A Review of Metal and Metal-Oxide Nanoparticle Coating Technologies to Inhibit Agglomeration and Increase Bioactivity for Agricultural Applications

Abstract

Coatings offer a means to control nanoparticle (NP) size, regulate dissolution, and mitigate runoff when added to crops through soil. Simultaneously, coatings can enhance particle binding to plants and provide an additional source of nutrients, making them a valuable component to existing nanoparticle delivery systems. Here, the surface functionalization of metal and metal-oxide nanoparticles to inhibit aggregation and preserve smaller agglomerate sizes for enhanced transport to the rooting zone and improved uptake in plants is reviewed. Coatings are classified by type and by their efficacy to mitigate agglomeration in soils with variable pH, ionic concentration, and natural organic matter profiles. Varying degrees of success have been reported using a range of different polymers, biomolecules, and inorganic surface coatings. Advances in zwitterionic coatings show the best results for maintaining nanoparticle stability in solutions even under high salinity and temperature conditions, whereas coating by the soil component humic acid may show additional benefits such as promoting dissolution and enhancing bioavailability in soils. Pre-tuning of NP surface properties through exposure to select natural organic matter, microbial products, and other biopolymers may yield more cost-effective nonagglomerating metal/metal-oxide NPs for soil applications in agriculture.

Synthesis, Characterization of Chitosan-Aluminum Oxide Nanocomposite for Green Synthesis of Annulated Imidazopyrazol Thione Derivatives

“…To increase the base character of chitosan, and to overcome its problem in forming a gel, chitosan-based magnesium oxide and copper oxide nanocomposites were used as efficient catalysts for the regioselective synthesis of (1,2,3) Triazoles [16,17]. On the other hand, metal oxide nanoparticles have found many uses in numerous fields, such as engineering, medicine, drug delivery, agricultural, and nano catalysis applications [18]. Growing interest to explore the utility of alumina as a catalyst, or catalytic support, has also been widely recognized for many organic transformations [19].…”

Engineered Nanomaterials in Soil: Their Impact on Soil Microbiome and Plant Health

“…The physico-chemical and biological transformations of ENMs in the environment determine their fate and bioavailability to the plants and to other microorganisms [ 154 ]. The physical transformation mainly involves agglomeration and deposition/sedimentation, as ENMs rarely exist as individual particles due to their high surface energy [ 155 ]. Once ENMs are released into the environment, they tend to undergo homo-agglomeration (interaction between ENMs) or hetero-agglomeration (ENMs interaction with foreign organic and inorganic particles) [ 156 ].…”

Synthesis, Properties, and Selected Technical Applications of Magnesium Oxide Nanoparticles: A Review

“…The category of inorganic materials can be further differentiated into metal-based and metal oxide-based materials [ 10 ]. Metal-based nanomaterials are synthesized using metallic materials, such as Au, Cu, Se, and Ag [ 11 ], and they find applications in areas, such as radiotherapy enhancement, gene delivery, or thermal ablation [ 12 ].…”