The substantial increase in multidrug-resistant (MDR) pathogenic bacteria is a major threat to global health. Recently, the Centers for Disease Control and Prevention reported possibilities of greater deaths due to bacterial infections than cancer. Nanomaterials, especially small-sized (size ≤10 nm) silver nanoparticles (AgNPs), can be employed to combat these deadly bacterial diseases. However, high reactivity, instability, susceptibility to fast oxidation, and cytotoxicity remain crucial shortcomings for their uptake and clinical application. In this review, we discuss various AgNPs-based approaches to eradicate bacterial infections and provide comprehensive mechanistic insights and recent advances in antibacterial activity, antibiofilm activity, and cytotoxicity (both in vitro and in vivo) of AgNPs. The mechanistic of antimicrobial activity involves four steps: (i) adhesion of AgNPs to cell wall/membrane and its disruption; (ii) intracellular penetration and damage; (iii) oxidative stress; and (iv) modulation of signal transduction pathways. Numerous factors affecting the bactericidal activity of AgNPs such as shape, size, crystallinity, pH, and surface coating/charge have also been described in detail. The review also sheds light on antimicrobial photodynamic therapy and the role of AgNPs versus Ag+ ions release in bactericidal activities. In addition, different methods of synthesis of AgNPs have been discussed in brief.

This review discusses the advances in fluorescent Schiff base sensors for metal ion detection with a focus on the strategies, mechanistic insights, and applications.

Negatively charged ions are integral parts of our ecosystem. Fluorescence-based approaches show great promise in terms of developing efficient sensing platforms for anion detection.

Interactions between the components of lysozyme/cytochrome c (lysozyme/ Cyt,c) and lysozyme/zein protein mixtures were determined by following the in vitro synthesis of gold (Au) nanoparticles (NPs). Both UV−visible and fluorescence studies were employed to monitor the interactions and simultaneous synthesis of protein coated NPs. Protein coated NPs were characterized by gel electrophoresis and TEM studies. Lysozyme/ Cyt,c complex coated NPs showed remarkable pH responsive behavior due to their amphiphilic nature, while lysozyme/zein complex coated NPs were not pH sensitive because of the predominantly hydrophobic nature. The results were further supported by molecular dynamics studies (MD) of protein−protein interactions and interactions of protein with the gold surface. Molecular simulations helped us to identify the amino acids that drove such interactions. Biological applications of protein coated NPs were determined from hemolytic and antimicrobial studies to demonstrate their potential in pharmaceutical and food industries. The results clearly differentiated between the greater applicability of predominantly amphiphilic lysozyme/Cyt,c complex coated NPs in comparison to predominantly hydrophobic lysozyme/zein complex coated NPs.

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