form the core surfaceome. At 18 h, the appearance of several r-proteins and glycolytic adhesive moonlighters, possibly via an autolysin (AtlA)-mediated release, was demonstrated in all materials, whereas classical surface adhesins, resistance- and virulence-associated proteins displayed greater variation in their abundances depending on the used material. Hydroxyapatite-associated biofilms were more susceptible to antibiotics than biofilms formed on titanium, but no clear correlation between the tolerance and biofilm age was observed. Thus, other factors, possibly the adhesive moonlighters, could have contributed to the observed chemotolerant phenotype. In addition, a protein-dependent matrix network was observed to be already well-established at the 18 h time point. To the best of our knowledge, this is among the first studies shedding light into matrix-associated surfaceomes of S. aureus biofilms grown on different clinically relevant materials and at different time points.