Compounds with antimicrobial activity have gained much attention in research due to the outbreak of coronavirus disease 2019 (COVID-19). Quaternary ammonium salts (QASs) are an emerging group of antibacterial agents that are used as disinfectants. Many studies have been carried out involving the applications of QASs as antifouling agents for the inhibition of biofilm growth on medical implants and antibacterials on surfaces and in an aquatic environment. In investigating the antibacterial activity of QASs, we addressed the structure-activity relationship and the physicochemical factors. This review is focused on the fine-tuning of the chemical structures of QASs for their applications as wide antibacterial agents.
Modified colloids and flat surfaces occupy an important place in materials science research due to their widespread applications. Interest in development of modifiers that adhere strongly to surfaces relates to the need for stability under ambient conditions in many applications. In the last 20 years, diazonium salts have evolved as the primary choice for modification of surfaces. The term 'diazonics' has been introduced in the literature to describe "the science and technology of aryldiazonium salt-derived materials". The facile reduction of diazonium salts via chemical or electrochemical processes, irradiation stimuli, or spontaneously, results in efficient modification of gold surfaces. Robust gold-organic nanoparticles and films modified by using diazonium salts are critical in electronics, sensors, medical implants, and materials for power sources. Experimental and theoretical studies suggest that gold-carbon interactions constructed via chemical reactions with diazonium salts are stronger than nondiazonium surface modifiers. This invited feature article summarizes the conceptual development of recent studies of diazonium salts in our laboratories and others with a focus on surface modification of gold nanostructures and flat surfaces, and their applications in nanomedicine engineering, sensors, energy, forensic science, and catalysis.
Nitric oxide-containing drugs present a critical remedy for cardiovascular diseases. Nitroglycerin (NG, O−NO) and S-nitrosoglutathione (SNG, S−NO) are the most common nitric oxide drugs for cardiovascular diseases. Insights regarding the binding affinity of NO drugs with lysozyme and human serum albumin (HSA) proteins and their dissociation mechanism will provide inquisitive information regarding the potential of the proteins as drug carriers. For the first time, the binding interactions and affinities are investigated using molecular docking, conventional molecular dynamics, steered molecular dynamics, and umbrella sampling to explore the ability of both proteins to act as nitric oxide drug carriers. The molecular dynamics simulation results showed higher stability of lysozyme−drug complexes compared to HSA. For lysozyme, cardiovascular drugs were bound in the protein cavity mainly by the electrostatic and hydrogen bond interactions with residues ASP53, GLN58, ILE59, ARG62, TRP64, ASP102, and TRP109. For HSA, key binding residues were ARG410, TYR411, LYS414, ARG485, GLU450, ARG486, and SER489. The free energy profiles produced from umbrella sampling also suggest that lysozyme−drug complexes had better binding affinity than HSA−drug. Binding characteristics of nitric oxidecontaining drugs NG and SNG to lysozyme and HSA proteins were studied using fluorescence and UV−vis absorption spectroscopy. The relative change in the fluorescence intensity as a function of drug concentrations was analyzed using Stern−Volmer calculations. This was also confirmed by the change in the UV−vis spectra. Fluorescence quenching results of both proteins with the drugs, based on the binding constant values, demonstrated significantly weak binding affinity to NG and strong binding affinity to SNG. Both computational and experimental studies provided important data for understanding protein−drug interactions and will aid in developing potential drug carrier systems in cardiovascular diseases.
Gold nanoparticles (AuNPs) have gained increasing attention as novel drug-delivery nanostructures for the treatment of cancers, infections, inflammations, and other diseases and disorders. They are versatile in design, synthesis, modification, and functionalization. This has many advantages in terms of gene editing and gene silencing, and their application in genetic illnesses. The development of several techniques such as CRISPR/Cas9, TALEN, and ZFNs has raised hopes for the treatment of genetic abnormalities, although more focused experimentation is still needed. AuNPs, however, have been much more effective in trending research on this subject. In this review, we highlight recently well-developed advancements that are relevant to cutting-edge gene therapies, namely gene editing and gene silencing in diseases caused by a single gene in humans by taking an edge of the unique properties of the AuNPs, which will be an important outlook for future research.
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