Orientations of nentatic liquid crystals on surfaces presenting controlled densities of peptides: Amplification of protein-peptide binding events
Orientations of nentatic liquid crystals on surfaces presenting controlled densities of peptides: Amplification of protein-peptide binding events
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DOI：
10.1021/la050336s
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发表时间：
2005-07-05
期刊：
影响因子：
3.9
通讯作者：
Abbott, NL
中科院分区：
文献类型：
--
作者：
Clare, BH;Abbott, NL
研究了多肽修饰的含寡甘醇的自组装单分子膜(SAM)与向列相液晶(LCS)的取向。用物理气相沉积的方法在倾斜入射角的金膜上制备了自组装膜。对两种多肽进行了研究：优化的Src蛋白激酶底物(IYGEFKKKC)和蛋白激酶修饰后的合成等价物(IpYGEFKKKC)。用偏振调制红外反射吸收光谱(PM-IRRAS)表征了这些多肽在界面上的相对面密度和取向。我们得出结论，磷酸基团的存在或不存在会影响固定化多肽的最大堆积密度。我们用偏光显微镜研究了向列相液晶5CB与这些多肽修饰表面接触时的取向。研究发现，5CB向列相呈现长程取向有序(均匀排列)所需的时间随固定化多肽的面密度增加而增加。我们还发现，抗酪氨酸抗体与表面固定的磷肽之间的特异性结合事件导致了液晶实现均匀锚定所需的时间增加(超过了实验可获得的时间尺度)。这些结果结合在一起表明，生物分子在界面上的面密度和大小可以影响液晶与纳米结构表面接触所需的时间，从而显示出长程取向有序。最后，我们通过展示液晶可以用来放大和报告发生在空间分辨的多肽阵列上的蛋白质结合事件来说明该系统的潜在用途。
We report a study of the orientations of nematic liquid crystals (LCs) in contact with peptide-modified, oligoethylene glycol-containing, self-assembled monolayers (SAMs). The SAMs were formed on gold films that were prepared by physical vapor deposition at an oblique angle of incidence. Two peptides were investigated: the optimized substrate for the Src protein kinase (IYGEFKKKC) and the synthetic equivalent of that peptide after kinase modification (IpYGEFKKKC). Polarization modulation-infrared reflectance absorbance spectroscopy (PM-IRRAS) was used to characterize the relative areal densities and orientations of these peptides at the interface. We conclude that the presence/absence of a phosphate group can influence the maximum packing density of immobilized peptide. We evaluated the orientations of the nematic liquid crystal 5CB in contact with these peptide-modified surfaces by using polarized microscopy. The time required for the nematic phase of 5CB to exhibit long-range orientational ordering (uniform alignment) was found to increase with increasing areal densities of immobilized peptide. We also found that the specific binding event between anti-phosphotyrosine IgG and the surface-immobilized phosphopeptide leads to an increase in the time required for the liquid crystal to achieve uniform anchoring (exceeding the experimentally accessible time scales). These results, when combined, suggest that the areal density and size of biomolecules at an interface can influence the time required for liquid crystals in contact with nanostructured surfaces to exhibit long-range orientational order. Finally, we illustrate the potential utility of this system by demonstrating that liquid crystals can be used to amplify and report protein binding events occurring on a spatially resolved peptide array.