Nanoparticles as Nonviral Transfection Agents

Abstract

Metal-based micro and nanostructured materials are used in a variety of foodrelated applications as nutrient bioactive delivery systems texture and flavor encapsulation, microbiological control, and food packaging. In this chapter, we are focus on metal-based micro- and nanostructured materials incorporated into food-contact surfaces and packaging polymers. Heavy metals are effective antimicrobial agents in the form of salts, oxides, colloids, and complexes such as silver zeolites. Although it is not a metal base composite, montmorillonite (MMT) is widely used in industrial processes, in particular in metal-based micro- and nanostructured materials (MMT-silver) for food packaging applications. Silver-based nano-engineered materials are currently the most common nanocomposites used in commodities mainly due to their antimicrobial capacity. Copper, zinc, and titanium nanostructures have shown promise in food safety. Titanium dioxide is resistant to abrasion and UV-blocking capabilities. Copper has been shown to be an efficient sensor for humidity with antibacterial properties in active food packaging. Other important properties in active food packaging, which can be positively influenced by metal-based micro- and nanostructured materials, are ethylene oxidation and oxygen scavenging. In this chapter, we review synthesis methodologies and properties of the metalbased nanoparticles used in food-contact materials. Size, shape, crystal structure, surface functionality, and composition will determine their mobility and biological activity in different systems. Migration between ions and nanoparticles from the polymer matrices is one key point to determine their antimicrobial effectiveness; however, this migration may affect the consideration status of the polymer as a food-contact material.