论文标题
用有效培养基理论解释全息分子结合测定
Interpreting Holographic Molecular Binding Assays with Effective Medium Theory
论文作者
论文摘要
全息分子结合测定法使用全息视频显微镜直接检测分子通过监测珠子光散射特性中相关的变化，从而与微米尺度胶体珠的表面结合。通过基于Lorenz-Mie光散射理论拟合生成模型来分析单个球体的全息图。每种拟合都会产生探针珠直径和折射率的估计值，并具有足够精确的精度，可以观察珠子在分子结合时生长。但是，这些拟合使用有效的培养基理论，而不是对分子尺度涂层进行建模，而是将涂层球对待，就好像它是均匀的。这种有效的球体分析在数字上是稳健的，因此对于无标签免疫测定的实际实现非常有用。在这里，我们评估了有效的球体特性如何通过用离散偶极近似涂层的球体建模分子尺度涂层的性质，并使用有效的透明模型分析其全息图。
Holographic molecular binding assays use holographic video microscopy to directly detect molecules binding to the surfaces of micrometer-scale colloidal beads by monitoring associated changes in the beads' light-scattering properties. Holograms of individual spheres are analyzed by fitting to a generative model based on the Lorenz-Mie theory of light scattering. Each fit yields an estimate of a probe bead's diameter and refractive index with sufficient precision to watch the beads grow as molecules bind. Rather than modeling the molecular-scale coating, however, these fits use effective medium theory, treating the coated sphere as if it were homogeneous. This effective-sphere analysis is rapid and numerically robust and so is useful for practical implementations of label-free immunoassays. Here, we assess how effective-sphere properties reflect the properties of molecular-scale coatings by modeling coated spheres with the discrete-dipole approximation and analyzing their holograms with the effective-sphere model.
