Incidents of viral outbreaks have increased at an alarming rate over the past decades. The most recent human coronavirus known as COVID-19 (SARS-CoV-2) has already spread around the world and shown R 0 values from 2.2 to 2.68. However, the ratio between mortality and number of infections seems to be lower in this case in comparison to other human coronaviruses (such as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV)). These outbreaks have tested the limits of healthcare systems and have posed serious questions about management using conventional therapies and diagnostic tools. In this regard, the use of nanotechnology offers new opportunities for the development of novel strategies in terms of prevention, diagnosis and treatment of COVID-19 and other viral infections. In this review, we discuss the use of nanotechnology for COVID-19 virus management by the development of nano-based materials, such as disinfectants, personal protective equipment, diagnostic systems and nanocarrier systems, for treatments and vaccine development, as well as the challenges and drawbacks that need addressing.

Agrochemicals are used to improve the production of crops. Conventional formulations of agrochemicals can contaminate the environment, in particular in the case of intensive cropping. Hence, there is a need for controlledrelease formulations of agrochemicals such as polysaccharides to reduce pollution and health hazards. Natural polysaccharides are hydrophilic, biodegradable polymers. This article reviews the use of polysaccharides in the form of micro-and nanoparticles, beads and hydrogels. The main points are: (1) slow release formulations minimize environmental impact by reducing agrochemical leaching, volatilization and degradation. For example, 50 % of the encapsulated insecticide chlorpyrifos is released in 5 days, whereas free chlorpyrifos is released in 1 day. (2) Slow release formulations increase the water-holding capacity of soil. (3) Slow release formulations better control weeds in the long run. (4) Polymer-clay formulations store ionic plant nutrients. (5) Polymer hydrogel formulations reduce compaction, erosion, and water run-off. They increase soil permeability and aeration, infiltration rates, and microbial activity, and, in turn, plant performance. In conclusion, polysaccharide formulations can be used for safer use of agrochemicals.

Recent decades have witnessed major growth in the use of agrochemicals worldwide,for maximizing the food production for a rapidly growing human population. However, the indiscriminate use of these substances especially the pesticides has led to the accumulation of toxic residues in food, soil, air, and water, as well as the development of resistance in pests. Moreover, pesticides affect soil enzymes, which are essential catalysts that govern soil quality. In order to meet the food security, it is necessary to produce more food, sustainably and safely, in a diminishing area of available arable land and with decreased water resources. Given this situation, there is an increased interest in the use of alternative substances to synthetic agrochemicals that present less risk to the environment and human health while increasing the food safety. Promising results have been obtained using compounds derived from aromatic plants for the control of agricultural pests. Such compounds of botanical origin can be highly effective, with multiple mechanisms of action, while at the same time having low toxicity towards nontarget organisms. However, the large-scale application of these substances for pest control is limited by their poor stability and other technological issues. In this backdrop, the present work discusses perspectives for the use of compounds of botanical origin, as well as strategies employing the encapsulation techniques that can contribute to the development of systems for use in sustainable agricultural practices.