羧基化氧化石墨烯的血液相容性

Hemocompatibility of Carboxylic Graphene Oxide

采用超声法制备了氧化石墨烯,并利用化学改性的方法,将氧化石墨烯表面的羟基和环氧基转变为羧基.在红外光谱中羧基化氧化石墨烯(GeneO-COOH)的羧基振动明显,峰强增大.静态水接触角测试结果表明,羧基化氧化石墨烯改性成功,其亲水性提高显著.GeneO-COOH的主要失重表现为羧基官能团缩合以一个水分子的形态释放失去结构水[OH2].复钙动力学曲线随着GeneO-COOH的浓度增加,曲线上升趋势由陡峭趋于平缓,当浓度为1.25μg/mL时复钙时间延长了11min,平台期OD值降低了8.14%;GeneO-COOH在0.5～100μg/mL浓度范围内溶血率均小于5%.GeneO-COOH比GeneO在同等低浓度下的抗凝血性能有一定程度的改善,主要是因为GeneO-COOH中—COO-带有负电,其与血浆蛋白的静电排斥和对凝血因子Ca2+的络合,使得GeneO-COOH的抗凝血性能有所提高.结果表明,羧基修饰氧化石墨烯是提高抗凝血性能的有效手段.

Functionalization of graphene oxide is important for technological applications since it allows integrating into different environments such as biological fluids,polymer matrices,silicon surface and others.Graphene oxide was made through the ultrasonic separation of graphite oxide,and then it was modified with functional group by chloroacetic acid,and finally,the graphene oxide modified with carboxyl groups was prepared.Compared with graphene oxide,the FTIR spectrum of GeneO-COOH showed a weaker —OH peak,a stronger —COOH peak,and a bigger peak width.The results showed that partial epoxy and hydroxyl were activated into carboxyl.Static water contact angle showed that modification of GeneO with —COOH was successful,and hydrophilicity of GeneO-COOH increased significantly.On TG curve,the main mass loss of GeneO-COOH showed condensation of COOH groups in the form of a loss of structural water.The curve which reflected the kinetic profiles of recalcification time was changed from steep to gentle along with the increases of the consistency of GeneO-COOH.The recalcification time of GeneO-COOH was prolonged by 11 min at 1.25 μg/mL,and the value of OD reduced by 8.14%.The hematolysis ratio was less than 5% within a range of 0.5—50 μg/mL.The anti-clotting property of GeneO-COOH was better than that of GeneO at the same low concentration.The improvement was mainly made by carboxyl group with a negative charge.Electrostatic repulsions between carboxyl groups and blood plasma proteins prevented the adhesion of plasma proteins on the surface of GeneO-COOH.Meanwhile,direct complexation between carboxyl group and clotting factor could not be ignored.Then,the recalcification time was significantly delayed.Therefore,modification with carboxyl groups was a method to increase anti-coagulation effective of GeneO.