Spectral extinction of colloidal gold and its biospecific conjugates
Spectral extinction of colloidal gold and its biospecific conjugates
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DOI：
10.1006/jcis.1996.0323
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发表时间：
1996-06-25
影响因子：
9.9
通讯作者：
Melnikov, AG
中科院分区：
文献类型：
--
作者：
Khlebtsov, NG;Bogatyrev, VA;Melnikov, AG
我们制备了平均粒径 d(m) 在 4 至 50 nm 范围内的金溶胶，并测量了它们的消光光谱以及消光峰位置 lambda(max) 和值 E(max) 的尺寸依赖性。测得的增函数 lambda(max)(d(m)) 在粒径 d(m) 附近呈现出类似于 10 nm 的明显弯曲，其中 lambda(max) 值随着粒径的减小而急剧减小。为了解释这些发现，使用米氏理论、T 矩阵方法和针对尺寸限制效应修改的块状金光学常数的各种实验组计算了具有粒径和轴比多分散性的溶胶的消光光谱。结果表明，测量的 lambda(max)(d(m)) 和 E(max)(d(m)) 依赖性与基于 Mie 理论和块状金光学常数的计算不一致。最广义的模型包括介电导磁率虚部的尺寸依赖性以及尺寸和形状多分散性，与 5、10、24 和 40 nm 溶胶的实验消光光谱以及测量的函数 lambda(max)(d(m)) 和 E(max)(d(m)) 具有良好的一致性。基于电子显微镜和光谱数据，获得校准曲线，以对颗粒尺寸进行有效的分光光度控制，并估计制备给定尺寸颗粒所必需的恢复剂的量。采用最简单的两层球形模型阐明了与特定生物大分子共轭后溶胶光谱的基本变化，并得出了有关共轭壳结构的一些结论。 (C) 1996 学术出版社
We have prepared gold sols with mean particle diameters d(m) in the range 4 to 50 nm and measured their extinction spectra and size dependences of the extinction peak position lambda(max) and value E(max). The measured increasing function lambda(max)(d(m)) displays a pronounced bend near the particle diameter d(m) similar to 10 nm, where the value of lambda(max) sharply decreases with reduction in the particle size. To explain these findings, the extinction spectra of sols with the particle size and axial ratio polydispersity are calculated using Mie's theory, the T-matrix method, and various experimental sets of the bulk gold optical constants modified with regard to size-limiting effects. It is shown that the measured lambda(max)(d(m)) and E(max)(d(m)) dependences are inconsistent with calculations based on Mie's theory and the bulk gold optical constants. The most generalized model including the size dependence of the imaginary part of the dielectric permeability and the size and shape polydispersity gives good agreement with experimental extinction spectra for 5-, 10-, 24-, and 40-nm sols, as well as with the measured functions lambda(max)(d(m)) and E(max)(d(m)). Based on electron-microscopic and spectral data, calibration curves are obtained for efficient spectrophotometric control over the particle size and for estimation of the amount of restorer essential for the preparation of particles of a given size. A simplest two-layer spherical model is employed to elucidate the basic changes in sol spectra after conjugation with specific biomacromolecules and to draw some conclusions about the conjugate shell structure. (C) 1996 Academic Press, Inc.