Aptamer-based Au nanoparticles-enhanced surface plasmon resonance detection of small molecules
Aptamer-based Au nanoparticles-enhanced surface plasmon resonance detection of small molecules
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DOI：
10.1021/ac801281c
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发表时间：
2008-09-15
影响因子：
7.4
通讯作者：
Zhou, H. Susan
中科院分区：
文献类型：
--
作者：
Wang, Jianlong;Zhou, H. Susan
小分子很难通过传统的SPR技术直接检测，因为小生物分子的结合过程引起的折射率变化通常很小。为了拓展SPR生物传感器在小分子检测中的应用，我们将核酸适配体技术的优势与Au纳米粒子的放大作用相结合，设计了一种灵敏的SPR生物传感器来检测小分子。该传感器的原理基于表面抑制检测。适配体首先以其 ss-DNA 结构固定在 SPR 金膜上。具有这种结构的适配体可以与金纳米颗粒标记的互补单链DNA杂交，并导致SPR信号发生较大变化。然而，在SPR细胞中添加腺苷后，适配体的结构会从单链DNA转变为三级结构。具有三级结构的适体不能与金纳米粒子标记的互补单链DNA杂交。因此，SPR信号的变化导致适体与Au纳米颗粒标记的互补ss-DNA之间的杂交反应会随着具有三级结构的适体数量的增加而减少，这与小分子的浓度成正比。基于这一原理，我们选择一个简单的系统（抗腺苷适体/腺苷）来检测该SPR生物传感器对小分子的传感能力。实验结果证实我们开发的SPR传感器对腺苷具有良好的灵敏度和高选择性。腺苷的检测范围为 1 x 10(-9) 至 1 x 10(-6) M。更重要的是，很容易推广此策略，使用不同的适体通过 SPR 光谱检测小分子光谱。因此，预计该方法可以为设计高性能SPR生物传感器以灵敏、选择性地检测广谱小分子提供新的方向。
Small molecules are difficult to detect by conventional SPR technique directly because the changes in the refractive index resulting from the binding processes of small biomolecules are often small. In order to extend the application of SPR biosensor in detecting a small molecule, we combine the advantage of aptamer technique with the amplifying effect of Au nanoparticles to design a sensitive SPR sensor for detecting small molecules. The principle of this sensor is based on surface inhibition detection. The aptamer is first immobilized on SPR gold film with its ss-DNA structure. The aptamer possessing this structure can be hybridized with Au nanoparticles-tagged complementary ss-DNA and result in a large change of SPR signal. However, the aptamer will change its structure from ss-DNA to tertiary structure after adenosine is added to the SPR cell. The aptamer possessing tertiary structure could not hybridize with Au nanoparticles-tagged complementary ss-DNA. Thus, the change of SPR signal resulted in the hybridization reaction between aptamer and Au nanoparticles-tagged complementary ss-DNA will decrease with the increase of the number of aptamers possessing tertiary structure, which is proportional to the concentration of the small molecule. Based on this principle, we choose a simple system (antiadenosine aptamer/adenosine) to detect the sensing ability of this SPR biosensor for a small molecule. The experimental results confirm that the SPR sensor we developed possesses a good sensitivity and a high selectivity for adenosine. The detection range for adenosine is from 1 x 10(-9) to 1 x 10(-6) M. More significantly, it is fairly easy to generalize this strategy to detect a spectrum of small molecules by SPR spectroscopy using different aptamers. Therefore, it is expected that this method may offer a new direction in designing high-performance SPR biosensors for sensitive and selective detection of a wide spectrum of small molecules.