CO 2 -concentrating nanoparticles drive progressive photosynthetic and cell-wall remodelling in Arabidopsis thaliana cells

Plant cells offer a distinctive platform for biohybrid engineering because they combine growth and proliferation with photosynthetic carbon acquisition and the continuous fabrication of structurally complex biomass. Harnessing these capabilities could enable living systems in which synthetic functionality develops together with cellular physiology and material organization. Yet nanomaterial engineering of proliferating plant cell populations remains largely unexplored. Here, we establish a biohybrid system combining photosynthetically active Arabidopsis thaliana suspension cells with chitosan-modified polyethyleneimine (gPEI-Chi) nanoparticles, a synthetic CO 2 -concentrating nanomaterial. By supplying fresh nanoparticles at each subculture, newly generated cell populations were successively functionalized, driving progressive changes in cellular and multicellular phenotypes. Nanoparticle functionalization reduced net headspace CO 2 accumulation, increased chlorophyll content and induced stage-dependent reorganization of photosynthetic function and carbon-handling pathways. These physiological changes were accompanied by altered cell wall regeneration and progressive remodelling of cell wall composition, spatial organization and ultrastructure, ultimately promoting more cohesive multicellular aggregates. Our findings establish successive nanomaterial functionalization as a strategy to steer the evolving physiology and structural organization of proliferating plant cell populations, opening opportunities for plant biohybrid systems and engineered living materials.