Compact biocompatible quantum dots functionalized for cellular imaging
Compact biocompatible quantum dots functionalized for cellular imaging
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DOI：
10.1021/ja076069p
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发表时间：
2008-01-30
影响因子：
15
通讯作者：
Bawendi, Moungi G.
中科院分区：
文献类型：
--
作者：
Liu, Wenhao;Howarth, Mark;Bawendi, Moungi G.
我们提出了一个家庭的水溶性量子点（QD），表现出低非特异性结合细胞，小流体动力学直径，可调的表面电荷，高量子产率，并在很宽的pH范围内良好的溶液稳定性。这些量子点是顺从的共价修饰通过简单的碳二亚胺偶联化学，这是通过功能化的量子点的表面与一类新的异双功能配体纳入二氢硫辛酸，短的聚（乙二醇）（PEG）间隔，和胺或羧酸酯末端。通过附加罗丹明染料以形成表现出荧光共振能量转移（FRET）的QD-染料缀合物来证明分子的共价附着。高亲和性标记通过链霉亲和素的共价连接来证明，从而能够跟踪与活细胞上的EGF受体结合的生物素化表皮生长因子（EGF）。此外，用异双功能配体溶解的QD保留其与多组氨酸标记的蛋白质的金属亲和性驱动的缀合化学。通过同时共价连接罗丹明FRET受体和结合多组氨酸标记的链霉亲和素在相同的引物上以产生具有双波长发射的靶向QD来证明这种双重功能。这种发射特性可以作为细胞受体的局部化学环境的比率传感的基础。
We present a family of water-soluble quantum dots (QDs) that exhibit low nonspecific binding to cells, small hydrodynamic diameter, tunable surface charge, high quantum yield, and good solution stability across a wide pH range. These QDs are amenable to covalent modification via simple carbodiimide coupling chemistry, which is achieved by functionalizing the surface of QDs with a new class of heterobifunctional ligands incorporating dihydrolipoic acid, a short poly(ethylene glycol) (PEG) spacer, and an amine or carboxylate terminus. The covalent attachment of molecules is demonstrated by appending a rhodamine dye to form a QD-dye conjugate exhibiting fluorescence resonance energy transfer (FRET). High-affinity labeling is demonstrated by covalent attachment of streptavidin, thus enabling the tracking of biotinylated epidermal growth factor (EGF) bound to EGF receptor on live cells. In addition, QDs solubilized with the heterobifunctional ligands retain their metal-affinity driven conjugation chemistry with polyhistidine-tagged proteins. This dual functionality is demonstrated by simultaneous covalent attachment of a rhodamine FRET acceptor and binding of polyhistidine-tagged streptavidin on the same nanocrystal to create a targeted QD, which exhibits dual-wavelength emission. Such emission properties could serve as the basis for ratiometric sensing of the cellular receptor's local chemical environment.