Atmospheric Pressure Plasma Activation of Hydroxyapatite to Improve Fluoride Incorporation and Modulate Bacterial Biofilm

Despite the technological progress of the last decade, dental caries is still the most frequent oral health threat in children and adults alike. Such a condition has multiple triggers and is caused mainly by enamel degradation under the acidic attack of microbial cells, which compose the biofilm of the dental plaque. The biofilm of the dental plaque is a multispecific microbial consortium that periodically develops on mammalian teeth. It can be partially removed through mechanical forces by individual brushing or in specialized oral care facilities. Inhibition of microbial attachment and biofilm formation, as well as methods to strengthen dental enamel to microbial attack, represent the key factors in caries prevention. The purpose of this study was to elaborate a cold plasma-based method in order to modulate microbial attachment and biofilm formation and to improve the retention of fluoride (F−) in an enamel-like hydroxyapatite (HAP) model sample. Our results showed improved F retention in the HAP model, which correlated with an increased antimicrobial and antibiofilm effect. The obtained cold plasma with a dual effect exhibited through biofilm modulation and enamel strengthening through fluoridation is intended for dental application, such as preventing and treating dental caries and enamel deterioration.

Surface Modification to Modulate Microbial Biofilms—Applications in Dental Medicine

Recent progress in materials science and nanotechnology has led to the development of advanced materials with multifunctional properties. Dental medicine has benefited from the design of such materials and coatings in providing patients with tailored implants and improved materials for restorative and functional use. Such materials and coatings allow for better acceptance by the host body, promote successful implantation and determine a reduced inflammatory response after contact with the materials. Since numerous dental pathologies are influenced by the presence and activity of some pathogenic microorganisms, novel materials are needed to overcome this challenge as well. This paper aimed to reveal and discuss the most recent and innovative progress made in the field of materials surface modification in terms of microbial attachment inhibition and biofilm formation, with a direct impact on dental medicine.

The Importance of Not Being Too Attached: Pharmaceutical Equipment Characteristics and Bacterial Attachment

In this article the author provides an overview of the characteristics of microbial attachment and the essential considerations when developing a contamination control strategy. This review paper assesses the factors affecting finish and roughness, primarily in relation to microbial attachment to stainless steel, while considering other related variables like contact height and shape of surface defects

Assessment of a Weak Mode of Bacterial Adhesion by Applying an Electric Field

Microbial attachment to surfaces is ubiquitous in nature. Most species of bacteria attach and adhere to surfaces via special appendages such as pili and fimbriae, the roles of which have been extensively studied. Here, we report an experiment on pilus-less mutants of Caulobacter crescentus weakly attached to polyethylene surface. We find that some individual cells transiently but repeatedly adhere to the surface in a stick-slip fashion in the presence of an electric field parallel to the surface. These bacteria move significantly slower than the unattached ones in the same field of view undergoing electrophoretic motion. We refer this behavior of repeated and transient attachment as “quasi-attachment”. The speed of the quasi-attached bacteria exhibits large variation, frequently dropping close to zero for short intervals of time. We propose a polymeric tethering model to account for the experimental findings. This study sheds light on bacteria–surface interaction, which is significant in broader contexts such as infection and environmental control.

Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections

Biofilm formation represents a significant cause of concern as it has been associated with increased morbidity and mortality, thereby imposing a huge burden on public healthcare system throughout the world. As biofilms are usually resistant to various conventional antimicrobial interventions, they may result in severe and persistent infections, which necessitates the development of novel therapeutic strategies to combat biofilm-based infections. Physicochemical modification of the biomaterials utilized in medical devices to mitigate initial microbial attachment has been proposed as a promising strategy in combating polymicrobial infections, as the adhesion of microorganisms is typically the first step for the formation of biofilms. For instance, superhydrophobic surfaces have been shown to possess substantial anti-biofilm properties attributed to the presence of nanostructures. In this article, we provide an insight into the mechanisms underlying biofilm formation and their composition, as well as the applications of nanomaterials as superhydrophobic nanocoatings for the development of novel anti-biofilm therapies.

The roles of biomolecules in corrosion induction and inhibition of corrosion: a possible insight

Biofilms cause huge economic loss to the industry through corrosion. A deeper understanding of how biofilms form, develop and interact will help to decipher their roles in promoting and inhibiting corrosion, thus in controlling it. The present review explores most mechanisms of biofilm development and maintenance with particular emphasis on the roles of the biomolecules characteristic of biofilms, including exopolysaccharides (EPSs), proteins/enzymes, lipids, DNA and other metabolites in the corrosion process. These biomolecules play a significant role in the electron transfer process resulting in corrosion induction and inhibition. Microbial attachment, biofilm formation, the EPS matrix and both positive and negative effects by specific biofilm-forming genes all play roles in the electron transfer process. The current review describes these roles in detail. Although challenging to understand and control, the potential of biomolecules in the corrosion process is huge, and the coming decades will witness significant progress in the field. As well as discussing the technologies available for investigating corrosion induction and its inhibition, we also point to gaps in this knowledge.

Effects of Alginate and Chitosan on Activated Carbon as Immobilisation Beads in Biohydrogen Production

In this study, the effects of alginate and chitosan as entrapped materials in the biofilm formation of microbial attachment on activated carbon was determined for biohydrogen production. Five different batch fermentations, consisting of mixed concentration alginate (Alg), were carried out in a bioreactor at temperature of 60 °C and pH 6.0, using granular activated carbon (GAC) as a primer for cell attachment and colonisation. It was found that the highest hydrogen production rate (HPR) of the GAC–Alg beads was 2.47 ± 0.47 mmol H2/l.h, and the H2 yield of 2.09 ± 0.22 mol H2/mol sugar was obtained at the ratio of 2 g/L of Alg concentration. Next, the effect of chitosan (C) as an external polymer layer of the GAC–Alg beads was investigated as an alternative approach to protecting the microbial population in the biofilm in a robust environment. The formation of GAC with Alg and chitosan (GAC–AlgC) beads gave the highest HPR of 0.93 ± 0.05 mmol H2/l.h, and H2 yield of 1.11 ± 0.35 mol H2/mol sugar was found at 2 g/L of C concentration. Hydrogen production using GAC-attached biofilm seems promising to achieve consistent HPRs at higher temperatures, using Alg as immobilised bead material, which has indicated a positive response in promoting the growth of hydrogen-producing bacteria and providing excellent conditions for microorganisms to grow and colonise high bacterial loads in a bioreactor.