Novel self-assembling conjugates as vectors for agrochemical delivery

Abstract

BackgroundModern agricultural practises rely on surfactant-based spray applications to eliminate weeds in crops. The wide spread and indiscriminate use of surfactants may result in a number of deleterious effects that are not limited to impacts on the crop and surrounding farm eco-system but include effects on human health. To provide a safer alternative to the use of surfactant-based formulations, we have synthesised a novel, self-assembling herbicide conjugate for the delivery of a broad leaf herbicide, picloram.ResultsThe synthesized self-assembling amphiphile–picloram (SAP) conjugate has three extending arms: a lipophilic lauryl chain, a hydrophilic polyethylene glycol chain and the amphiphobic agrochemical active picloram. We propose that the SAP conjugate maintains its colloidal stability by quickly transitioning between micellar and inverse micellar phases in hydrophilic and lipophilic environments respectively. The SAP conjugate provides the advantage of a phase structure that enables enhanced interaction with the hydrophobic epicuticular wax surface of the leaf. We have investigated the herbicidal efficiency of the SAP conjugate compared against that of commercial picloram formulations using the model plant Arabidopsis thaliana and found that when tested at agriculturally relevant doses between 0.58 and 11.70 mM a dose-dependent herbicidal effect with comparable kill rates was evident.ConclusionThough self-assembling drug carriers are not new to the pharmaceutical industry their use for the delivery of agrochemicals shows great promise but is largely unexplored. We have shown that SAP may be used as an alternative to current surfactant-based agrochemical formulations and has the potential to shift present practises towards a more sustainable approach.Electronic supplementary materialThe online version of this article (10.1186/s12951-018-0423-5) contains supplementary material, which is available to authorized users.

Use of Mg–Al Nanoclay as an Efficient Vehicle for the Delivery of the Herbicide 2,4-Dichlorophenoxyacetic Acid

“…For the quantification of the herbicidal effect, a robust and routinely used single-blind assessment method was adopted. , Images collected after day three and seven for all the spray applications were subjected to a process as described earlier . Briefly, all the images obtained for various treatments of the two replicates were assessed by three independent reviewers on a scale between 0 and 5 where, 0 = healthy plants with no visual signs of tissue damage; 1 = minor chlorosis, tissue necrosis; 2 = minor chlorosis and necrosis along with lamina and petiole curling along the axis of the stem; 3 = moderate chlorosis and necrosis, leaf and petiole curling, first signs of apical bud deformation; 4 = severe chlorosis, necrosis, leaf lamina and petiole curling associated with deformation of apical buds and 5 = very severe phytotoxicity associated with complete necrosis and death.…”

“…Similarly, perylene-3-ylmethanol nanoparticles have been used for controlled release of 2,4-D to brown pea seedlings (Cicer arietinum) . Nanostructured liquid crystalline particles (NLCP) and self-assembling lipid-based nanoparticles were used to deliver 2,4-D and picloram respectively to wild radish (Raphanus raphanistrum) in field trials and the model plant Arabidopsis thaliana in laboratory studies. Though NLCP efficiently delivered 2,4-D for weed eradication, dose dependency was not demonstrated, limiting their use as a commercial agrochemical carrier vehicle.…”

Importance of chemical polymorphism in modern crop protection

“…12,13 However, in agrochemical development, nanostructured liquid crystalline particles play a role as surfactants. 14,15 They enable the distribution of the a.i. solution on the surface of the leaves by reducing the contact angles of the droplets sprayed on the plants.…”

“…Mesophases with their special kind of molecular arrangements are well‐known in optoelectronic displays 12,13 . However, in agrochemical development, nanostructured liquid crystalline particles play a role as surfactants 14,15 . They enable the distribution of the a.i.…”