High-Resolution Imaging of Dendrimers Used in Drug Delivery via Scanning Probe Microscopy
Figure 2
STM and AFM topographic lateral and height measurements determine the volume of single G4 PAMAM-OH-- and G4 PAMAM-OH- dendrimers. (a) A 20 × 20 nm2 STM topograph of G4 PAMAM-OH-- dendrimers immobilized on Au(111). Cursors 1 and 2 reflect the and lateral measurements. (b) A 20 × 20 nm2 STM topograph of G4 PAMAM-OH- dendrimers immobilized on Au(111). Cursors 4 and 5 reflect the STM height and lateral measures. STM images (a) and (b) were obtained using circa 0.3 V and 20 pA set points. (c) A 300 × 300 nm2 AFM topograph of the same surface as (a). Cursor 3 is a representative of the cursors used to ascertain from the bare Au surface to the dendrimer apex. (d) A 300 × 300 nm2 AFM topograph of the same surface as (b). Cursor 6 serves the same purpose for G4 PAMAM-OH- as cursor 3 does for drug-loaded dendrimers.
