In recent years, the study of metal complexes and metal-based nanomaterials has aroused particular interest, leading to the promotion of new effective systems for the abatement of various viral diseases. Starting from the analysis of chemical properties, this review focuses on the employment of metal-based nanoparticles as antiviral drugs and how this interaction leads to a substantial enhancement in antiviral activity. The use of metal-based antiviral drugs has also spread for the formulation of antiviral vaccines, thanks especially to the remarkable adjuvant activities of some of the metal complexes. In particular, the small size and inert nature of Au- and Ag-based nanoparticles have been exploited for the design of systems for antiviral drug delivery, leading to the development of specific and safe therapies that lead to a decrease in side effects.

This work deals with the synthesis of bare and curcumin (CUR)-loaded chitosan (CS)-based macroparticles by ionic gelation using sodium hydroxide (NaOH) or sodium tripolyphosphate (TPP). The resulting spherical-shaped macroparticles were studied using various characterization techniques, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The release of CUR from the CS-based particles with respect to time was analyzed, and the encapsulation efficiency and degree of swelling were studied. All formulations showed excellent CUR trapping efficiency, exceeding 90%. In particular, the TPP-crosslinked macrobeads released 34 wt% of the charged CUR within minutes, while the remaining 66 wt% was released slowly. The results indicate that the correct choice of gelling agent and its concentration leads to spherical particles capable of encapsulating CUR and releasing it in a wide range of kinetics so that macrospheres can be used in different applications.

This work deals with the synthesis of bare and curcumin (CUR)-loaded chitosan (CS)-based macroparticles by ionic gelation using sodium hydroxide (NaOH) or sodium tripolyphosphate (TPP) as cross-linking agents. The resulting spherical-shaped macroparticles were studied using various characterization techniques, Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The release of CUR from the CS-based particles with respect to time was analyzed, and the encapsulation efficiency and degree of swelling were studied. All formulations showed excellent CUR trapping efficiency, exceeding 90%. In particular, the TPP-crosslinked macrobeads released 34 wt% of the charged CUR within minutes, while the remaining 66 wt% was released slowly due to the biodegradation of CS. The results indicate that the correct choice of gelling agent and its concentration leads to spherical particles capable of encapsulating CUR and releasing it in a wide range of kinetics depending on the specific application.