Layer-by-Layer Surface-Modified Supramolecular Fullerene Microrods for Cell Feeding

By combining amphiphilic polymers with natural biomolecules, layer-by-layer (LbL) surface modification technology provides a versatile strategy to tailor the interfacial properties of self-assembled fullerene nanostructures for biomedical applications. Herein, we developed LbL surface-modified supramolecular fullerene microrods (FMR) to investigate tunable cell-material interactions associated with a cell-feeding phenomenon. Using LbL surface modification, FMR (average length 55 ± 8 μm and diameter 1.7 ± 0.6 μm) prepared by the liquid-liquid interfacial precipitation (LLIP) method was endowed with a layered polymer structure, thereby forming multilayer-coated fullerene microrods (FMR-P/G) with enhanced surface hydrophilicity. After 12 h of gelatin cross-linking, the resulting FMR-P/G_12 h sample exhibited layered structures, with Pluronic and gelatin layers stacked with thicknesses of ∼19 ± 6 and ∼31 ± 4 nm, respectively. The contact angle of FMR decreased from 104° to 44°, reflecting a pronounced enhancement in surface wettability. The impact of the surface-modified FMR-P/G_12 h sample on the biological behavior of NIH/3T3 fibroblasts was explored to assess its potential for biomedical applications. When FMR-P/G_12 h was used to treat NIH/3T3 fibroblasts, the cells exhibited markedly enhanced early stage viability (∼152% at 1-day culture and ∼349% at 3-day culture), while showing comparable survival levels during extended culture (cell viability ∼323% at 14-day culture). This effect may be attributed to the improved hydrophilicity and interfacial properties of the polymer-modified fullerene microrods, which facilitate favorable cell-material interactions during the early culture stage. These results suggest that FMR-P/G_12 h can modulate cellular responses through surface-engineered interfaces, highlighting the feasibility of LbL surface-modified self-assembled fullerene nanostructures for biointerface-related applications. Overall, this study demonstrates the potential of LbL-engineered fullerene constructs for interface-driven biomedical material design.