Quantum dots (QDs) possess optical properties of superbright fluorescence, excellent photostability, narrow emission spectra, and optional colors. Labeled with QDs, single molecules/viruses can be rapidly and continuously imaged for a long time, providing more detailed information than when labeled with other fluorophores. While they are widely used to label proteins in single-molecule-tracking studies, QDs have rarely been used to study virus infection, mainly due to a lack of accepted labeling strategies. Here, we report a general method to mildly and readily label enveloped viruses with QDs. Lipid-biotin conjugates were used to recognize and mark viral lipid membranes, and streptavidin-QD conjugates were used to light them up. Such a method allowed enveloped viruses to be labeled in 2 h with specificity and efficiency up to 99% and 98%, respectively. The intact morphology and the native infectivity of viruses were preserved. With the aid of this QD labeling method, we lit wild-type and mutant Japanese encephalitis viruses up, tracked their infection in living Vero cells, and found that H144A and Q258A substitutions in the envelope protein did not affect the virus intracellular trafficking. The lipid-specific QD labeling method described in this study provides a handy and practical tool to readily “see” the viruses and follow their infection, facilitating the widespread use of single-virus tracking and the uncovering of complex infection mechanisms.

中文翻译：

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用量子点对包膜病毒进行脂质特异性标记，用于单病毒跟踪。

量子点（QD）具有超亮荧光，出色的光稳定性，窄发射光谱和可选颜色的光学特性。标记有QD的单分子/病毒可以长时间连续快速成像，比起其他荧光团标记可以提供更详细的信息。尽管它们在单分子跟踪研究中广泛用于标记蛋白质，但由于缺乏公认的标记策略，量子点很少用于研究病毒感染。在这里，我们报告了一种一般的方法，可以用QD轻度轻松地标记包膜病毒。脂质-生物素偶联物用于识别和标记病毒脂质膜，而链霉亲和素-QD偶联物用于将其点亮。这种方法可使包膜病毒在2小时内标记，特异性和效率高达99％和98％，分别。病毒的完整形态和天然感染力得以保留。借助这种QD标记方法，我们点燃了野生型和突变型日本脑炎病毒，跟踪了它们在活Vero细胞中的感染情况，发现包膜蛋白中的H144A和Q258A替代不影响病毒的细胞内运输。本研究中描述的脂质特异性QD标记方法提供了一种方便实用的工具，可以轻松地“看到”病毒并跟踪其感染，从而促进了单病毒跟踪的广泛使用以及复杂感染机制的发现。并发现包膜蛋白中的H144A和Q258A取代不影响病毒的细胞内运输。本研究中描述的脂质特异性QD标记方法提供了一种方便实用的工具，可以轻松地“看到”病毒并跟踪其感染，从而促进了单病毒跟踪的广泛使用以及复杂感染机制的发现。并发现包膜蛋白中的H144A和Q258A取代不影响病毒的细胞内运输。这项研究中描述的脂质特异性QD标记方法提供了一种方便实用的工具，可以轻松地“看到”病毒并跟踪其感染，从而促进了单病毒跟踪的广泛使用以及复杂感染机制的发现。