Zein Nanoparticles as Eco-Friendly Carrier Systems for Botanical Repellents Aiming Sustainable Agriculture

Abstract

Botanical repellents represent one of the main ways of reducing the use of synthetic pesticides and the contamination of soil and hydric resources. However, the poor stability and rapid degradation of these compounds in the environment hinder their effective application in the field. Zein nanoparticles can be used as eco-friendly carrier systems to protect these substances against premature degradation, provide desirable release characteristics, and reduce toxicity in the environment and to humans. In this study, we describe the preparation and characterization of zein nanoparticles loaded with the main constituents of the essential oil of citronella (geraniol and R-citronellal). The phytotoxicity, cytotoxicity, and insect activity of the nanoparticles toward target and nontarget organisms were also evaluated. The botanical formulations showed high encapsulation efficiency (>90%) in the nanoparticles, good physicochemical stability, and effective protection of the repellents against UV degradation. Cytotoxicity and phytotoxicity assays showed that encapsulation of the botanical repellents decreased their toxicity. Repellent activity tests showed that nanoparticles containing the botanical repellents were highly repellent against the Tetranychus urticae Koch mite. This nanotechnological formulation offers a new option for the effective use of botanical repellents in agriculture, reducing toxicity, protecting against premature degradation, and providing effective pest control.

Association of zein nanoparticles with botanical compounds for effective pest control systems

“…This indicates good physicochemical stability of the prepared nanoparticle formulations, which is extremely important for commercial applications that require storage over long periods. These results also corroborate a previous study by our research group that prepared zein nanoparticles for encapsulation of geraniol and R‐citronellal separately. The results of that study also showed that the prepared nanoparticle formulations were stable over time, with mean size of 200 nm, polydispersion index of 0.3 and zeta potential of −20 mV.…”

“…The ultrafiltration/centrifugation method was used to quantify the botanical compounds encapsulated in zein nanoparticles . The technique is based on the use of Microcon 10 kDa regenerated cellulose ultrafilters (Millipore), which allows the passage of only the non‐encapsulated substances.…”

“…Geraniol is a compound derived from different essential oils (citronella and palmrose, among others) and is classified as an acyclic alcohol having a vapor pressure of 2.21 × 10 −2 mmHg at 25 °C, water solubility of 100 mg L −1 and boiling point at 230 °C. Several applications of geraniol are reported in the literature, including in the control of agricultural pests . Eugenol, the main component of clove essential oil, belongs to the chemical class of phenylpropanoids.…”

“…In this context, innovative formulations based on nanoencapsulation have been shown to improve the stability and efficacy of natural compounds . Protection against premature degradation coupled with sustained release and increased solubility of active compounds have been reported in numerous studies for nanoencapsuled botanical pesticides . Such nanostructured systems can be produced from different matrices (natural and synthetic).…”

Safe nanotechnologies for increasing the effectiveness of environmentally friendly natural agrochemicals

“…Many other biodegradable polymeric nanocarriers are under development; these show promising results for use in nanoformulations for pesticides or natural compounds, such as those based on zein, cellulose, lipid/protein nanodisks, or syntetic polymers (e.g., poly‐ϵ‐caprolactone) . Moreover, particularly intriguing for the practical “consequences” are the studies on nanopolymers that are triggered under specific environmental or biotic conditions …”