Self-assembled cellulose particles for agrochemical applications

[Display omitted] •Water-soluble cellulose esters were functionalized with bioactive steroids.•Synthesised cellulose conjugates self-assembled as particles in aqueous solution.•Almost constant release rates were observed the first 8h, and extended for 72h.•Brassinosteroid-cellulose particles showed good in vitro agrochemical activity.•Hydrophobic functionalization of polymers for agrochemicals release is envisioned. The present work focuses on the hydrophobic functionalization of water soluble celluloses methyl cellulose, hydroxyethyl cellulose and (hydroxypropyl)methyl cellulose with the anticancer steroid diosgenin, and two synthetic brassinosteroids (DI31 and S7) used as agrochemicals. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies confirmed the cellulose modification. Prepared amphiphilic steroid-cellulose conjugates can self-assemble in water as stable and almost neutral particles with micelle-like structure, as depicted using dynamic light scattering. Whereas scanning and transmission electron microscopies showed 50–300nm almost spherical particles and aggregates in dried state, atomic force microscopy assessed particles aggregates with mean sizes of 220–355nm. These cellulose particles showed sustained steroid release in acidic aqueous medium over 72h, and good stimulatory agrochemical activity in radish cotyledons assay. Thus, the outlined synthesis of steroid-cellulose conjugates, which would be capable to form self-assembled particles in water for controlled release of agrochemicals, is envisioned as a promising strategy.