Development of clove oil based nanoencapsulated biopesticide employing mesoporous nanosilica synthesized from paddy straw via bioinspired sol-gel route

Paddy straw (PS) burning is a concerning issue in South Asian countries, clamoring for exploring alternative management strategies. Being a rich source of silica, PS can be a potential nanosilica (SiNPs) source. The current study reports a pioneering approach for green synthesis of high-purity mesoporous SiNPs by sol-gel method using the aqueous extract of Sapindus mukorossi seed pericarp as a stabilizer. The mesoporous nature of SiNPs was harnessed as a carrier for the essential oil to develop the carrier-based formulation. SiNPs were characterized using XRD, EDX, FTIR, FE-SEM, TEM, AFM, DLS, water contact angle, and BET analysis. The synthesized SiNPs possessed a spheroid morphology with an average particle size of 20.34 ± 2.64 nm. XRD results confirmed its amorphous nature. The mesoporous nature of SiNPs was confirmed using BET analysis which showed a cumulative pore volume of 2.059 cm³/g and a high surface area of 746.32 m²/g. The SiNPs were further loaded with clove essential oil (CEO), and the encapsulation of CEO was assessed using UV–Vis, FTIR, and BET analysis. The in-vitro antifungal activity of CEO and CEO-loaded SiNPs (CEO-SiNPs) was evaluated using the agar plate assay. UV–Vis results depicted 62.64% encapsulation of CEO in SiNPs. The antifungal efficacy of CEO-SiNPs against F. oxysporum exhibited minimum inhibitory concentration (MIC), i.e., 125 mg/L, while the MIC of CEO was found to be 250 mg/L. The study delivers new insights into the holistic utilization of PS and propitious contribution toward the circular economy and Sustainable Development Goals (SDGs).