Current Research on Silver Nanoparticles: Synthesis, Characterization, and Applications

Over the past couple of decades, nanomaterials have advanced the research in materials; biomedical, biological, and chemical sciences; etc., owing to their peculiar properties at the nanoregime compared to their bulk composition. Applications of nanoparticles in the fields like medicine and agriculture have been boosted due to the development of different methodologies developed to synthesize specific shapes and sizes. Silver nanoparticles have tunable physical and chemical properties, so it has been studied widely to improve its applicability. The antimicrobial properties of Ag NPs are finding their application in enhancing the activity of drugs (like Amphotericin B, Nystatin, Fluconazole) and composite scaffolds for controlled release of drugs and targeted delivery of drugs due to their low toxicity and biocompatibility. Similarly, their surface plasmon resonance property makes Ag NPs a top-notch material for developing (bio)sensors, for instance, in surface-enhanced Raman spectroscopy, for detecting biomarkers, diseases, pollutants, and higher catalytic activity in photochemical reactions. Besides these, highly conducting Ag NPs are used in wearable and flexible sensors to generate electrocardiographs. Physicochemical or biological approaches are used to prepare Ag NPs; however, each method has its pros and cons. The prohibitive cost and use of hazardous chemicals hinder the application of physicochemical synthesis. Likewise, biological synthesis is not always reproducible for extensive use but can be a suitable candidate for therapeutic activities like cancer therapy. Excess use of Ag NPs is cytotoxic, and their unregulated discharge in the environment may have effects on both aquatic and terrestrial biota. The research in Ag NPs has always been driven by the need to develop a technology with potential benefits and minimal risk to environmental and human health. In this review, we have attempted to provide an insight into the application of Ag NPs in various sectors along with the recent synthetic and characterization techniques used for Ag NPs.