Recent development in water-based resins for surface coatings

To develop hydrophilic resin-based surface coatings containing bioactive agents (proanthocyanidins from Vitis vinifera and calcium silicate) and assess their protective role at the dentin and enamel margins of cervical restorations against demineralization under simulated conditions of high and low caries activity. Suboptimal resin composite restorations were placed on cervical cavity preparations on buccal and lingual surfaces of thirty-two molars after a contamination protocol. Groups were divided according to the resin-based coatings (n=8): resin without bioactive (C), resin containing 2% enriched Vitis Vinifera (VVE), and resin coat containing 10% calcium silicate (CaSi). The control group did not receive a resin (NC). To simulate a hydrolyticenzymatic degradation, specimens were subjected to 2-month storage followed by incubation in esterase at 37°C for 8 days. Afterwards, recurrent caries was induced using a pH-proteolytic model on half of the specimens to simulate high caries activity, and the other half remained in simulated body fluid (SBF). Measurements of cross-section microhardness (KHN) and infiltration with rhodamine-B assessed the micropermeability (MP), the extent of demineralization (ED), and the demineralization area (DA). Data were analyzed using analysis of variance (ANOVA) and post-hoc tests (α=0.05). VVE and CaSi presented higher cross-sectional KHN values for enamel and dentin (p<0.001). The bioactive coatings resulted in lower MP, ED, and DA compared to NC (p<0.005) in enamel and dentin. CaSi coating preserved the enamel from demineralization (p=0.160). The application of bioactive coatings represents a potential strategy to protect the enamel-dentin margins of resin restorations.

Chapter 14 - Polymer nanocomposites as industrially useful corrosion inhibitors: recent developments

The transmission of pathogens through contact with contaminated surfaces is an important route for the spread of infections. The recent outbreak of COVID-19 highlights the necessity to attenuate surface-mediated transmission. Currently, the disinfection and sanitization of surfaces are commonly performed in this regard. However, there are some disadvantages associated with these practices, including the development of antibiotic resistance, viral mutation, etc.; hence, a better strategy is necessary. In recent years, peptides have been studied to be utilized as a potential alternative. They are part of the host immune defense and have many potential in vivo applications in drug delivery, diagnostics, immunomodulation, etc. Additionally, the ability of peptides to interact with different molecules and membrane surfaces of microorganisms has made it possible to exploit them in ex vivo applications such as antimicrobial (antibacterial and antiviral) coatings. Although antibacterial peptide coatings have been studied extensively and proven to be effective, antiviral coatings are a more recent development. Therefore, this study aims to highlight antiviral coating strategies and the current practices and application of antiviral coating materials in personal protective equipment, healthcare devices, and textiles and surfaces in public settings. Here, we have presented a review on potential techniques to incorporate peptides in current surface coating strategies that will serve as a guide for developing cost-effective, sustainable and coherent antiviral surface coatings. We further our discussion to highlight some challenges of using peptides as a surface coating material and to examine future perspectives.

The radical polymerization of vinyl monomers is the most versatile method of producing carbon backbone polymers, both industrially and in the laboratory. The use of free radical attack on monomer double bonds to initiate chain polymerization dates back to at least 1838 when the free radical polymerization of vinylidene chloride was reported.1 Indeed, a range of monomers, including vinyl chloride,2 isoprene,3 methacrylic acid4 and methyl acrylate,5 were polymerized prior to 1900! Advances in radical polymerization have led to a range of commercial products through the development of new polymerization processes. The need to carry out radical polymerization on an industrial scale has led to the development of both emulsion and suspension polymerizations which have become important technologies over a wide area of industry. Commercial products from radical polymerization range from emulsions and latices for surface coatings and adhesives, to optically transparent materials for building, medical and electronic applications.

Background Glass ionomer cement (GIC) is a widely used tooth coloured material. However, GIC holds certain undesirable properties. In order to overcoming the major drawback of moisture sensitivity, surface coatings like petroleum jelly, varnish are applied over GIC restoration. Thus, the present study was planned to compare efficacy of newly formulated nano silver fluoride resin coat with G Coat Plus and petroleum jelly on microhardness and microleakage of Type IX GIC. Methods Class V cavities were prepared on the buccal surface of thirty-six non carious premolars and restored with type IX GIC. The restored teeth were divided into 3 groups: Petroleum gel, G Coat plus and Nano silver fluoride resin coat. Protective surface coatings were applied over the restorations, dried for 2 minutes and thermocycled. Teeth were then placed in 1% methylene blue for 24 hours. Longitudinally sections were prepared and were observed under stereomicroscope at 25x magnification for dye penetration. Forty-five blocks of PVC were prepared and restored with GIC. Samples were divided into three groups equally as mentioned earlier and a layer of each coating was applied on all samples according to the groups and dried for 2 minutes. Further, surface microhardness (SMH) of the samples was tested by Vickers microhardness machine under a load of 50 grams for 10 seconds at 3 sites and a mean was calculated. Statistical analysis was conducted using post hoc and one way-ANOVA tests. Results The microleakage scores of three groups were statistically insignificant. The mean microhardness of all samples in the three groups showed no statistically significant difference. The mean surface microhardness of group 1 was 66.44±4.57 whereas for group 2 and group 3 it was 76.15±3.02 and 79.22±4.03 respectively. Conclusions The novel agent containing nano silver fluoride is showed superior results and is intended to augment the properties of GIC.

Surface engineering: An enabling technology for manufacturing industry

Design and fabrication of bipolar plates for PEM water electrolyser

Supramolecular assembly is commonly driven by noncovalent interactions (e.g., hydrogen bonding, electrostatic, hydrophobic, and aromatic interactions) and plays a predominant role in multidisciplinary research areas ranging from materials design to molecular biology. Understanding these noncovalent interactions at the molecular level is important for studying and designing supramolecular assemblies in chemical and biological systems. Cation-π interactions, initially found through their influence on protein structure, are generally formed between electron-rich π systems and cations (mainly alkali, alkaline-earth metals, and ammonium). Cation-π interactions play an essential role in many biological systems and processes, such as potassium channels, nicotinic acetylcholine receptors, biomolecular recognition and assembly, and the stabilization and function of biomacromolecular structures. Early fundamental studies on cation-π interactions primarily focused on computational calculations, protein crystal structures, and gas- and solid-phase experiments. With the more recent development of spectroscopic and nanomechanical techniques, cation-π interactions can be characterized directly in aqueous media, offering opportunities for the rational manipulation and incorporation of cation-π interactions into the design of supramolecular assemblies. In 2012, we reported the essential role of cation-π interactions in the strong underwater adhesion of Asian green mussel foot proteins deficient in l-3,4-dihydroxyphenylalanine (DOPA) via direct molecular force measurements. In another study in 2013, we reported the experimental quantification and nanomechanics of cation-π interactions of various cations and π electron systems in aqueous solutions using a surface forces apparatus (SFA).Over the past decade, much progress has been achieved in probing cation-π interactions in aqueous solutions, their impact on the underwater adhesion and cohesion of different soft materials, and the fabrication of functional materials driven by cation-π interactions, including surface coatings, complex coacervates, and hydrogels. These studies have demonstrated cation-π interactions as an important driving force for engineering functional materials. Nevertheless, compared to other noncovalent interactions, cation-π interactions are relatively less investigated and underappreciated in governing the structure and function of supramolecular assemblies. Therefore, it is imperative to provide a detailed overview of recent advances in understanding of cation-π interactions for supramolecular assembly, and how these interactions can be used to direct supramolecular assembly for various applications (e.g., underwater adhesion). In this Account, we present very recent advances in probing and applying cation-π interactions for mussel-inspired supramolecular assemblies as well as their structural and functional characteristics. Particular attention is paid to experimental characterization techniques for quantifying cation-π interactions in aqueous solutions. Moreover, the parameters responsible for modulating the strengths of cation-π interactions are discussed. This Account provides useful insights into the design and engineering of smart materials based on cation-π interactions.

Glioblastoma multiforme (GBM) is an aggressive brain tumor with poor prognosis and high mortality, with no curative treatment to date as limited trafficking across the blood-brain barrier (BBB) combined with tumor heterogeneity often leads to therapeutic failure. Although modern medicine poses a wide range of drugs that are otherwise efficacious in treating other tumors, they often do not achieve therapeutic concentrations in the brain, hence driving the need for more effective drug delivery strategies. Nanotechnology, an interdisciplinary field, has been gaining immense popularity in recent years for remarkable advancements such as nanoparticle (NP) drug carriers, which possess extraordinary versatility in modifying surface coatings to home in on target cells, including those beyond the BBB. In this review, we will be highlighting recent developments in biomimetic NPs in GBM therapy and how these allowed us to overcome the physiological and anatomical challenges that have long plagued GBM treatment.

Applications of ion-beam-assisted deposition