关键词: 木质素, 水凝胶, pH响应性, 聚合物, 药物, 生物质, 凝胶

Abstract:

A water-soluble alkali lignin (AL) extracted from pine wood was used as raw material to prepared amphoteric lignin (AML-45) which used (3-chloro-2-hydroxypropyl)trimethylammonium chloride solution to chemical modify the AL by quaternization. AML-45 was activated in 8g/L NaOH, 12g/L urea and -10℃, then in alkaline medium activated AML-45 and polyethylene glycol diglycidyl ether were co-polymerized to prepare lignin-based pH-responsive hydrogel. The structures of AML-45 and lignin-based hydrogel were characterized by FTIR spectroscopy, DLS measurement. Scanning Electron Microscope was used to discover hydrogel's morphological characteristics. The swelling behavior of the hydrogel at different pH PBS-buffered solution was tracked. These results showed that the hydrogel was highly pH-responsive to a range of pH 2—7.4, with the swelling rate reaching minimum of 260%(pH=4) and maximum of 330% (pH=7.4). In addition, the swelling rate of hydrogel related to the lignin concentration, amount of cross-linker polyethylene glycol diglycidyl ether and 5-fluorouracil was used as model drug to explore its drug release behavior in buffer media in the acidic range (pH=2—7.4). The cumulative drug release from the loaded hydrogel in buffer solution (pH=7.4) was up to 78% within 30h which was higher than the cumulative drug release of 62% (pH=4) and 69% in (pH=2) in acidic buffer environment. The hydrogel had significantly drug retarded effect.

Key words: lignin, hydrogel, pH responsiveness, polymers, pharmaceuticals, biomass, gels