Nanocarriers, the use of nanoparticles as a transport module for another substance, has been widely studied for their applications in biomedical and pharmaceutical fields. Prepared nanocarriers from unimolecular polymeric micelle has caught most of our attention in this area. In our previous research, we have synthesized biocompatible and biodegradable poly(propargyl glycolide) (PPGL) polymer and its grafting derivatives and studied their ability to form unimolecular micelles and be used as nanocarriers. Moreover, the encapsulation of macromolecules using PPGL derivatives has inspired the thought of utilizing these materials as artificial chaperones for assisting protein refolding. However, the degradability of PPGL derivatives makes long-term study difficult; hence, synthesizing poly(ethylene glycol) (PEG) based analog will help us to further understand the role of degradability in PPGL derivatives and to design the materials based on the needs.A series of PEG-based alkyne-functionalized polymers have been synthesized using a tetraoctylammonium bromide-triisobutylaluminum initiating system and the relationship between [monomer]/[initiator] ratio and molecular weights was studied. By increasing [monomer]/[initiator] ratio, the molecular weight of the resulting polymer also increases. In addition, copper(I)-catalyzed 1,3-dipolar cycloaddition of azides and alkynes "click" chemistry was used for the post-polymerization modification of these polymers. Water-soluble polymers that show lower critical solution temperature (LCST) behavior were obtained by varying the ratio between mDEG and decyl side chains. A relationship between cloud point temperatures and mol% mDEG in polymer was observed. Significantly, the LCST results were comparable with our previous research. Therefore, a conclusion could be drawn that the LCST behavior is related to the nature of the side chains rather than the nature of the polymer backbone. Preliminary results have shown that these "click" modified PEG-base polymers have the ability to form unimolecular micelles and to encapsulate azobenzene. These results show that the newly synthesized PEG-based polymers have common properties as PPGL-based polymers.
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