Self-Assembly and Drug Encapsulation Properties of Biocompatible Amphiphilic Diblock Copolymers

To prepare amphiphilic diblock copolymers (M₁₀₀P_m), a controlled radical polymerization approach was employed, incorporating hydrophilic poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) with hydrophobic poly(3-methoxypropyl acrylate) (PMPA). The synthesized diblock copolymers feature a PMPC block with a degree of polymerization (DP) of 100 and a PMPA block with DP (=m) values of 171 and 552. The hydrophilic PMPC block exhibits biocompatibility, such as inhibition of platelet and protein adsorption, because of its hydrophilic pendant zwitterionic phosphorylcholine groups that have the same chemical structure as cell membrane surfaces. The PMPA block exhibits hydrophilicity because of its hydrophilic ether groups; however, it is predominantly hydrophobic. In addition, PMPA exhibits biocompatibility. Because both blocks of M₁₀₀P_m are biocompatible, M₁₀₀P_m has potential applications in the biomedical field as an innovative material. Because of the hydrophobicity of the PMPA blocks, which were surrounded by hydrophilic PMPC shells, M₁₀₀P_m aggregated when dispersed in water. M₁₀₀P₁₇₁ and M₁₀₀P₅₅₂ formed spherical micelles and vesicles, respectively. As the DP of the PMPA block increased, the aggregate size and number also increased. Doxorubicin was successfully encapsulated within the M₁₀₀P_m aggregates. Given their biocompatible properties, M₁₀₀P_m aggregates have potential applications in drug delivery systems.