Binding of fluorescent dendrimer-folate conjugates to KB cells after 30 min incubation.
 All panels except Panel D demonstrate experiments performed at 37 °C. Panel A demonstrates increases of cell-associated fluorescence after incubation with 30 nm of acetamide, hydroxyl, or carboxyl-surfaced dendrimer-folate conjugates. Panel B documents progressive increases of cell fluorescence after incubation with increasing concentrations of acetamide-surfaced fluorescent dendrimer-folate conjugate. Significant background fluorescence was not observed until the concentration of non-targeted complex reached 300 nm. Cell-associated fluorescence as a function of dendrimer-folate conjugate concentration is presented for each of the three types of dendrimer, at 37 °C in Panel C and at 4 °C in Panel D. Amine surfaced dendrimer-folate conjugates demonstrated no binding.
 Reprinted with permission from Quintana et al.²⁰