Microfluidic synthesis of polymeric nanoparticles for innovative applications in plant drug delivery

Researchers have only recently begun to explore the potential of nanocarriers in the field of plant biology. In the future, nanobiotechnology may play a crucial role in the development of new crop management techniques. Currently, agrochemicals are administered to crops by spraying and only a small fraction of active molecules reaches the target sites, due to leaching, degradation by photolysis, hydrolysis and biodegradation. Hence, multiple treatments with high doses of agrochemicals are needed, causing water and soil pollution. Biodegradable and biocompatible nanocarriers able to penetrate into plant or fungal cells could be an effective tool to deliver and gradaually release pesticides directly at the target site. The first step to designing nanoparticles (NPs) to deliver agrochemicals in plants is to study their uptake, transport and accumulation in cells and tissues. Such internalization mechanisms depend on the characteristics of the nanocarrier and differ from one plant species to another. Therefore, we developed a continuous flow microfluidic reactor that allows to precisely control some characteristics that are crucial for NPs applications such as size and polydispersion. The optimization of the operating conditions allowed us to obtain spherical monodisperse NPs with controllable and tunable dimensions in the range from 25 to 300 nm. Fluorescent NPs were used to test their ability to penetrate inside plants of agronomic interest (Vitis vinifera) and some common pathogenic fungi. Also, we entrapped in PLGA NPs some model drugs (i.e. ribavirin, methyl jasmonate, fluopyram) and studied the uptake, cytotoxicity and biochemical effects of such nanocarriers on different plant species. The results obtained have demonstrated the potential of PLGA NPs for their use in sustainable agricultural applications.