In recent decades, temperature/pH dual responsive amphiphilic polymers have attracted the interest of researchers because they can perform certain functions by changing the hydrophilic hydrophobic balance in conformity with changes in the external environment. Therefore, these types of amphiphilic polymers are very useful, especially for drug delivery, tissue engineering, biotechnology, and related fields.
However, most of the temperature/pH dual responsive polymers are prepared using petroleum chemical monomers as the main raw material and their use has biocompatibility and toxicity problems. In recent years, many researchers have focused on biomass derivatives to improve the temperature/pH dual responsiveness of polymers.
Jong Kwang Hyok, a section head at the Faculty of Chemical Engineering, has synthesized a novel type of temperature-pH dual responsive amphiphilic hydrogel, PD(Hydroxyethyl starch(HES)-propynyl glycidylether(PGE)-2-dimethylamino ethanethiol (DMAET)- Triethoxyvinylsilane(TEVS)) and studied its characteristics.
First, HES, a hydrophilic polysaccharide, underwent etherification of hydroxyl groups in its glucose units with PGE and then click reaction between carbon-carbon triple bonds in PGE and thiol groups in DMAET, thereby possessing a hydrophilic-hydrophobic structure to be used for the preparation of PD, a temperature-pH dual responsive material, with pH-responsive tertiary amine groups. Next, it further became a dual responsive hydrogel through the formation of its internal network by TEVS.
He found that during the test experiments to use it as a drug carrier for oral delivery, the doxorubicin(DOX) release was ≤15% in acidic conditions in the stomach (pH < 2.0) and ≤94% in basic conditions in the small intestine, which ensures that it exhibits relatively good protective and release properties of drugs.
You can find the details in his paper “ Preparation of temperature-pH dual responsive hydrogel from hydroxyethyl starch for drug delivery” in “Colloid and Polymer Science” (SCI).
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