Amphiphilic star‐shaped poly(ε‐caprolactone)‐block‐poly(l‐lysine) copolymers with porphyrin core: Synthesis, self‐assembly, and cell viability assay

Star‐shaped copolymers poly(ε‐caprolactone)‐ bolck ‐poly( ε ‐benzyloxycarbonyl‐ l ‐lysine) (SPPCL‐ b ‐PZLLs) with porphyrin core were synthesized by a sequential ring‐opening polymerization (ROP) of CL and N ε ‐Benzyloxycarbonyl‐ l ‐lysine N ‐Carboxyanhydride. After the deprotection of benzyloxycarbonyl groups in polylysine blocks, the star‐shaped amphiphilic copolymers SPPCL‐ b ‐PLLs were obtained. These amphiphilic copolymers can self‐assemble into micelles or aggregates in aqueous solution. Investigation shows that the morphology of micelles/aggregates varied according to the change of pH values of media, indicating the pH‐responsive property of SPPCL‐ b ‐PLL copolymers. Furthermore, associated with conjugated porphyrin cores, the SPPCL‐ b ‐PLL copolymers micelles showed a certain degree of Photodynamic Therapy (PDT) effects on tumor cells, suggesting its potential application as carrier for hydrophobic drug with additional therapeutic ability of inherent porphyrin segments.