Nida D L, Nitin N, Yu W W, Colvin V L, Richards-Kortum R
Department of Bioengineering, Rice University, 6100 Main Street MS 142, Houston, TX 77005, USA.
Nanotechnology. 2008 Jan 23;19(3):035701. doi: 10.1088/0957-4484/19/03/035701. Epub 2007 Dec 11.
Quantum dots (QDs) have many appealing properties for biological fluorescence imaging, but exhibit photostabilities that are dependent upon surface passivation to minimize susceptibility to oxygen and light. Here, through spectroscopy and imaging techniques, we compare the photostability of micelle-encapsulated QDs with QDs passivated with either crosslinked amphiphilic polymers or crosslink-free amphiphilic polymers. Both crosslinked and crosslink-free amphiphilic polymer passivation strategies produced QDs with high photoluminescence stability for exposure to light under ambient conditions. In contrast, micelle encapsulation resulted in QDs with photoluminescence emission levels that were highly sensitive to both light exposure and oxygen, exhibiting a reduction of up to 70% in photoluminescence intensity within twenty minutes of exposure. With the addition of reducing agents, the photoluminescence level of the micelle-encapsulated QDs was significantly stabilized. We conclude that amphiphilic polymers provide coatings with considerably higher integrity and stability than micelle encapsulation, reducing the QDs' sensitivities to oxygen and light, both of which are relevant factors in biological imaging applications.
量子点（QDs）在生物荧光成像方面具有许多吸引人的特性，但它们的光稳定性取决于表面钝化，以尽量减少对氧气和光的敏感性。在这里，通过光谱学和成像技术，我们比较了胶束包裹的量子点与用交联两亲聚合物或无交联两亲聚合物钝化的量子点的光稳定性。交联和无交联两亲聚合物钝化策略都产生了在环境条件下暴露于光时具有高光致发光稳定性的量子点。相比之下，胶束包裹导致量子点的光致发光发射水平对光照和氧气都高度敏感，在暴露二十分钟内光致发光强度降低高达70%。加入还原剂后，胶束包裹的量子点的光致发光水平得到显著稳定。我们得出结论，两亲聚合物提供的涂层比胶束包裹具有更高的完整性和稳定性，降低了量子点对氧气和光的敏感性，而这两个因素在生物成像应用中都很重要。
