Evaluation of biofilm formation in the presence of saliva on poly(ethylene glycol)deposited titanium

Lectin-Functionalized Polyethylene Glycol for Relief of Mucosal Dryness

The importance of lubrication between oral surfaces provided by the salivary film is most acutely apparent when it is disrupted, a prevalent consequence of salivary gland hypofunction experienced with aging, a symptom of certain diseases, or a side effect of some medical interventions. Sufferers report difficulty with speech and oral food processing and collectively is detrimental to quality of life. Polyethylene glycol (PEG) is widely employed as a successful biocompatible boundary lubricant in engineering and biomedical applications. It is hypothesized that the immobilization of PEG to biological materials such as oral epithelial cells and tissue can mimic the salivary film and provide durable relief from the symptoms of mucosal dryness. To do so, PEG is functionalized with a sugar binding lectin (wheat germ agglutinin) to enhance epithelial adhesion through lectin-sugar interactions. Retention and lubricity are characterized on an ex vivo oral tissue tribology rig. WGA-PEG coats and retains on mucin films, oral epithelial cells, and porcine tongue tissue, and offers sustained reduction in coefficient of friction (COF). WGA-PEG could be developed into a useful topical treatment for reducing oral friction and the perception of dry mouth.

Evaluation of adding nanosized natural zeolite to photodynamic therapy against P. gingivalis biofilm on titanium disks

BACKGROUND

Antibacterial photodynamic therapy (aPDT) can be used as an adjunctive therapy for eliminating bacterial biofilm. The application of nanotechnology in aPDT, which is a growing trend, has improved the delivery of photosensitizers (PSs) into microorganisms. Encapsulation of molecules and ions is considered an outstanding potential feature of zeolites. This study sought to enhance the effect of aPDT using a diode laser (810 nm) with a potential PS, indocyanine green (ICG), combined with nanosized natural zeolite (NZ), against biofilm of P. gingivalis on sandblasted, large-grit, and acid-etched (SLA) implant titanium disks surface.

METHODS

A bacterial suspension of standard P. gingivalis (™ATCC® 33277) strains was prepared. To prepare bacterial biofilm, the titanium disks were added to 48 microtubes containing bacterial suspension, and divided into eight groups, i.e., the control groups (positive and negative), and 6 test groups (ICG; NZ; Diod laser; NZ+ICG; aPDT; NZ+aPDT). After the treatments, the total number of colony-forming units per disk was calculated. Finally, the data was analyzed, and the eight groups were compared together.

RESULTS

The highest reduction in the number of P. gingivalis was seen in group 8 (NZ+aPDT) with 3.55 log₁₀ CFU/ml and the antibacterial effect of 45.7% compared with the negative control group. Conversley, group 5 (Diode Laser solely) represented the highest mean of colony count with the lowest antibacterial effects per disk (6.42 log₁₀ CFU/ml, 1.8%).

CONCLUSIONS

The antibacterial effect of NZ+aPDT against P. gingivalis biofilm was noticeable. Thus, adding NZ to ICG improved the result of aPDT in this study.

Innovative Coatings of Metallic Alloys Used as Bioactive Surfaces in Implantology: A Review

Metallic implants are widely used in the field of implantology, but there are still problems leading to implant failures due to weak osseointegration, low mechanical strength for the implant, inadequate antibacterial properties, and low patient satisfaction. Implant failure can be caused by bacterial infections and poor osteointegration. To improve the implant functionalization, many researchers focus on surface modifications to prepare the proper physical and chemical conditions able to increase biocompatibility and osteointegration between implant and bone. Improving the antibacterial performance is also a key factor to avoid the inflammation in the human body. This paper is a brief review for the types of coatings used to increase osseointegration and biocompatibility for the successful use of metal alloys in the field of implantology.

Electrophoretic deposition of polymers and proteins for biomedical applications

This review is focused on new electrophoretic deposition (EPD) mechanisms for deposition biomacromolecules, such as biopolymers, proteins and enzymes. Among the rich literature sources of EPD of biopolymers, proteins and enzymes for biomedical applications we selected papers describing new fundamental deposition mechanisms. Such deposition mechanisms are of critical importance for further development of EPD method and its emerging biomedical applications. Our goal is to emphasize innovative ideas which have enriched colloid and interface science of EPD during recent years. We describe various mechanisms of cathodic and anodic EPD of charged biopolymers. Special attention is focused on in-situ chemical modification of biopolymers and crosslinking techniques. Recent innovations in the development of natural and biocompatible charged surfactants and film forming agents are outlined. Among the important advances in this area are the applications of bile acids and salts for EPD of neutral polymers. Such innovations allowed for the successful EPD of various electrically neutral functional polymers for biomedical applications. Particularly important are biosurfactant-polymer interactions, which facilitate dissolution, dispersion, charging, electrophoretic transport and deposit formation. Recent advances in EPD mechanisms addressed the problem of EPD of proteins and enzymes related to their charge reversal at the electrode surface. Conceptually new methods are described, which are based on the use of biopolymer complexes with metal ions, proteins, enzymes and other biomolecules. This review describes new developments in co-deposition of biomacromolecules and future trends in the development of new EPD mechanisms and strategies for biomedical applications.

Surface Characterization of Electro-Assisted Titanium Implants: A Multi-Technique Approach

The understanding of chemical-physical, morphological, and mechanical properties of polymer coatings is a crucial preliminary step for further biological evaluation of the processes occurring on the coatings' surface. Several studies have demonstrated how surface properties play a key role in the interactions between biomolecules (e.g., proteins, cells, extracellular matrix, and biological fluids) and titanium, such as chemical composition (investigated by means of XPS, TOF-SIMS, and ATR-FTIR), morphology (SEM-EDX), roughness (AFM), thickness (Ellipsometry), wettability (CA), solution-surface interactions (QCM-D), and mechanical features (hardness, elastic modulus, adhesion, and fatigue strength). In this review, we report an overview of the main analytical and mechanical methods commonly used to characterize polymer-based coatings deposited on titanium implants by electro-assisted techniques. A description of the relevance and shortcomings of each technique is described, in order to provide suitable information for the design and characterization of advanced coatings or for the optimization of the existing ones.

Impact of surface topography on biofilm formation by Candida albicans

Candida albicans is a fungal pathogen that causes serious biofilm-based infections. Here we have asked whether surface topography may affect C. albicans biofilm formation. We tested biofilm growth of the prototypical wild-type strain SC5314 on a series of polydimethylsiloxane (PDMS) solids. The surfaces were prepared with monolayer coatings of monodisperse spherical silica particles that were fused together into a film using silica menisci. The surface topography was varied by varying the diameter of the silica particles that were used to form the film. Biofilm formation was observed to be a strong function of particle size. In the particle size range 4.0-8.0 μm, there was much more biofilm than in the size range 0.5-2.0 μm. The behavior of a clinical isolate from a clade separate from SC5314, strain p76067, showed results similar to that of SC5314. Our results suggest that topographic coatings may be a promising approach to reduce C. albicans biofilm infections.