Antibacterial Polysiloxane Polymers and Coatings for Cochlear Implants

Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These membranes were subjected to in vitro testing for microbial adherence against S. pneumoniae using standardized tests. WISTAR rats were implanted for 4 weeks with crosslinked siloxane samples without and with NAC. A set of physical characterization methods was employed to assess the chemical structure and morphological aspects of the new synthetized materials before and after contact with the microbiological medium.

Development and characterization of k-carrageenan platforms as periodontal intra-pocket films

Purpose: To prepare emulsion-based Intrapocket polymeric films for the treatment of periodontitis. Method: Films were fabricated by dehydration of an emulsion containing k-carrageenan (KC) in aqueous phase and Compritol® 888 ATO (Compritol® ) or Dimodan® UJ (DU® ) or different ratios of both. The resulting films were characterized by mechanical texture analyser to determine Young’s modulus and tensile strength. Glass transition temperature (Tg) of the films was evaluated by dynamic mechanical and thermal analyser while surface morphology was evaluated using scanning electron microscope. In-vitro drug release was conducted in pre-warmed phosphate buffer. Bacterial adherence was assessed after 24 h. Results: Young’s modulus was highest for KC films to which no lipid was added (5.33 ± 0.38 GPa) and decreased following lipid incorporation. Tg was highest in KC films (106.25 ± 4.53 ° C) but decreased upon addition of lipids. The surface of KC was smooth but roughness increased with increasing Compritol® load. Drug release from KC films was complete (99.80 ± 8.43 %) after 2 h; however, upon adding lipid, the release was extended 8 h and was affected by lipid type and ratio. Microbiologic assay demonstrated noticeable reduction in viable count compared to control and was affected by lipid type and ratio. The film formulated from a combination of DU® and Compritol® in a ratio of 80:20 was strong, flexible and reduced microbial adherence. Moreover, it showed a smooth surface and extended release for over 8 h. Conclusion: Intra-pocket films were prepared by drying emulsion-based films. Resulted films were strong, flexible, prolonged drug release over 8 h and could lower bacterial growth. The prepared film may offer efficient treatment in periodontitis patients.

Exposure to Heated Tobacco Products and Adverse Health Effects, a Systematic Review

Heated tobacco products (HTP) are a form of nicotine delivery intended to be an alternative to traditional cigarettes. HTP tobacco products are sold to consumers as a less harmful alternative to traditional cigarettes, both for users and bystanders. The actual impact of HTP on the health of users and its overall impact on public health is still not fully known. A systematic search of the literature was carried out to identify relevant studies published in English from 2015 to February 2021. The following databases were used: PubMed, Scopus, Elsevier and ClinicalKey. 25 studies (independent and sponsored by the tobacco industry) were considered. The analysis of exposure biomarkers and cardiovascular and respiratory biomarkers showed differences between smokers and people using heated tobacco products. Improvements in clinically relevant risk markers, especially cholesterol, sICAM-1, 8-epi-PGF2α, 11-DTX-B2, HDL and FEV1, were observed compared to persistent cigarette smokers. On the other hand, exposure to IQOS has been reported to alter mitochondrial function, which may further exaggerate airway inflammation, airway remodeling and lung cancer. These products have the potential to increase oxidative stress and increase respiratory tract infections by increasing microbial adherence to the respiratory tract. Our review suggests that HTP products may be products with a reduced risk of chronic diseases, including respiratory and cardiovascular diseases and cancer compared to traditional smoking, although in the case of non-smokers so far, they may pose a risk of their occurrence. Research seems to be necessary to assess the frequency of HTP use and its potential negative health effects.

Effects of Irregularities in the Microstructure of Surgical Instruments on Microbial Adherence and Challenges for Processing

Background: A surgical instrument can have areas that pose different challenges to cleaning, hindering the removal of dirt. This can directly impact the effectiveness of its processing while potentially promoting cross contamination. Moreover, structural changes (ie, cracks or fissures) on the instrument surface, although rarely addressed, can act as reservoirs for microorganisms, contributing to organic matter retention, microbial growth, and biofilm formation. Our aim was to determine the effect of irregularities in the microstructure of surgical instruments on microbial adherence. Methods: We analyzed 18 fragments of 3 distinct areas of new crile forceps: the ratchet, shank, and jaw. Of these fragments, 15 were artificially contaminated by immersion in tryptic soy broth containing 10 6 CFU/mL of Escherichia coli (ATCC 25922), for 4, 6, 8, and 12 hours of incubation at 37C with agitation at 100 rpm. The other 3 fragments were used as controls. All fragments were subjected to scanning electron microscopy to evaluate the adhesion of the microorganism. Results: An irregular surface was found in 3 of 6 shank fragments (50%) (Fig. 1) and in all the jaw and ratchet fragments, grooves, and cracks. Initially, there was less adherence of E. coli to the smooth shank surface after contamination, but the concentration of the microorganism increased progressively over time in relation to that in the jaw or ratchet at the same time, and a higher concentration occurred in the cracks and grooves. Conclusions: Structural damage was observed in all fragments, especially in the ratchet and jaw areas, favoring microbial accumulation. Microorganisms housed in the cracks and grooves were better protected from removal by scrubbing with a brush (being unlikely to reach them), making these areas a microbial reservoir and source of contamination. Prolonged contact of the instrument with the contaminating microorganism allowed for greater adherence, even on the smooth areas. The results support the relevance of the early onset of cleaning, considering that even microscopic changes on the surface of the instrument may represent an additional challenge to its effective processing.Funding: NoneDisclosures: None

Influence of microbial adherence on corrosion of UNS 1008 carbon steel and hybrid nano-structured coatings

Purpose Microbes that are able to grow on different surfaces can cause the deterioration of the underlying layers because of their metabolic activity. The purpose of this study is report the ability of fungi-bacteria consortium (FBC) in anaerobic media, and marine strain bacteria, to attach onto UNS 1008 carbon steel and zinc epoxy coats. Design/methodology/approach Impedance analysis, scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to evaluate the adherence, biofilm formation and corrosion effect of FBC and marine bacteria onto UNS1008 carbon steel in anaerobic and aired conditions, respectively. In a similar way, the anticorrosive performance of hybrid coats on UNS 1008 carbon steel against marine bacteria. Findings In aerobic conditions, the outer layer shows a micro-crack appearance and several semi-sphere products that could be because of spore formation. In anaerobic conditions, evidence of iron sulfide surrounded by a mixture of sulfur-containing extracellular polymer substance was observed by SEM images and EDS analysis. The presence of hybrid coats (zinc epoxy with carbon nanotubes CNT content) affected the level of microbial adherence and the concentration of corrosion products (Fe2O3, Fe(OH)2 and FeS); the cell attachment was lower when the steel surface was coated with Zn/CNTs. Originality/value This study opens a window for further evaluations of CNTs associated with metals as active materials to assess the corrosion on extreme corrosive environments, like in oil and gas industries the microorganisms play an important role either to increase or reduce the corrosion processes.

Methods for eradication of the biofilms formed by opportunistic pathogens using novel techniques – A review

The inconvenient environmental conditions force microorganisms to colonize either abiotic surfaces or animal and plant tissues and, therefore, form more resistant structures – biofilms. The phenomenon of microbial adherence, opportunistic pathogens in particular, is of a great concern. Colonization of medical devices and biofilm formation on their surface, may lead to severe infections mainly in humans with impaired immune system. Although, current research consider various methods for prevention of microbial biofilms formation, still, once a biofilm is formed, its elimination is almost impossible. This study focuses on the overview of novel methods applied for eradication of mature opportunistic pathogens' biofilms. Among various techniques the following: cold plasma, electric field, ultrasounds, ozonated water treatment, phagotherapy, matrix targeting enzymes, bacteriocins, synthetic chemicals and natural origin compounds used for biofilm matrix disruption were briefly described.