Advances in silica nanoparticles for agricultural applications and biosynthesis.

Nanotechnology has emerged as a revolutionary force in modern agriculture, opening new avenues for crop enhancement and sustainable farming practices. This review systematically evaluates the roles of silica nanoparticles (SiO₂ NPs) in agricultural applications, with particular emphasis on their biosynthesis pathways and functional mechanisms. SiO₂ NPs have demonstrated considerable potential to enhance crop resilience against both biotic (pathogens, pests) and abiotic (heavy metals, salinity, drought) stresses through phytohormonal regulation, defense gene activation, and metabolic modulation. As nanocarriers, these particles enhance pesticide and fertilizer delivery accuracy, reduce environmental contamination, and promote plant growth. Biosynthesis methods of SiO₂ NPs range from conventional physical-chemical techniques to eco-friendly green approaches, including the utilization of biological cells/extracts, natural biomaterials, and peptide templates. Although green synthesis offers sustainability advantages, the agricultural adoption of SiO₂ NPs faces critical challenges, such as insufficient understanding of their long-term environmental persistence and ecotoxicological impacts, high production costs related to green synthesis, and incomplete regulatory frameworks. Addressing these challenges is essential to enable their broader use in agriculture.