Hydrophobic Bacteria-Repellant Graphene Coatings from Recycled Pencil Stubs

The COVID-19 pandemic redefining the mundane food packaging material industry?

COVID-19 pandemic has been the talk of the globe, as it swept across the world population, changing enumerable aspects. The pandemic affected all sectors directly or indirectly. The food sector took a direct hit. The food packaging sector rose to the occasion to serve and feed the pandemic affected, but there were interactions, reactions, and consequences that evolved through the course of the journey through the pandemic. The aim of this perspective is to address the importance of the food packaging industry (from the COVID-19 point of view) and to highlight the unpreparedness of the food packaging materials, for times as these. As the world has been asked to learn to live with Corona, improvisations are definitely necessary, the lapses in the system need to be rectified, and the entire packaging industry has to go through fortification to co-exist with Corona or confront something worse than Corona. This discussion is set out to understand the gravity of the actual situation, assimilating information available from the scattered shreds of reports. Food packaging materials were used, and plastic wastes were generated in bulks, single-use plastics for fear of contamination gained prominence, leading to an enormous turnover of wastes. Fear of Corona, sprayed overloads of sanitizers and disinfectants on food package material surfaces for surface sterilization. The food packages were tailored for food containment needs, never were they planned for sanitizer sprays. The consequences of these sanitization procedures are unprecedented, neglected and in the post-COVID-19 phase no action appears to have been taken. Corona took us by surprise this time, but next time atleast the food packaging industry needs to be fully equipped. Speculated consequences have been reviewed and plausible suggestions have been proposed. The need for extensive research focus in this direction in exploring the ground-reality has been highlighted.

Inhibition performances of graphene oxide/silver nanostructure for the microbial corrosion: molecular dynamic simulation study

Steel is one of the mainly used materials in the oil and gas industry. However, it is susceptible to the marine corrosion, which 20% of the total marine corrosion is caused by microbiologically influenced corrosion (MIC). The economic and environmental impacts of corrosion are significant, and it is crucial to fight against corrosion in a proper sustainability context and environmental-friendly methods. In this study, the graphene oxide/silver nanostructure (GO-Ag) inhibitory effect on the corrosion of steel in the presence of sulfate reducing bacteria (SRB) was investigated, via weight loss (WL) and Tafel polarization measurements. Moreover, molecular dynamic (MD) simulations were performed to obtain a deep understanding of the corrosion inhibition effect of GO-Ag. GO-Ag showed a significant antibacterial effect at 80 ppm. Moreover, WL and Tafel polarization measurements illustrated a great inhibition efficiency, which reached up to 84% reduction of WL and 98% reduction of corrosion current density (I_corr) after 7 days of incubation with GO-Ag. Based on MD simulations, bonding energy reached to the larger value in the presence of GO-Ag, which indicated the ability of graphene oxide nanosheets to be adsorbed on the steel surface and prevent the access of corrosive agents to the steel surface. The radial distribution function (RDF) results implied distance between corrosive agent (water and SRB) and steel surface (Fe atoms), which indicated protection of the steel surface due to the effective adsorption of GO nanosheets through the active sites of the steel surface. The mean square displacement (MSD) result showed smaller displacement of the corrosive particles on the surface of steel, resulting that the GO-Ag molecules bonded with Fe molecules on the surface of steel.

Antibiofouling Activity of Graphene Materials and Graphene-Based Antimicrobial Coatings

Microbial adhesion and biofilm formation is a common, nondesirable phenomenon at any living or nonliving material surface in contact with microbial species. Despite the enormous efforts made so far, the protection of material surfaces against microbial adhesion and biofilm formation remains a significant challenge. Deposition of antimicrobial coatings is one approach to mitigate the problem. Examples of such are those based on heparin, cationic polymers, antimicrobial peptides, drug-delivering systems, and other coatings, each one with its advantages and shortcomings. The increasing microbial resistance to the conventional antimicrobial treatments leads to an increasing necessity for new antimicrobial agents, among which is a variety of carbon nanomaterials. The current review paper presents the last 5 years' progress in the development of graphene antimicrobial materials and graphene-based antimicrobial coatings that are among the most studied. Brief information about the significance of the biofouling, as well as the general mode of development and composition of microbial biofilms, are included. Preparation, antibacterial activity, and bactericidal mechanisms of new graphene materials, deposition techniques, characterization, and parameters influencing the biological activity of graphene-based coatings are focused upon. It is expected that this review will raise some ideas for perfecting the composition, structure, antimicrobial activity, and deposition techniques of graphene materials and coatings in order to provide better antimicrobial protection of medical devices.

Graphene: An Antibacterial Agent or a Promoter of Bacterial Proliferation?

Graphene materials (GMs) are being investigated for multiple microbiological applications because of their unique physicochemical characteristics including high electrical conductivity, large specific surface area, and robust mechanical strength. In the last decade, studies on the interaction of GMs with bacterial cells appear conflicting. On one side, GMs have been developed to promote the proliferation of electroactive bacteria on the surface of electrodes in bioelectrochemical systems or to accelerate interspecies electron transfer during anaerobic digestion. On the other side, GMs with antibacterial properties have been synthesized to prevent biofilm formation on membranes for water treatment, on medical equipment, and on tissue engineering scaffolds. In this review, we discuss the mechanisms and factors determining the positive or negative impact of GMs on bacteria. Furthermore, we examine the bacterial growth-promoting and antibacterial applications of GMs and debate their practicability.

Superhydrophobic graphene-based materials with self-cleaning and anticorrosion performance: An appraisal of neoteric advancement and future perspectives

Lotus like materials having superhydrophobicity is attaining greater demand due to the possibility of molding them into different high end applications. The major issue related to self-cleaning superhydrophobic surfaces is their restricted mechanical properties. The development of nanotechnology has brought many advantages in the fabrication and properties of superhydrophobic surfaces and thus it enhanced the demand of superhydrophobic surfaces. Many scientific groups have studied and reported about the superhydrophobicity exhibited by graphene and its analogous derivatives. The fabrication of the devices having properties ranging from anti-sticking and self-cleaning to anti-corrosion and low friction is made possible by the incorporation of this wonderful two-dimensional material. This review focuses on the preparation and properties of graphene based superhydrophobic coating materials with special mention to the wide range of applications rendered by them.