AFM analysis of C60 and a poly(amido amine) dendrimer-C60 nanoconjugate

Atomic force microscopy (AFM) was used to study the nanoscopic structure and topography of buckminsterfullerene (C60) and a conjugate of C60 with generation four, amine-terminated, poly(amido amine) dendrimer (PAMAM-G4). The conjugate contains a PAMAM-G4 core and C60 shell formed by reacting PAMAM-G4 with an excess of C60. Fractal patterns of C60 were observed in nanoscopic AFM images when solutions of different concentrations of C60 in pyridine or toluene were dried at room temperature. In contrast, no fractal patterns were detected in the AFM images of the dendrimer-C60 nanoconjugate, prepared from pyridine solution in a similar manner. Thus, the C60-shell alone is not sufficient to impart the same fractal patterns on the conjugate.