Carboxymethyl chitosan-cinnamaldehyde coated dendritic silica hybrid nanoparticles: A new improved antifungal agent for seed treatment through dual release of terpenes

Regulatory restrictions on synthetic plant protection products (PPPs) have increased the demand for sustainable alternatives that combine antifungal efficacy with environmental safety. This study reports the development of a multimatrix nanosystem (dMSNP–Ger–CMC=CIN) integrating dendritic mesoporous silica nanoparticles (dMSNPs) loaded with geraniol (Ger) and coated with a carboxymethyl chitosan–cinnamaldehyde (CMC=CIN) biopolymer. The hybrid platform enables pH-responsive, sustained release of natural bioactives with dual antifungal and biostimulant functions. Characterization confirmed spherical-dendritic nanoparticles (~80 nm) and preserved porosity. Encapsulation achieved high efficiency (EE 32.3%, LC 55.6%) and stability post-functionalization. Controlled Ger release occurred mainly at basic pH due to CMC swelling. In vitro assays showed strong inhibition of Fusarium oxysporum, Aspergillus niger, and Penicillium citrinum, with Minimum Inhibitory Concentration (MIC) <1 mg/mL, outperforming free Ger. In vivo tests on Triticum aestivum seeds revealed improved germination, biomass, and pigment balance under fungal stress. After 126 days, biochemical analyses indicated restored chlorophyll and carotenoids, reduced oxidative stress, and recovery of physiological homeostasis. These results highlight dMSNP–Ger–CMC=CIN as a promising eco-friendly nanoformulation for seed protection and sustainable crop management, bridging nanotechnology and natural product-based agriculture. • New dMSNP–Ger–CMC=CIN nano-antifungal agent for seed treatment was developed. • dMSNP–Ger–CMC=CIN obtained a successful encapsulation of terpenes (LC 55.6%) a dual delivery. • Strong in vitro inhibition of phytopathogenic fungi with MIC <1 mg/mL, improving the effect of free GER. • New nano-treatment displayed a well phytosecurity profile after 126 days of seed treatment