Cell-Targeting Bio-Catalytic Killer Protocell for High-Order Assembly Guided Cancer Cell Inhibition

The design and construction of synthetic therapeutic protocells capable of engaging in high-order assembly with living cells represent a significant challenge in synthetic biology and bioengineering. Inspired by cell membrane receptor-ligand systems, a protocell bioreactor is developed for targeted cancer cell elimination. This is achieved by constructing orthogonal, polysaccharide-based protocells (polysaccharidosomes, P-somes) through a bottom-up approach that leverages host-guest chemistry. The protocells are assembled via electrostatically-driven self-assembly of β-cyclodextrin (β-CD)-modified amino-dextran on a sacrificial template encapsulating glucose oxidase (GOx). To enable specific cancer cell targeting and catalytic activity, cell-targeting ligands (arginylglycylaspartic acid, cRGD) and catalase-like platinum-gold nanoparticles (Pt-AuNPs) are introduced through host-guest interactions, forming a fully functional, cell-targeting, bio-catalytic killer protocell. These protocells are programmed to spatially couple the GOx/Pt-AuNP catalytic reaction cascade. In the presence of glucose and hydroxyurea, this cascade generates a localized flux of nitric oxide (NO), which is exploited for in vitro cancer cell inhibition. Overall, the results highlight the potential of integrating orthogonal and synergistic tumor inhibition mechanisms within synthetic microcompartments. This platform demonstrates promise for future therapeutic applications, especially in cancer treatment, and represents a step forward in the development of programmable protocell-based therapeutic systems.