Simple and facile preparation of lignosulfonate-based composite nanoparticles with tunable morphologies: From sphere to vesicle

Lignosulfonate/SiO₂ composite nanoparticles with tunable morphologies (sphere, hollow, and vesicle) were prepared in this work. Sodium lignosulfonate (NaLS) was first modified by cetyltrimethylammonium bromide (CTAB) to increase its hydrophobicity and then dissolved in pure ethanol in the presence of tetraethylorthosilicate (TEOS). Following the continuous addition of ammonia aqueous solution, NaLS started to form sphere micelles by self-assembly at a critical water content. TEOS droplets were first stabilized by NaLS micelles and then hydrolyzed and condensed to form Si-O-Si under the catalysis of ammonia. Uniform sphere composite particles with small particle size (70 ˜200 nm) were achieved with lower TEOS content in the primary solution, while composite particles with hollow or vesicle morphologies were obtained with higher TEOS content. Finally, NaLS/SiO₂ composite sphere particles (112 nm) were used for the in-situ encapsulation of doxorubicin (Dox) drugs and the release profile and antitumor effects were investigated and compared with those of free Dox. This simple and facile method, involving tunable particle size and morphologies, and potential drug or gene delivery capacity allow for further applications of these green, sustainable composite nanoparticles in many fields.