Doose Sören, Tsay James M, Pinaud Fabien, Weiss Shimon
Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California 90095, USA.
Anal Chem. 2005 Apr 1;77(7):2235-42. doi: 10.1021/ac050035n.
A number of different surface chemistries have been developed in recent years to render semiconductor nanocrystals (NCs) stable in water and biocompatible. However, most of these surface modifications affect NCs' photophysical properties, calling for a method to simultaneously monitor colloidal and fluorescence properties. Fluorescence correlation spectroscopy (FCS) combined with ensemble spectroscopic methods and Monte Carlo simulations were used to interpret and derive photophysical as well as colloidal properties of four different NC surface treatments. Using a novel FCS scheme with alternating laser excitation at two different intensities, we first ruled out influences from optical gradient forces (optical trapping). We then compared concentration of emitting particles, brightness per particle, saturation intensity, blinking (intermittency), hydrodynamic radius, and propensity for aggregation of the different bioconjugated NCs. This approach was successfully applied during the development and optimization of peptide-coated NCs.
近年来，人们开发了多种不同的表面化学方法，以使半导体纳米晶体（NCs）在水中稳定且具有生物相容性。然而，这些表面修饰大多会影响NCs的光物理性质，因此需要一种能够同时监测胶体性质和荧光性质的方法。荧光相关光谱法（FCS）结合整体光谱方法和蒙特卡罗模拟，用于解释和推导四种不同NC表面处理的光物理性质以及胶体性质。我们使用一种新颖的FCS方案，在两种不同强度下交替进行激光激发，首先排除了光学梯度力（光学捕获）的影响。然后，我们比较了不同生物共轭NCs的发光粒子浓度、每个粒子的亮度、饱和强度、闪烁（间歇性）、流体动力学半径以及聚集倾向。这种方法在肽包被的NCs的开发和优化过程中得到了成功应用。
