Dendrimer conjugates are presented, which are formed between a dendrimer and a protein solubilising substance. Such dendrimer conjugates are effective in the treatment of protein aggregate-related diseases (e.g. prion-related diseases). The protein solubilising substance and the dendrimer together show a protein aggregate solubilising effect higher than a physical mixture of the dendrimer and the protein solubilising substance (i.e. a synergistic effect). Such dendrimer conjugates are useful in the treatment or prevention of protein aggregate-relates diseases, in disinfection/decontamination processes and in classifying or identifying protein aggregates. The synthesis of such dendrimer conjugates from readily-available starting materials is described.