Size effect of cellulose nanocrystals in cellular internalization and exosome-packaging exocytosis

With the purpose of investigating the bio-interaction between CNC and cells, the end-fluorescence CNC (FCNC) and surface-adsorbed glucosamine [(g)FCNC] were prepared by the region-selective modification and electrostatic adsorption strategy in this study. The cell growth was arrested in a time dependent manner when incubated with CNC in the low glucose environment. The small-size FCNC was preferred by the cells with the observation of higher affinity. Specifically, the affinity of (g)FCNC to the phagocytic cell RAW264.7 cell and kidney derived cell 293 t was generally increased in response to the “Warburg effect”, which on the contrary was observed with the weak effect in the tumor cells. We confirmed the exocytosis of internalized rod-like nanocrystal was achieved by the packaging effect of exosomes. Our results revealed the underappreciated bio-interaction between CNC and different cells, which contributed the evidence of an inspiration for this natural nanomaterial in the cell-level application.