Poly(L-lysine)-g-poly(ethylene glycol) layers on metal oxide surfaces:: Surface-analytical characterization and resistance to serum and fibrinogen adsorption
Poly(L-lysine)-g-poly(ethylene glycol) layers on metal oxide surfaces:: Surface-analytical characterization and resistance to serum and fibrinogen adsorption
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DOI：
10.1021/la000736
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发表时间：
2001-01-23
期刊：
影响因子：
3.9
通讯作者：
Spencer, ND
中科院分区：
文献类型：
--
作者：
Huang, NP;Michel, R;Spencer, ND
聚（L-赖氨酸）-g-聚（乙二醇）（PLL-g-PEG）是聚阳离子PEG接枝共聚物家族的成员，其已显示出在阴离子表面（包括各种金属氧化物表面）上化学吸附，从而提供对蛋白质吸附的高度抗性。PLL-g-PEG修饰的表面对于各种应用都是有吸引力的，包括用于生物亲和性测定和血液接触生物医学装置的传感器芯片。采用反射-吸收红外光谱（RAIRS）、角度依赖X射线光电子能谱（XPS）和飞行时间二次离子质谱（ToF-SIMS）研究了PLL-g-PEG在氧化铌（Nb 2 O 5）、氧化钽（Ta 2 O 5）和氧化钛（TiO 2）表面的吸附性能。结合的分析信息提供了明确的证据与阳离子聚（L-赖氨酸）静电附着的氧化物表面（带负电荷的生理pH值）和聚（环氧乙烷）侧链从表面延伸出来的架构。在RAIRS光谱和角度依赖的XPS数据点的PLL骨干直接位于和平行于氧化物/聚合物界面的振动模式的相对强度，而PEG链优先在垂直于表面的方向取向。正和负ToF-SIMS光谱均由PEG相关的二次离子片段主导，其具有强烈降低的金属（氧化物）强度，指向密集堆积的PEG梳状接枝物的（几乎）完全覆盖。发现等电点远低于7的三种不同的过渡金属氧化物表面在聚合物吸附层吸附的动力学和性质以及PLL-g-PEG改性表面的蛋白质抗性方面表现非常相似。血清和纤维蛋白原的吸附进行了评价，使用OWLS光平面波导技术。吸附在改性表面上的人血清的量始终低于所使用的光学传感器技术的检测极限（
Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) is a member of a family of polycationic PE G-grafted copolymers that have been shown to chemisorb on anionic surfaces, including various metal oxide surfaces, providing a high degree of resistance to protein adsorption. PLL-g-PEG-modified surfaces are attractive for a variety of applications including sensor chips for bioaffinity assays and blood-contacting biomedical devices. The analytical and structural properties of PLL-g-PEG adlayers on niobium oxide (Nb2O5), tantalum oxide (Ta2O5), and titanium oxide (TiO2) surfaces were investigated using reflection-absorption infrared spectroscopy (RAIRS), angle-dependent X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The combined analytical information provides clear evidence for an architecture with the cationic poly(L-lysine) attached electrostatically to the oxide surfaces (charged negatively at physiological pH) and the poly(ethylene oxide) side chains extending out from the surface. The relative intensities of the vibrational modes in the RAIRS spectra and the angle-dependent XPS data point to the PLL backbone being located directly at and parallel to the oxide/polymer interface, whereas the PEG chains are preferentially oriented in the direction perpendicular to the surface. Both positive and negative ToF-SIMS spectra are dominated by PEG-related secondary ion fragments with strongly reduced metal (oxide) intensities pointing to an (almost) complete coverage by the densely packed PEG comblike grafts. The three different transition metal oxide surfaces with isoelectric points well below 7 were found to behave very similarly, both in respect to the kinetics of the polymer adlayer adsorption and properties as well as in terms of protein resistance of the PLL-g-PEG-modified surface. Adsorption of serum and fibrinogen was evaluated using the OWLS optical planar waveguide technique. The amount of human serum adsorbed on the modified surfaces was consistently below the detection limit of the optical sensor technique used(