Synthesis of novel biodegradable cationic dendrimers

Dendrons and dendrimers with cationic amino groups at their periphery were successfully synthesized up to the third and second generation, respectively. The results obtained by ¹H NMR spectroscopy and gel permeation chromatography analysis supported the formation of the targeted dendrons and dendrimers. The dendrons were grown via ester linkages, which endowed them with biodegradability in D₂O at 37°C. The degradation rate depends upon the steric hindrance and reactivity caused by the bulkiness and compact structure of the dendrons. All of the synthesized dendrons were degraded within a month, while 60% of the ester groups in the sterically crowded dendrimers were degraded over the same time period. The cytotoxicity of the dendrons was evaluated by the MTT assay on a 293T cell line which indicated that the obtained dendrons were completely non-toxic. These non-toxic, biodegradable cationic dendrons and dendrimers are believed to have potential applications in the biomedical field.