pH-Responsive Amphiphilic Chitosan–Lignin System Loaded with Samarium Oxide Nanoparticles for Curcumin Delivery

Polymer nanoparticle-based drug carriers represent a new avenue for cancer therapy. In this work, we study the formation of chitosan/lignin (Chi/Lig) core-shell particles doped with samarium oxide nanoparticles as potential carriers for the hydrophobic anticancer drug curcumin. Electrostatic coassembly was responsible for the formation of Chi/Lig core-shell particles. The structural characterization suggested interactions between chitosan, lignin, and Sm₂O₃ through electrostatic interactions, such as hydrogen bonding. The incorporation of lignin into the chitosan matrix results in the formation of an amphiphilic core-shell structure, offering the potential for dual-drug-loading strategy studies, wherein one hydrophobic drug could reside in the lignin core while another hydrophilic drug occupies the chitosan shell. Additionally, the incorporation of lignin into the polymer systems not only contributes to a slower release of curcumin but also enables the design of pH-responsive drug carriers. Moreover, the strong red fluorescence observed in the samarium-containing composites suggests their potential for applications in bioimaging and in vitro assays, particularly with orally delivered microcarriers.