Prevention of biofilm formation by polyquaternary polymer

Time-Resolved Killing of Individual Bacterial Cells by a Polycationic Antimicrobial Polymer

Polycationic polymers are widely studied antiseptics, and their efficacy is usually quantified by the solution concentration required to kill a fraction of a population of cells (e.g., by Minimum Bactericidal Concentration (MBC)). Here we describe how the response to a polycationic antimicrobial varies greatly among members of even a monoclonal population of bacteria bathed in a single common antimicrobial concentration. We use fluorescence microscopy to measure the adsorption of a labeled cationic polymer, polydiallyldimethylammmonium chloride (PDADMAC, Mw ≈ 4 × 105 g mol-1) and the time course of cell response via a cell permeability indicator for each member of an ensemble of either Escherichia coli, Staphylococcus aureus, or Pseudomonas aeruginosa cells. This is a departure from traditional methods of evaluating synthetic antimicrobials, which typically measure the overall response of a collection of cells at a particular time and therefore do not assess the diversity within a population. Cells typically die after they reach a threshold adsorption of PDADMAC, but not always. There is a substantial time lag of about 5-10 min between adsorption and death, and the time to die of an individual cell is well correlated with the rate of adsorption. The amount adsorbed and the time-to-die differ among species but follow a trend of more adsorption on more negatively charged species, as expected for a cationic polymer. The study of individual cells via time-lapse microscopy reveals additional details that are lost when measuring ensemble properties at a particular time.

Ag2O-Containing Biocidal Interpolyelectrolyte Complexes on Glass Surfaces-Adhesive Properties of the Coatings

Biocidal coatings are of great interest to the healthcare system. In this work, the biocidal activity of coatings based on a complex biocide containing polymer and inorganic active antibacterial components was studied. Silver oxide was distributed in a matrix of a positively charged interpolyelectrolyte complex (IPEC) of polydiallyldimethylammonium chloride (PDADMAC) and sodium polystyrene sulfonate (PSS) using ultrasonic dispersion, forming nanoparticles with an average size of 5-6 nm. The formed nanoparticles in the matrix are not subject to agglomeration and changes in morphology during storage. It was found that the inclusion of silver oxide in a positively charged IPEC allows a more than 4-fold increase in the effectiveness of the complex biocide against E. coli K12 in comparison with the biocidal effect of PDADMAC and IPEC. Polycation, IPEC, and the IPEC/Ag2O ternary complex form coatings on the glass surface due to electrostatic adsorption. Adhesive and cohesive forces in the resulting coatings were studied with micron-scale coatings using dynamometry. It was found that the stability of the coating is determined primarily by adhesive interactions. At the macro level, it is not possible to reliably identify the role of IPEC formation in adhesion. On the other hand, use of the optical tweezers method makes it possible to analyze macromolecules at the submicron scale and to evaluate the multiple increase in adhesive forces when forming a coating from IPEC compared to coatings from PDADMAC. Thus, the application of ternary IPEC/Ag2O complexes makes it possible to obtain coatings with increased antibacterial action and improved adhesive characteristics.

Modification of Polydiallyldimethylammonium Chloride with Sodium Polystyrenesulfonate Dramatically Changes the Resistance of Polymer-Based Coatings towards Wash-Off from Both Hydrophilic and Hydrophobic Surfaces

Polymer coatings based on polycations represent a perspective class of protective antimicrobial coatings. Polydiallyldimethylammonium chloride (PDADMAC) and its water-soluble complexes with sodium polystyrenesulfonate (PSS) were studied by means of dynamic light-scattering, laser microelectrophoresis and turbidimetry. It was shown that addition of six mol.% of polyanion to polycation results in formation of interpolyelectrolyte complex (IPEC) that was stable towards phase separation in water-salt media with a concentration of salts (NaCl, CaCl₂, Na₂SO₄, MgSO₄) up to 0.5 M. Most of the polyelectrolyte coatings are made by layer-by-layer deposition. The utilization of water-soluble IPEC for the direct deposition on the surface was studied. The coatings from the PDADMAC and the PSS/PDADMAC complex were formed on the surfaces of hydrophilic glass and hydrophobic polyvinylchloride. It was found that formation IPEC allows one to increase the stability of the coating towards wash-off with water in comparison to individual PDADMAC coating on both types of substrates. The visualization of the coatings was performed by atomic force microscopy and scanning electron microscopy.

Biocompatible Materials in Otorhinolaryngology and Their Antibacterial Properties

For decades, biomaterials have been commonly used in medicine for the replacement of human body tissue, precise drug-delivery systems, or as parts of medical devices that are essential for some treatment methods. Due to rapid progress in the field of new materials, updates on the state of knowledge about biomaterials are frequently needed. This article describes the clinical application of different types of biomaterials in the field of otorhinolaryngology, i.e., head and neck surgery, focusing on their antimicrobial properties. The variety of their applications includes cochlear implants, middle ear prostheses, voice prostheses, materials for osteosynthesis, and nasal packing after nasal/paranasal sinuses surgery. Ceramics, such as as hydroxyapatite, zirconia, or metals and metal alloys, still have applications in the head and neck region. Tissue engineering scaffolds and drug-eluting materials, such as polymers and polymer-based composites, are becoming more common. The restoration of life tissue and the ability to prevent microbial colonization should be taken into consideration when designing the materials to be used for implant production. The authors of this paper have reviewed publications available in PubMed from the last five years about the recent progress in this topic but also establish the state of knowledge of the most common application of biomaterials over the last few decades.

The Mechanisms and the Applications of Antibacterial Polymers in Surface Modification on Medical Devices

Medical device contamination caused by microbial pathogens such as bacteria and fungi has posed a severe threat to the patients' health in hospitals. Due to the increasing resistance of pathogens to antibiotics, the efficacy of traditional antibiotics treatment is gradually decreasing for the infection treatment. Therefore, it is urgent to develop new antibacterial drugs to meet clinical or civilian needs. Antibacterial polymers have attracted the interests of researchers due to their unique bactericidal mechanism and excellent antibacterial effect. This article reviews the mechanism and advantages of antimicrobial polymers and the consideration for their translation. Their applications and advances in medical device surface coating were also reviewed. The information will provide a valuable reference to design and develop antibacterial devices that are resistant to pathogenic infections.

Study of the Effectiveness of Multipurpose Solutions on the Bacterial Disinfection of Silicone Hydrogel Contact Lenses In Vitro

OBJECTIVES

To assess the antimicrobial effectiveness of multipurpose solutions in regard to the disinfection of silicone hydrogel contact lenses (CL) using a study of clinical bacterial isolates from ocular material.

METHODS

Three multipurpose solutions (solution A: polyhexamethylene biguanide 0.00025 g/100 mL; solution B: polyquaternary-1 0.001% and myristamidopropyl dimethylamine 0.0006%; and solution C: polyaminopropyl biguanide 0.00013% and polyquaternary 0.0001%) were used as a 3-phase disinfection on silicone hydrogel CL contaminated with bacteria from clinical isolates that were divided into five groups (group 1: Pseudomonas aeruginosa; group 2: Staphylococcus aureus; group 3: Staphylococcus epidermidis; group 4: Streptococcus spp; and group 5: enterobacteria).

RESULTS

No differences were observed between the 24- and 48-hr measurements in any of the samples, and the positivity of microorganisms in T0 was 100% for all solutions; it was 0% in T3. Therefore, only steps T1 (rubbing followed by rinsing) and T2 (rubbing followed by rinsing and immersion of CL into solution) were considered for analysis at the 24-hr measurement time. Throughout the phases, a decrease in the number of bacteria was observed, culminating in the elimination (no recovery) of all microorganisms in the three solutions.

CONCLUSIONS

At the end of the proposed process, the tested solutions were effective.