A thermo-responsive amphiphile was developed from oligo-phenylalanine [oligo(Phe)]. The hydrophobic moiety of the amphiphile, oligo(Phe) was synthesized via reverse hydrolysis catalyzed by bromelain in dimethyl sulfoxide and dioxane solutions. The production of oligo(Phe) increased by 80.7% by screening suitable reaction conditions. The average degree of polymerization of oligo(Phe) was determined to be four by ¹H NMR. By grafting with aldehyde-ended methoxypolyethylene glycol (mPEG), oligo(Phe) was converted to amphiphilic oligo(Phe)-mPEG. The surface tension of oligo(Phe)-mPEG solution increased with decreasing chain length of the mPEG moiety. Cytotoxicity studies showed oligo(Phe)-mPEGs are biocompatible. On varying temperature, a reversible phase transition of oligo(Phe)-mPEG solutions could be observed. N-octane-in-water emulsions and 0.5% beta-carotene containing squalene-in-water emulsions stabilized by oligo(Phe)-mPEGs occurred at 25 °C but de-emulsification took place at >40 °C. Emulsification could be restored once the separated mixture cooled and re-homogenized. The emulsification/de-emulsification cycling could be repeated many times. The time required for de-emulsification decreased with elevated temperature but increased with a reduced concentration of oligo(Phe)-mPEGs and a reduction in the chain length of the mPEG moiety.

从寡苯丙氨酸[oligo（Phe）]开发了一种热响应性两亲物。两亲物的疏水部分oligo（Phe）是通过菠萝蛋白酶在二甲基亚砜和二恶烷溶液中进行逆水解反应合成的。通过筛选合适的反应条件，寡聚（Phe）的产量增加了80.7％。通过¹ H NMR确定低聚（Phe）的平均聚合度为4 。通过接枝醛末端的甲氧基聚乙二醇（mPEG），将寡聚（Phe）转化为两亲性寡聚（Phe）-mPEG。寡聚（Phe）-mPEG溶液的表面张力随着mPEG部分链长的减少而增加。细胞毒性研究表明，寡聚（Phe）-mPEG具有生物相容性。在变化的温度下，可以观察到寡聚（Phe）-mPEG溶液的可逆相变。N-辛烷水乳液和含0.5％β-胡萝卜素的角鲨烯水乳液经oligo（Phe）-mPEG稳定后在25°C发生，但在超过40°C时发生了反乳化作用。一旦分离的混合物冷却并重新均质，就可以恢复乳化。乳化/去乳化循环可以重复多次。反乳化所需的时间随着温度的升高而减少，但随着寡聚（Phe）-mPEG浓度的降低和mPEG部分链长的减少而增加。