钛种植体表面纳米改性及其与机体免疫应答

采用纳米颗粒紧压法、离子束辅助沉积技术、表面化学处理和阳极氧化法等辅助方式将种植体表面结构进行改性。种植体植入后可能引起机体免疫反应。研究显示,多形核白细胞、巨噬细胞、单核细胞和树突细胞在机体天然免疫反应中起重要作用。这些细胞针对种植体表面分别介导不同的免疫反应。一些细胞因子参与免疫反应的调节,对于消除该区域的炎症,提高骨整合,促进伤口愈合提供帮助。本文就钛种植体表面的纳米改性方法、钛种植体表面纳米改性与机体免疫应答之间的联系等研究进展作一综述。     

肝素铁复合物纳米修饰提高异种移植血管的血液相容性

目的:采用肝素铁复合物纳米修饰去细胞异种血管以提高其血液相容性。方法:采用层层自组装技术将二羟基铁和肝素交替固定在去细胞牛颈静脉(DC-BJV) 表面,构建一种新型的多层肝素铁复合物(HICMs) 抗凝表面,并通过扫描电镜(SEM) 检测其表面微结构、拉力器检测其生物力学稳定性、抗凝血活性实验和血小板黏附实验检测其血液相容性。结果:每组装一次,约有(808±86) μg/cm² 肝素固定在BJV 表面;SEM 图片显示HICMs 是均匀地包裹在胶原纤维表面并形成纳米膜;组织切片甲苯胺蓝染色提示肝素主要结合在DC-BJV 的表层;拉力试验提示实验组的生物力学稳定性有显著提高;经过1 d 及1,2,3,4,6,8 周的洗脱,肝素的释放量分别为(281±43),(422±60),(729±81),(1053±116),(1317±157),(1618±187),(1945±228 ) μg/cm²;抗凝血活性检测显示实验组凝血酶原时间(PT)和活化部分凝血酶原时间(APTT) 高于正常值范围;血小板黏附试验显示每10000 μm² HICMs 层层自组装修饰的牛颈静脉(LBL-BJV) 和DC-BJV 的血小板计数分别为8±4 和48±16。结论:HICMs 牢固地结合在DC-BJV 表层,形成纳米厚度的抗凝表面,并长时间地缓慢释放肝素。HICMs 纳米修饰能够提高去细胞异种血管的血液相容性。     

Mechanical Characteristics of Graphene Nanoplatelets-Modified Asphalt Mixes: A Comparison with Polymer- and Not-Modified Asphalt Mixes

In recent years, nanotechnology has sparked an interest in nanomodification of bituminous materials to increase the viscosity of asphalt binders and improves the rutting and fatigue resistance of asphalt mixtures. This paper presents the experimental results of laboratory tests on bituminous mixtures laid on a 1052 m-long test section built in Rome, Italy. Four asphalt mixtures for wearing and binder layer were considered: two polymer modified asphalt concretes (the former modified with the additive Superplast and the latter modified with styrene–butadiene–styrene), a “hard” graphene nanoplatelets (GNPs) modified asphalt concrete and a not-modified mixture. The indirect tensile strength, water sensitivity, stiffness modulus, and fatigue resistance of the mixtures were tested and compared. A statistical analysis based on the results has shown that the mixtures with GNPs have higher mechanical performances than the others: GNP could significantly improve the tested mechanical performances; further studies will be carried out to investigate its effect on rutting and skid resistance.