磁性温敏水凝胶的制备及其在交变磁场中的热效应研究

Systhesis of Magnetic Thermosensitive Hydrogel and Its Heat Effect under Alternating Magnetic Field

目的制备磁性温敏水凝胶并考察其在体外交变磁场中的升温情况以及影响因素。方法以混旋丙交酯、乙交酯和聚乙二醇1500为原料采用开环聚合法合成聚丙交酯-乙交酯-聚乙二醇-聚丙交酯-乙交酯(PLGA-PEG-PLGA)共聚物,加入不同剂量的磁流体配制成不同浓度的磁性温敏水凝胶,设定不同交变磁场电流,分别观察磁流体浓度和交变磁场电流对体系升温的影响。结果所制备的聚丙交酯-乙交酯-聚乙二醇-聚丙交酯-乙交酯共聚物具有良好的温度敏感性,加入磁流体后仍可保持其原有的温敏性;磁流体5、10、20 min的温升与磁流体的浓度呈直线正相关关系(r=0.998 5、0.989 3和0.971 1,n=3),与磁场电流呈直线正相关关系(r=0.994 8、r=0.997 7和0.999 4,n=4)。结论磁性温敏水凝胶具有良好的温度敏感性,并且在体外交变磁场中能够很好的升温并达到水凝胶相变温度使其发生相变。并可通过改变磁流体的浓度和交变磁场电流来实现对体系温度的控制。

OBJECTIVE To synthesize magnetic thermosensitive hydrogel and study its heat effect under alternating magnetic field in vitro. METHODS PLGA-PEG-PLGA triblock copolymer was synthesized by ring-opening polymerization of D,L-lactide and glycolide with PEG1500 in the presence of stannous iso caprylate. Magnetic thermosensitive hydrogel of different concentrations were prepared using different currents. The influences of the concentration of magnetic fluid and current of magnetic field on the heat effect were separately ob- served. RESULTS The synthetized PLGA-PEG-PLGA triblock copolymer was excellently temperature sensitive. It retained the thermo- sensitivity of original hydrogel when the magnetic fluid was loaded. The 5,10 and 20 min heating ability of magnetic fluid was positively linearly correlated with its concentration （r =0. 998 5, 0. 989 3 and 0. 971 1, respectively, n =3） and current of magnetic field （r = 0. 994 8, 0. 997 7 and 0. 999 4, respectively, n = 4）. CONCLUSION The magnetic thermosensitive hydrogel has excellent temperature sensitivity. When alternating magnetic field is applied, the temperature of the system can rise and reach above LCST of hydrogel. The temperature Can be controlled by changing the concentration of magnetic fluid and the current of magnetic field.