The present invention relates to novel dendrimer conjugates, methods for their preparation and their use for treatment of diseases. The invention discloses a new method for the delivery of dendrimer conjugates with therapeutically active molecules into the cell by utilizing transmembrane solute carrier proteins enabling uptake of the inventive dendrimer conjugates. Particular subject-matter of the present invention is a conjugate of the formula E-┌G-L-D(OSO3−M+)n┐m, wherein E is a therapeutic or diagnostic effector molecule, wherein D(OSO3−M+)n is a dendrimer D carrying a number n of sulfate groups OSO3−M+, wherein the number n of sulfate groups is selected from 6 to 96, wherein M is a cationic inorganic or organic counter ion to the anionic sulfate group, wherein L is a linker or spacer between D and E, wherein G is a connecting functional group forming the attachment between L and E, and wherein m is an integer from 1 to 20.
