Synthesis, conjugating capacity and biocompatibility evaluation of a novel amphiphilic polynorbornene.

Polynorbornenes, prepared by the 'living' and 'controlled' ring-opening metathesis polymerization (ROMP) method, have emerged as a stimuli-sensitive new class of polymer carriers. Herein, we reported a novel amphiphilic diblock polynorbornene, , containing active benzaldehyde units, which exhibited good conjugating capacity to amino-containing molecules (e.g., doxorubicin (DOX)) via the pH-sensitive Schiff base linkage. The copolymer and its conjugate with DOX, , were adequately analyzed by various techniques including H NMR, C NMR, gel permeation chromatography, etc. Especially, the formed conjugate of could self-assemble into near-spherical micelles with the diameter of 81 ± 10 nm, and exhibit acid-triggered DOX release behavior, and the release rate could be adjusted by changing the environmental pH value. The excellent biological safety of was further demonstrated by the results from both toxicity evaluation to murine fibroblast cells (L-929 cells) and evaluation of acute developmental toxicity and cell death in zebrafish embryos. Hence, the present polynorbornene-based possesses great potential application as a biocompatible polymeric carrier and could be employed to fabricate various pH-sensitive conjugates.