Synthesis of fully degradable cationic polymers with various topological structures via postpolymerization modification by using thio-bromo click reaction

Synthesis of cationic polymers possessing significant therapeutic potential is of tremendous research interest. Here, we report a facile synthesis of poly(epsilon-caprolactone) (PCL) based cationic polymers with controlled topological structures and tunable charge densities via postpolymerization modification using thio-bromo click chemistry. Three types of polymeric precursors were prepared by ring-opening polymerization (ROP) or combination of ROP and azide-alkyne click reaction, including linear homopolymer poly(alpha-bromo-epsilon-caprolactone) (P(CL-Br)), block copolymer PCL-b-P(CL-Br), and bottlebrush polymer PCL-g-(PCL-b-P(CL-Br)), and then the P(CL-Br) blocks or segments were modified using the thio-bromo click reaction with a thiol bearing a tertiary amino group, yielding the corresponding cationic polymers, respectively. Size exclusion chromatography (SEC) and H-1 NMR characterization demonstrated successful synthesis of the cationic polymers with controlled molecular weights and topological structures that may have great potential for biomedical applications.

Automated summary

The study presented a facile method for the synthesis of cationic polymers with controlled topological structures and tunable charge densities using thio-bromo click chemistry. Three types of polymeric precursors were prepared and modified to yield cationic polymers with potential for biomedical applications. Size exclusion chromatography (SEC) and H-1 NMR characterization confirmed the successful synthesis of these cationic polymers with controlled molecular weights and topological structures.