A'即插即用'的方法来创建水分散性Nanoassemblies包含两亲聚合物，有机染料和上变频纳米粒子
Summary
Organic dye molecules and oleic acid coated upconverting nanoparticles are not water-soluble. This protocol describes a ‘plug and play’ method that enables the transfer of organic dye molecules and upconverting particles from their initial hydrophobic solvent to water.
Abstract
In this protocol, we first describe a procedure to synthesize lanthanide doped upconverting nanoparticles (UCNPs). We then demonstrate how to generate amphiphilic polymers in situ, and describe a protocol to encapsulate the prepared UCNPs and different organic dye molecules (porphyrins and diarylethenes) using polymer shells to form stable water-dispersible nanoassemblies. The nanoassembly samples containing both the UCNPs and the diarylethene organic dyes have interesting photochemical and photophysical properties. Upon 365 nm UV irradiation, the diarylethene group undergoes a visual color change. When the samples are irradiated with visible light of another specific wavelength, the color fades and the samples return to the initial colorless state. The samples also emit visible light from the UCNPs upon irradiation with 980 nm near-infrared light. The emission intensity of the samples can be tuned through alternate irradiation with UV and visible light. Modulation of fluorescence can be performed for many cycles without observable degradation of the samples. This versatile encapsulation procedure allows for the transfer of hydrophobic molecules and nanoparticles from an organic solvent to an aqueous medium. The polymer helps to maintain a lipid-like microenvironment for the organic molecules to aid in preservation of their photochemical behavior in water. Thus this method is ideal to prepare water-dispersible photoresponsive systems. The use of near-infrared light to activate upconverting nanoparticles allows for lower energy light to be used to activate photoreactions instead of more harmful ultraviolet light.
Introduction
今天，仍然是一个迫切需要开发新型生物成像剂。许多新的荧光探针已经有案可稽1-6然而，在图像分辨率实质性改进仍然是一个挑战。7的一个实际方法是直接调制“光”发射状态和一个“暗”淬火状态之间的荧光探针。 8-12这种特殊方法已被应用到开发的技术，如受激发射损耗（STED）显微镜13和随机光学重构显微术（STORM）14
来调制荧光另一种方法是为耦合光响应性的发色团一起用荧光探针。15,16切换两种异构体，即只有一个异构体可以作为有效的能量转移受体之间的光响应发色团，允许控制从第荧光猝灭通过荧光共振能量转移（FRET）等机制Ë探头。的结果是创建的发射状态，并且可以由光响应发色团，以不同波长的光的曝光交替急冷状态。
光响应二芳基乙烯的发色团可以为无色开环异构体和着色环封闭异构体照射时，用紫外和可见光之间发生可逆切换。17-19的两种异构体的闭环异构体的化妆和可调谐吸收光谱的热稳定性二芳基乙烯非常好的候选者可控的FRET受体20-23的镧系元素掺杂的NaYF 4纳米颗粒上变换是用于生物成像是有用的。24这些纳米颗粒吸收的近红外光并发光，在可见光谱的几个区域。荧光调制通过组合光响应二芳基乙烯的发色团和纳米颗粒的例子已预先viously报告由我们的组25-27然而，在每个实施例中描述的系统需要一个额外的合成修饰的二芳基乙烯附着到纳米颗粒的表面，其中复杂更多样化的系统的开发。
在这里我们展示了一个简单的“即插即玩”的方法准备使用自组装策略水分散性有机染料分子和光响应上变频纳米粒子。聚合物的选择;聚（苯乙烯-马来中高音酐）和聚醚胺2070同时提供疏水性和亲水性的环境。的聚合物帮助疏水部分以保持正常的水不溶性有机分子，并上变频纳米颗粒一起，而该聚合物的亲水区是用于保持水溶解度的关键。首先，我们将展示由热核方法合成上变频纳米粒子。然后，我们将证明豪瓦特的有机分子，并上变频纳米颗粒的聚合物壳的疏水区内包封和保持稳定在水介质中通过简单地共同搅拌该升压变换纳米颗粒，聚合物和不同的有机染料分子的溶液，接着通过一种方便的处理过程。我们还演示了如何调制使用外部光线照射组件的荧光发射。我们预计，采用这种“即插即用”的方法，使水分散性nanoassemblies将继续扩大范围。
Protocol
Representative Results
Discussion
根据此协议中合成的纳米颗粒具有从20至25纳米的中心在左右22.5纳米。-26,27-它们可以被分类为球形颗粒与α-NaYF 4主晶格结构的尺寸分布。还有在这个协议中的两个关键步骤。在UCNP合成，关键的是要维持加热温度和时间尽可能精确，以保证颗粒尺寸分布窄。同时加入的NaOH和NH 4 F一起在反应没有产生纳米颗粒的良好分布尺寸和良好的形态的开头添加镧系元素离子。加入的NaOH?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This research was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Canada Research Chairs Program, and Simon Fraser University. This work made use of 4D LABS shared facilities supported by the Canada Foundation for Innovation (CFI), British Columbia Knowledge Development Fund (BCKDF) and Simon Fraser University.
Materials
| yttrium acetate | sigma | 326046 | Yttrium(III) acetate hydrate |
| ytterbium acetate | sigma | 544973 | Ytterbium(III) acetate hydrate |
| erbium acetate | sigma | 325570 | Erbium(III) acetate hydrate |
| oleic acid | sigma | 75096 | analytical standard |
| octadecene | sigma | O806 | Technical grade |
| NaOH | S5881 | reagent grade | |
| NH4F | 216011 | ACS reagent | |
| poly(styrene-alt-maleic anhydride) | sigma | 4422699 | Average Mn= 1700 |
| JeffAmine 2070 | Huntsman | M-2070 | |
| Varian Carry 300 | Agilent | ||
| JDSU NIR laser | JSDU | L4-9897510-100M | 980 nm diode laser |
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