Synthesis and self-assembling behaviors of biotinylated pluronic/poly(lactic acid) biocompatible block copolymers in aqueous solutions

Four kinds of Biotinylated Pluronic/PLA block copolymers were synthesized by two-step reactions. Pluronic were firstly modified by biotin to obtain B-Pluronic-OH. Biotin-Pluronic-PLA block copolymers were then produced by ring-opening polymerization of the monomer L-lactide using Biotin-Pluronic-OH as the initiator and stannous octoate (Sn(Oct)₂) as the catalyst. The self-assembling behaviors of Biotin-Pluronic-PLA block copolymers in aqueous solutions were examined by fluorescence measurement, dynamic light scattering (DLS), and transmission electron microscopic (TEM) techniques. The size of Biotin-F127-PLA-61, Biotin-F87-PLA, and Biotin-P85-PLA nanoparticles were determined to be 198, 229, and 257 nm, respectively, and their morphologies were found to be spherical micelles. Biotin-F127-PLA-87 produces both spherical micelles and large compound micelles with the size of 127 and 906 nm. The cytotoxicity studies using human ovarian cancer cells OVCAR-3 indicate that Biotin-Pluronic-PLA block copolymers have good biocompatibility.