Wood cellulose-based polyelectrolyte complex nanoparticles as protein carriers

Novel wood cellulose-based polyelectrolyte complex nanoparticles were prepared by mixing negatively charged carboxymethyl cellulose (CMC) and positively charged quaternized cellulose (QC) in aqueous medium. As observed by transmission electron microscopy (TEM), the CMC–QC nanoparticles were approximately spherical and dispersed homogeneously. The impacts of CMC and QC concentration, as well as encapsulation of bovine serum albumin (BSA), on nanoparticle size, surface charge and cytotoxicity, were investigated. CMC–QC nanoparticles displayed high encapsulation efficiency for BSA, and their particle size and zeta potential could be modulated by adjusting either CMC or QC concentration. BSA-encapsulated CMC–QC nanoparticles had significantly decreased particle size and surface charge in comparison to BSA-free nanoparticles. Even at a relatively high concentration, the optimized CMC–QC nanoparticles exhibited low cytotoxicity as well as significant BSA cellular uptake in Caco-2 cells. The encapsulated BSA could be steadily released from CMC–QC nanoparticles within the first 8 h. The novel CMC–QC nanoparticles show promise as protein delivery systems.