Optoelectronics Group, Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , U.K.
Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , U.K.
Langmuir. 2018 Aug 28;34(34):10073-10080. doi: 10.1021/acs.langmuir.8b01828. Epub 2018 Aug 17.
Many industrial soft materials include oil-in-water (O/W) emulsions at the core of their formulations. By using tuneable interface stabilizing agents, such emulsions can self-assemble into complex structures. DNA has been used for decades as a thermoresponsive, highly specific binding agent between hard and, recently, soft colloids. Up until now, emulsion droplets functionalized with DNA had relatively low coating densities and were expensive to scale up. Here, a general O/W DNA-coating method using functional nonionic amphiphilic block copolymers, both diblock and triblock, is presented. The hydrophilic poly(ethylene glycol) ends of the surfactants are functionalized with azides, allowing for efficient, dense, and controlled coupling of dibenzocyclooctane-functionalized DNA to the polymers through a strain-promoted alkyne-azide click reaction. The protocol is readily scalable due to the triblock's commercial availability. Different production methods (ultrasonication, microfluidics, and membrane emulsification) are used with different oils (hexadecane and silicone oil) to produce functional droplets in various size ranges (submicron, ∼20 and >50 μm), showcasing the generality of the protocol. Thermoreversible submicron emulsion gels, hierarchical "raspberry" droplets, and controlled droplet release from a flat DNA-coated surface are demonstrated. The emulsion stability and polydispersity is evaluated using dynamic light scattering and optical microscopy. The generality and simplicity of the method opens up new applications in soft matter, biotechnological research, and industrial advances.
许多工业软材料的配方核心都包含油包水 (O/W) 乳液。通过使用可调谐的界面稳定剂，这些乳液可以自组装成复杂的结构。几十年来，DNA 一直被用作硬胶体和最近的软胶体之间的热响应、高特异性结合剂。到目前为止，功能化的 DNA 乳液滴的涂层密度相对较低，而且规模化成本很高。在这里，提出了一种使用功能性非离子两亲嵌段共聚物（包括二嵌段和三嵌段）的通用 O/W DNA 涂层方法。表面活性剂的亲水聚（乙二醇）端用叠氮化物官能化，允许通过应变促进的炔基-叠氮点击反应高效、密集和受控地将二苯并环辛烷功能化的 DNA 偶联到聚合物上。由于三嵌段共聚物的商业可用性，该方案很容易规模化。不同的生产方法（超声处理、微流控和膜乳化）与不同的油（十六烷和硅油）一起使用，以在各种尺寸范围内（亚微米、约 20 和 >50 μm）产生功能化的液滴，展示了该方案的通用性。热可逆亚微米乳液凝胶、分层的“覆盆子”液滴以及从平坦的 DNA 涂层表面控制液滴释放得到了展示。使用动态光散射和光学显微镜评估乳液的稳定性和多分散性。该方法的通用性和简单性为软物质、生物技术研究和工业进步开辟了新的应用。
