Gold nanorods functionalized with copper containing coordination compounds showing promising antiviral activity: structural and morphological characterization

The global imperative for infectious disease research is to develop new antibacterial and antiviral drugs since several fatal infectious diseases caused by pathogenic viruses and bacteria are responsible for the gravest health concerns over the world. In particular, the outbreak of the SARS-CoV-2 since early 2020 poses dramatic problems to the health systems as no truly effective drugs are yet available therefore, the identification of innovative strategies selectively interfering with the pandemic disease is a thrilling challenge for chemical and biochemical research. For this purpose, extensive screenings are conducted on thousands of molecules using combinatorial libraries or in silico docking experiments to discover new effective antiviral agents. Among other, metal-based agents are an attractive class of drugs for their versatile applications in medicinal inorganic chemistry. The great structural versatility, compared to purely organic molecules, depends on the combination of different metal ion(s) with distinct ligand(s) in the same molecular entity. Metals can coordinate ligands in a precise three-dimensional configuration thus allowing the tailoring of the molecule to recognize and interact with a defined molecular target. Copper-based agents are an attractive class of drugs for their versatile applications in medicinal inorganic chemistry and several Cu species have been reported to exhibit significant antiviral activity. Copper is a fundamental micronutrient for the functioning of human immune cells and it can kill some infectious DNA or RNA viruses, including bronchitis virus, poliovirus, human immunodeficiency virus type 1 (HIV-1); moreover, it blocks PLpro-2, which is crucial for SARSCoV-1 replication. Altogether, these observations strongly encourage to explore the potential of Cu-based drugs against COVID-19 disease. Recently, new chelating ligands showing potential activity against SARS-CoV-2 have been prepared by our research group, and the coordination chemistry of related Cu(I/II) complexes has been detailly investigated. In addition, to enhance their solubility in water, these copper-based coordination compounds have been conjugated to the surface of nanocarriers: gold nanoparticles of spherical or rod-like shape. Here, we will present the structural and morphological investigation carried out on the Cu(I/II) coordination compounds both pristine and charged on the nanoparticles surface, as well as some interesting results from the photoluminescence studies.