Xiang Zeng,Jinhu Li,Jinhong Zheng,Ying Pan,Jinzhi Wang,Lumian Zhang,Xiaoying He,Daojun Liu
Cylindrical copolypeptide brushes PLLF- g -(PLF- b -PLG) with poly( l -lysine- co - l -phenylalanine) (PLLF) as the backbone and poly( l -phenylalanine)- b -poly( l -glutamic acid) (PLF- b -PLG) as the side chains have been synthesized and evaluated as drug delivery carriers. The synthesized copolypeptide brushes were characterized by 1 H NMR, gel permeation chromatography (GPC), and transmission electron microscopy (TEM). In aqueous solution, the copolypeptide brushes adopt cylindrical morphologies and resemble unimolecular polymeric micelles with a hydrophobic poly( l -phenylalanine) core and a hydrophilic poly( l -glutamate) shell. An encapsulation study demonstrated that these water soluble, biodegradable copolypeptide brushes encapsulate hydrophobic compounds and cationic hydrophilic guest molecules simultaneously. Furthermore, the encapsulated cationic model compounds exhibit a pH-responsive releasing property.
A new polypeptide-based copolymer brush composed of poly (γ-propargyl- L -glutamate)- block -poly (propylene oxide)- block -poly (γ-propargyl- L -glutamate) backbone (PPLG- b -PPO- b -PPLG) and oligo (ethylene glycol) (PEG) side-chain was synthesized by combination of N -carboxyanhydride ring-opening polymerization and click chemistry. Nearly 100% grafting efficiency was achieved by copper-catalyzed azide-alkyne Huisgen 1,3-dipolar cycloaddition (CuAAc) reaction. The α -helical conformation adopted by the grafted polypeptide blocks in water was relatively stable and showed a reversible change in a heating–cooling circle from 5 to 70 °C. It displayed weak stability against elevated temperature but still reversible changes in the presence of 0.47 M NaCl. The brushes were amphiphilic and could self-assemble into thermo-sensitive micelles in water. Big micelles could break into small micelles upon heating due to the improved solubility.
危险品化学品经营许可证（带存储）