Learning lessons from nano-medicine to improve the design and performances of nano-agrochemicals

Abstract

Sharing concepts and knowledge between medical and agricultural fields can promote the development of improved nano-enabled technologies. A central idea behind drug delivery systems is that the active substances are encapsulated in nanoparticles (nano-medicines) to protect the drugs from premature degradation and allow them to be transported to the target site within the body. After three decades of development, nano-medicines are now used in many practical applications, including clinical oncology, infectious disease, cosmetics, and vaccines. Nano-agrochemicals are increasingly considered to tackle challenges associated with food production, sustainability and food security. Despite obvious differences between nano-medicines and nano-agrochemicals in terms of uptake mechanisms, target and environmental and economic constraints, the principles behind nanoparticle design share many similarities. This article hopes to share experiences and lessons learnt from nano-medicines that will help design more effective and safer nano-agrochemicals.

Fig. 1. Designing nanoparticles to reduce premature loss and to increase bioavailability.

a Amphiphilicity of nanomaterials to enhance their adhesion to leaves. The hydrophobic part is used to load hydrophobic active substances and increase the adhesion to leaves. The hydrophilic part helps improve the dispersibility of the nanoparticles in water. b Using the shape of nanoparticles to optimise the adhesion to leaves. Rod-shaped nanoparticles show favoured adhesion and entropic losses compared to nanospheres. c Surface roughness of nanoparticles is expected to increase the binding affinity to the target. a Reprinted with permission from Dickson et al., copyright 2012 American Chemical Society. b Reproduced with permission from ref. , PNAS. c Reproduced with permission from ref. , American Chemical Society.

Fig. 2. Suggestion for nano-agrochemical designs for leaf, soil and hydroponics applications.

The nanoparticle physiochemical parameters should be included in the nanoparticle design to maximise the benefits. Adjusting the composition, size, shape (length and width) and roughness, and surface chemistry of nanoparticles allows an increase in the adhesion of nanoparticles to the leaves and improves the uptake and translocation to the targets.

Fig. 3. Nanoparticle designs for foliar and soil applications.

For foliar application there are three designs; design 1: nano-pesticide for non-systemic applications; design 2: nano-pesticide for systemic application: nanoparticles enter the leaf, and translocate to the roots; design 3: nano-agrochemical for systemic application: nanoparticles enter the leaf, and translocate between the leaves.

Fig. 4. Key similarities and differences between nano-medicine and nano-agrochemical designs.

Starting from the top, the uptake pathway of the target drives the nanoparticle design based on a range of different criteria; then analytical tools are used to study the uptake pathway. A SciFinder search with key words ‘nano-medicines’, ‘nano-pesticides’ and ‘nano-fertilisers’ was conducted in April 2024 to compare the number of publications and patents in two areas.