Bacterial Adhesion Capacity of Uropathogenic Escherichia coli to Polyelectrolyte Multilayer Coated Urinary Catheter Surface

The combined effect of essential oils on wood physico-chemical properties and their antiadhesive activity against mold fungi: application of mixture design methodology

In the heritage field, the microbial adhesion on wood, and consequently the formation of biofilm led to inestimable losses of historical and cultural monuments. Thereby, this study aimed to examine the combined effect of Thymus vulgaris, Myrtus communis, and Mentha pulegium essential oils on wood surface physico-chemical properties, and to elaborate the optimal mixture using the mixture design approach coupled to the contact angle method. It was found that both wood hydrophobicity and electron donor character increased significantly after treatment using an optimal mixture containing 57% and 43% of M. pulegium and M. communis essential oils, respectively. The theoretical and experimental fungal adhesion on untreated and treated wood were also investigated. The results showed that the adhesion was favorable on untreated wood and reduced using the optimal mixture. Moreover, the experimental data demonstrated that the same mixture exhibited an antiadhesive efficacy effect with a reduction of 36-75% in adhesion.

Suppressing the Hofmeister Anion Effect by Thermal Annealing of Thin-Film Multilayers Made of Weak Polyelectrolytes

Thin films made of weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) have been fabricated on silicon wafers using the layer-by-layer (LbL) method. To study the influence of counteranion type on the growth and properties of PAH/PAA multilayers, the nature of the supporting sodium salt was varied from cosmotropic to chaotropic anions (F^–, Cl^–, and ClO₄^–). Results of ellipsometry and AFM measurements indicate that the film thickness and surface roughness systematically increase on the order F^– < Cl^– < ClO₄^–. Furthermore, we found that the hydrophobicity of the PAH/PAA multilayer also follows the described trend when a polycation is the terminating layer. However, the heating of PAH/PAA multilayers to 60 °C during the LbL assembly suppressed the influence of background anions on the multilayer formation and properties. On the basis of the obtained results, it could be concluded that thermal annealing induces changes at the polymer–air interface in the sense of reorientation and migration of polymer chains.

Nanoparticles: From synthesis to applications and beyond

In modern-day research, nanoparticles (size < 100nm) are an indispensable tool for various applications, especially in the field of biomedicine. Although enormous efforts have been made to understand the properties and specificities of nanoparticles, many questions are still not answered and the new ones arise. In this review we summarize current trends in the nanoparticle synthesis and characterization and interpret the stability of nanoparticles in various media from aqueous solutions to biological milieu important for the in vitro and in vivo studies. To get more detailed insight into nanoparticle charging properties and interactions of nanoparticles with interfaces the theoretical models are presented. Finally, the overview of nanoparticle applications is given and the future prospects are discussed.

Predicting the outcomes of interpolyelectrolyte neutralization at surfaces on the basis of complexation experiments and vice versa

This study was carried out with the aim of establishing how the outcomes of polyelectrolyte multilayer formation can be predicted on the basis of the results of complexation studies in solution and vice versa. For this purpose, the correlation between the processes of complex and multilayer formation involving three pairs of vinylic polyions in solutions of binary 1 : 1 sodium salts (NaX; X = F, Cl, Br, I, NO₃, ClO₄) was explored by means of dynamic and electrophoretic light scattering, potentiometry, microcalorimetry, spectrophotometry and quartz crystal microbalance. The gradual reactant mixing in solution at lower salt concentrations resulted in a Fuoss-Sadek sequence of events (primary complexes → secondary complexes → 1 : 1 flocculate), whereby the obtained nano-complexes could be successively overcharged. At high salt concentration and with excess polycation present, metastable nano-complexes and precipitates containing surplus of positively charged monomers were formed. The amount of extrinsically compensated charge was in accord with the polycation affinities toward counteranions, established by monitoring the electrolyte-induced aggregation of positively charged nano-complexes. Perfect analogy with respect to counteranion influence on the amount of adsorbed polycation was noticed for corresponding multilayers. Aside from providing a deeper understanding of interpolyelectrolyte neutralization, the gained insights can also be used to steer the polyelectrolyte multilayer composition and properties.

An Amphiphilic Carbonaceous/Nanosilver Composite-Incorporated Urinary Catheter for Long-Term Combating Bacteria and Biofilms

Biofilms formed on urinary catheters remain a major headache in the modern healthcare system. Among the various kinds of biocide-releasing urinary catheters that have been developed to prevent biofilm formation, Ag nanoparticles (AgNPs)-coated catheters are of great promising potential. However, the deposition of AgNPs on the surface of catheters suffers from several inherent shortcomings, such as damage to the urethral mucosa, uncontrollable Ag ion kinetics, and unexpected systematic toxicity. Here, AgNPs-decorated amphiphilic carbonaceous particles (ACPs@AgNPs) with commendable dispersity in solvents of different polarities and broad-spectrum antibacterial activity are first prepared. The resulting ACPs@AgNPs exert good compatibility with silicone rubber, which enables the easy fabrication of urinary catheters using a laboratory-made mold. Therefore, ACPs@AgNPs not only endow the urinary catheter with forceful biocidal activity but also improve its mechanical properties and surface wettability. Hence, the designed urinary catheter possesses excellent capacity to resist bacterial adhesion and biofilm formation both in vitro and in an in vivo rabbit model. Specifically, a long-term antibacterial study highlights its sustainable antibacterial activity. Of note, no obvious toxicity or inflammation in rabbits was triggered by the designed urinary catheter in vivo. Overall, the hybrid urinary catheter may serve as a promising biocide-releasing urinary catheter for antibacterial and antibiofilm applications.